TM 55-1520-244-BD

TECHNICAL MANUAL

OPERATORS, AVIATION UNIT,

AND AVIATION
INTERMEDIATE MAINTENANCE

CHAPTER 1. GENERAL INFORMATION

CHAPTER 2. ASSESSING BATTLEFIELD DAMAGE
FOR
CHAPTER 3. GENERAL REPAIR
HELICOPTER,
CHAPTER 4. AIRFRAME
ATTACK
CHAPTER 5. ALIGHTING GEAR
AH-1E CHAPTER 6. POWER PLANT INSTALLATION
1520-01-192-2478
CHAPTER 7. ROTORS
AH-1 F CHAPTER 8. DRIVE TRAIN SYSTEM
1520-01-168-4260
CHAPTER 9. HYDRAULIC SYSTEMS
AH-1P
1520-01-168-4259 CHAPTER 10. INSTRUMENT SYSTEMS
CHAPTER 11. ELECTRICAL & AVIONICS SYSTEMS
CHAPTER 12. FUEL SYSTEM
CHAPTER 13. FLIGHT CONTROLS SYSTEM
CHAPTER 14. UTILITY SYSTEMS
CHAPTER 15. ENVIRONMENTAL CONTROL SYSTEM
CHAPTER 16. MISSION EQUIPMENT
CHAPTER 17. EMERGENCY EQUIPMENT
APPENDIX A REFERENCES
APPENDIX B SPECIAL OR FABRICATED TOOLS
APPENDIX C EXPENDABLE/DURABLE SUPPLIES & MATERIALS
APPENDIX D SUBSTITUTE MATERIALS/PARTS
APPENDIX E BDAR TRAINING PROCEDURES
APPENDIX F AVIONICS CONFIGURATIONS

HEADQUARTERS, DEPARTMENT OF THE A R M Y

26 NOVEMBER 1990
 TM 55-1520-244-BD

WARNING DATA

Personnel performing operations, procedures, and practices which are included or implied in this technical manual
shall observe the general following warnings. Disregard of these warnings can cause serious injury or death.

FLIGHT SAFETY

The standards contained herein allow aircraft to be flown with battle damage substantially in excess of peacetime
limits. Under no circumstances shall this manual be used entirely or in part for peacetime maintenance of the
aircraft. Assessment of aircraft battle damage requires extreme care and diligence and strict adherence to the in-
structions and standards contained in this manual. If at any stage of damage assessment the assessor believes
that oversights or errors have been made, the assessment shall be stopped at that point and repeated from the
beginning. Under no circumstances shall the requirements of this manual be waived or circumvented without the
express approval of the commander or his designated representative.

EXPLOSIVES

Battle damaged areas should be inspected for unexploded ordnance before attempting repairs. Disposal of unex-
ploded ordnance should be accomplished by qualified personnel.

ARMAMENT

Loaded weapons or weapons being loaded or unloaded shall be pointed in a direction which offers the least ex-
posure to personnel or property in the event of accidental firing. Personnel shall remain clear of hazardous area.

CANOPY REMOVAL SYSTEM

Ground safety pins must be installed in pilot and gunner arming/firing handles of canopy removal system when-
ever the helicopter is on the ground.

CLEANING SOLVENTS

Cleaning solvents may be flammable and toxic. Use only in well-ventilated areas. Avoid inhalation of vapor and
skin contact. Do not use solvents near open flame or in areas where very high temperatures prevail. Solvent flash
point must not be less than 100°F.

COMPRESSED AIR

Compressed air can blow dust into eyes. Wear eye protection. Do not exceed 30 psig air pressure.

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TM 55-1520-244-BD

HIGH VOLTAGE
is used in equipment.

DEATH ON CONTACT
may result if personnel fail to observe safety precautions.

Never work on electronic equipment unless there is another person nearbv who is
familiar with the operation and hazards of the equipment and who is competent in
administering first aid. When the technician is aided by operators, he must warn
them about dangerous areas.

Whenever the nature of the operation permits, keep one hand away from the equipment
as to reduce the hazard of current flowing through vital organs of the body.

Do not be mislead by the term “low voltage.” Potentials as low as 50 volts may
cause death under adverse conditions. For Artificial Respiration, refer to FM 21-11.

LIFTING

Lifting or moving heavy equipment incorrectly can cause serious injury. Do not try
to lift or move more than 50 pounds by yourself. Bend legs while lifting. Do not
support heavy weight with your back. Always use assistants during lifting opera-
tions. Use guide ropes to move hanging assemblies. Lack of attention or being in
an improper position during lifting operations can result in serious injury. Pay
close attention to movements of assemblies being lifted. Do not stand under lifted
assembly or in a position where you could be pinned against another object. Watch
your footing.

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 TM 55-1520-244-BD

ELECTROLYTE

Battery Electrolyte (Potassium Hydroxide) is corrosive. Wear rubber gloves, apron,

and face shield when handling leaking batteries. If potassium hydroxide is spilled
on clothing or other material, wash immediately with clean water. If spilled on
personnel, immediately start flushing the affected area with clean water. Continue
washing until medical assistance arrives.

EXTERNAL STORES

Prior to any helicopter maintenance functions that require external stores be

removed, JETTISON cartridge shall be removed. To prevent injury to personnel
and damage to equipment, remove jettison cartridges from stores ejection device
prior to placing helicopter in a hangar.

All ground safety pins must be removed before flight. Failure to do so will prevent
emergency jettison of stores.

FIRE EXTINGUISHER
Exposure to high concentrations of monobromotrifluoromethane (CF3BR) extinguishing
agent or decomposition products should be avoided. The liquid should not be allowed
to come into contact with the skin, as it may cause frost bite or low temperature
burns.

FUELING AND FUEL REPAIRS

When refueling helicopter, the refueling vehicle must be parked a minimum of 20 feet
from the helicopter. Before starting the fueling operation, always insert fueling
nozzle grounding cable of fuel truck into GROUND HERE receptacle. Refer to FM
10-68. When defueling, turn off all electrical switches and disconnect external
power from the helicopter. The helicopter must be electrically grounded prior to
defueling.
Fuel line and tank repairs often involve handling of highly flammable material.
Mishandling can result in serious injury or death.

GROUNDING HELICOPTER

The helicopter should be electrically grounded when parked to dissipate static

electricity. Turn off all power switches before making electrical connections or
disconnections.

HIGH PRESSURE

Extremely high pressure can occur during and after operation of certain equipment.
If this pressure is not relieved before working on this equipment, serious injury or
death may occur. Be sure to open all drains and vents before beginning disassembly.

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TM 55-1520-244-BD

HYDRAULIC FLUID

Prolonged contact with liquid or mist can irritate eyes and skin. Wear rubber gloves when handling liquid. After
contact with skin, immediately wash contacted area with soap and water. If liquid contacts eyes, flush immediately
with clear water. If liquid is swallowed, do not induce vomiting. Get immediate medical attention. If prolonged ex-
posure with mist is likely, wear an appropriate respirator. When fluid is decomposed by heating, toxic gases are
released.

NOISE

Sound pressure levels in and around this aircraft during operating conditions exceed the Surgeon General’s hear-
ing conservation criteria, as defined in TB MED 501. Hearing protection devices such as aviator helmet or ear
plugs are required to be worn.

SANDING DUST

Sanding on reinforced laminated glass produces fine dust that may cause skin and lung irritations. Observe neces-
sary protective measures.

TOXIC POISONS

Turbine fuels, lubricating oils, and adhesives contain additives which are poisonous and readily absorbed through
the skin. Do not allow them to remain on skin longer than necessary. Wear protective equipment.

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 TM 55-1520-228-BD

LASER LIGHT

You can be blinded if you look into a laser beam when you are not wearing laser
safety goggles. Never aim the laser range finder (LRF) at personnel.

If laser beam reflects from a flat, mirror-like surface, it can blind you unless you
are wearing laser safety goggles.

RADIOACTIVE MATERIALS
Self-luminous dials and ignition units may contain radioactive materials. If such
an instrument or unit is broken or becomes unsealed, avoid personal contact. Use
forceps or gloves made of rubber or polyethylene to pick up-contaminated material.
Place materials and gloves in a plastic bag. Seal bag and dispose of it as radio-
active waste in accordance with AR 708-1 and TM 3-261 (Refer to TB 43-0108). Repair
shall conform to requirements in AR 385-11.

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 TM 55-1520-244-BD

Technical Manual HEADQUARTERS

DEPARTMENT OF THE ARMY
No. 55-1520-244-BD WASHINGTON, D. C., 26 November 1990

TECHNICAL MANUAL

OPERATORS, AVIATION UNIT, AND AVIATION INTERMEDIATE MAINTENANCE

BATTLEFIELD DAMAGE ASSESSMENT AND REPAIR

FOR

HELlCOPTER, ATTACK

AH-1E 1520-01-192-2478
AH-1F 1520-01-168-4260
AH-1P 1520-01-168-4259

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistake or if you know of a way to im-
prove the procedure, please let us know. Mail your letter or DA Form 2028 (Recommended
Changes to Publications and Blank Forms) directly to: Commander, U.S. Army Aviation
Systems Command, ATTN: AMSAV-MC, 4300 Goodfellow Blvd., St. Louis, MO 63120-1798.
A reply will be provided to you.

TABLE OF CONTENTS

Page

HOW TO USE THIS MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

CHAPTER 1- GENERAL INFORMATION

Section I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Section Il. Standards and Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Section Ill. Tasks and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

CHAPTER 2- ASSESSING BATTLEFIELD DAMAGE

Section I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Section II. General Fault Assessment Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

CHAPTER 3- GENERAL REPAIRS ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

CHAPTER 4- AIRFRAME

Section I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Section Il. Airframe Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-36

CHAPTER 5- ALIGHTING GEAR

Section I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Section II. Skid Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

CHAPTER 6- POWER PLANT INSTALLATION

Section I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Section Il. Oil Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Section Ill. Oil Pressure Indicator/Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

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TM 55-1520-244-BD

TABLE OF CONTENTS (Cont)

Page

Section IV. Fuel Filter. . . . . . . . . . . . . . . . . . . . . . . . . 6-14

Section V. Fuel Control and Accessory Gearbox . . . . . . . . . . . . . 6-14
Section VI. Emergency Engine Start. . . . . . . . . . . . . . . . . . . 6-17

CHAPTER 7 - ROTORS

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 7-1

Section II. Main Rotor Hub and Blade. . . . . . . . . . . . . . . . . . 7-1
Section III. Tail Rotor System.. . . . . . . . . . . . . . . . . . . . . 7-19

CHAPTER 8 - DRIVE TRAIN SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 8-1

Section II. Transmission. . . . . . . . . . . . . . . . . . . . . . . . 8-1
Section III. Tail Rotor Driveshaft. . . . . . . . . . . . . . . . . . . . 8-14

CHAPTER 9 - HYDRAULIC SYSTEMS

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 9-1

Section II. Hoses. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
Section III. Metal Tubing. . . . . . . . . . . . . . . . . . . . . . . . 9-15
Section IV. Hydraulic Components . . . . . . . . . . . . . . . . . . . . 9-21
Section V. Hydraulic System Isolation . . . . . . . . . . . . . . . . . 9-23
Section VI. O-Ring, Packing, and Gaskets . . . . . . . . . . . . . . . . 9-30
Section VII. Hydraulic Fluid Substitutions. . . . . . . . . . . . . . . . 9-31

CHAPTER 10 - INSTRUMENT SYSTEM.. . . . . . . . . . . . . . . . . . . . . 10-1

CHAPTER 11 - ELECTRICAL AND AVIONICS SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 11-1

Section II. Wire and Cable Splicing. . . . . . . . . . . . . . . . . . . 11-6
Section III. Connector Repair. . . . . . . . . . . . . . . . . . . . . . 11-24
Section IV. Overcurrent Protection Devices . . . . . . . . . . . . . . . 11-25
Section V. Bus Bars . . 11-30
Section VI. Power Relays 11-34
Section VII. Antennas . . 11-46
Section VIII. Electrical Wire Insulation 11-50

CHAPTER 12 - FUEL SYSTEM

Section I. Introduction 12-1

Section II. Lines and Hoses 12-1
Section III. Fuel Cells . . 12-7
Section IV. Fuel Boost Pumps 12-23
Section V. Fuel Filters . . . 12-23

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 TM 55-1520-244-BD

TABLE OF CONTENTS (Cont)

Page

CHAPTER 13 - FLIGHT CONTROL SYSTEM

Section I. Introduction.. . . . . . . . . . . . . . . . . . . . . . . . . . 13-1

Section II. Flight Control Tubes. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 13-5

CHAPTER 14 - UTILITY SYSTEMS . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 14-1

CHAPTER 15 - ENVIRONMENTAL CONTROL SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 15-1

Section II. Environmental Control Unit (ECU) . . . . . . . . . . . . . . 15-1
Section III. Ducting. . . . . . . . . . . . . . . . . . . . .... 15-6
Section IV. Bleed Airlines. . . . . . . . . . . . . . . . . . . . . . . 15-9

CHAPTER 16- MISSION EQUIPMENT

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . 16-1

Section II. Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . 16-3
Section III. Hydraulics. . . . . . . . . . . . . . . . . . . . . . .. . ...... . . . . . 16-5
Section IV. Air Data Subsystem. . . . . . . . . . . . . . . . . . . . . . . . . 16-5

CHAPTER 17 - EMERGENCY EQUIPMENT. . . . . . . .. . . . . . . . . . . . . . . . . . 17-1

APPENDIX A - REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

APPENDIX B - SPECIAL OR FABRICATED TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
APPENDIX C - EXPENDABLE/DURABLE SUPPLIES AND MATERIALS . . . . . . . . . . . . . C-1
APPENDIX D - SUBSTITUTE MATERIALS/PARTS. . . . . . . . . . . . . . . . . . . . . . . . . D-1
APPENDIX E - BDAR TRAINING PROCEDURES. . . . . . . . . . . . . . . . . . . . . . . . . . E-1
APPENDIX F - AVIONICS CONFIGURATION. . . . . . . . . . . . .. F-1
GLOSSARY . . . GLOS-1
INDEX . . . . INDEX-1

LIST OF ILLUSTRATIONS

Figure Title Page

1-1 DA Form 2408-13. . . . . . . . . . . . . . . . . . . . . . 1-6

1-2 DA Form 2408-18. . . . . . . . . . . . . . . . . . .. . . . . . 1-7
1-3 Damage Assessment Markings (Sheet 1 of 3). . . . . . . . . . 1-8
4-1 Aircraft Zones. . . . . . . . . . . . . . . . . . . . . . . . 4-2
4-2 DA Form 2404. . . . . . . . . . . . . . . . . . . . 4-7
4-3 Measuring Cap or Longeron Damage . . . . . . . . . . . . . . 4-9
4-4 Damaged Cross Section . . . . . . . . . . . . . . . . . . . 4-9
4-5 Measuring Skin Panel Damage . . . . . . . . . . . . . . . . . 4-11
4-6 Measuring Damage in Floors or Decks . . . . . . . . . . . . 4-11
4-7 Measuring Damage in Honeycomb Panels . . . . . . . . . . . . 4-12
4-8 Airframe Reference Lines . . . . . . . . . . . . . . . . . . 4-15
4-9 Primary Structural Caps L/H . . . . . . . . . . . . . . . . 4-16

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TM 55-1520-244-BD

LIST OF ILLUSTRATIONS (Cont)

Figure Title Page

4-10 Structural WebsL/H . . . . . . . . . . . . . . . . . . . . 4-16

4-11 Primary Structural Caps R/H . . . . . . . . . . . . . . . . 4-17
4-12 Structural Webs R/H . . . . . . . . . . . . . . . . . . . . 4-17
4-13 Fuselage Box Beam Panels. . . . . . . . . . . . . . . . . . 4-18
4-14 L/H Fuselage Beam . . . . . . . . . . . . . . . . . . . . . 4-19
4-15 R/HFuselage Beam . . . . . . . . . . . . . . . . . . . . . 4-20
4-16 Upper Panels. . . . . . . . . . . . . . . . . . . . . . , . 4-21
4-17 Lower Panels. . . . . . . . . . . . . . . . . . . . . . . . 4-22
4-18 Pylon Support . . . . . . . . . . . . . . . . . . . . . . . 4-26
4-19 Post Member Consisting of Three Elements . . . . . . . , . . 4-28
4-20 Tail Boom . . . . . . . . . . . . . . . . . . . . . . . . . 4-30
4-21 Fin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-31
4-22 Skin Panel Damage WL Versus Frame Spacing S. . . . . . . . . 4-34
4-23 Typical Skin Panel and Frame Damage . . . . . . . . . . . . 4-34
4-24 AH-1S Left Wing - Skins Removed . . . . . . . . . . . . . . 4-36
4-25 Typical Former Repair. . . . . . . . . . . . . . . . . . . . 4-39
4-26 Cut and Drill Former Repair. . . . . . . . . . . . . . . . . 4-40
4-27 Cutout in Damaged Skin . . . . . . . . . . . . . . . . . 4-42
4-28 Stringer/Stiffener Repair. . . . . . . . . . . . . . . . . . 4-42
4-29 Expedient Cap/Longeron Repair . . . . . . . . . . . . . . . 4-44
4-30 Repair of Damage Bulkhead Flange . . . . . . . . . . . . . . 4-46
4-31 Typical Combination Repair (angle view). . . . . . . . . . . 4-47
4-32 Typical Combination Repair (side view) . . . . . . . . . . . 4-48
4-33 Damaged Honeycomb Core Panel - Small Damage to One Skin and
and Core. . . . . . . . . . . . . . . . . . . . . . . . . . 4-50
4-34 Damaged Honeycomb Core Panel, 2-8 Inch Damage - One Skin
and Core. . . . . . . . . . . . . . . . . . . . . . . . . . 4-50
4-35 Repaired Honeycomb Core Panel, 2-8 Inch Damage - One Skin
and Core. . . . . . . . . . . . . . . . . . . . . . . . . . 4-51
4-36 Damaged Honeycomb Core Panel, 2-8 Inch Damage - Both Skins
and Core. . . . . . . . . . . . . . . . . . . . . . . . . . 4-52
4-37 Repaired Honeycomb Core Panel, 2-8 Inch Damage - Both Skins
and Core. . . . . . . . . . . . . . . . . . . . . . . . . . 4-52
4-38 Damage Repair, Accessible One Side Only. . . . . . . . . . . 4-54
4-39 Fabrication of Patch Plate. . . . . . . . . . . . .. O . . 4-54
4-40 Repair of Honeycomb Core Panel - Damage Over 8 Inches - Both
Skins and Core. . . . . . . . . . . . . . . . . . . . . . .
4-41 Fracture Lacing with Safety Wire . . . . . . . . . . . . . .
5-1 Landing Gear and Support Installation. . . . . . . . . . . .
5-2 Skid Tube Damage Zones . . . . . . . . . . . . . . . . . . .
5-3 Skid Shoe Repair. . . . . . . . . . . . . . . . . . . . . .
5-4 Clamp Repair. . . . . . . . . . . . . . . . . . . . . . . .
5-5 Fabricated Clamp. . . . . . . . . . . . . . . . . . . . . .
6-1 Engine, Right-Hand View. . . . . . . . . . . . . . . . . . . 6-2
6-2 Engine, Left-HandView . . . . . . . . . . . . . . . . . . . 6-3
6-3 Oil Tank. . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
6-4 Wood Plug. . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
6-5 Sealant Repair. . . . . . . . . . . . . . . . . . . . . . . 6-8
6-6 Screw, Washer, and Gasket.. . . . . . . . . . . . . . . ., 6-8

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 TM 55-1520-244-BD

LIST OF ILLUSTRATIONS (Cont)

Figure Title Page

6-7 Hose Assembly, Sealant, Nut, and Bolt . . . . . . . . . . . . . . . 6-9

6-8 Sheet Metal with Sealant or Blind Rivets . . . . . . . . . . . . . . 6-11
6-9 Oil Pressure Transmitter . . . . . . . . . . . . . . . . . . . . . 6-12
6-10 Torque Pressure Transmitter . . . . . . . . . . . . . . . . . . . 6-13
6-11 Fuel Control Assembly and Accessory Gearbox Assembly . . . . . . . 6-15
6-12 Tach Generator Removal . . . . . . . . . . . . . . . . . . . . 6-16
6-13 External Power Plug . . . . . . . . . . . . . . . . . . . . . . 6-18
7-1 Main Rotor System . . . . . . . . . . . . . . . . . . . . . . . 7-2
7-2 Application of Tape . . . . . . . . . . . . . . . . . . . . . . . 7-5
7-3 Marking Work Area . . . . . . . . . . . . . . . . . . . . . . . 7-7
7-4 Application of Adhesive and Position of Patch 7-7
7-5 Balance Adjustment for Patches (K747 Blade) (Sheet 1 or 2) . . . . . . . . . 7-9
7-6 Maximum Allowable Repairable Damage to Rotor Blade . . . . . . . . 7-11
7-7 Typical Double Plug Patch Repair . . . . . . . . . . . . . . . . . 7-12
7-8 Marking Work Area . . . . . . . . . . . . . . . . . . . . . . . 7-13
7-9 Removal of Damage Skin . . . . . . . . . . . . . . . . . 7-14
7-10 Setting Router Depth . . . . . . . . . . . . . . . . . . . . . . 7-15
7-11 Insertion of Patch . . . . . . . . . . . . . . . . . . . . . . . 7-16
7-12 Drag Brace . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18
7-13 Tail Rotor installation . . . . . . . . . . . . . . . . . . . . . . 7-20
7-14 Tail Rotor Blade-Area Authorized for Patch-Type Repair . . . . . . . . 7-21
7-15 Aluminum Skin Patch . . . . . . . . . . . . . . . . . . . . . . 7-21
7-16 Skin Patch Tape Cover . . . . . . . . . . . . . . . . . . . . . 7-22
8-1 Drive Train (Typical) . . . . . . . . . . . . . . . . . . . . . . 8-2
8-2 Transmission Oil Pressure Switch and Transmitter Repair . . . . . . . . 8-5
8-3 Transmission Assembly, Unaltered . . . . . . . . . . . . . . . . . 8-6
8-4 Altered Configuration (Transmission Oil System) Bypassing
Filter and Outlet Hose . . . . . . . . . . . . . . . . . . . . . . 8-7
8-5 Altered Configuration (Transmission Oil System) Bypassing
Oil Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
8-6 Altered Configuration (Transmission Oil System) Bypassing
Filter and lnlet Hose . . . . . . . . . . . . . . . . . . . . . . 8-11
8-7 Altered Configuration (Transmission Oil System) Substituting
Hose at Sump Outlet (Sheet 1 of 2) 8-12
8-8 Damage Passing Through Center of Shaft . . . . . . . . . . . . . . . 8-16
8-9 Damage Not Passing Through Center of Shaft . . . . . . . . . . . . 8-17
8-10 Balance Restoring Repair for Damage Not Passing Through
Center of Shaft . . . . . . . . . . . . . . . . . . . . . . . . 8-18
8-11 Y and S Graph . . . . . . . . . . . . . . . . . . . . . . . . . 8-19
8-12 Area and Diameter Graph . . . . . . . . . . . . . . . . . . . . 8-19

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TM 55-1520-244-BD

LIST OF ILLUSTRATIONS (Cent)

Figure Title Page

8-13 Damaged Shaft; Petals Straightened Smooth. . . . . . . . . . 8-21

8-14 Repaired Shaft. . . . . . . . . . . . . . . . . . . . . . . 8-22
8-15 Shaft Area (in*) vs. Number of Rivets. . . . . . . . . . . . 8-23
9-1 Hydraulic System Schematic (Sheet 1 of 2). . . . . . . . . . 9-2
9-2 Hydraulic System - SYSTEM No. 2 (Sheet 1 of 2) . . . . . . . 9-4
9-3 Hydraulic System - SYSTEM No. 1. . . . . . . . . . . . . . . 9-6
9-4 Hydraulic System - Armament (Sheet 1 of 2) . . . . . . . . . 9-7
9-5 Emergency (Electric Motor Driven) Hydraulic System . . . . . 9-9
9-6 Two-Part Fitting. . . . . . . . . . . . . . . . . . . . . . 9-12
9-7 Four-Part Fitting. . . . . . . . . . . . . . . . . . . . . . 9-12
9-8 Installation of MS Hose Fitting Socket and Sleeve. . . . . . 9-14
9-9 Assembly of MS Fitting . . . . . . . . . . . . . . . . . . . 9-14
9-10 Using Tube Cutter. . . . . . . . . . . . . . . . . . . . . . 9-16
9-11 Properly Burred Tubing . . . . . . . . . . . . . . . . . . . 9-16
9-12 Damaged Tube Sections . . . . . . . . . . . . . . . . . . . 9-18
9-13 MS Tube Fitting Installation . . . . . . . . . . . . . . . . 9-19
9-14 Completed Tubing Installation. . . . . . . . . . . . . . . . 9-19
9-15 Completed High Pressure Hose Substitution. . . . . . . . . . 9-20
9-16 MS Union Installation . . . . . . . . . . . . . . . . . . . 9-21
9-17 Lock-Out Valve Assembly. . . . . . . . . . . . . . . . . . . 9-22
9-18 Hydraulic System Unaltered . . . . . . . . . . . . . . . . . 9-24
9-19 Hydraulic System, Isolating No. 1 System . . . . . . . . . . 9-25
9-20 Hydraulic Pump and Drive Pad . . . . . . . . . . . . . . . . 9-27
9-21 Hydraulic System, Isolating No. 2 System . . . . . . . . . . 9-29
11-1 Circuit Identification.. . . . . . . . . . . . . . . . . . 11-3
11-2 Crimp Splice . . . . . . . . . . . . . . . . . . . . . . . 11-8
11-3 Splicing with Terminal Lug Barrel. . . . . . . . . . . . . . 11-9
11-4 Twist Wire Splice . . . . . . . . . . . . . . . . . . . . . 11-11
11-5 Replacement Section; Twist Wire Splice . . . . . . . . . . . 11-11
11-6 Metal Casing Splice. . . . . . . . . . . . . . . . . . . . . 11-12
11-7 Replacement Section; Terminal Lug Repair . . . . . . . . . . 11-13
11-8 Ram Wire Repair . . . . . . . . . . . . . . . . . . . . . . 11-14
11-9 Shielded Cable Repair Preparation. . . . . . . . . . . . . . 11-15
11-10 Shielded Cable Splice Preparation. . . . . . . . . . . . . . 11-16
11-11 Completed Shielded Cable Splice. . . . . . . . . . . . . . . 11-16
11-12 Sheath Connector Splice. . . . . . . . . . . . . . . . . . . 11-17
11-13 Pigtail Sheath Splice . . . . . . . . . . . . . . . . . . . 11-19
11-14 Substitute Shielded Braid Splice . . . . . . . . . . . . . . 11-20
11-15 Shield Terminator Repair Preparation . . . . . . . . . . . . 11-22
11-16 Shield Terminator Repair. . . . . . . . . . . . . . . . . . 11-22
11-17 Component Bypass. . . . . . . . . . . . . . . . . . . . . . 11-23
11-18 Connector Pin and Socket. . . . . . . . . . . . . . . . . . 11-24
11-19 Damaged Connector and Wire . . . . . . . . . . . . . . . . . 11-25
11-20 Typical Original Circuit Breaker Connection. . . . . . . . . 11-26
11-21 Construction of Fuse Link. . . . . . . . . . . . . . . . . . 11-28
11-22 Typical Fuses. . . . . . . . . . . . . . . . . . . . . . . . 11-29
11-23 Fabricated Fuse, Type A... . . . . . . . . . . . . . . . . 11-30
11-24 Fabricated Fuse, Type B. . . . . . . . . . . . . . . . . . . 11-30
11-25 Splicing Bus Bars. . . . . . . . . . . . . . . . . . . . . . 11-32

vi
 TM 55-1520-244-BD

LIST OF ILLUSTRATIONS (Cont)

Figure Title Page

11-26 Lengthening Bus Bars. . . . . . . . . . . . . . . . . . . . 11-32

11-27 Battery Cell Layout. . . . . . . . . . . . . . . . . . . . . 11-33
11-28 Block Diagram Power Relay, Check and Test. . . . . . . . . . 11-34
11-29 AH-1 PROD Battery Compartment, Forward View (Sheet 1 of 2) . 11-36
11-30 AH-1 PROD Battery Compartment, Side View (Sheet 1 of 2). . . 11-38
11-31 AH-1 ECAS and MC Battery Compartment (Sheet 1 of 2). . . . . 11-40
11-32 AH-1 ECAS and MC Battery Compartment (Sheet 1 of 3). . . . . 11-42
11-33 Block Diagram, Typical Power Relays. . . . . . . . . . . . . 11-45
11-34 Jumper Wire Fabrication. . . . . . . . . . . . . . . . . . . 11-45
11-35 Frequency vs. Wavelength . . . . . . . . . . . . . . . . . . 11-47
11-36 Preparation of Coax . . . . . . . . . . . . . . . . . . . . 11-47
11-37 Installation of Field Expedient Antenna. . . . . . . . . . . 11-49
11-38 Pigtail Termination for Shielded Wire. . . . . . . . . . . . 11-50
11-39 Heat Shrinkable Tape. . . . . . . . . . . . . . . . . . . . 11-52
11-40 Insulation Repair with Sleeving. . . . . . . . . . . . . . . 11-52
12-1 Fuel System . . . . . . . . . . . . . . . . . . . . . . . . 12-2
12-2 Use of String Bead. . . . . . . . . . . . . . . . . . . . . 12-5
12-3 Long Replacement Tube Section. . . . . . . . . . . . . . . . 12-5
12-4 Repair of Small Hole in Tube . . . . . . . . . . . . . . . . 12-6
12-5 Expedient Repair of Damaged Hose . . . . . . . . . . . . . . 12-8
12-6 Replacement of Damaged Hose Section. . . . . . . . . . . . . 12-8
12-7 Inlet Line to Fuel Control. . . . . . . . . . . . . . . . . 12-10
12-8 Emergency Mechanical Clamp Repair . . . . . . . . . . . . . 12-11
12-9 Rubber Repair Plug Assembly . . . . . . . . . . . . . . . . 12-13
12-10 Plug Modification for Three Plane (Corner) Repair. . . . . . 12-14
12-11 Aft Cell Isolation Access Panels . . . . . . . . . . . . . . 12-16
12-12 Crossover Line Flange Template . . . . . . . . . . . . . . . 12-17
12-13 Blocked Off Crossover Line . . . . . . . . . . . . . . . . . 12-18
12-14 Fuel Manifold. . . . . . . . . . . . . . . . . . . . . . . . 12-19
12-15 Blocked Off Fuel Cell. . . . . . . . . . . . . . . . . . . . 12-22
12-16 Floor Baffle Assembly . . . . . . . . . . . . . . . . . . . 12-24
12-17 Fuel Quality Probe; Fuel Inlet . . . . . . . . . . . . . . . 12-25
12-18 External Fuel Filter Assembly. . . . . . . . . . . . . . . . 12-26
12-19 External Fuel Filter. . . . . . . . . . . . . . . . . . . . 12-28
12-20 Bypassing External Fuel Filter . . . . . . . . . . . . . . . 12-29
13-1 Flight Controls . . . . . . . . . . . . . . . . . . . . . . 13-2
13-2 Stability and Control Augmentation System (SCAS) . . . . . . 13-3
13-3 Collective Flight Controls . . . . . . . . . . . . . . . . . 13-6
13-4 Cyclic, Lateral Controls . . . . . . . . . . . . . . . . . . 13-7
13-5 Cyclic, Fore and Aft Controls . . . . . . . . . . . . . . . 13-8
13-6 Tail Rotor Controls. . . . . . . . . . . . . . . . . . . . . 13-9
13-7 Control Tube Splice. . . . . . . . . . . . . . . . . . . . . 13-12
13-8 Control Rod with Bearing and Clevis Assemblies . . . . . . . 13-14
13-9 Flattened End of Fabricated Flight Control . . . . . . . . . 13-15
13-10 Corner Rounding on Fabricated Flight Control . . . . . . . . 13-15
13-11 Bell Crank or Lever Assembly Connection of Fabricated
Flight Control . . . . . . . . . . . . . . . . . . . . . . . 13-15
15-1 Environmental Control System . . . . . . . . . . . . . . . 15-2
15-2 ECU Housing. . . . . . . . . . . . . . . . . . . . . . . . . 15-4

vii
TM 55-1520-244-BD

LIST OF ILLUSTRATIONS (Cont)

Figure Title Page

15-3 Ducts, Flexible Plastic . . . . . . . . . . . . . . . . . . 15-7

15-4 Ducts, Rigid Plastic. . . . . . . . . . . . . . . . . . . . 15-8
15-5 Bleed Air Lines. . . . . . . . . . . . . . . . . . . . . . . 15-10
15-6 Bleed Line Patch Repair. . . . . . . . . . . . . . . . . . . 15-11
16-1 Turret Gun Brake Toggle (ECAS and MC). . . . . . . . . . . . 16-4
16-2 Outboard Wing Stores Pylon.. . . . . . . . . . . . . . . . 16-6
16-3 ADS Pneumatic Lines. . . . . . . . . . . . . . . . . . . . . 16-7
F-1 UHF Command Communication System AN/ARC-116() or AN/ARC-164
(Sheet l of 2) . . . . . . . . . . . . . . . . . . . . . . . F-1
F-2 VHF Command Communication System AN/ARC-115 (Sheet 1 of 2) . F-5
F-3 VHF Command Commnunication System AN/ARC-115 or AN/ARC-186
(Sheet l of 2) . . . . . . . . . . . . . . . . . . . . . . . F-7
F-4 FM Liaison Communication System AN/ARC-114 (Sheet 1 of 3). . F-9
F-5 FM Liaison Communication System AN/ARC-114A (Sheet 1 of 3) . F-14
F-6 Gyromagnetic Compass System AN/ASN-43 (Sheet 1 of 2) . . . . F-19
F-7 Automatic Direction Finder AN/ARN-89B (Sheet 1 of 2) . . . . F-23
F-8 VOR/MB/GS Receiving Set Radio AN/ARN-123(V)3 (Sheet 1 of 3). F-27
F-9 Doppler Navigation System AN/ASN-128 (MC) (Sheet 1 of 2) . . F-37
F-10 Radar Altimeter System AN/APN-209 (Sheet 1 of 2) . . . . . . F-42
F-11 IFF System AN/APX-72 (Sheet 1 of 2). . . . . . . . . . . . . F-45
F-12 IFF System AN/APX-100(V) (Sheet 1 of 2). . . . . . . . . . . F-50
F-13 Radar Warning System AN/APR-39(V)1 (Sheet 1 of 2). . . . . . F-54
F-14 Countermeasures Set AN/ALQ-136 (MC) (Sheet 1 of 2) . . . . . F-57
F-15 Countermeasures Set AN/ALQ-144(V) (MC) (Sheet 1 of 2). . . . F-59

LIST OF TABLES

Table No. Title Page

2-1 General Decision Logic . . . . . . . . . . . . . . . . . . . 2-2

2-2 Assessment Table. . . . . . . . . . . . . . . . . . . . . . 2-3
4-1 Structure Damage Assessment Procedures . . . . . . . . . . . 4-4
4-2 Allowable Fuselage Damage Limits-Condition 1, Fuselage Caps. 4-24
4-3 Allowable Tail Boom Damage Limits-Condition 1, Tail Boom
Longerons. . . . . . . . . . . . . . . . . . . . . . . . . . 4-32
5-1 Alighting Gear Assessment Procedures . . . . . . . . . . . . 5-2
6-1 Power Plant Assessment Procedures. . . . . . . . . . . . . . 6-4
7-1 Rotor Assessment Procedures. . . . . . . . . . . . . . . . . 7-3
7-2 Plug Patch Kits. . . . . . . . . . . . . . . . . . . . . . . 7-11
8-1 Drive Train Assessment Procedures. . . . . . . . . . . . . . 8-3
8-2 Shaft Area (in2) vs. Number of Rivets. . . . . . . . . . . . 8-23
9-1 Hydraulic System Assessment Procedures . . . . . . . . . . . 9-10
11-1 Electrical and Avionics Assessment Procedures. . . . . . . . 11-2
11-2 Function and Designation Letters . . . . . . . . . . . . . . 11-3
11-3 Unshielded Crimp Splice Application. . . . . . . . . . . . . 11-7
11-4 Shielded Cable Repair . . . . . . . . . . . . . . . . . . . 11-15
11-5 Fuse Link Strands. . . . . . . . . . . . . . . . . . . . . . 11-27
12-1 Fuel System Assessment Procedures. . . . . . . . . . . . . . 12-3

viii
 TM 55-1520-244-BD

LIST OF TABLES (Cont)

Table No. Title Page

13-1 Flight Control System Assessment Procedures. . . . . . . . . 13-4

13-2 Control Tube Dimensions. . . . . . . . . . . . . . . . . . . 13-10
13-3 Bolt/Drill Sizes for Control Tube Repairs. . . . . . . . . . 13-11
14-1 Utility Systems Assessment Procedures. . . . . . . . . . . . 14-2
15-1 Environmental Control System Assessment Procedures . . . . . 15-3
16-1 Mission Equipment Assessment Procedures. . . . . . . . . . . 16-3
D-1 Spare and Repair Parts . . . . . . . . . . . . . . . . . . . D-2
D-2 Armament Parts. . . . . . . . . . . . . . . . . . . . . . . D-10
D-3 Packing Reference and Temperature Guides Chart . . . . . . . D-12
D-4 Substitute U.S. Fuels. . . . . . . . . . . . . . . . . . . . D-17
D-5 Substitute Foreign Fuels.. . . . . . . . . . . . . . . . . D-18
D-6 Substitute Commercial Fuels. . . . . . . . . . . . . . . . . D-19
D-7 Alternate and Expedient Fuel Blends. . . . . . . . . . . . . D-20
D-8 Substitute Lubricants and Hydraulic Fluids . . . . . . . . . D-21
D-9 Metal Substitution Chart.. . . . . . . . . . . . . . . . . D-24
F-1 UHF AN/ARC-1160, Wire Chart . . . . . . . . . . . . . . . . F-4
F-2 UHF AN/ARC-1640, Wire Chart . . . . . . . . . . . . . . . . F-4
F-3 VHF AN/ARC-1150, Wire Chart . . . . . . . . . . . . . . . . F-6
F-4 VHF Command Commnunication System AN/ARC-l15 or AN/ARC-186,
Wire Chart. . . . . . . . . . . . . . . . . . . . . . . . . F-8
F-5 FM AN/ARC-1140, Wire Chart (with KY-28) PROD and ECAS . . . F-12
F-6 FM AN/ARC-1140, Wire Chart (with KY-28) MC. . . . . . . . . F-17
F-7 AN/ASN-43,Wire Chart . . . . . . . . . . . . . . . . . . . . F-21
F-8 AN/ARN-89B, Wire Chart, ADF. . . . . . . . . . . . . . . . . F-25
F-9 AN/ARN-123(V)3, Wire Chart, MC, P, E . . . . . . . . . . . . F-30
F-10 AN/ASN-128,Wire Chart... . . . . . . . . . . . . . . . . F-39
F-11 AN/APN-209,Wire Chart... . . . . . . . . . . . . . . . . F-44
F-12 AN/APX-72,Wire Chart . . . . . . . . . . . . . . . . . . . . F-47
F-13 AN/APX-lOO,Wire Chart... . . . . . . . . . . . . . . . . F-52
F-14 AN/APR-39,Wire Chart . . . . . . . . . . . . . . . . . . . . F-56
F-15 AN/ALQ-136,Wire Chart... . . . . . . . . . . . . . . . . F-58
F-16 AN/ALQ-144,Wire Chart... . . . . . . . . . . . . . . . . F-61

ix
TM 55-1520-244-BD

HOW TO USE THIS MANUAL

This manual is developed to assist the soldier in a battlefield environment make assessment and repair of
damage to the AH-1 attack helicopter which cannot, due to asset availability or environmental factors, be
repaired in the normal prescribed manner. Within this technical manual, the word shall is used to indicate a man-
datory requirement. The word should is used to indicate a nonmandatory but preferred method of accomplish-
ment. The word may is used to indicate an acceptable method of accomplishment.

1. Organization of the Manual. This manual contains a general information chapter (chapter 1), a general
assessment chapter (chapter 2), and specific repair chapters (chapters 4 thru 17). Chapter 3 is not used. It also
contains five appendixes.

2. Chapter 2 is used to assess the helicopter in general and references specific chapters for detailed repair pro-
cedures of the major functional groups. The major functional groups correspond with the functional groups of the
-23 series manuals that are employed in routine repairs to the helicopter.

3. Chapter 3 is not used in this manual. It would normally contain repairs for equipment which does not fall under
one of the standard helicopter functional groups.

4. Each functional group chapter is organized as follows:

a. Section I - Introduction.

(1) Scope. Purpose of the chapter.

(2) Assessment Procedures. General assessment information for the repairs covered therein.
(3) Repair Procedure Index.

b. Section II - Repair Item. A subsection is included for each repair item covered in that functional group. It
contains the following:

(1) General. About the nature and cause of damage and repair.
(2) Item and trouble statement with:

(a) Limits given.

(b) Personnel and time required to effect repairs.
(c) Materials and tools needed.
(d) Procedural steps to accomplish the repair.

(3) If more than one method of repair can be used, the various options will be included next.

NOTE

The first option is the preferred choice, the second option is the next preferred, etc. Selec-
tion of the option should be the most preferred method possible under the circumstances
and with the available materials and manpower.

x
 TM 55-1520-244-BD

HOW TO USE THIS MANUAL (Cont)

5. Finding Repairs in this Manual.

a. When the damage is obvious and known, find the functional group chapter of which the damaged item is a
part. Turn to the repair procedure index, section I, subparagraph 3 of each chapter to locate the item being
repaired. Then turn to the repair section and review each option to ascertain the appropriate fix. Read the entire
section for the option, then effect the repairs following the procedures given.

b. When the damage is hidden or unknown, follow the overall assessment procedures provided in chapter 2,
and follow the procedures and directions provided.

6. Preparation.

a. Each mechanic/technician shall read chapters 1 and 2 and shall be familiar with the repairs and layout of
the manual prior to attempting to accomplish BDAR repairs.

b. All warnings, cautions, and standard safety precautions shall be followed, inasmuch as possible, at all
times during BDAR procedures so as not to further damage or jeopardize either personnel or the equipment
during or subsequent to the BDAR action. Ensure all documentation is completed as directed in this manual and
by local command.

7. Expendable/Durable Supplies and Materials.

a. Each fix or repair option contains a short listing of materials and tools considered basic to the repair. It is im-
portant to note that the expendable materials listed usually cover a wide range for any one item.

Example: MATERIALS/TOOLS REQUIRED:

● Drill with Bit
● Sheet Metal (items 131-142, App. C)

• Rivets (items 98-115, App. C)

In this example, sheet metal covers the range of items 131 thru 142 listed in Appendix C. This means that,
depending on the circumstances and location of the fix, any one of these metals could be used. Likewise any one
of the rivets, items 98 thru 115, may be used to attach the patch plate depending on the application.

b. One of the key points concerning successful BDAR repairs is flexibility. The users of this manual should
strive to use the items on hand, provided a safe repair is made. The stringent requirements of normal main-
tenance may be lifted.

xi/(xii blank)
 TM 55-1520-244-BD

CHAPTER 1

GENERAL INFORMATION

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

1-1. PURPOSE. The purpose of Battlefield failures of helicopters and is not intended to be a com-
Damage Assessment and Repair (BDAR) is to quickly plete catalog of all possible emergency repairs. The
return the disabled helicopter to the operational com- repairs described here will serve as guidelines and
mander by expediently fixing, bypassing, or jury-rig- will stimulate the experienced mechanic/operator to
ging components to restore the minimum essential devise repairs as needed to rapidly return equipment
systems required for the support of the specific com- to operation in a combat situation.
bat mission or for self-recovery. These repairs will be
temporary and may not restore full performance d. The direct replacement of a piece of equip-
capability. Standard repair will be completed as soon ment by its spare, even under battlefield conditions, is
as practical. not a BDAR fix and may not be covered is in this TM.
A standard procedure should be performed in
1-2. SCOPE. preference to a BDAR fix when time and spares are
available.
a. This technical manual (TM) describes BDAR
procedures applicable to AH-1S attack helicopter 1-3. APPLICATION.
series and these procedures are to be used by crew,
operators, aviation unit maintenance (AVUM) teams, a. The procedures in this manual are designed
and aviation intermediate maintenance (AVIM) sup- for battlefield environments and should be used in
port teams. situations where standard maintenance procedures
are impractical. These procedures are not meant to
b. Standard repair techniques for the attack replace standard maintenance practices, but rather to
helicopter are included in other technical manuals supplement them strictly in a battlefield environment.
which are referenced in Appendix A of this TM. Standard maintenance procedures will provide the
Details of these procedures are not duplicated in most effective means of returning damaged equip-
whole in this TM. If the repairs are more than one ment to ready status provided that adequate time,
page in length, the repairs may only be referenced in replacement parts, necessary tools, and
appropriate chapter. trained/qualified repair persons are available. BDAR
procedures are only authorized for use in an emergen-
c. All possible types of combat damage and cy situation in a battlefield environment, and only at
failure modes cannot be predicted, nor are all effec- the direction of the commander. They are not to be
tive field expedient repairs known. This TM provides continued after the equipment is out of the battle en-
guidelines for assessing and repairing battlefield vironment.

1-1
TM 55-1520-244-BD

b. BDAR techniques are not limited to (6) Fabrication of parts from kits
simple restoration of minimum functional or readily available materials.
combat capability. If full functional
capability can be restored expediently (7) Jury-rigging.
with a limited expenditure of time and
assets, it will be accomplished. (8) Use of substitute materials.

c. Some of the special techniques in c. Damage Assessment. A procedure to

this manual, if applied, may result in rapidly determine what is damaged,
shortened life or in further damage to whether it is repairable, what assets
major components of the helicopter. The are required to make the repair, who can
commander must decide whether the risk do the repair (e.g., crew, maintenance
of having one less helicopter available team or maintenance support team), and
for combat outweighs the risk of where the repair should be made. The
applying the potentially destructive assessment procedure includes the
expedient repair technique. Each tech- following steps:
nique gives appropriate warnings,
cautions, and lists systems limitations (1) Determine if the repair can be
caused by this action. deferred, or if it must be done.

1-4. DEFINITIONS. (2) Isolate the damaged areas and

components.
a. Battlefield Damage. Any incident
such as combat damage, random failures, (3) Determine which components
operator errors, accidents, and wear-out must be fixed.
failures which occur on the battlefield
and which prevent the helicopter from (4) Prescribe fixes.
accomplishing its mission.
(5) Determine if parts or com-
b. Repair or Fix. Any expedient ponents, materials, and tools are
action that returns a damaged part or available.
assembly to a full or an acceptably
degraded operating condition, including: (6) Estimate the manpower and
skill required.
(1) Short cuts in parts removal or
installation. (7) Estimate the total time (clock
hours) required to make the repair.
(2) Installation of components
from other equipment that can be (8) Establish the priority of the
modified to fit or interchange with fixes.
components on the damaged equipment.
(9) Decide where the fix shall be
(3) Repair using parts that serve performed.
a noncritical function elsewhere on
the same equipment for the purpose of (10) Decide if recovery or evacua-
restoring a critical function. tion is necessary and to what location.

(4) Bypassing of noncritical com- d. Fully Mission Capable (FMC). The

ponents in order to restore basic func- helicopter can perform all its combat
tional capability. missions. To be FMC, the helicopter must
be complete and fully operable with no
(5) Expeditious cannibalization faults listed in the aircraft inspection
procedures. and maintenance record as prescribed in
DA PAM 738-751.

1-2
 TM 55-1520-244-BD

e. Combat Capable.
. Equipment meets the mini- j. Self-Recovery. The ability of the helicopter to
mum functional combat capability requirements. (See fly at reduced airspeed and altitude from the bat-
paragraph 1-8.) tlefield, or immediate vicinity to a maintenance collec-
tion point, main supply route, or maintenance activity
f. Combat Emergency Capable. The equipment for disposition, repair, or evacuation.
meets the needs for specific tactical missions; how-
ever, all systems are not functional. Also, additional k. Maintenance Co llection Point. A point
damage due to the nature of an expedient repair may operated by AVIM unit for the collection of equipment
occur to the equipment if it is used. The commander for repair.
must decide if these limitations are acceptable for that
specific emergency situation. l. Ma intenance Support Team (MST). A team of
AVIM mechanics and technical specialists who are
g.. Cannibalization or Controlled Exchange. trained in assessing battlefield damage and field
Throughout this manual, cannibalization and control- repair procedures.
led exchange are used interchangeably to mean the
removal of an item of materiel from one piece of m. Maintenance Team (MT). Helicopter crew
equipment for immediate use in another. Generally chief or AVUM mechanics/technicians who are trained
the rules for cannibalization/controlled exchange in assessing battlefield damage and field repair proce-
provided in TM55-1500-328-25, as modified by local dures.
authority, will prevail.
1-5. QUALITY DEFICIENCY REPORT/EQUIP-
h. Evacuation. A combat service support func- MENT IMPROVEMENT RECOMMENDATION
tion which involves the movement of recovered (QDR/EIR). If your helicopter and equipment needs
helicopters from a main supply route, maintenance improvement, let us know. Send us an EIR. You, the
collection point, or maintenance activity to higher user, are the only one who can tell us what you don’t
categories of maintenance. The materiel may be like about your equipment. Let us know why you don’t
returned to the user, to the supply system for reissue, like the design. Put it on an SF 368 (Quality Deficien-
or to property disposal activities. cy Report). Mail it to Commander, U.S. Army Aviation
Systems Command, ATTN: AMSAV-QRF, 4300
i. Recovery. The retrieval of immobile, inopera- Goodfellow Boulevard, St. Louis, MO 63120-1798.
tive, or abandoned helicopter from the battlefield or We’ll send you a reply.
immediate vicinity, and its movement to a main-
tenance collection point, the main supply route, or a
maintenance activity for disposition, repair, or evacua-
tion.

Section Il. STANDARDS AND PRACTICES

1-6. BDAR CHARACTERISTICS. BDAR capa- practices. In a combat emergency situation, greater
bility requires simplicity, speed, and effectiveness. risks are sometimes necessary and acceptable.
Some BDAR procedures include repair techniques Refer to Appendix I of FM 1-500 for additional informa-
that violate standard peacetime maintenance tion concerning BDAR concepts.

1-3
TM 55-1520-244-BD

1-7. WAIVER OF PRECAUTIONS. Under combat NOTE

conditions, BDAR may be performed on helicopters
which are in flight or which are under power while on Careful consideration shall be given to the
the ground. While some of these BDAR actions may operation of the Identify Friend or FOE
require waiving of safety precautions, the cautions to (IFF), Mode 4, avionics system. Failure of
protect personnel life should not be overlooked. the IFF or failure to properly communicate
Other similar precautions may be waived at the discre- with area air defense command prior to lift-
tion of the commander. BDAR fixes maybe required off could result in an attack from friendly
in a chemically toxic environment or under other ad- forces due to mistaken identity.
verse battlefield conditions with severe limitations in
personnel, facilities, equipment, and materials. Perfor- (4) Instruments/avionics as required to meet
mance of repair tasks may be necessary while wear-
mission needs.
ing protective gear. Decontamination procedures are
described in FM 3-5.
b. Flight Capability for Mission Completion.
1-8. OPERATING CHARACTERISTICS. This
manual covers expedient repairs for the helicopter (1) Sufficient power delivered to main and tail
and its components. It is entirely possible that in a rotor to accommodate lift capability for helicopter
combat situation, the helicopter having undergone crew and cargo.
one or more of these repairs may suffer degradation
of its normal operating characteristics (e.g., reduced (2) No fuel leaks which will curtail the intended
speed, reduced load capability, reduced range, etc.), length of flight.
and still be able to carry out all or parts of an as-
signed mission. The minimum functional combat (3) No degradation of any component/system
capability (M FCC) criteria is as follows: which will end in failure and curtailment of intended
mission.
NOTE
(4) Communications. Must have intercom
These criteria may be waived for recovery communications within aircraft and at least two tacti-
or to meet tactical situation demands other- cal receiver-transmitter (R-T) units operating at full
wise. capability.

a. Flight Capability for Self-Recovery. 1-9. TRAINING.

(1) Must have power delivered to main and tail a. BDAR by its nature involves fixes, bypasses,
rotor at minimum acceptable limits. or jury-rigging, which is outside authorized standard
repairs, and may degrade the inherent safety of the
(2) Lift capability for crew members. helicopter. Therefore, BDAR actions are not intended
to supplement, or replace standard maintenance prac-
tices during peacetime, nor should they be employed
(3) Flight controls at minimum function level ac-
indiscriminately to facilitate training.
ceptable for flight.
b. Repairs described in this manual, which can
be appropriately accomplished in order to provide
training, are listed in Appendix E and are highlighted
in each chapter’s repair procedure index. The
trainable repair in the index will be blocked in.

1-4
 TM 55-1520-244-BD

Section Ill. TASKS AND RESPONSIBILITIES

1-10. TAGGING/IDENTIFYING BDAR REPAIRS. (4) Red diagonal (/). This symbol indicates a
defect exists that is not serious enough to ground the
a. All damage will be identified on aircraft inspec- aircraft.
tion and maintenance record, DA Form 2408-13 and
DA PAM 2408-18, per DA PAM 738-751. Refer to e. Maintenance of Forms. Instructions for the
Figures 1-1 and 1-2. maintenance of forms, records, and reports are listed
in DA PAM 738-751. When battle damage repair
b. Recording of BDAR repairs and the use of (BDR) becomes necessary, the procedures in DA
status symbols, as defined in DA PAM 738-750, will PAM 738-750 will apply. Refer to Figures 1-1 and 1-2
be completed as soon as practical to indicate any for examples.
limitations and restrictions or required standard
repairs. (1) In block 17 of DA Form 2408-13, list the
fault.
c. In addition to recording all damage, the area
damaged will be marked on aircraft or component (2) In block 16 of DA Form 2408-13, enter the
part using damage assessment markings as shown in status symbol.
Figure 1-3.
(3) In block 18 of DA Form 2408-13, enter the
d. Status Symbols. Status symbols used in corrective action taken.
aircraft logbooks to record defects are defined below.
(4) The individual completing the repair will
(1) Red “X.” A red “X” shows that a defect sign the form in block 19 opposite the first line of the
exists and the aircraft is unsafe for flight. action taken, and will place his last name initial over
the status symbol in block 16.
(2) Circled red “X.” A red “X’ inside a red
circle indicates a limiting defect. The aircraft may be f. Temporary Repair. If the repair is temporary,
flown under specific limits as directed by higher take the following additional action:
authority, or as directed locally until corrective action
is taken. (1) In block 18 of DA Form 2408-13, enter the
corrective action and a statement that the repair is
(3) Red horizontal dash (-). temporary. Then make an entry in DA Form 2408-14,
block b. The entry will be a duplicate of the entry in
(a) This symbol indicates an inspection, spe- block 17 of DA Form 2408-13 to include a statement
cial inspection, component replacement, maintenance that a temporary repair has been made.
operational check, or test flight is needed. The sym-
bol is also used to indicate that a normal modification (2) If the temporary repair limits the capability
work order (MWO) is overdue. of the aircraft, the following entry will be made on DA
Form 2408-13:
(b) This symbol also shows that the condi-
tion of the equipment is unknown. A potentially (a) Place a circled red “X” in bolck 16.
dangerous condition may exist. The condition will be
corrected as soon as possible.

1-5
TM 55-1520-244-BD
Figure 1-1. DA Form 2408-13
1-6
 TM 55-1520-244-BD
Figure 1-2. DA Form 2408-18
1-7
TM 55-1520-244-BD

MEANINGS MARKINGS

TO INDICATE DAMAGE HAS BEEN ASSESSED AND EVALUATED:

Draw a circle around the damage.

TO INDICATE NO BDAR REPAIR REQUIRED:

Write “OK” inside the circle.

TO INDICATE STRUCTURAL REPAIRS ARE REQUIRED:

Draw a second line about 1/4 to 1/2

way around the initial circle then
draw slashes or crosshatch between
the two circular lines.

STRINGER REPAIR: Place an X to the

left and right of the circle.

FRAME REPAIR: Place an X above and

below the circle.

TO INDICATE DAMAGE TO SYSTEMS REQUIRING REPAIRS:

Draw a series of ’’curly cue” lines about

1/4 to 1/2 way around the initial circle.

TO INDICATE REPAIR INSTRUCTIONS:

For internal damage - draw a dashed

circle around the repair instructions.

For external damage - write repair REPAIR

instructions but do NOT enclose INSTRUCTIONS PARTIAL
with a circle.

Figure 1-3. Damage Assessment Markings (Sheet 1 of 3)

1-8
 TM 55-1520-244-BD

WRITTEN INSTRUCTIONS MEANING

See me - print name & See assessor or whoever has signed written instructions
rank. (Signature) for additional information. -

Names of parts to Where compound damage occurs, the names or abbreviation:

be repaired, (item, of specific items can be written adjacent to the damage
skin, stringer. to clarify repair instructions.

Full A full strength repair is required.

Partial Partial strength repair required in accordance with

specific aircraft BDAR manual.

OK No repairs required - damage is within acceptable limit:

for battle conditions.

? Continual assessment or reinspection is required after

each sortie.

Instruction markings for system are in two parts:

(1) Repair instruction markings and meanings are shown on this sheet and are
used to indicate repair actions required.

(2) System Identification - When known, identify the system using markings
shown on sheet 3 of this figure.

MARKINGS MEANING

Fix Repair the damaged system in accordance with approved

standard BDAR techniques for type of system, item,
high pressure, low pressure, etc.

Cap Terminate or block the system to prevent leakage.

Repl Replace damaged part - repairs not acceptable.

OK No repairs required.

Tag Repair instructions are written on tags tied to indivi-

dual damaged lines/components.

Figure 1-3. Damage Assessment Markings (Sheet 2 of 3)

1-9
TM 55-1520-244-BD

System identification markings are primarily abbreviations of the system.

MARKINGS SYSTEM/MEANING

Sys Damage to unknown system.

Fuel Fuel

Hyd Hydraulic

HP High Pressure

LP Low Pressure

Elect Electrical

AV Avionics

Flt Cent Flight Control

Main Rotor Main Rotor Group

Tail Rotor Tail Rotor Group

Air Pneumatic

Air Cond Air Conditioning

BL Air Bleed Air System

BLC Boundary Layer Control

N2 Nitrogen

O2 Oxygen

Eng Contr Engine Control

Pow Tr Power Train

EJ Ejection

NOTE

More than one identification marking may be used to describe

the system (e.g., HP, Hyd).

Figure 1-3. Damage Assessment Markings (Sheet 3 of 3)

1-10
 TM 55-1520-244-BD

(b) State the limitation in a. Aircraft damage (out-of-action or

block 17. function partially impared).

(3) If the temporary repair b. Location of aircraft.

requires an inspection at intervals,
list the required inspection on DA Form c. Defense status.
2408-18.
d. Mobility.
(a) Enter item to be inspected
in block 5. e. Personnel report.

(b) List the applicable TM in f. Current and anticipated hostile

block 6. action.

(c) State the frequency of the Anticipated BDAR fixes and repair
inspection in block 7. time.

1-11. REPORTS. All required written

reports for BDAR fixes are found in DA
PAM 738-751. If communication capa-
bility is damaged, the aircraft
commander should approach the nearest
friendly radio and make his report
if possible. The report should
include these essentials:

1-11/(1-12 Blank)
 TM 55-1520-244-BD

CHAPTER 2

ASSESSING BATTLEFIELD DAMAGE

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

2-1. SCOPE. (3) If you find a problem, determine its effect

on helicopter’s mobility, and capability.
a. This chapter provides guidelines for use in
assessing battlefield damage to the AH-1 E/F/P attack (4) If you cannot fix the problem with standard
helicopter. It directs you to an expedient BDAR fix or fixes, then apply this TM and use general and specific
to the standard system fix toTM 55-1520-236-23 if an assessment tables, charts, and BDAR action.
expedient BDAR repair does not exist. General
decision logic chart, Table 2-1, assists in BDAR dis- (5) If the damage does not affect aircraft’s
cussions. flying status, the aircraft or flight commander will
decide whether to fix or defer fix, and whether to con-
b. Each chapter will have a specific fault assess- tinue or to start a mission.
ment table for each functional group and this flow
chart will direct you to specific BDAR fixes for and (6) If damage does affect flight status, do one
within the functional group. of the following:

c. Use the following guidelines to find and fix sus- (a) Replace damaged part with a service-
tained damage or suspected damage to your helicop- able part.
ter. Keep in mind that damage can be sustained while
on the ground or in flight. The helicopter location can
(b) Replace damaged part with suitable sub-
have a considerable effect on the assessment. The
stitute if it exists.
following appraisal shall be accomplished,

(c) Apply a BDAR fix.

(1) If possible and if time permits, inspect, and
check the helicopter using operator’s checklist (CL),
operator’s manual (–1 O), and other records and forms (7) After repairing the damage, replace all lost
kept in aircraft log book. At the same time be looking fluids/lubricants. If one specified by aircraft TM is not
for obvious damage to aircraft. available, refer to Appendix D for alternative
materials/parts.
(2) If applicable and possible, use standard
troubleshooting recommendations in –23 series TMs.

2-1
TM 55-1520-244-BD

Figure 2-1. General Decision Logic

2-2
 TM 55-1520-244-BD

Section II. GENERAL FAULT ASSESSMENT TABLE

2-2. GENERAL FAULT ASSESSMENT. The BDAR assessment procedure will refer
Aircraft assessment chart, Table 2-2, you to a guide fix in this manual, a
guides you through the aircraft’s standard TM 55-1520-236-23 repair if it
capability so that all the necessary is feasible, or a higher AVIM level of
capabilities are evaluated. If a fault repair if extent of damage, time con-
is found, Table 2-2 (assessment table) straint, tooling requirements, repair
directs you to the chapter for the func- part or material, and any other necessary
tional group which contains the fault. requirements are only available at a
higher level of maintenance.

Figure 2-2. Assessment Table

2-3
TM 55-1520-244-BD

Figure 2-2. Assessment Table (Cont)

2-4
 TM 55-1520-244-BD

Figure 2-2. Assessment Table (Cent)

2-5
TM 55-1520-244-BD

Figure 2-2. Assessment Table (Cent)

2-6
 TM 55-1520-244-BD

Figure 2-2. Assessment Table (Cont)

2-7
TM 55-1520-244-BD

Figure 2-2. Assessment Table (Cont)

2-8
 TM 55-1520-244-BD

CHPT 13

CHPT 15

CHPT 16

Figure 2-2.
2-9
 TM 55-1520-244-BD

CHAPTER 3

GENERAL REPAIRS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

No general repairs have been identified Chapters 4 thru 17 for functional group
for this model helicopter. Proceed to assessment and repair procedures.

3-1/(3-2 Blank)
 TM 55-1520-244-BD

CHAPTER 4

AIRFRAME

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

4-1. SCOPE. should be made. A detailed assessment involves the

identification of all damage to primary structural ele-
a. This chapter contains methods for assessing ments, possibly some cleanup and measurement of
battlefield damage to the primary structure of the - the damage and of the damaged elements. This
AH-1 airframe, classification of damage, rules for process requires damage measurement and deter-
deferring repair, and expedient field fixes of battlefield mination of the corresponding damage limits. An over-
damaged airframe structures. all view of all the aircraft zones used in damage
assessment is shown in Figure 4-1.
b. Aircraft structure is classified as primary and
secondary structure. NOTE

(1) The primary structure is the basic structure The standards contained herein allow
which holds the aircraft together. Any serious damage aircraft to be flown with battle damage sub-
to any element of the primary structure will restrict the stantially in excess of peacetime limits.
combat capability of the aircraft. The primary struc- Under no circumstances shall this manual
tures for each major airframe subassembly are be used wholly or in part for peacetime
defined throughout this chapter. maintenance of the aircraft. Assessment of
aircraft battle damage requires extreme
(2) Secondary structures are mounted on the care and diligence and strict adherence to
primary structure. No amount of structural damage to the instructions and standards contained in
secondary structures will restrict combat capability this manual. If at any stage of damage as-
from a structural safety point of view; however, secon- sessment the assessor believes that over-
dary structure may be required for aerodynamic sights or errors have been made, the
reasons or to accomplish or support mission functions. assessment shall be stopped at that point
and repeated from the beginning. Under
no circumstances shall the requirements of
4-2. ASSESSMENT PROCEDURES. The battle- this manual be waived or circumvented
field structural damage assessment consists of two without the express approval of the com-
steps: an initial assessment, and a detailed assess- mander or his designated representative.
ment. The initial assessment is a quick visual assess-
ment to decide whether or not a detailed assessment

4-1
TM 55-1520-244-BD

Figure 4-1. Aircraft Zones

4-2
 TM 55-1520-244-BD

(3) An adequate assessment can be made and

the damage can be repaired by BDAR techniques to
enable the aircraft to self-recover;
● Battle damaged areas should be inspected
for unexploded ordnance before attempt-
(4) A detailed assessment cannot be made or
ing repairs. Disposal of unexploded
the damage cannot be repaired by BDAR techniques
ordnance should be accomplished by
within the available time; or
qualified EOD personnel.

● Loaded weapons, or weapons being (5) The aircraft is damaged beyond repair, and
loaded or unloaded, shall be pointed in a its disposition shall be arranged (e.g., recovery, canni-
direction which offers the least exposure to balization, or destruction).
personnel or property in the event of ac-
cidental firing. Personnel shall remain b. Detailed Assessment.
clear of hazardous area of all loaded
weapons. (1) Access to damaged structure. Locate all
damage to airframe primary structure. Remove
● Ground safety pins must be installed in access panels, covers, and fairings in the damaged
pilot and gunner arming/firing handles of area. Remove aircraft components as required to in-
canopy removal system whenever the spect the structure. Use the location of entrance and
helicopter is on the ground. Pins should be exit wounds and the estimates of projectile paths to
installed by crew. determine the areas where damage may be present
and access to interior inspection will be needed. If an
a. Initial Assessment. Refer to Table 4-1. To per- area of structure suspected of being damaged cannot
form an initial assessment, the assessor must be ac- be reached by other means, cut small inspection
quainted with structural damage modes and the holes in the exterior skin. Then inspect internal mem-
primary structure. He shall be capable of differentiat- bers with an inspection light and mirror.
ing between primary and secondary structure, and he
must understand the function of primary structural ele- NOTE
ments. The initial assessment consists of a visual in-
spection of primary structure. The assessor Inspection holes cut in the exterior skin if
determines if any primary caps, webs, or panels are left unrepaired will have to be treated as
damaged or fractured and decides whether– damaged structure in the damage evalua-
tion. Allow for access to the areas immedi-
(1) The damage appears to be deferrable; ately next to the area where damage is
known to have occurred. This will ensure
(2) A detailed assessment can be made and that damage caused by stray particles and
the damage can be repaired by BDAR techniques dislodged sections of material can be
within the time available to return the aircraft to ser- found. All significant damage to the
vice in the ongoing battle; airframe primary structure must be lo-
cated. Small damage can be critical to
some components.

4-3
 TM 55-1520-244-BD

Table 4-1.

4-4
 TM 55-1520-244-BD

(2) Inspecting for cracks. (3) Inspecting for structural

changes.
(a) Impact cracks. Cracks may
be caused by projectile impact or (a) Structural changes.
penetration. They may also be caused as Inspect for structural changes when the
a direct result of blast pressures. aircraft has taken an HEI hit or the
Battle damaged elements carrying reduced aircraft has flown with primary struc-
loads will place more severe loads on ture damaged or missing. Inspect both
surviving members and may also produce the damaged structure and the surrounding
cracks. When cracks are a result of undamaged area for evidence of buckling,
these last two factors, they may occur crippling, and misalignment. This type
in regions away from the site of the of damage is usually revealed by kinks
primary damage. or wrinkling and “oil canning” of skin
panels. Sheared, pulled-through, and
(b) Projectile damage site missing fasteners are also indications
cracks. Cracks will primarily be found of structural changes.
at the site of the projectile damage.
Holes, spans, and gouges caused by (b) Buckling, crippling, and
ricochets and embedded particles will misalignment. Structural changes in the
often have cracks associated with them. form of buckling, crippling, and misa-
These may be large and visible or lignment can happen as a result of blast
hairline and microscopic. Small cracks pressures. These could be associated
may be as critical as large cracks with a HEI attack or as a result of the
because they may grow rapidly under overstress placed on a member. Such
continued loading, particularly when members may have to carry the load of
located at the edge of a hole. another member which has been broken or
crippled by projectile damage. This
(c) Airframe structure cracks. type of damage can be critical to the
Locate all cracks in airframe primary structural performance of a member and
structure. At each damage site, inspect may also cause interference with mecha-
the area for cracks. Use inspection nical moving components which may bind
aids such as magnifying glasses or dye or jam. This is especially true when
penetrant to locate small cracks. the member has to support compression
Cracks may not go all the way through loads. A stringer that has been damaged
the material, so it is necessary to can continue to support some tension;
inspect both sides. When a structure for example, but may be completely inef-
shows signs of overstress, it is vital fective in compression.
to inspect for cracks around fasteners.
(c) Twisting or bowing.
(d) High explosive incendiary Examine the component for alignment and
(HEI) explosion cracks. For aircraft signs of twisting or bowing. Use a
damaged by an HEI strike, inspect all of straight edge to inspect these con-
the structure in the area of the explo- ditions.
sion. Aircraft may have been flown with
major structural battle damage or failure. (4) Inspecting for embedded
It is vital to inspect for cracks in all projectiles and fragments.
areas to which additional load may have
been distributed.

4-5
TM 55-1520-244-BD

(a) Embedded projectile. The (c) Initial fire damage evi-

effect of an embedded projectile or dence. The first signs of possible fire
fragment in a tension member can be as damage will be a discoloration of the
severe as that of a hole or crack of the structure. Any discoloration indicates
same size. The embedded object creates that the member has been exposed to high
an interruption in the structural sec- temperature. Conduct a hardness test to
tion. Since it is difficult to detect, determine if the temper of the material
it must be assumed that the projectile has changed. Such tests should be con-
has nearly gone through the structure. ducted in accordance with standard prac-
tices. If a hardness test shows
(b) Embedded projectile inspec- heat damage, record the information on
tion. Inspect for embedded projectiles DA Form 2408 and clearly mark the
and fragments when either of the follow- member.
ing conditions occur:
(6) Detecting substructural damage
1 The aircraft has suffered in adjoining areas.
HEI damage.
(a) Secondary damage. When the
2 Inspection of the aircraft airframe has been subjected to severe
indicates that a solid projectile has overstress, members undamaged by projec-
not exited the aircraft, has broken tiles may bend or buckle. This might be
apart, or has created shrapnel by caused by explosive blast or maneuvering
striking internal components. loads imposed on damaged structures.
Sometimes this secondary damage will
(C) Projectile path deter- occur in a region away from the primary
mination. The determination of projec- area of damage. The airframe near the
tile paths will aid in identifying projectile damage should be inspected
internal structures that may contain for evidence of secondary damage.
embedded projectiles or fragments.
Inspect all structures in the region (b) Secondary damage indicators.
using a bright light and magnifying Inspect the skin for creases, wrinkles,
glass. Clearly mark embedded objects and dents. Inspect fasteners for
and record them on DA Form 2404, Figure chipped or flaked paint, looseness, and
4-2. serviceability. These conditions are
signs of damage to structure. Open or
(5) Inspecting for fire damage. remove access panels and doors, deter-
mine whether the frame is warped, and
(a) Armor piercing incendiary inspect the interior members for cracks
(API) and HEI fire damage. The API and and structural changes. Clearly mark
HEI threats include the possibility of and record all damage.
fire damage. These threats have a fire-
starting capability if flammable (7) Inspecting for broken and
materials are present. missing fasteners.

(b) Fire effects. Some fires (a) Fastener damage or loss.

may not adversely effect metal airframe Some fasteners join parts together in an
structures. When aluminum is exposed to assembly, and some join one structural
temperatures above 300°F (149°C) for a member to another. Sheared, pulled-
prolonged period, the temper and through, torn-out, elongated fastener
strength of the material will be holes, and the damage or loss of fas-
reduced. teners can severely weaken the soundness
of a structure.

4-6
 TM 55-1520-244-BD

Figure 4-2. DA Form 2404

4-7
TM 55-1520-244-BD

(b) Riveted and bolted joints. CAUTION

Inspect all riveted and bolted joints
near the battle damage. Look for Use of lead pencil in some areas
sheared, pulled-through, torn-out will cause corrosion.
fasteners, and elongated fastener holes.
Carefully inspect members showing signs 1 Use a bright color to
of structural change and for fasteners outline each area of damage as it is
with chipped or cracked paint. Where located and recorded on the DA Form
possible, inspect fasteners from both 2404. Attempt to make the outline
sides. Clearly mark and record all visible from all angles.
damaged fasteners on DA Form 2404.
2 Draw arrows on inside skin
(8) Inspecting for delamination. panels, webs, and bulkheads to point
To verify suspected damage to honeycomb toward areas of damage that are hidden.
structures, use coin tapping method to
determine size and shape of c. Damage Measurement. If the assess-
disbonds/delaminations. ment indicates that the damage should be
repaired by BDAR or standard procedures,
NOTE no damage measurement is
necessary. Damage measurement is
Resonation of coin tapping on the required to determine if structural
structure will determine hollow- repair (other than cleanup) can be
ness or existence of delamination. deferred, or if self-recovery of the
damaged aircraft is feasible. Damage
(9) Marking and recording damage. measurement may also be required if a
BDAR repair does not restore original
(a) Damage recording. Accurate strength. Begin damage measurement with
recording of damage is an important part the largest damage.
of battle damage assessment. Record all
detected damage on DA Form 2404. Deter- (1) Caps and longerons.
mine allowable damage limits. Establish
an order of repair on DA Form 2404. (a) The parameters involved in
Record individual areas of damage to a measuring damage to a cap or longeron
single structural element separately on are shown in Figure 4-3. The pertinent
the form. If a structural member is values are as follows:
massively damaged or severed, recording
individual areas of damage is CD = Depth of damage.
unnecessary. CL = Length (width) of damage.
A = CL x CD = area of damage.
(b) Damage diagrams. Show the D = Distance between damages.
location and extent of damage on copies
of the diagrams given in this chapter. In Figure 4-4, the length of the flat-
The damage can be drawn by hand. tened cross section shown is a+b.
Accurately locating damage on a diagram
will greatly help the damage assessment If CD is the depth of the damage into
procedure. the flattened cross section, then CS Is
the length of the remaining effective
(c) Marking damage. Mark the cross section still capable of support-
damaged structure using grease pencil or ing load, and CS= (a+b)-CD. Always
paint. Use the labeling scheme given in measure CD.
Figure 1-3.

4-8
 TM 55-1520-244-BD

Figure4-3. Measuring Cap or Longeron Damage

Figure 4-4. Damaged Cross Section

4-9
TM 55-1520-244-BD

(b) Damage measurements apply across the damage, regardless of direc-

after cleanup and smoothing or after tion and must include all radiated
BDAR has been accomplished; however, as cracks. “D” is the distance between
a practical matter, measurements must damages. Take and record measurements
often be taken before smoothing to make as described in paragraph 4-2.c(1) (b).
a decision on deferrability. Hence,
when estimating damage limits before (b) Honeycomb sandwich struc-
cleanup and smoothing, make allowance tures. Refer to Figure 4-7 for the
for the material that will be removed in measurement of “WL” and “D.” If a pro-
smoothing. This applies particularly to jectile hits a sandwich panel at an
cracks; the length of the crack must be angle, the damages in the two skins may
included in the depth (CD) and length be off-set and of different sizes.
(CL) measurements. When measuring Measure the damage on the side with the
damage, use the following procedures if largest damage (usually the exit side),
possible: and make sure that the measurement
includes the damaged area on the other
1 Clean all damaged areas side. “WL” is the largest dimension
thoroughly. Use brushes and rags to across the damage (both sides),
remove dirt and film from small crevices regardless of direction, and must
where damage may be present. include all radiated cracks. “D” is the
distance between damages. Take and
2 Smooth all jagged and record the measurements as previously
rough edges and be sure to cut out all described.
radiated cracks. Use largest corner
radii possible in the cut-outs; avoid d. General Damage Limits.
sharp corners.
(1) The allowable damage limits
3 Measure damage after corresponding to the damage measurements
smoothing or if measuring before of paragraph 4-2.c are designated for a
smoothing, make allowance for the given condition as follows:
material which must be removed during
smoothing. CD' = Allowable depth of
cap/longeron damage.
4 Use a steel rule graduated
in tenths of an inch and measure each DL' = Allowable length (width) of
damage dimension to the next higher cap/longeron damage.
tenth.
A' = Allowable area of damage.
5 Include the size of the
hole when measuring damage that extends D' = Minimum allowable distance
into a fastener hole or lightening hole. between damages.

6 Record on DA Form 2404. WL' = Allowable largest dimension

across web/panel damage.
(2) Webs, panels, floors, and
decks. N = Minimum Damage Factor.

(a) Refer to Figures 4-5 and

4-6 for the measurements of "WL" and
"D." "WL" is the largest dimension

4-10
 TM 55-1520-244-BD

Figure 4-5. Measuring Skin Panel Damage

Figure 4-6. Measuring Damage in Floors and Decks

4-11
TM 55-1520-244-BD

Figure 4-7. Measuring Damage in Honeycomb Panels

(2) Allowable damage limits are damages. Therefore, aircraft with struc-
associated with the conditions of tural damage whether repaired or repair
the primary structural elements as deferred should be inspected after every
described below. A damage limit for a flight. The inspector should look for
given condition is a measure of the crack growth, evidence of overstress,
amount of damage that a structural growth of allowable deformation, or the
member can sustain and still support development of new cracks at other loca-
the loads associated with the given tions.
condition. These limits were developed
from the aircraft manufacturer’s origi- (b) Condition 2. Self-recovery
nal engineering design calculations. capable. Self-recovery may be required
to move a damaged aircraft to a repair
(3) Condition is an indicator of site or from one site to another, when
the residual capacity of a damaged struc- towing is not feasible. Self-recovery
tural element to perform its function. is preferable to disassembly and boxing
Battlefield damaged structures or BDAR an aircraft for transportation. As time
repair ed structures are classified in permits, proceed as follows:
three conditions:
1 Mark all visible cracks
(a) Condition 1. Aircraft and the extent of other structural
fully flight capable. No flight damage with chalk, grease pencil, paint,
restri ctions; however, on a battlefield tape, or other available means so that
under the pressures of time and tactical any growth in the damage can be quickly
situations’, the assessment of structural recognized.
damage may not have revealed all the

4-12
 TM 55-1520-244-BD

2 Perform any feasible on- petaling. Petals may vibrate in the

site BDAR fixes as required for self- passing airflow, rapidly creating cracks
recovery. in the supporting base metal. Large
pieces of metal may peel off and damage
(c) Condition 3. Structural other parts of the aircraft. The
damage not repairable by BDAR tech- distance D between damage sites for
niques, not self-recovery capable. The most structures has a minimum required
airframe is so extensively damaged that spacing. The spacing requirement is
no useful or needed functions can be expressed as a multiple factor (N) of
restored within the available time and the measured area of damage.
resources. These aircraft will be:
(a) The factor applies to the
1 recovered or evacuated to damage actually measured not to the
a facility with the resources to repair maximum damage limit for the structure.
the airframe,
(b) The factor applies to the
2 used as a source of can- largest dimension of the largest damage
nibalized components, or between which separation is being
measured.
3 destroyed. This is a last
resort. (c) The factor applies only if
the dimensions of both damages, when
(d) These conditions apply to added together, exceed the single damage
the primary structure and should not be limit.
confused with the mission capability
classifications. Mission capability is (5) Continuous members. Allowable
dependent on equipment condition. damage limits for caps, longerons, webs,
floors, decks, and stiffness are given
(4) In a given condition if all throughout this section as appropriate.
damages are equal to or less than the
corresponding allowable damage limits (6) Damaged fittings, attachments,
and the distance between damages are and splices are classified as unservice-
equal to or greater than the correspond- able and must be repaired, reinforced,
ing minimal allowable limit, that is, or replaced if any of the following
conditions exist:
CD < CD'
CL < CL' (a) Damage to the fitting has
WL < WL' removed more than 20 percent of the
D > D ' structural cross section at any one
location.
the aircraft may be released for flight
in that condition. Repair may be (b) One or more fasteners
deferred although some clean-up and connecting the fitting to a continuous
smoothing of the damage will be required aircraft component are bent, sheared,
as will inspection for damage growth stripped, or loose.
after every flight. Special con-
sideration should be given to damage (c) The fitting shows signs of
exposed to the airstream, particularly overstress or structural distortion.
to the effects of ram air, rain, and

4-13
TM 55-1520-244-BD

(7) Damage limits are calculated (b) Refer to Figures 4-9 to

on the basis of the AH-1S structural 4-13 for definition and identification
analysis and tend to be conservative. of primary fuselage structural elements.
Assessors using damage limits to prepare
damage assessments should consider them (c) Mark all detected damage on
as guides and balance the damage limits the appropriate figure, and add remarks
against the judgment resulting from to clarify markings as described in
their own experience. paragraph 4-2.b(9).

e. Fuselage Damage Assessment. (d) Refer to paragraph 4-2. c

and for each damaged element, measure
(1) General. the depth "CD" and the length (width)
"CL" or "WL" of each damage. Count the
(a) The fuselage midsection number of damages and measure the "D"
primary basic structure consists of a between damages. Start with the worst
box beam starting at FS 148.5 and damage. Record the values on DA Form
extending to FS 300.68, Figure 4-8. 2404 and compare therewith the allowable
Forward of the box beam (FS 148.5), two damage limits given in this section.
fuselage beams and cockpit floors extend Select the set of allowable damage
forward to FS 61.25 to support the cock- limits which are next larger than the
pit and gun turret. The tail boom measured damage, determine the
attaches to the fuselage at FS 300.68 corresponding condition. Consider
and extends to the fin which supports whether damage could result in flight
the tail rotor and the stinger (tail failure of other elements. Attempt to
bumper). visualize what effect large defections
of damaged member will have on adjacent
(b) The fuselage box beam con- structure.
sists of 4 caps (Figures 4-9 and 4-11)
connected vertically by the webs of the (e) Decide on whether repair
fuselage beams (Figures 4-10 and 4-12) can be deferred or whether damage should
and connected horizontally by the upper be fixed and what the condition of
and lower panels (Figure 4-13). Bulk- deferred or repaired damage would be.
head flanges act as spacers between
the caps, both vertically and horizon- (f) Determine the priority of
tally, and should be treated as caps in the various required repairs based on
a damage assessment. The bulkheads also repair time, difficulty of repair,
hold the shape of the aircraft and resources available, tactical situation,
distribute concentrated loads into the and need for the aircraft, etc. The
vertical panels and/or horizontal longest repair time normally is given
panels. The concentrated loads include the highest priority and is most
the loads from the landing gear, pylon, critical.
wing attachments, elevator, tail rotor,
fin, and tail bumper. (g) Enter repair requirements
on DA Forms 2404.
(2) Damage measurement.
(3) Allowable fueslage damage
(a) Reproduce Figures 4-14 to
4-17 as required, and use to mark up
damaged areas.

4-14
 TM 55-1520-244-BD

Figure 4-8. Airframe Reference Lines

4-15
TM 55-1520-244-BD

Figure 4-9. Primary Structural Caps L/H

Figure 4-10. Structural Webs L/H

4-16
 TM 55-1520-244-BD

Figure 4-11. Primary Structural Caps R/H

Figure 4-12. Structural Webs R/H

4-17
TM 55-1520-244-BD

Figure 4-13. Fuselage Box Beam Panels

4-18
 TM 55-1520-244-BD

Figure 4-14. L/H Fuselage Beam

4-19
TM 55-1520-244-BD

Figure 4-15. R/H Fuselage Beam

4-20
 TM 55-1520-244-BD
Figure 4-16. Upper Panels
4-21
TM 55-1520-244-BD
Figure 4-17. Lower Panels
4-22
 TM 55-1520-244-BD

(a) Fuselage caps. Mark damage condition 1. Criteri a for conditions 2

to fuselage caps on Figures 4-14 and and 3 for cap damage also applies to
4-15. damage limits for bul khead flanges.

1 Condition 1. The damage (c) Webs, panels, decks,

limits for cap damage for condition 1 floors. Refer to Figure 4-14 thru 4-17.
are shown in Table 4-2. The damage
limits are given in terms of CL , CD’, 1 Condition 1.
and D .
a Web 1 (1, Figure 4-14
2 Condition 2. and 9, Figure 4-12) between FS 61.25 and
FS 138.70.
a If a damaged aircraft
has been flown back from a mission, it Largest allowable damage -
can be assumed that a degree of struc- WL' = 2 inches.
tural integrity remains.
Closest allowable damage
b For the self-recovery spacing - D' = 4 inches.
flight of paragraph 4-2.d(3) (b), damage
may exceed the maximum allowable of Allowable number of damages per
Table 4-2 except that: panel - 2.

[1] No cap may be Other: see d below.

completely ruptured; local CS may be
3/8 to 1/2 inch and attached to either b Web (1, Figure 4-10 and
a web or a floor. (9, Figure 4-12) between FS 138.70 and
FS 148.5.
[2] If a cap has rup-
tured or appears near rupture, apply a Largest allowable damage -
quick external patch before self- WL' = 2 inches.
recovery.
Allowable number of damages - 1.
[3] If a cap is badly
damaged in a number of locations close Other: see d below.
together, apply a long external stringer
over the damaged area, and secure to c For item numbers: 2, 4,
undamaged structure at the ends and at 6, 7, Figure 4-14.
each opportunity in between.
Largest allowable damage -
3 Condition 3. If any cap WL ‘ = 2 inches.
is completely ruptured and available
resources to apply an external patch are Closest allowable damage
not available, the aircraft should not spacing - D’ = 4 inches.
be flown.
Allowable number of damages per
(b) Bulkhead flanges. Bulkhead panel - 4.
flanges act as vertical and horizontal
spacers between the caps. CL’, CD’, and Other: see d below.
D’ damage limits on the bulkhead flanges
are the same as the cap damage limits qdApplicable to a, b, and
in that fuselage station. The limit c above:
values are found in Table 4-2 for

4-23
 TM 55-1520-244-BD

(1) All dimensions in inches. See Figure 4-3.

(2) Always measure CD. CS' is an approximate value and is listed here only as a
reference dimension.
(3) The D' limit may be waived if the CL' values of both adjacent damages combined
do no exceed the CL' value for that member.
(4) All damage 10 inches fore and aft of station 186.25 must be repaired per
TM 55-1500-204-25/1, Chapter 4.
(5) CS' varies-cap is tapered and changes in cross section.
(6) Damage limit values for caps, CL', CD', and D', also apply to damage limits
for bulkhead flanges in that fuselage station for a given condition.

4-24
 TM 55-1520-244-BD

[1] Three cap/bulkhead On non-adjacent panels as much as 25

to web/panel attachments may be damaged. percent of the area may be missing
(blast damage). Within reason, visible
[2] No visible defor- buckling and deformation (blast damage)
mation or buckling. are allowable, provided that they do not
occur at the same place as major frag-
[3] Any damage 10 mentation damage and aggravate flight
inches fore and aft of station 186.25 loads on the damaged members. Heavily
must be repaired. damaged capstrips (say CS=O.375 to
0.5 inch) must be relatively straight in
2 Condition 2. the area of maximum-damage and the
remaining cross-sectional area must be
a Web (1, Figure 4-10 attached to a side panel or web.
and 9, Figure 4-12) between FS 61.25 and
FS 138.70. 3 Condition 3. Damage ex-
ceeds the damage limits of condition 2.
Largest allowable damage -
WL' = 4 inches. (d) Pylon support.

Closest allowable damage - 1 General.

spacing D' = 3 inches.
a The pylon support
Allowable number of damages per extends from FS 186.25 to FS 213.94, and
panel - 2. is located directly above the deck at
about WL 65, Figure 4-18. It provides
b Web (1, Figure 4-10 and five flexible mounts for the transmission
9, Figure 4-12) between FS 138.70 and FS one at each corner and one approximately
148.5. at FS 213 at aircraft center line and
under the transmission/engine attachment
Largest allowable damage - point.
WL' = 4 inches.
b The wing carry-through
Allowable number of damage - 1. structure for the center wing spar is
located directly under the pylon sup-
c For item numbers: 2, port, approximately one third the length
4, 7, Figure 4-14. The maximum limit of the bay behind FS 186.25. The
for any adjacent webs or panels are as transmission is attached by link (1) to
follows: the top of the wing carry-through.

Largest allowable damage - c Link (1) provides a

WL' = 4 inches. direct load path from the rotor shaft to
the wing carry-through which distributes
Closest allowable damage - the rotor thrust to the aircraft side
spacing D’ = 3 inches. skin. The pylon support with its five
flexible mounts provides stability to
Allowable number of damages per the transmission and pylon installation,
panel 10. and distributes loads other than the
direct tension in link (1) to adjacent
bulkhead and skin panels. Such loads
are primarily due to the inertia of the
transmission and pylon during violent
maneuvers.

4-25
 TM 55-1520-244-BD

Figure 4-18. Pylon Support

4-26
 TM 55-1520-244-BD

d The pylon support con- No damage to transmission mounts.

sists primarily of built-up sheet metal Geometry of mounts is not compromised by
members. It consists of an open frame warpage or deformation of frame, posts,
(6), (5), (3) at about WL 77, held in or other structure.
place by four posts (9), (7), (4), and
(10), one at each corner. Bulkhead Machined members:
186.25 forms the front edge of the frame
but is not shown on Figure 4-18. CD' = 0.5 inch
WL' = 1.0 inch
2 Damage measurement. D' = 8.0 inches

a Reproduce Figure 4-18 No damage within 3 inches of an attach-

as required for markup. ment boss. No warpage or permanent
deformation.
b Mark all detected
damage on Figure 4-18, add remarks to Link (1, Figure 4-18):
clarify markings as described in
paragraph 4-2.(b)(9). This paragraph No visible damage except for nicks and
contains instructions for marking dama- scratches, in which case inspect after
ges on the aircraft itself. every flight for development of cracks.

c Refer to paragraph b Condition 2. Built-up

4-2.c and, for each damaged member, sheet metal members (frame, posts):
measure the depth "CD" and the maximum
length (width) "WL" of each damage. CD' = 1.5 inches
Count the number of damages and measure WL' = 75 percent of the width of
the distance “D” between damages. any one element in a
Compare them with the damage limits member may be missing.
given in paragraph 4-2.e. Select the See Figure 4-19 for de-
set of allowable damage limits which are finition of an element.
next larger than the measured damage and
determine the corresponding condition. Two transmission mounts may be damaged
and in effective.
d Consider whether
damage could result in flight failure of Machi ned members:
other members. Attempt to visualize
what effect large deflections of damaged CD' = 1.5 inches
members will have on adjacent structure. WL' = 3.0 inches
D' = 6.0 inches
e Decide on whether
repair can be deferred or whether damage Warpage from blast damage may not inter-
should be fixed and what the condition fere with functioning of other essential
of the deferred or repaired damage would systems such as causing binding in the
be. flight control system.

3 Allowable damage limits. Link (1, Figure 4-18):

a Condition 1. Built-up CD' = 0.25 inches

metal members (frame, posts):
c Condition 3. The allow-
CD' = 0.5 inch able damage of condition 2 is exceeded.
WL' = 1.0 inch
D' = 8.0 inches

4-27
TM 55-1520-244-BD

Figure 4-19. Post Member Consisting of Three Elements

f. Tail Boom Damage Assessment. (c) The tail boom is a semi-

monocoque shell consisting of four
(1) General. longerons acting as caps, covered by
a skin stiffened with stringers and
(a) The tail boom is attached bulkheads or frames. The bulkheads
to the fuselage midsection at FS 300.68, or frames act as spacers between the
Figure 4-8. The tail boom and the fin longerons and hold the shape of the
each have their own sets of reference shell. There are five structural
lines. At FS 300.68 the corresponding bulkheads. The two at BS 41.32 and
Boom Station (BS) is 41.32. 59.50 distribute the fuselage-tail
boom attachment loads into the shell.
(b) The tail boom supports the The one at BS 143.28 distributes the
elevator, fin, tail rotor, and tail boom elevator loads. The two at BS 206.00
stinger. The tail rotor and fin apply and 227.00 support the fin and tail
lateral loads to the tail boom at a boom bumper. The fin is a honeycomb
point in space some 60 inches above the core airfoil section.
centroid of the tail boom. This results
not only in a lateral bending moment on (d) The damage assessment
the tail boom and fuselage but also in a procedure described in paragraph 4-2
twisting action or torsion. The tail consists of damage measurement and
rotor driveshaft runs along the top of determination of the corresponding
the tail boom and the leading edge of allowable damage limits and associated
the fin. condition. A repair plan is recorded
on DA Form 2404.

4-28
 TM 55-1520-244-BD

(2) Damage measurement. (g) The areas around the tail

boom/fin attachment and around the tail
(a) Reproduce Figure 4-20 and rotor attachment are particularly sen-
Figure 4-21 as required. The figures sitive since the tail rotor gearboxes
identify primary boom structural members are mounted in these areas. If the
by bubble number. structure supporting the gearboxes is
damaged and deformed such that gearbox
(b) Mark all detected damages alignment is disturbed. the driveshafts
on the appropriate figure, add remarks will probably bind. -
to clarify markings as described in
paragraph 4-2.b(9). (3) Damage limits.

(c) Refer to paragraph 4-2.c (a) Because ground fire aiming

and for each damaged element, measure sometimes does not fully account for
the depth “CD” and length (width) “CL” aircraft speed, the rear of the aircraft
or “WL” of each damage. Count the is more susceptible to combat damage
number of damages, N, and measure the than the front.
distance “D” between damages. Record
these values for each damaged element (b) Tail boom caps, bulkhead
on DA Form 2404 and compare them with flanges (between caps), fin spar caps,
the allowable damage limits given in and fin trailing edge.
paragraph 4-2.f(3). Select the set of
allowable damage limits which are next 1 Mark damage to continuous
larger than the measured damage and structural elements on Figures 4-20 and
determine the corresponding condition. 4-21. The main continuous structural
members are identified by bubble
(d) Consider whether the damage numbers.
could result in flight failure of other
elements. Attempt to visualize what 2 Condition 1.
effect large deflections of damaged mem-
bers will have on adjacent structure. a The damage limits for
condition 1 for the tail boom longerons,
(e) Decide on whether repair BS 41.37 to 194.30, are shown in Table
can be deferred or whether damage should 4-3. The damage limits are given in
be fixed and what the condition of the terms of CL', CD', and D'.
deferred or repaired damage would be.
b If there is struc-
(f) The fin is attached to the tural damage to the tail boom between
tail boom in Bays 13 and 14 of Figure BS 194.30 and 227.00 or to the fin but
4-20. Damage in these bays to the tail the fin does not visibly deflect under
boom or fin may result in structural full rotor power and operation is nor-
deformation or structural deflections mal, repair may be deferred and the
under flight conditions that may prevent aircraft released to fly in condition
operation of the driveshaft to the tail 1. Some cleanup and covering of ope-
rotor. Availability of tail rotor nings may be required for aerodynamic
control will determine if the aircraft purposes or to keep water out.
frame is in condition 1, 2, or 3.

4-29
TM 55-1520-244-BD
Figure 4-20. Tail Boom
4-30
 TM 55-1520-244-BD
Figure 4-21. Fin
4-31
TM 55-1520-244-BD

Table 4-3.

paragraph 4-2.f(3) (b)

paragraph 4-2.f(3) (b)

(1) All dimensions in inches. See Figure 4-3.

(2) The D limit may be waived if the CL’ values of both adjacent damages combined
do not exceed the CL’ value for that member.
(3) Always measure CO. CS’ is an appromixate value and is listed here only as a
reference dimension. CS’ (inches) is given in terms of “length of flattened
cross section” as defined in Figure 4-4, and must include at least one
flange and attached 3/4 inches of effective inner and outer skin.

4-32
 TM 55-1520-244-BD

3 Condition 2. percent of the length of the flattened

cross section, CD, of bordering
a Considerable damage stringers of frames may be damaged pro-
to the longerons can be tolerated. If vided that 75 percent of the skin to
the lower right longeron is not stringer or frame fasteners along adja-
damaged, any one of the other longerons cent panels are intact. Stringer or
can be completely severed in one place. frame damage, CD, may not exceed 50
Otherwise, the minimum allowable CS’ percent of the length of the flattened
for any longeron is 1.5 inches. stringer or effective frame cross
section.
b With respect to the
fin structure and the tail boom/fin 3 Condition 2.
attachment area, BS 194.30 to 227.00,
the critical consideration is tail a Between BS 41.37 and
rotor operation. As long as the tail 59.50 and 194.30 and 227.00, one skin
rotor provides sufficient control for panel may be missing. Other allowable
condition 2 flight and the structural damages are the same as paragraph
fractures do not grow, the airframe may 4-2.f(2)(b).
be released for condition 2 flight.
b Between BS 59.50 and
(c) Stringers and Skin Panels. 194.30, two complete adjacent bays may
be missing provided the longerons are
1 Mark the damage to intact. Other damage to skin panels
stringers and skin panels on Figures may not exceed 25 percent of the area
4-20 and 4-21. A skin panel is bounded of the panel, and stringers may be
by a longeron and a stringer or two severed in connection with such damage.
stringers and two frames. A bay is
bounded by two longerons and two 4 Condition 3. The damage
frames. exceeds the allowable criteria listed
for condition 2.
2 Condition 1.
(d) Fin Panels. The fin
a BS 41.37 to 59.50 and panels consist of an honeycomb core
194.30 to 227.06. Damage to a skin sandwich and damage should be evaluated
panel, WL, may neither exceed 1.5 by the criteria given for the fuselage
inches nor one half the distance panels, paragraph 4-2.e(3)(b).
between frames (S, Figure 4-22) and
the distance, D, between damages in (e) Elevators. The elevators
adjoining panels must exceed 3 inches. are not required for flight. If one
See Figure 4-5 for measurement tech- elevator is badly damaged and cannot
niques. Stringer or frame damage, CD, function and quick repair is not feasible,
may not exceed 50 percent of the length remove both elevators. However, without
of the flattened stringer or effective elevators, the SCAS system will not work
frame cross section. For typical so it should be disengaged at the pilot’s
damage see Figure 4-23. or gunner’s cyclic stick. It may be
difficult to perform certain missions
b BS 59.50 to 194.30. without the SCAS.
Two individual non-adjacent panels in
different bays may be missing. Fifty

4-33
TM 55-1520-244-BD

Note:THE MEASURED LONGITUDINAL DAMAGE MAY BE AN ACCUMULATION OF SEVERAL DAMAGES.

Figure 4-22. Skin Panel Damage WL Versus Frame Spacing S

Figure 4-23. Typical Skin Panel and Frame Damage

4-34
 TM 55-1520-244-BD

g. Wing Damage Assessment (b) The wing has two functions. Its main
function is to support two pylon stations for mounting
stores. As a secondary function, it includes a jacking
point above the inboard pylon.

● Prior to any helicopter maintenance func- (c) The wing is designed primarily for stiff-
tions that require external stores be ness as required by the weapon delivery system. Criti-
removed, JETTISON cartridge shall be cal design conditions include recoil and flight fatigue
removed. Remove jettison cartridges from and jacking. The wing is not necessary for flight;
stores ejection device prior to placing hence, no criteria for damage assessment can be
helicopter in a hangar, to prevent injury to made from a flight worthiness viewpoint.
personnel and damage to equipment.
(d) The forged spars are so heavy that
● Loaded weapons, or weapons being small arms projectiles will probably do little damage.
loaded or unloaded, shall be pointed in a However, such a projectile could first hit the maze of
direction which offers the least exposure to stores hanging on the pylons and detonate before
personnel or property in the event of ac- reaching the wing or even inside the wing. In this
cidental firing. Personnel shall remain case, considerable damage could be done. Because
clear of hazardous area of all loaded accurate weapons delivery requires a stiff platform,
weapons. any substantial damage to the wing structure cannot
be deferred and the wing should be replaced.
● Ground safety pins must be installed in
pilot and gunner arming/firing handles of 4-3. REPAIR PROCEDURE INDEX.
canopy removal system whenever the
helicopter is on the ground. Pins should be
PARA.
installed by crew.
Former Damage . . . . . . . . . . . .4-5
Skin/Stiffener Damage . . . . . . . . .4-6
(1) General Information. Cap/Longeron, Damage . . . . . . . .4-7
Frame or Bulkhead, Damage . . . . .4-8
(a) The wing is an airfoil section with three Honeycomb Core Floor Panel,
spars as shown in Figure 4-24. The spars are Damage . . . . . . . . . . . . . . . 4-9
machined precision forgings of 7075-T3 aluminum Windshield/Window, Damage . . . . .4-10
alloy.

4-35
TM 55-1520-244-BD

Figure 4-24. AH-1S Left Wing - Skins Removed

Section II. AIRFRAME REPAIRS

4-4. GENERAL. Many of these repairs not be considered by itself. Suitable
will restore the airframe to condition 1 repair will often depend on the condi-
although inspection for damage growth tion of the adjacent structure. In some
will generally be required after every cases undamaged adjacent structure may
flight, and damage should be repaired as satisfactorily take the load of the
soon as feasible by standard maintenance damaged item. Since time is an over-
procedures. TM 55-1500-204-25/1 descri- riding consideration on the battlefield,
bes many structural repairs suitable for BDAR airframe repairs are usually per-
BDAR use. formed on the outside of the aircraft
to save the time required to gain access
a. Multiple Damage. Special atten- to the interior. If, however, access to
tion should be given to structural com- the interior damaged structure is
ponents which have sustained damage in already available, inside BDAR repairs
multiple locations. It is essential that may be made.
damage to an individual structural item

4-36
 TM 55-1520-244-BD

b. Fasteners. BDAR can be carried out using

any form of fastening device which is available at the
time (e.g., nuts, bolts, and rivets, etc.), as long as
strength requirements are met. Use accepted prac- •Sanding on reinforced laminated glass
tices regarding fastener edge distance and spacing. produces fine dust that may cause skin
The fasteners used in a single repair should be of the and lung irritations. Observe necessary
same type. protection measures.

c. Metal Selection. All repair patches should be •Lifting or moving heavy equipment incor-
manufactured from material of the same or similar rectly can cause serious injury. Do not try
specification as the damaged area but at least one to lift or move more than 50 pounds by
gage or 10 percent thicker. When required repair yourself. Get an assistant. Bend legs while
materials are unavailable, substitutions can often be lifting. Do not support heavy weight with
made to produce a desired strength. Table D-9, your back. Always use assistants during lift-
Appendix D, lists metals and cross references factors ing operations. Use guide ropes to move
for obtaining the equivalent strength using various hanging assemblies. Lack of attention or
other metals. Alternate repair materials can be ob- being in an improper position during lifting
tained from scrapped aircraft. It is also permissible to operations can result in serious injury. Pay
fabricate from thinner gage material and use multiple close attention to movements of as-
thickness. semblies being lifted. Do not stand under
lifted assembly or in a position where you
could be pinned against another object.
Watch your footing.

•Compressed air can blow dust into the NOTE

eyes. Wear eye protection. Do not exceed
30 psig air pressure. •Steel and aluminum are incompatible
materials and normally require special
•Sound pressure levels in this aircraft precautions to prevent electrolysis cor-
during some operating conditions exceed rosion. However, for BDAR, this is an ac-
the Surgeon General’s hearing conserva- ceptable materials mix.
tion criteria, as defined in TB MED 501.
Hearing protection devices such as aviator •Refinements to patch repairs such as
helmet or ear plugs are required to be countersunk fasteners, chamfered edges,
worn by all personnel in and around the anti-corrosive treatment and radius
aircraft during its operation. corners of the patches are unnecessary.

4-37
TM 55-1520-244-BD

4. Install fasteners.

5. Record BDAR action taken. When mission is

Battle damaged areas should be inspected
complete, as soon as practical, repair the equipment/-
for unexploded ordnance before attempt-
system using standard maintenance procedures.
ing repairs. Disposal of unexploded
ordnance should be accomplished by
qualified EOD personnel. OPTION 2: Fabricate Former with Small, Complex
Radius/Bends.
4-5. FORMER DAMAGE.
LIMITATIONS: None
GENERAL INFORMATION. One method to create
PERSONNEL/TIME REQUIRED:
a complex curve in a normally straight angle or
T-angle member is to place appropriate cuts and stop 2 Soliders
drill holes to allow bends as given in Figures 4-25 and 2 Hours
4-26. This field expedient procedure will allow former
repair from stray stock. MATERIALS/TOOLS REQUIRED:
T or 90° Angle Stock (items 35-48,
App. C)
OPTION 1: Fabricate Former with Large Radius.
Fasteners (items 8-24, 63-70, or
98-114, App. C)
LIMITATIONS: None Drill and Bit
Structures Repair Kit (item 12,
PERSONNEL/TIME REQUIRED: App. B)
2 Soldiers
2 Hours PROCEDURAL STEPS:

MATERIALS/TOOLS REQUIRED: 1. Measure damaged former with flexible tape or

T or 90° Angle Stock (items 35-48, rule.
App. C)
Stock (items 131-142,
2. Cut equivalent length of T or angle stock to suit.
App. C)
Fasteners (item 8-24, 63-70, or
98-114, App. C) 3. Drill and cut stock as shown in Figure 4-26.
Drill and Bit
Structures Repair Kit (item 12, 4. Bend fabricated former to fit aircraft damaged
App. B) area.

PROCEDURAL STEPS: 5. Hold fabricated former in place and drill mounting

holes.
1. Cut and hand form angle stock as shown in
Figure 4-25. 6. Install fasteners.

2. Cut Sheet stock as shown in Figure 4-25. 7. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
3. Hold sheet and angles in place on aircraft and system using standard maintenance procedures.
drill proper size fastener holes.

4-38
 TM 55-1520-244-BD

Figure 4-25. Typical Former Repair

4-39
TM 55-1520-244-BD

Figure 4-26. Cut and Drill Former Repair

4-40
 TM 55-1520-244-BD

4-6. SKIN-STIFFENER DAMAGE. sections, remove rivets which attach the damaged
stringer/stiffener to skin.
GENERAL INFORMATION: These repairs are ap-
plicable to any skin-stiffener structure such as the tail 5. Drill rivet holes on the substitute stringer/stiffener
boom, fairings, and many secondary structures other and the installed skin patch to match the existing rivet
than sandwich construction. holes of the damaged stringer/stiffener.

OPTION 1: Patch Plate and Substitute Stiffener/- 6. Rivet the substitute stringer/stiffener in place. Stif-
Stringer. fener can be placed on outside; however, this con-
figuration is nonpreferred.
LIMITATIONS: None – Condition 1. Inspect after
every flight for damage growth. 7. Rivet patch plate over hole using rivets.

PERSONNEL/TIME REQUIRED: 8. Record BDAR action taken. When mission is

Ž2 Soldiers complete, as soon as practical, repair the equipment/-
•2 Hours system using standard maintenance procedures.

MATERIAL/TOOLS REQUIRED: OPTION 2: Tape Repair.

Substitute Stiffener or Stringer
(items 35-48, App. C) LIMITATIONS: Repair may only be used on secon-
Skin Patch Metal (items 131-139, dary structure to keep moisture out. No damage to
App. C)
stringer/stiffener allowed.
Drill and Bit
Rivets (items 98-115, App. C)
Structures Repair Kit (item 12, PERSONNEL/TIME REQUIRED:
App. B) Ž 1 Soldier
Ž 10 Minutes
PROCEDURAL STEPS:
MATERIALS/TOOLS REQUIRED:
• Green Tape or Aluminum Tape
1. With sheet metal snips, cut hole in sheet includ- (item 150 or 153, App. C)
ing all cracks. Do not cut stringers but cut off ragged • Brush (item 25, App. C)
ends, Figure 4-27. Ž Sand Paper (items 117-121, App. C)

2. Make a patch plate. Plate should be as strong PROCEDURAL STEP:

or stronger than original skin. Overlap the hole at
least 1-1/2 inches on all sides, Figure 4-28. 1. Smooth off ragged edges on damaged skin.

3. Cut a piece of substitute stringer or stiffener to ex- 2. Tape over hole. Use several layers as neces-
tend at least 10 inches on each side of damaged sec- sary and overlap onto skin well beyond damaged
tion. Sometimes a single substitute stringer or area.
stiffener can be extended to provide support for
several damages. This is better than individual
repairs, as it will stiffen the airframe. 3 Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
4. In the areas where the substitute stringer/stiffener
will overlap on the damaged stringer/stiffener,

4-41
TM 55-1520-244-BD

Figure 4-27. Cutout in Damaged Skin

Figure 4-28. Stringer/Stiffener Repair

4-42
 TM 55-1520-244-BD

4-7. CAP/LONGERON, DAMAGE. 3. Cut a piece of substitute cap/longeron to extend

at least 10 inches each side of damaged section.
GENERAL INFORMATION: Non-deferrable Sometimes a single substitute cap/longeron can be
cap/longeron damage may be substantial, combined extended to provide support for several damages.
with skin damage. It will generally be necessary to This is better than individual repairs, as it will stiffen
repair the cap and longeron first and then the skin. It the airframe.
may not be necessary to repair the skin for structural
reasons, but generally skin repair is recommended to 4. In the areas where the substitute cap/longeron
make a watertight repair. will overlap on the damaged cap/Iongeron sections,
remove rivets which attach the damaged
LIMITATIONS: None – Condition 1. cap/longeron to skin.
Inspect after every flight for damage growth.
5. Rivet the substitute cap/longeron in place, using
PERSONNEL/TIME REQUIRED: the same size rivets as those removed in step 4.
Ž 2 Soldiers
Ž 2 Hours 6. Rivet patch plate over hole using rivets, 2 rivet
diameters (2D) minimum edge distance. If possible,
MATERIAL/TOOLS REQUIRED: apply sealant to edge of patch pIate on side against
Rivets (items 98-115, App. C) skin to assure water tight seal.
Riveter (items 8-10, App. B)
Drill and Bit 7. Drill rivet holes on the substitute cap/longeron
Structures Repair Kit (item 12, and the installed patch plate to match the existing
App. B) rivet holes of the damaged cap/longeron. (Rivets pre-
NOTE viously removed in step 4.)

Cap/Longeron - Sections used in outside 8. Record BDAR action taken. When mission is
repairs should be angular. The strength of complete, as soon as practical, repair the equipment/-
the new cap/longeron (or caps, if 2 are system using standard maintenance procedures.
used) should be at least that of the
damaged cap/longeron. Refer to App. D
4-8. FRAME OR BULKHEAD, DAMAGE.
for substitute materials to use on repair if a
cap/longeron section is not available.
GENERAL INFORMATION: A damaged flange on a
bulkhead or frame could be repaired from the outside
PROCEDURAL STEPS: in the same way as is a cap/longeron. However, it is
not desirable to have a section on the outside of the
1. With sheet metal snips, cut hole In sheet includ- aircraft sticking out normal to the airstream. Frame
ing all cracks. Do not cut cap/longeron but cut off flanges are therefore repaired by applying a strap
ragged ends, Figure 4-29. over the damage. If the damage to a highly loaded
bulkhead is severe, then treat it like a cap and let the
2. Make a patch plate. Plate should be as strong or section stick out in the airstream. Only the front one
stronger than original skin. Overlap the hole at least third of the aircraft is really important to aerodynamics.
1-1/2 inches on all sides.

4-43
TM 55-1520-244-BD

SECTION A - A

Figure 4-29. Expedient Cap/Longeron Repair

4-44
 TM 55-1520-244-BD

OPTION 1: Fabricated Repair Strap. 5. Rivet the repair strap in place using the same
size rivets as those removed. Refer to Figure 4-30.
LIMITATIONS: None – Condition 1.
Inspect after every flight. 6. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
PERSONNEL/TIME REQUIRED: system using standard maintenance procedures.
2 soldiers
2 Hours OPTION 2: Combination Repair for Major Frame or
Bulkhead Damage.
MATERIALS/TOOLS REQUIRED:
Sheet Metal (items 131-142, App. C) LIMITATIONS: None - Condition 1.
Rivets (items 98-115, App. C) Inspect after every flight.
Riveter (items 8-10, App. B)
Drill and Bit PERSONNEL/TIME REQUIRED:
Tape (item 153, App. C) 2 Soldiers
Sheet Metal Snips 3 Hours
Structures Repair Kit (item 12,
App. B) MATERIALS/TOOLS REQUIRED:
Sheet Metal (items 131-142, App. C)
PROCEDURAL STEPS: Brush (item 25, App. C)
Rivets (items 98-115, App. C)
1. Drill small stop holes at the ends of all cracks, Structures Repair Kit (item 12,
Figure 4-30. App. B)

2. Cover the damage with tape. Be sure to cover PROCEDURAL STEPS:

the ends of all cracks.
1. Remove sections of the skin and frame or
3. Fabricate a repair strap using sheet metal. The bulkhead containing the damage. Smooth and round
sheet metal should be 2 times thickness of the the cutouts, Figures 4-31 and 4-32.
original flange material. The repair strap should over-
lap both ends of the damaged bulkhead flange to 2. Cut and fit repair doubler for frame or bulkhead.
allow for 2 rows of fasteners. Apply a skin patch first Cut skin patch allowing overlap for at least two rows
as follows: of rivets. Repair patch and doubler should be the
same material and one gage thicker than original
a. Make a patch plate. Plate should overlap the material.
hole at least 1-1/2 inches on all sides.
3. Remove existing rivets where the repair parts will
b. Rivet patch plate over damaged skin using overlap existing rivets if the area is accessible for
rivets at 2D minimum edge distance. If possible, back drilling holes. If not, install rivets between exist-
apply some sealant to edge of patch plate on side ing rivets if space permits.
against skin to assure water tightness.
4. Rivet the repair parts in place using original
4. Drill rivet holes along the center of the repair diameter rivets or larger if necessary.
strap and installed patch plate to match the existing
rivet holes of the damaged bulkhead flange.

4-45
TM 55-1520-244-BD

Figure 4-30. Repair of Damaged Bulkhead Flange

4-46
 TM 55-1520-244-BD

SECTION A-A

Figure 4-31. Typical Combination Repair (Angle View)

4-47
TM 55-1520-244-BD

SECTION B-B

Figure 4-32. Typical Combination Repair (Side View)

4-48
 TM 55-1520-244-BD

5. Record BDAR action taken. When mission is PERSONNEL/TIME REQUIRED:

complete, as soon as practical, repair the equipment/- 1 Soldier
system using standard maintenance procedures. 1-1/2 Hours

4-9. HONEYCOMB CORE FLOOR/PANEL MATERIALS/TOOLS REQUIRED:

DAMAGE. Drill and Bit
Router
Metal Set or Equivalent Filler
GENERAL INFORMATION:
(item 4 or 127, App. C)
Patch Plate Metal (items 131-142,
a. Most of the floors, decks, side panels in the App. C)
fuselage, and the fin panels are honeycomb core Rivets (items 98-115, App. C)
structures. Riveter (items 8-10, App. B)
Solvent (item 7 or 129, App. C)
b. Various repair options are given for a range of Structures Repair Kit (item 12,
damage size. App. B)

OPTION 1: Small Damage to One or Both Skins PROCEDURAL STEPS:

and Core (1 inch max. in any direction).
1. Remove damaged skin and core, Figure 4-34.
LIMITATIONS: Procedure is designed only to keep Clean surface 6 inches around holes with cleaner.
moisture out. No additional strength has been added. The maximum damaged area that may be cut out is 8
inches.
PERSONNEL/TlME REQUIRED:
1 Soldier 2. Make a patch plate as shown in Figure 4-35.
1/4 Hour Make plate 2 inches larger than cutout. Lay out and
drill rivet pattern.
MATERIALS/TOOLS REQUIRED:
Green Tape or Aluminum Tape 3. Completely fill void with metal set fill compound.
(item 150 or 153, App. C) Add slight excess to allow for shrinkage.

PROCEDURAL STEPS: 4. Assemble patch plate to panel with rivets.

1. Apply tape over repair to keep out moisture, 5. Record BDAR action taken. When mission is
Figure 4-33. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
2. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/- OPTION 3: 2 to 8 Inch Damage to Both Skins and
system using standard maintenance procedures. Core.

OPTION 2: 2 to 8 Inch Damage (One Skin and LIMITATIONS: None

Core).
PERSONNEL/TlME REQUIRED:
LIMITATIONS: None 1 Soldier
2 Hours

4-49
TM 55-1520-244-BD

Figure 4-33. Damaged Honeycomb Core Panel - Small

Damage to One Skin and Core

Figure 4-34. Damaged Honeycomb Core Panel, 2-8 Inch

Damage - One Skin and Core

4-50
 TM 55-1520-244-BD

Figure 4-35. Repaired Honeycomb Core Panel, 2-8 Inch

Damage-One Skin and Core

MATERIALS/TOOLS REQUIRED:

Drill with Bit 2. Make two patch plates as shown in Figure 4-37,
Router Make plates 2 inches larger than the cutout. Lay out
Metal Set or Equivalent Filler and drill rivet pattern.
(item 4 or 127, App. C)
Patch Plate Metal (items 131-142, 3. Apply sealant to the area between patch plate
App. C) and panel. Assemble it to the lower skin with rivets.
Rivets (items 98-115, App. C)
Riveter (items 8-10, App. B)
4. Completely fill void with metal set fill compound.
Solvent (item 7 or 129, App. C)
Add slight excess to allow for shrinkage.
Structures Repair Kit (item 12,
App. B)
5. Assemble plate on upper surface of panel with
rivets.
PROCEDURAL STEPS:
6. Record BDAR action taken. When mission is
1. Remove damaged skin and core, Figure 4-36. complete, as soon as practical, repair the equipment/-
Clean top and bottom skins 6 inches around holes system using standard maintenance procedures.
with cleaner. The maximum damaged area that may
be cut out is 8 inches.

4-51
TM 55-1520-244-BD

Figure 4-36. Damaged Honeycomb Core Panel, 2-8 Inch

Damage - Both Skins and Core

Figure 4-37. Repaired Honeycomb Core Panel, 2-8 Inch

Damage - Both Skins and Core

4-52
 TM 55-1520-244-BD

OPTION 4: Damage to Both Skins and Core, Only PROCEDURAL STEPS:

One Side of Panel is Accessible.
1. Remove damaged skin and core, Figure 4-40.
LIMITATIONS: None The maximum damaged area that may be cut out is
12 inches.
PERSONNEL/TlME REQUIRED:
● 1 Soldier 2. Make two patch plates, 0.040 inch thick. Make
● 2 Hours plates two inches larger than the cutout. Lay out and
drill a rivet pattern, two rows as shown. If damage is
MATERIALS/TOOLS REQUIRED: in an area where installing an interior patch is not pos-
Drill and Bit sible or where sharp edges from rivets on an interior
Router patch might cause damage (example for fuel cell
Metal Set or Equivalent Filler panels), a single exterior patch plate, 0.050 inch, may
(item 4 or 127, App. C) be used.
Patch Plate Metal (items 131-142,
App. C) 3. Make a stiffener as shown in Figure 4-40. For
Rivets damage exceeding 12 inches, install additional stif-
Riveter (items 8-10, App. B) feners at 6 inch maximum spacing. Assemble with
Solvent (item 7 or 129, App. C) rivets, 2D minimum edge distance.
Structures Repair Kit (item 12,
App. B)
4. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
PROCEDURAL STEPS:
system using standard maintenance procedures.
1. Remove damaged skin and core using a router to
4-10. WINDSHIELD/WINDOW, DAMAGE.
route all damage on outer and inner skins. Enlarge
the hole on the outer skin and honeycomb so that a
one inch rim surface of the inner skin is exposed, as GENERAL INFORMATION: Repairs to transparent
shown in Figure 4-38. plastics will provide good service if laced tight. Drill
stop holes at the end of ALL cracks.
2. Make two patch plates. One patch plate for inner
skin. The other for the outer skin, Figure 4-39. OPTION: Lacing with Safety-Wire.

OPTION 5: Damage Over 8 Inches to Both Skins LIMITATIONS: Restricted vision. Inspect after
and Core. every flight for damage growth.

LIMITATIONS: None - Condition. Inspect after PERSONNEL/TlME REQUIRED:

every flight. 1 Soldier
1 Hour
PERSONNEL/TIME REQUIRED:
MATERIALS/TOOLS REQUIRED:
l 1 Soldier
Drill
l 2 Hours
Safety Wire (items 60-62, App. C)
Tape (item 153, App. C)
MATERIALS/TOOLS REQUIRED:
Sealant (item 123-128, App. C)
Patch Plate Metal (items 131-142,
App. C)
Rivets (items 98-115, App. C)
Riveter (items 8-10, App. B)

4-53
TM 55-1520-244-BD

Figure 4-38. Damage Repair, Accessible One Side Only

Figure 4-39. Fabrication of Patch Plate

4-54
 TM 55-1520-244-BD

SECTION A - A

Figure 4-40. Repair of Honeycomb Core Panel - Damage

Over 8 Inches - Both Skins and Core

4-55
TM 55-1520-244-BD

PROCEDURAL STEPS: 4. Brush sealant over safety wire and

crack to make a water tight seal.
1. Drill a small stop hole at the
end of each crack, Figure 4-41. If NOTE
tolerable, cutout a hole to include the
ends of all cracks. This will restrict Holes too large to be closed with
vision further. Smooth ragged edges. safety-wire and epoxy may be sealed
temporarily with green tape or
2. Drill small holes 1/2 to 3/4 inch aluminum tape.
spacing, 3/8 inch edge distance along
both sides of any crack and along the 5. Record BDAR action taken. When
sides of the hole. mission is complete, as soon as
practical, repair the equipment/system
3. Lace safety-wire with needle nose using standard maintenance procedures.
pliers through holes and across cracks
and over hole forming a web with 1/2 to
3/4 inch spacing between wires. Pull
wires tight.

4-56
 TM 55-1520-244-BD

Figure 4-41. Fracture Lacing with Safety Wire

4-57/(4-58 Blank)
 TM 55-1520-244-BD

CHAPTER 5

ALIGHTING GEAR

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

5-1. SCOPE. This chapter contains the fault as- if it is still functional and aircraft may be released for
sessment and expedient repair procedures for locat- fully mission capable flight. Watch for any unusual
ing and fixing damage to the alighting gear (landing vibrations in flight. Inspect after every flight until alight-
gear and supports). The landing gear assembly, ing gear can be replaced.
Figure 5-1, consists of two skid tubes (1) and two ar-
ched cross tubes (2) and (3) of formed aluminum b. If alighting gear supporting structure is
alloy fastened together with skid saddles (4) and at- damaged but still functional and the transmission at-
taching hardware. The assembly is attached to the tachment and supporting structure show no damage,
lower fuse- Iage structure with support assemblies (5) release for flight. Watch for any unusual vibrations in
and (6) at four points. To prevent damage from con- flight. Inspect after every flight until structure and
tact with the ground, replaceable steel skid shoes (7) alighting gear can be replaced.
attach to the bottom side of the skid tubes.
c. If alighting gear or its supporting structure is
5-2. ASSESSMENT PROCEDURES. Assessment not functional or the transmission or its supporting
procedures are contained in Table 5-1. Assessments structure show any sign of damage, aircraft will be
refer to parts identified in Figures 5-1 and 5-2. grounded until problem is corrected. This will probab-
ly go beyond the scope of BDAR; if so, use Standard
a. Visually inspect structures supporting alighting Maintenance procedures.
gear attachment points and transmission attachment
points for any signs of structural distress such as 5-3. REPAIR PROCEDURE INDEX.
buckling, cracks, rupture, deformations, popped
rivets, or elongated rivet holes. If no such damage is PARA.
found, replacement of alighting gear may be deferred
Skid Tube Damage . . . . . . . . . .5-4

5-1
TM 55-1520-244-BD

Table 5-1. Alighting Gear Assessment Procedures

FIG 5-2

FIG 5-2

PARA 5-4

FIG 5-2

PARA 5-4

5-2
 TM 55-1520-244-BD

Figure 5-1. Landing Gear and Support Installation

Figure 5-2. Skid Tube Damage Zones

5-3
TM 55-1520-244-BD

Section II. SKID TUBE

5-4. SKID TUBE DAMAGE. 3. Locate center of plate at center of skid tube. If
there are no impediments, the new plate maybe in-
GENERAL INFORMATION: stalled over the old shoes otherwise remove-shoes.

a. In battle conditions, parts of the skid tube may 4. Install plate using blind fasteners or steel clamps,
sustain various amounts of damage which may be Figure 5-4.
deferred or even removed.
5. Clamps maybe fabricated if not available, Figure
b. Skid shoes (7, Figure 5-1) maybe damaged 5-5.
by wear or enemy fire. The most critical areas are 12
inches fore and aft of the cross tube attachments. If
time to replace shoes is not available, damage may
be deferred provided that the damage to the skid tube
does not exceed the criteria of paragraph 5-2. If time Compressed air can blow dust into eyes.
is available and replacement shoes are not available, Wear eye protection. Do not exceed 30
substitute shoes can be fabricated to prevent future psig air pressure.
damage to skid tubes.
Sound pressure levels during some repair
OPTION: Fabricate Skid Shoe. operations exceed the Surgeon General’s
hearing conservation criteria as defined in
TB MED 501. Hearing protection devices
LIMITATIONS: Use care in landing.
such as aviator helmet or ear plugs are re-
quired to be worn by all personnel in and
PERSONNEL/TIME REQUIRED: around the aircraft.
2 Soldiers
2 Hours
Sanding on reinforced laminated glass
produces fine dust that may cause skin
MATERIALS/TOOLS REQUIRED:
and lung irritations. Observe necessary
0.032 In. Sheet Metal
protection measures.
(item 131, App. C)
Blind Fasteners or Steel Clamps
items 98-115,59, App. C) NOTE
Drill Bit
Aircraft Jack The aft end of the skid tube is bent up and
Drill a steel plate cannot be formed to follow
this contour. Do not extend steel plate
PROCEDURAL STEPS: beyond start of curvature.

1. Form steel plate to fit snug around skid. 6. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
2. Drill oversize holes along each edge to match at- system using standard maintenance procedures.
tachment holes in skid tube. Plate should extend one
foot on each side of damaged area.

5-4
 TM 55-1520-244-BD

Figure 5-3. Skid Shoe Repair

Figure 5-4. Clamp Repair

5-5
TM 55-1520-244-BD

Figure 5-5. Fabricated Clamp

5-6
 TM 55-1520-244-BD

CHAPTER 6

POWER PLANT INSTALLATION

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

6-1. SCOPE. This chapter contains the engine replacement, not BDAR. Some
fault assessment and expedient repair engine accessories may be repaired. The
procedures for locating and fixing fault assessment, Table 6-1, refers to
damage to the power plant. The power BDAR repair procedures in this chapter.
plant consists of a T53-L-703 series
shaft turbine engine mounted horizon- 6-3. REPAIR PROCEDURE INDEX.
tally on the fuselage behind the main
rotor pylon, Figures 6-1 and 6-2. PARA.
Engine connections are provided for the
fuel, oil, electrical, instrument, and Oil Tank Punctured . . . . . . 6-4
engine control systems. Major sections Low Oil Pressure, Defective
of the engine are the air-inlet, Indicator/Transmitter . . . . 6-5
compressor, diffuser, combustion, and Fuel Filter Clogged . . . . . . 6-6
exhaust. Housing Cracks, Fuel Control
and Accessory Gearbox . . . . 6-7
6-2. ASSESSMENT PROCEDURES. Combat Jump Start Engine . . . . . . . 6-8
damage to the engine usually requires

Section II. OIL TANKS

6-4. OIL TANK, PUNCTURED. WARNING

GENERAL INFORMATION: The engine oil Turbine fuels and lubricating oils
tank is located in the upper pylon contain additives which are poiso-
fairing, Figure 6-3. The oil level may nous and readily absorbed through
be checked by the sight glass adjacent the skin. Do not allow them to
to the filler cap. The engine will remain on skin longer than
seize in a matter of minutes if run necessary. Wear protective
without oil. This procedure lists equipment.
several methods to fix a leaking oil
tank, depending on the size of the leak Extremely high pressure can occur
and the materials available. If fuel during and after operation of
cell repair kit is available, utilize certain equipment. If this
its contents. pressure is not relieved before
working on equipment, serious
WARNING injury or death may occur. Be
sure to open all drains and vents
Compressed air can blow dust into before beginning any disassembly.
eyes. Wear eye protection. Do
not exceed 30 psig air pressure.

6-1
TM 55-1520-244-BD

Figure 6-1. Engine, Right-Hand View

6-2
 TM 55-1520-244-BD

Figure 6-2. Engine, Left-Hand View

6-3
TM 55-1520-244-BD

Table 6-1. Power Plant Assessment Procedures

PARA 6-5

6-7
PARA 8-10
CHPT 9

CHPT 12

CHPT 11

PARA 6-8

PARA 6-8

PARA 6-5

6-4
 TM 55-1520-244-BD

Figure 6-3. Oil Tank

6-5
TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED:
Plug, Wooden
Hose or Tubing
Starting and operation of the helicopter will
be performed only by authorized personnel. PROCEDURAL STEPS:

When refueling helicopter, the refueling 1. Obtain a small piece of hose or tubing and insert
vehicle or forward air refueling unit must the piece into the hole on the oil tank, Figure 6-4.
be parked a minimum of 20 feet from the
helicopter. Before starting the fueling
2. Insert a tapered wooden plug inside the hose or
operation, always insert fueling nozzle
tubing (wooden plug should be checked periodically
ground cable of fuel truck into GROUND
and retightened if necessary).
HERE receptacle. Refer to FM 10-68.
When defueling, turn off all electrical
switches and disconnect external power 3. Replenish oil supply.
from the helicopter. The helicopter must be
electrically grounded. 4. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
Fuel line and tank repairs often involve system using standard maintenance procedures.
handling of highly inflammable material.
Mishandling can result in serious injury or OPTION 2: Green (Duct) Tape (for thin cracks).
death.
LIMITATIONS: None
Self-luminous dials and ignition units may
contain radioactive materials. If such an in- PERSONNEL/TIME REQUIRED:
strument or unit is broken or becomes un- 1 Soldier
sealed, avoid personal contact. Use 30 Minutes
forceps or gloves made of rubber or
polyethylene to pickup contaminated MATERIALS/TOOLS REQUIRED:
material. Place materials and gloves in a Tape, Fiber glass or Green Tape
plastic bag. Seal bag and dispose of it as (items 50,153, App. C)
radioactive waste in accordance with AR Solvent, Dry Cleaning, (items 7, 129,
708-1 and TM 3-261 (refer to TM 43- App. C)
0108). Repair shall conform to require-
ments in AR 385-11. PROCEDURAL STEPS:

1. Clean area around crack with solvent to remove

the oil.
Some repairs may come loose due to heat
and vibration. 2. Seal crack with tape.
LIMITATIONS: None
3. Replenish oil supply.
OPTION 1: Wood Plug (for smooth round holes).
4. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
PERSONNEL/TIME REQUIRED: system using standard maintenance procedures.
1 Soldier
30 Minutes

6-6
 TM 55-1520-244-BD

Figure 6-4. Wood Plug

OPTION 3: Sealant (for small holes). PROCEDURAL STEPS:

LIMITATIONS: None 1. Clean area around hole with solvent to remove all
traces of oil so sealant will stick.
PERSONNEL/TIME REQUIRED:
1 Soldier 2. Fill hole and surrounding area with sealant.
1 Hour
3. If hole is large enough, use wood plug as a filler
MATERIAL/TOOLS REQUIRED: while filling hole with sealant, Figure 6-5.
Solvent, Dry Cleaning, Naptha
(items 7,-129, App.C) 4. After sealant has dried, replenish oil supply.
Silicon Sealant or Equivalent
(items 5,6,123, 124, 125,
126,128, App. C) 5. Record BDAR action taken. When mission is
Wood Plug complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

6-7
TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED:
Screw, Sheet Metal (items 143, 144,
App. C)
Gasket Material (items 52 or 116,
App. C)
Washer

PROCEDURAL STEPS:

1. Cut a piece of gasket material that will over lap

the hole by about 1 inch from the center of the hole.

2. Pierce a small hole in the center of the gasket

material.

3. Using the sheet metal screw and washer, screw

the gasket material through the pierced hole and
through the small hole on the oil tank on to the oil tank
wall to stop the leak, Figure 6-6.

4. Replenish oil supply.

5. Record BDAR action taken. When mission is

complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

Figure 6-5. Sealant Repair

OPTION 4: Screw, Washer, and Gasket

LIMITATIONS: None

PERSONNEL/TIME REQUIRED:
1 Soldier
30 Minutes

Figure 6-6. Screw, Washer, and Gasket

6-8
 TM 55-1520-244-BD

OPTION 5: Hose Assembly, Sealant, Nut and Bolt. 2. Use a piece of hose/tubing about the same
diameter of the hole. Assemble bolt, hose/tubing,
LIMITATIONS: None washer, and nut, Figure 6-7. Apply sealant to all
edges. Start nut on bolt and tubing until assembly is
snug.
PERSONNEL/TIME REQUIRED:
1 Soldier
2 Hours 3. File edge of hole until round and smooth. Push
hose assembly about half way through hole. Tighten
MATERIAL/TOOLS REQUIRED: nut on bolt, expand hose to seal hole. If necessary,
Nut, Bolt, and Washer (items 8-24, remove oil tank plate to allow a wrench or pliers in-
63-70, & 162-169, App. C) side of oil tank to hold nut while turning bolt.
Sealant (items 123-128, App. C)
Hose or Tubing 4. If oil tank plate was removed, reinstall.
Solvent (item 7 or 129, App. C)
5. After sealant has dried, replenish oil supply.
PROCEDURAL STEPS:
6. Record BDAR action taken. When mission is
1. Clean area around hole with solvent to remove all complete, as soon as practical, repair the equipment/-
traces of oil so sealant will stick. system using standard maintenance procedures.

PIECE OF HOSE

Figure 6-7. Hose Assembly, Sealant, Nut and Bolt

6-9
TM 55-1520-244-BD

OPTION 6: Sheet Metal with Sealant Blind Rivets PROCEDURAL STEPS:

(for large holes),
1. Cut a piece of sheet metal that will overlap the
LIMITATIONS: None hole by 1 1/2 inches at all points, Figure 6-8.

PERSONNEL/TlME REQUIRED: 2. If sealant is to be used, clean area around hole

2 Soldiers with solvent so sealant will stick and sand rough.
3 Hours
3. Put sealant or gasket material over hole. Put
MATERIALS/TOOLS REQUIRED: sheet metal plate over hole and secure with sheet
Sheet Metal (items 131-138, App. C) metal screws or blind rivets.
Sealant (items 68, 123-128, App. C)
Blind Rivets (items 98-115, App. C) 4. After sealant has dried, replenish oil supply.
Sheet Metal Screws (items 143-144)
App. C) 5. Record BDAR action taken. When mission is
Sandpaper (items 117-121, App. C) complete, as soon as practical, repair the equipment/-
Solvent system using standard maintenance procedures.
Gasket Material

Section Ill. OIL PRESSURE lNDICATOR/TRANSMITTER

6-5. LOW OIL PRESSURE lNDlCATOR/TRANS- PROCEDURAL STEPS:

MITTER, DEFECTIVE.
1. Remove oil pressure transmitter, Figure 6-9, and
GENERAL INFORMATION: This procedure ex- interchange it with one of the two engine torque trans-
plains how to check if a low oil pressure reading is mitters. Refer to Figure 6-10 for location.
being caused by a defective oil pressure indicator/-
transmitter. 2. Start engine.

OPTION 3. Check to see if reading on oil pressure gage is

normal.
LIMITATIONS: None
4. If the oil pressure indicator reading is good and
the torque pressure indicator reading with which the
PERSONNEL/TIME REQUIRED: transmitters were interchanged is not good, the prob-
1 Soldier lem is with the transmitter. Use the other torque in-
15 Minutes dicator to monitor the engine torque during flight.
Engine will be fully mission capable.
MATERIALS/TOOLS REQUIRED:
Towels (item 161, App. C)

6-10
 TM 55-1520-244-BD

SECTION A - A

SECTION B - B

SHEET METAL PLATE WITH BLIND RIVETS

Figure 6-8. Sheet Metal with Sealant or Blind Rivets

6-11
TM 55-1520-244-BD

Figure 6-9. Oil Pressure Transmitter

6-12
 TM 55-1520-244-BD

TORQUE PRESSURE TRANSMITTERS

Figure 6-10. Torque Pressure Transmitters

6-13
TM 55-1520-244-BD

5. If the oil pressure indicator reading is not good b. If oil pressure exists, oil will spray from
and the torque reading with which the transmitter was loosened connection. Tighten connection. Engine will
interchanged is good, do the following: be partially mission capable.

a. Place a rag over engine oil pressure line con- C. If oil pressure does not exist, troubleshoot prob-
nection to transmitter. Gently loosen but do not un- Iem using standard maintenance procedures.
screw connection.
6. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equip-
ment/system using standard maintenance procedures.

Section IV. FUEL FILTER

6-6. FUEL FILTER CLOGGED. OPTION: Options are described in paragraph 12-10
and 12-11.
GENERAL INFORMATION: If engine will not run
and there is no fuel flow from the main fuel manifold,
check the fuel filter for clogging.

Section V. FUEL CONTROL AND ACCESSORY GEARBOX

6-7. HOUSING CRACKS-FUEL CONTROL AND MATERIALS/TOOLS REQUIRED:

ACCESSORY GEARBOX. Solvent (items 7 or 129, App. C)
Sealant (items 6 or 128, App. C)
GENERAL INFORMATION: This procedure shows
how silicon sealants can be used to temporarily seal PROCEDURAL STEPS:
small cracks on the fuel control and the accessory
gearbox housings when crack edges do not protrude 1. Visually locate crack wherever there is an oil leak
inward. The symptom will normally be loss of engine on the fuel control housing or the accessory gearbox
oil which results in engine temperature running higher housing, Figure 6-11.
than normal.
2. Check for internal damage or internal obstruction
LIMITATIONS: Prolonged exposure to heat and by manually inducing rotation to the entire engine as-
pressure will cause patch to fail. Failure of seal will sembly which includes turbines, compressors, the ac-
lead to oil loss and catastrophic engine failure. cessory gearbox, the fuel control, etc. To do this,
follow these steps:
PERSONNEL/TIME REQUIRED:
2 Soldiers a. Remove the tach generator, Figure 6-12.
3 Hours

6-14
 TM 55-1520-244-BD

ACCESSORY GEARBOX ASSEMBLY

Figure 6-11. Fuel Control Assembly and Accessory Gearbox Assembly

6-15
TM 55-1520-244-BD

Figure 6-12. Tach Generator Removal

6-16
 TM 55-1520-244-BD

b. Insert a 1/4 inch ratchet into the square slot present, there is internal damage and an inspection of
which engaged with the tack generator shaft. the internal parts will be required.

c. Turn the ratchet which in turn will rotate the en- 3. Reinstall tach generator.
tire engine assembly including the accessory gearbox
and the fuel control. 4. Clean area of crack thoroughly with solvent.

d. Listen and feel for any scraping or snagging in 5. Apply sealant material. Allow curing or drying
the accessory gearbox and fuel control assemblies time. Use duct tape if possible.
that might disrupt the function of these parts.
6. Record BDAR action taken. When mission is
e. If no scraping or snagging is felt or heard, complete, as soon as practical, repair the equipment/-
proceed to step 3. If there is scraping or snagging system using standard maintenance procedures.

Section VI. EMERGENCY ENGINE START

6-8. JUMP START ENGINE. PROCEDURAL STEPS:

GENERAL INFORMATION: If the aircraft starter- 1. Locate and open cover on external power plug,
generator is not sufficiently powered by the battery Figure 6-13 (use slot screwdriver).
and an auxiliary power unit (APU) is not available, the
following procedure may be used to start the aircraft. 2. Strip 1/4 inch of insulation from one end of both
jumper cables.
LIMITATIONS: Procedure must be repeated
everytime aircraft engine is turned off until standard 3. Modify other end as needed and connect to
maintenance can be performed power supply source.

PERSONNEL/TIME REQUIRED:
2 Soldiers
15 Minutes
When making connections, DO NOT touch
MATERIAL/TOOLS REQUIRED: the uninsulated part of the slave cables.
Jumper Cable 4 to 8 feet of No. 4 Awg Wear protective gloves. Shield eyes from
Wire (2 each) (item 173, App. C) possible sparks.
28 V dc Power Supply or Batteries
Knife

Observe polarity (+) to (+) and (-) to (-)

when making connections.

6-17
TM 55-1520-244-BD

Figure 6-13. External Power Plug

NOTE 5. Follow the same instructions in

step 4 for the negative connection.
Firm contact must be maintained
between jumper cable end and 6. Start aircraft.
aircraft external power plug.
Sparking will occur. 7. Remove jumper cables when engine
starts and secure external power-plug
4. Connect one end of the jumper cables cover.
to the positive terminal of the power
source and take the other end of the 8. Record BDAR action taken. When
slave cable (modified in step 2) and mission is complete, as soon as
hold against the positive terminal of practical, repair the equipment/system
the external power plug. using standard maintenance procedures.

6-18
 TM 55-1520-244-BD

CHAPTER 7

ROTORS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

7-1. SCOPE. This chapter contains the fault as- ponents when damaged, must therefore be replaced
sessment and expedient repair procedures for locat- by standard maintenance procedures. For those com-
ing and fixing damage to the rotor systems. The two ponents that are identified as repairable, repair proce-
rotor systems are shown in Figures 7-1 and 7-13. dures are provided. The fault assessment, Table 7-1,
refers to those repair procedures.
7-2. ASSESSMENT PROCEDURES. The main
rotor systems include a number of components which 7-3. REPAIR PROCEDURE INDEX.
cannot tolerate damage. If such components are
damaged or deformed (bent) in any way, the rotor PARA
cannot perform properly. With the exception of items Main Rotor Blade, Hole
6, 7, 19, and 24, none of the items listed in Figure 7-1 1 Inch or Less . . . . . . . . . . . .7-4
can tolerate any damage. Such components, when Main Rotor Blade, Hole
damaged, must therefore be replaced by standard Larger Than 1 Inch . . . . . . . . .7-5
procedures. Except for the blades (23) and the tail Lateral Vibrations . . . . . . . . . . .7-6
rotor gearbox (28), none of the components shown in Tail Rotor Blade Damage . . . . . . .7-8
Figure 7-13 can tolerate any damage. Such com-

Section Il. MAIN ROTOR HUB AND BLADE

7-4. MAIN ROTOR BLADE, HOLE 1 INCH OR Blades must contain sufficient balance weight to per-
LESS, THROUGH BOTH SKINS. mit adjustment of blade balance after repair. Use a
lead pencil to mark blades; never use a grease pencil.
GENERAL INFORMATION: The following repairs
can be made while blades are installed in aircraft.

7-1
TM 55-1520-244-BD

1. Main Rotor Hub Yoke 12. Friction Collet 20. Drive Link
2. Trunnion 13. Antidrive Link 21. Swashplate Outer Ring
3. Mast Nut 14. Collective Lever 22. Swashplate Inner Ring
4. Elastomeric Bearing 15. Swashplate Support 23. Scissors and Sleeve
5. Grip 16. Collective Control Assembly
6. Main Rotor Blade B540 Hydraulic Cylinder 24. Sand Deflector
7. Main Rotor Blade K747 17. Lateral Cyclic Control 25. Mast Nut Lock
8. Drag Brace Hydraulic Cylinder 26. Main Rotor Blade
9. Pitch Horn 18. Fore and Aft Cyclic Retention Bolt
10. Connecting Tube Control Hydraulic 27. Collective Idler
(Pitch Link) Cylinder
11. Mast 19. Transmission

Figure 7-1. Main Rotor System

7-2
 TM 55-1520-244-BD

Table 7-1. Rotor Assessment Procedures

FIG 7-1,

FIG 7-13,

PARA 7-8
CHPT 8

7-5, 7-6
PARA 7-4,

CHPT 8

7-3
TM 55-1520-244-BD

2. Smooth damage; remove all rough edges.

Cleaning solvents, adhesives, and fillers 3. Clean area around damage and completely
may be flammable and toxic. Use only in around blade where tape is to be applied.
well-ventilated areas. Avoid inhalation of
vapors and skin contact. Do not use sol- 4. Cover hole with a chordwise layer of tape, top
vents near open flame or in areas where and bottom of blade. Extend ends of tape 2 inches
very high temperatures prevail. Solvent beyond area of damage, Figure 7-2.
flash point must not be less than 100° F.
5. Wrap a second layer of tape chordwise over the
Sanding on reinforced laminated glass first layer and around the entire blade, Figure 7-2.
produces fine dust that may cause skin Overlap ends by 3 inches with outside edge of top
and lung irritations. Observe necessary toward trailing edge.
protective measures.
6. Adjust blade balance by adding approximately
Operation of power tools may exceed the same amount of tape to the opposite blade at ap-
recommended noise thresholds. Wear proximately the same distance away from the hub.
hearing protection equipment.
7. Record BDAR action taken. When mission is
Compressed air can blow dust into eyes. complete, as soon as practical, repair the equipment/-
Wear eye protection. Do not exceed 30 system using standard maintenance procedures.
psig air pressure.
OPTION 2: Skin Patch Repair (K747 blade only).
NOTE
LIMITATIONS: None
The sand deflector (24, Figure 7-1 ) can
sustain any amount of damage without PERSONNEL/TIME REQUIRED:
restricting aircraft capability as long as no 2 Soldiers
sections become loose. Inspect after every 2 Hours
flight. Replace as soon as possible and
record damage. MATERIALS/TOOLS REQUIRED:
Clock or Watch
OPTION 1: Tape Over Damage. Adhesive Package (item 1 or 2
App. C)
LIMITATIONS: Restricted from combat capable. Skin Patch Repair Kit (items 72-77,
88-96, App. C)
Sealing Iron (item 11, App. B)
PERSONNEL/TIME REQUIRED:
2 Soldiers PROCEDURAL STEPS:
15 Minutes

MATERIALS/TOOLS REQUIRED: 1. Place the kit template on the blade. Position the
Green Tape or Aluminum Tape (item 150 inner circle to enclose the damage. Hold the template
or 153, App. C) from slipping and draw a pencil-line around the outer
Cleaning Solvent (item 7 or 129, circle of the template, Figure 7-3.
App. C)

PROCEDURAL STEPS:

1. Position blades for access to damaged area. Sup-

port blades to prevent movement and droop.

7-4
 TM 55-1520-244-BD
Figure 7-2. Application of Tape
7-5
TM 55-1520-244-BD

WARNING CAUTION

Cleaning solvent is flammable and Surfaces to be bonded must be clean,

toxic. Provide adequate ventila- dry, and free of finger prints and
tion. Avoid prolonged breathing all foreign material.
of vapors and contact with skin
or eyes. 8. Dampen clean cheesecloth (kit) with
solvent and clean inside masked area.
CAUTION Wipe with clean, dry cheesecloth before
dampness evaporates.
Care shall be taken to prevent sol-
vent from entering core area of WARNING
blade. Spillage shall be avoided.
Solvent can damage leading edge Adhesive contains toxic ingredients.
erosion guard. Provide adequate ventilation and
protect the skin and eyes from con-
2. Put on cotton gloves (kit) and then tact with uncured resins and curing
plastic gloves (kit). Dampen cheese- agent. Wash off uncured resins and
cloth (kit) with solvent and rub off curing agent from skin with warm
paint from skin in area within the guide water and soap. Avoid use of sol-
circle. vents for cleaning human skin.

CAUTION NOTE

Excessive sanding will weaken blade Never mix less than a complete
skin. Sand only until yellow color 32 gram two part package of
is removed. adhesive. Mix the full batch
and then discard the excess
3. Starting with 120 grit and finishing after the repair is completed.
with 220 grit abrasive paper (from kit),
sand the paint and the yellow primer 9. Open the envelope containing the
from the blade in the area within the adhesive and empty both components of
guide circle. Sand only until yellow the curing agent into the cup. Stir
color is removed. Do not sand fibers. with kit wooden spatula until both com-
Also, sand off any damaged material ponents have been throughly intermixed.
raised above normal contour of blade,
Figure 7-3. NOTE

4. Wipe off all sanding dust. Pot life of adhesive is 15 minutes

at 72°F (22°C). It is shorter at
5. Use template to redraw guide circle. higher temperatures. Repair proce-
dures shall be completed without
6. Cut short lengths of the masking delay.
tape (kit) and mask around the outside
of guide circle, Figure 7-4. 10. Using clean 1 inch brush, apply a
light coat of adhesive to blade skin
7. Put on cotton gloves (kit) and then within guide circle and to underside
plastic gloves (kit). Leave gloves on of skin patch, Figure 7-4.
until completion of step 13.

7-6
 TM 55-1520-244-BD

Figure 7-4.

7-7
TM 55-1520-244-BD

11. Center skin patch within guide circle with sten- c. Painting may be deferred until termination of
ciled arrow pointing outboard (spanwise) and press the emergency.
firmly into place. Slide patch back and forth slightly
under hand pressure to even adhesive. Use light 16. Adjust blade balance weights as required by
hand pressure to squeeze the patch from the center Figure 7-5.
to edge to work out any air bubbles.
17. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
Cleaning solvent is flammable and toxic.
Provide adequate ventilation. Avoid 7-5. MAIN ROTOR BLADE DAMAGE, HOLE
prolonged breathing of vapors and contact LARGER THAN 1 INCH DIA; 1 1/2 INCHES WIDE X
with skin or eyes. 4 INCHES LONG MAX.

12. Using clean cheesecloth (kit) dampened with GENERAL INFORMATION: Size and location of
solvent, temporarily lift edges of peel-ply and wipe off repairable damage to a rotor blade is shown in Figure
excess adhesive. 7-6. Repairs can be made provided blades contain
sufficient balance weight to permit adjustment of
13. Place masking tape over edge of patch in four blade balance after repair. Repairs can be made
places to prevent movement of patch. Place two long while blades are installed on aircraft. Use a lead pen-
pieces of masking tape at right angles centered over cil to mark blades; never use a grease pencil.
the patch spanwise and chordwise. Remove gloves, Damage to the shaded areas in Figure 7-6 is struc-
turally sensitive; clean holes up to 1 inch diameter will
result in partial mission capability. Smooth any such
14. Cure patch adhesive with sealing iron
damage which extends above the external surface of
the blade and cover hole with Army green tape. In-
a. Connect sealing iron to 110 V ac electrical out- spect after every flight.
let and allow iron to heat up.
OPTION: Plug Patch Repair Kit (K747 blade only).
b. Heat patch with sealing iron for a minimum of
15 minutes to cure adhesive. Press down hard on LIMITATIONS: None. This repair will produce
patch and keep moving the sealing iron. Condition 1 aircraft.
c. Following the curing time, disconnect the seal-
PERSONNEL/TIME REQUIRED:
ing iron.
2 Soldiers
6 Hours
15. Refinish repair area,
ATERIALS/TOOLS REQUIRED:
a. Remove peel-ply and masking tape from blade. Clock or Watch
Adhesive Package (item 1 or 2, App. C)
Plug Patch Repair Kit (items 79-84,
90-96, App. C)
Sealing Iron (item 11, App. B)
Sanding skin fibers can weaken blade.

b. Using 220 or finer grit abrasive paper, feather

edge of adhesive squeezed-out around patch.

7-8
 TM 55-1520-244-BD

Figure 7-5. Balance Adjustment for Patches (K747 Blade) (Sheet 1 of 2)

7-9
TM 55-1520-244-BD

Figure 7-5. Balance Adjustment for Patches (K747 Blade) (Sheet 2 of 2)

7-10
 TM 55-1520-244-BD

NO PATCHES PERMITTED
WITHIN ONE INCH OF
DOUBLERS OR FRONT SPAR NOTE

AN OBLONG HOLE IS PERMISSIBLE IF THE GENERAL DIRECTION OF THE

HOLE IS WITHIN 15 DEGREES OF A LINE PARALLEL TO THE LEADING
OR TRAILING EDGE OF THE BLADE. MAXIMUM SIZE OF THE HOLE SHALL
NOT EXCEED 1.5 INCHES WIDE BY 4 INCHES LONG. THE ENDS OF THE
HOLE MUST HAVE A MINIMUM RADIUS OF 0.25 INCH TO BREAK CORNERS.

Figure 7-6. Maximum Allowable Repairable

Damage to Rotor Blade

PROCEDURAL STEPS: Table 7-2. Patch Kits

KIT PART NO. DIAMETER THICKNESS
1. Position blade for access to damaged
area. Support blade to prevent movement 70072-15001-015 3.00 inch 1/4 inch
and droop. 70072-15001-016 3.00 inch 1/2 inch
70072-15001-017 3.00 inch 7/8 inch
2. Measure diameter and depth of 70072-15001-018 6.00 inch 1/4 inch
damage. 70072-15001-019 6.00 inch 1/2 inch
70072-15001-020 6.00 inch 7/8 inch
3. Obtain plug patch repair kit no
larger than necessary to replace damage.
A core void 1 inch or less in diameter 4. Damage deeper than 7/8 inch can be
is permitted after repair. Plug patch repaired with a single patch. Damage
kits are available as shown in Table 7-2. that passes completely through blade and
is larger than 1 inch diameter will be
repaired by installing plug patches from
both top and bottom sides of blade.
Install larger diameter and thicker plug
patch first, Figure 7-7.

7-11
TM 55-1520-244-BD

Figure 7-7. Typical Double Plug Patch Repair

5. Obtain at least four adhesive pack- CAUTION

ages.
Care shall be taken to prevent sol-
6. Obtain proper size plug patch kit, vent from entering core area of
Table 7-2. Select proper template from blade. Spillage shall be avoided.
kit. Use 3 to 7 inch template for 3
inch plug and 6 to 10 inch template for 8. Put on cotton gloves (kit) and then
6 inch plug. plastic gloves (kit). Dampen cheese-
cloth (kit) with solvent and rub off
7. Place the kit template on the blade. paint from-skin in area between ci rcles
Position the inner circle to enclose the A and B. Remove gloves.
damage. Hold the template from slipping
and draw pencil lines around the inner CAUTION
and outer circles of the template,
Figure 7-8. Excessive sanding will weaken b lade
skin. Sand only until yellow color
is removed.

Cleaning solvent is flammable and 9. Sand the paint from the blade area
toxic. Provide adequate ventila- between circles A and B. Start with 120
tion. Avoid prolonged breathing grit, and finish with 220 grit abrasive
of vapors and contact with skin paper. Sand only until yellow color is
or eyes. removed. Do not sand skin fibers,
Figure 7-8.

7-12
 TM 55-1520-244-BD

Figure 7-8. Marking Work Area

10. Redraw circle A. This circle is CAUTION

the routing guideline.
During all routing operations, long
WARNING dimension of route base shall be
kept in spanwise direction. End
Disconnect router cord from outlet mills will burn out if used to
before changing or installing bits cut skin.
or end mills, or making adjustments.
Ensure router switch is in off posi- 11. Insert rasp-type bit, P/N 4-BR, in
tion before connecting router to router collet.
electrical power. Keep hands and
fingers away from rotating bits 12. Set router depth of cut for 0.020
and end mills. Guide router with inch.
both hands on router grip. Use
personnel protection equipment 13. Moving in a clockwise direction,
(e.g., respirator, goggles, apron, route a complete circle through the
etc.). skin, inside of, and following circle A,
Figure 7-9.
Adhesive contains toxic ingredients.
Provide adequate ventilation and 14. Using duckbill pliers, lift the
protect the skin and eyes from con- edge of the cut circle of skin and peel
tact with uncured resins or curing the cut circle of skin off core, Figure
agent. Wash off uncured resins and 7-9.
curing agent from skin with warm
water and soap. Avoid use of sol-
vents for cleaning human skin.

7-13
TM 55-1520-244-BD

Figure 7-9. Removal of Damaged Skin

15. After removing skin, check depth of CAUTION

core at trailing edge of circle. If the
core thickness at the trailing edge side Do not damage the spar and trailing
is less than the depth of plug selected, edge during routing. The spar and
a more shallow plug must be used. trailing edge can be located by
using Figure 7-6. Spare, core,
16. Insert end mill in router collet. and trailing edge assembly areas
underlying the skin also can be
17. Set router depth of cut to match verified by the difference in
depth of plug plus thickness of kit sound when the blade surface is
wafer, Figure 7-10. tapped with a coin.

18. Route out core. First route a 19. Wipe off all cuttings, sanding
complete circle following inside circle dust, etc. from repair area.
A. Then route out remainder of core
moving router in chordwise direction, 20. Use template to redraw circle B.
Figure 7-11.

7-14
 TM 55-1520-244-BD

Figure 7-10. Setting Router Depth

21. Cut short lengths of the masking NOTE

tape (kit) and mask around the outside
of circle B, Figure 7-11. ● Wafer may be larger than cutout and
have to be trimmed down.
22. Put on cotton gloves (kit) and then
plastic gloves (kit). Leave gloves on ● Never mix less than a complete 32
until completion of step 30. gram two part package of adhesive.
When less than a full batch is
CAUTION required, mix the full batch and
then discard the excess after the
Surfaces to be bonded must be clean, repair is completed.
dry, and free of finger prints and
all foreign matter. 24. Open the envelope containing the
adhesive and empty both components of
23. Dampen clean cheesecloth (kit) with the curing agent into the cup. Stir
solvent and clean skin inside masked with wooden spatula (kit) until both
area. Also, clean both sides of kit components have been throughly inter-
wafer and underside of plug patch mixed. Repeat if more than one package
flange. Wipe with clean, dry cheese- is required.
cloth before dampness evaporates.

7-15
 TM 55-1520-244-BD
Figure 7-11.
FIG. 5-10
Figure 7-11.
7-16
 TM 55-1520-244-BD

NOTE 29. Use light hand pressure to squeeze

patch area overlapping blade skin to
Pot life of adhesive is 15 minutes expel excess adhesive and air bubbles.
at 72°F (22°C). It is shorter at
higher temperatures. Repair pro- 30. Using clean cheesecloth (kit) dam-
cedure shall be completed without pened with solvent, temporarily lift
delay. edges of peel-ply and wipe off excess
adhesive. Remove gloves.
25. Using clean 1 inch brush (kit),
apply a liberal coat of adhesive to one 31. Place two long pieces of masking
side of wafer (kit), Figure 7-11. tape at ring angles centered over the
patch spanwise and chordwise.
a. If repair is on top of blade,
place wafer in routed cavity with adhe- 32. Cure patch adhesive with sealing
sive side down. iron.

b. If repair is on bottom of blade, a. Connect sealing iron to 110 V ac

place wafer in routed cavity with adhe- aircraft electrical outlet and all ow
sive side up. iron to heat up.

CAUTION b. Heat patch with sealing iron. for a

minimum of 15 minutes to cure adhesive.
Adhesive should not be packed into Press down hard on patch and keep moving
cells of blade core or plug patch. the sealing iron.
Excess adhesive can cause blade to
be out of balance. c. At end of the curing time, discon-
nect electrical power.
26. Using spatula or brush (kit), apply
a liberal coat of adhesive to walls of 33. Refinish repair area.
cavity in blade core.
a. Remove peel-ply and masking tape
27. Using brush (kit), apply a light from blade.
coat of adhesive to:
CAUTION
a. blade skin in masked off area
around core cavity, Sanding skin fibers can weaken
blade skin.
b. plug patch flange surrounding
plug, Using 220 grit abrasive paper
(kit), feather edge of adhesive
c. outside diameter of plug, and squeeze-out around plug patch.

d. second side of wafer (wafer was c. Painting may be deferred until

previously coated and placed in step termination of the emergency.
25).
34. Adjust blade balance wei ghts as
28. Position plug patch in cavity with required by Figure 7-5.
stenciled arrow pointing outboard
(spanwise) and press firmly into place. 35. Record BDAR action taken When
mission is complete. as soon as
practical, repair the equipment/system
using standard maintenance procedures.

7-17
TM 55-1520-244-BD

7-6. LATERAL VIBRATIONS. PERSONNEL/TIME REQUIRED:

● 2 Soldiers
GENERAL INFORMATION: ● 30 Minutes

a. To correct lateral vibrations, the MATERIALS/TOOLS REQUIRED:

barrel of the drag brace should be turned Comnon Hand Tools
in small increments in the direction of
the arrows on the decal on the barrel, PROCEDURAL STEPS:
Figure 7-12. There is a continuous red
line on the barrel and adjacent bosses 1. Rotate barrel opposite to the direc-
indicating the zero position, and tion indicated by the arrow on the decal
adjustments may only be made by turning back to the zero position so that the
the barrel in the direction of the arrow red line on the barrel lines up with the
away from the red line. lines on the adjacent bosses.

b. Occasionally, any adjustment in 2. Turn the barrel in small increments

the direction of the arrow past the red in the direction opposite the arrow.
line will not correct, or will even Total adjustment in this direction may
increase, lateral vibration. This pro- not exceed 1/3 of a turn.
cedure may correct this condition.
2. Flight test after each adjustment.
OPTION: Balance Weight Adjust.
3. Record BDAR action taken. When
LIMITATIONS: None mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

Figure 7-12.

7-18
 TM 55-1520-244-BD

Section Ill. TAIL ROTOR SYSTEM

7-7. GENERAL. The tail rotor system, Figure Sheet Metal Snips
7-13, performs a critical roll in maintaining helicopter Rivets (items 98-101, App. C)
controllability. All damage and repair to this system Rivet Gun (items 8-10, App. B)
should be considered critical in nature. Damaged Green Tape or Aluminum Tape
linkages, bolts, hardware, or hub must be replaced (item 150 or 153, App. C)
with spares or cannibalized parts. Tail rotor gearbox
damage is covered in Chapter 8. Flight control tubes PROCEDURAL STEPS:
and cables are covered in Chapter 13.
1. Position blade for access to damaged area.
7-8. TAIL ROTOR BLADE DAMAGE.
2. Smooth damage; remove all rough edges.
GENERAL INFORMATION: Damage to the tail
rotor blade that results in a crack or hole in the skin 3. Clean area around damage and completely
and is located in the authorized area for repair, Figure around blade where tape will later be applied.
7-14, maybe patch repaired.
4. Cut out an aluminum skin patch so that it over-
OPTION: Patch Hole in Blade laps hole by at least 1 inch on all sides, Figure 7-15.

LIMITATIONS: Maximum size of damage should 5. Apply sealant to underside of skin patch, against
not exceed 1-1 /2 inches. blade, and place over hole.

PERSONNEL/TIME REQUIRED: 6. Wrap a layer of tape over skin patch and com-
2 Soldiers pletely around entire blade to give repaired area a
2 Hours more streamlined surface, Figure 7-16.

MATERIAL/TOOLS REQUIRED: 7. Adjust blade balance by adding approximately

Aluminum Skin Patches (items 72-77,
the same amount of tape to the opposite blade at ap-
App. C) proximately the same distance away from the hub.
Sealant (item 123, App. C)

7-19
TM 55-1520-244-BD

1. Screw 11. Pitch Link 21. Pitch Horn

2. Washer 12. Counterweight Link 22. Barrel Nut and Retainer
3. Lock 13. Shield 23. Hub and Blade Assembly
4. Retainer 14. Retaining Nut 24. Sleeve
5. Nut 15. Bolt 25. Control Tube
6. Cotter Pin 16. Washer 26. Gearbox Output Shaft
7. Steel Washer 17. Counterweight Support 27. Split Cone Set
8. Bearing 18. Washer 28. Tail Rotor Gearbox
9. Nylatron Washer 19. Nut 29. Bolt
10. Crosshead 20. Cotter Pin 30. Bushing

Figure 7-13. Tail Rotor Installation

7-20
 TM 55-1520-244-BD

NOTE: NO REPAIR PERMITTED IN HATCHED AREA.

Figure 7-14. Tail Rotor Blade-Area Authorized for Patch-Type Repair

NOTE: NO REPAIR PERMITTED IN HATCHED AREA.

Figure 7-15. Aluminum Skin Patch

7-21
TM 55-1520-244-BD

NOTE: NO REPAIR PERMITTED IN HATCHED AREA

Figure 7-16. Skin Patch Tape Cover

7-22
 TM 55-1520-244-BD

CHAPTER 8

DRIVE TRAIN SYSTEM

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

8-1. SCOPE. b. Refer to Table 8-1 for fault assessment logic

flow.
a. This chapter contains the fault assessment
and expedient repair procedures for locating and 8-3. REPAIR PROCEDURE INDEX.
fixing damage to the drive train system.
PARA
b. The drive train is a system of shafts and gear- 8-5

boxes through which the engine drives the main rotor, 8-6
tail rotor, and such accessories as rotor tachometer, 8-7
generator, and hydraulic pump. Figure 8-1 shows an 8-8
overall view of the drive train system on the aircraft.
Transmission Ballistic Damage . . .8-9
8-2. ASSESSMENT PROCEDURES. Gearbox Damage . . . . . . . . . .8-10
Dents or Ballistic Damage to
Shafts . . . . . . . . . . . . ...8-12
a. The drive train system includes a number of
components which cannot tolerate damage. If such
components are damaged or deformed (bent) in any
way or fail internally, the drive train system is in-
operable and safety is severely degraded if com-
ponent is not replaced.

Section Il. TRANSMISSION

8-4. GENERAL. The transmission should be

evaluated carefully for ballistic damage that may have
cracked the cases. Small holes may be plugged and
repaired. Damage that may propagate cracks, caus- Turbine fuels and lubricating oils contain
ing failure or separation, are of greatest concern. Ex- additives which are poisonous and readily
ternal damage to fittings or accessories can often be absorbed through the skin. Do not allow
bypassed or repaired. them to remain on skin longer than neces-
sary. Wear protective equipment.
8-5. OIL PRESSURE SWITCH LEAK.
OPTION: Remove Pressure Switch.
GENERAL INFORMATION: If oil is being lost due
to damage at the oil pressure switch, eliminate switch LIMITATIONS: Early warning of low oil pressure will
from oil system. be unavailable since Trans Oil Pressure segment at
caution panels are inoperable. Oil pressure could be
monitored at oil pressure gage, provided transmitter
(3, Figure 8-2) is operable.

8-1
TM 55-1520-244-BD

1. Mast 4. Tail Rotor Driveshaft

2. Transmission 5. Intermediate Gearbox
3. Main Driveshaft 6. Tail Rotor Drive Gearbox

Figure 8-1. Drive Train (Typical)

8-2
 TM 55-1520-244-BD

Table 8-1.

PARA 8-5

PARA 8-6

PARA 8-7

PARA 8-8

PARA 8-9

PARA 8-10

PARA 8-12

8-3
TM 55-1520-244-BD

PERSONNEL/TlME REQUIRED: MATERIAL/TOOLS REQUIRED:

1 Soldier Cable Ties (item 26 or 27, App. C)
15 Minutes Fluid Repair Kit (item 4, App. B)
Safety Wire (items 60-62, App. C)
MATERIALS/TOOLS REQUIRED: Packing Assortment (item 71, App. C)
Cable Ties (item 26 or 27, App. C)
Fluid Repair Kit (item 4, App. B) PROCEDURAL STEPS: (Refer to Figure 8-2.)
Safety Wire (items 60-62, App. C) —
Packing Assortment (item 71, App.C 1. Cut safety wire and remove electrical connector
Towels (item 161, App. C) from pressure transmitter (3).

1. Cut safety wire and remove electrical connector 2. Cut safety wire and remove pressure transmitter
from pressure switch (1). (3) and o-ring (4). Retain o-ring.

2. Cut safety wire and remove pressure switch (1) 3. Install plug with o-ring (4) where transmitter (3)
and o-ring (2). Retain o-ring. was removed.

3. Install plug with o-ring (2) where switch(1) was 4. Check for leaks.
removed.
5. Secure loose electrical connector with tie wraps.
4. Check for leaks.
6. Record BDAR action taken. When mission is
5. Secure loose electrical connector with tie wraps. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
6. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/- 8-7. OIL FILTER (EXTERNAL ASSEMBLY AREA
system using standard maintenance procedures. LEAK).

8-6. OIL PRESSURE TRANSMITTER LEAK. GENERAL INFORMATION: If oil is being lost due
to a damage to the oil filter assembly area, isolate oil
GENERAL INFORMATION: If oil is being lost due filter from oil system by relocating oil hoses.
to damage at oil pressure transmitter, eliminate the
transmitter from the system. OPTION 1: Bypass Oil Filter.

OPTION: Remove Pressure Transmitter. LIMITATIONS: Fine suspended matter would not be
filtered from oil system. Rerouted hoses may chafe
LIMITATIONS: Indication of oil pressure conditions parts/structure.
would be eliminated since oil pressure gage would be
inoperable. Caution panels would give early warning PERSONNEL/TlME REQUIRED:
for low pressure conditions, provided switch (1, 1 Soldier
Figure 8-2) is still operable. 15 Minutes

PERSONNEL/TlME REQUIRED: MATERIALS/TOOLS REQUIRED:

1 Soldier Cable Ties (item 26 or 27, App. C)
15 Minutes Towels (item 161, App. C)

8-4
 TM 55-1520-244-BD

1. Transmission Oil
Pressure Switch
2. O-Ring
3. Transmission Oil
Pressure Transmitter
4. O-Ring

Figure 8-2. Transmission Oil Pressure Swithch and Transmitter Repair

8-5
TM 55-1520-244-BD

1. Transmission Oil 8. Oil Line

Pressure Switch 9. Oil Outlet Hose
2. Transmission Oil 10. Oil Manifold Assembly
Pressure Transmitter 11. Emergency Oil
3. Bolt Bypass Valve
4. Oil Inlet Hose 12. O-Ring
5. Jam Nut 13. Fitting
6. 90° Fitting 14. Oil Sump Outlet Hose
7. Oil Filter Assembly 15. Fitting

Figure 8-3. Transmission Assembly, Unaltered

8-6
 TM 55-1520-244-BD

1. Oil Inlet Hose.

2. Oil Filter Assembly.
3. Oil Manifold Assembly

Figure 8-4. Altered Configuration (Transmission Oil System)

Bypassing Filter and Outlet Hose

8-7
TM 55-1520-244-BD

PROCEDURAL STEPS: 4. Connect the two hoses (1, 6, Figure 8-5) together
using fitting (2). Tighten connections and check for
1. Disconnect inlet oilhose (4, Figure 8-3) from oil fil- leaks.
ter assembly (7), leave other end of hose connected.
5. Use tie wraps where possible to minimize any
2. Disconnect oil hose (9) from oil manifold assemb- chafing conditions caused by rerouting of hoses.
ly (10), leave other end connected.
6. Record BDAR action taken. When mission is
3. Reroute and connect loose end of inlet oil hose complete, as soon as practical, repair the equipment/-
(1, Figure 8-4) to oil manifold assembly (3) and system using standard maintenance procedures.
tighten.
OPTION 3: Bypass Filter with 90° Fitting.
4. Check for leaks.
LIMITATIONS: Fine suspended matter would not be
5. Use tie wraps where possible to minimize any filtered from oil system.
chafing conditions caused by rerouting of hose.
PERSONNEL/TlME REQUIRED:
6. Record BDAR action taken. When mission is ●
1 Soldier
● 30 Minutes
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
MATERIAL/TOOLS REQUIRED:
● Towels (item 161, App. C)
OPTION 2: Bypass Filter with Straight Fitting.
● Hand Tools
LIMITATIONS: Fine suspended matter would not be PROCEDURAL STEPS:
filtered from oil system. Rerouted hoses may chafe
adjacent parts/structure.
1. Disconnect and remove inlet oil hose (4, Figure
8-3).
PERSONNEL/TIME REQUIRED:
●
1 Soldier
● 15 Minutes 2. Disconnect outlet hose (9) from oil filter 90° fitting
(6), leave other end of hose connected.
MATERIALS/TOOLS REQUIRED:
● Cable Ties (item 26 or 27, App. C)
3. Loosen outlet hose (9) connection at oil manifold
● Towels (item 161, App. C)
(10).

PROCEDURAL STEPS: 4. Loosen jam nut (5) on 90° fitting at oil filter.

1. Disconnect inlet oil hose (4, Figure 8-3) from oil fil- 5. Break safety wire and remove two bolts (3) on fil-
ter assembly (7), leave other end of hose connected. ter mount bracket.

2. Disconnect outlet oil hose (9) from oil filter assemb- 6. Pull filter assembly slightly away from filter mount-
ly 90° fitting (6), leave other end of hose connected. ing bracket and remove 90° fitting (6) from filter as-
sembly.
3. Remove fitting (15) from oil filter assembly.
7. Reinstall bolts (3).

8-8
 TM 55-1520-244-BD

1. Oil Inlet Hose.

2. Fitting.
3. 90° Fitting.
4. Oil Filter Assembly.
5. Oil Line.
6. Oil Outlet Hose.
7. Oil Manifold Assembly.

Figure 8-5. Altered Configuration (Transmission Oil System)

Bypassing Oil Filter

8-9
TM 55-1520-244-BD

8. Remove jam nut (5) from 90° fitting and retain 2. Remove the sump outlet hose (14), fitting (13),
jam nut (5). and o-ring (12). Do not discard o-ring.

9. Install 90° fitting (1, Figure 8-6) on outlet hose 3. Install the oil filter inlet hose, removed in step 1,
(3). Do not tighten. in place of the sump outlet hose as follows. Refer to
Figure 8-7.
10. Connect outlet hose (3) to oil line, and tighten all
loose connections. NOTE

11. Check for leaks. The male end of the hose (1, Figure 8-7)
must be threaded into oil sump outlet hole
12. Record BDAR action taken. When mission is before the female end of hose is con-
complete, as soon as practical, repair the equipment/- nected to oil bypass valve (2).
system using standard maintenance procedures.
a. Install nut (3) on hose (1) at the male fitting
8-8. SUMP OUTLET HOSE LEAK. end and hand tighten nut (3) until it is touching
against the shoulder of male fitting.
GENERAL INFORMATION: If oil is being lost due
to damage at the oil sump outlet hose, the leak may b. Install o-ring (4) on hose (1) at male fitting.
be repaired by one of the following repair procedures.
c. Screw hose (1) into oil sump outlet hole (5)
OPTION 1: Replace Hose. and hand tighten until nut (3) jams oil sump housing.

OPTION 2: Substitute Transmission Oil Filter Line. d. Position the other end of hose (1) to oil bypass
valve (2).
LIMITATIONS: Transmission oil filter would be iso-
lated from oil system. Fine suspended matter would NOTE
not be filtered from transmission oil system.
If elbow fitting at female end of hose (1) re-
PERSONNEL/TIME REQUIRED: quires repositioning to facilitate hose con-
1 Soldier nection at oil bypass valve (2), slowly back
30 Minutes out hose (1) from oil sump hole (5) until
the elbow is in an acceptable position.
MATERIALS/TOOLS REQUIRED:
Towels (item 161, App. C) e. Tighten hose (1) connection at the oil bypass
Hand Tools valve (2).
Packing Assortment (item 71, App. C)
f. Tighten jam nut (3) against oil sump housing.
PROCEDURAL STEPS:
4. Check for leaks.
1. Isolate oil filter from oil system as outlined in para-
graph 8-7, OPTION 3, and remove the filter inlet hose
5. Record BDAR action taken. When mission is
(4, Figure 8-3) from the system. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

8-10
 TM 55-1520-244-BD

1. 90° Fitting
2. Oil Line
3. Oil Outlet Hose

Figure 8-6. Altered Configuration (Transmission Oil System)

Bypassing Filter and Inlet Hose

8-11
TM 55-1520-244-BD

Figure 8-7, Altered Configuration (Transmission Oil System)

Substituting Hose at Sump Outlet (Sheet 1 of 2)

8-12
 TM 55-1520-244-BD

VIEW A

1. Hose.
2. Emergency Oil Bypass Valve.
3. Jam Nut.
4. O-Ring.
5. Oil Sump Outlet Hole.

Figure 8-7. Altered Configuration (Transmission Oil System)

Substituting Hose at Sump Outlet (Sheet 2 of 2)

8-13
TM 55-1520-244-BD

8-9. TRANSMISSION BALLISTIC DAMAGE. 8-10. GEARBOX DAMAGE.

GENERAL INFORMATION: If the transmission is GENERAL INFORMATION: If a bullet strikes the

hit by a bullet which exits on the opposite side, the gearbox and exits and the gears do not jam or bind
transmission does not bind and there is no oil loss, and there is no loss of lubricant, repair may be
repair may be deferred. Oil loss will require patching deferred. Oil loss will require patching holes.
holes.
OPTION 1: Plug Repair. (Refer to para 6-4.)
OPTION: Patch Hole with Tape.
OPTION 2: Tape Repair.
LIMITATIONS: Small oil loss can be tolerated. in-
spect after every flight. LIMITATIONS: Small oil loss can be tolerated.
If aircraft is run for an extended period of time with lit-
NOTE tle or no oil, gearbox will wear itself out and fail.

Transmission will run for a maximum of 30 PERSONNEL/TIME REQUIRED:

minutes without oil. ●
1 Soldier
●
15 Minutes
PERSONNEL/TIME REQUIRED:
●
1 Soldier MATERIALS/TOOLS REQUIRED:
● Solvent (item 7 or 129, App. C)
● 15 Minutes
● Green Tape (item 153, App. C)

● Rubber for Patch (item116, App. C)

MATERIALS/TOOLS REQUIRED:
● Solvent (item 7 or 129, App. C)

● Green Tape (item 153, App. C)

PROCEDURAL STEPS:

PROCEDURAL STEPS: 1. Clean damaged area with solvent.

1. Clean damaged area with solvent. 2. Close bullet hole with a rubber patch, 3/4 inch
larger than hole, and secure with tape.
2. Close bullet inlet and exit hole with tape.
3. Inspect after every flight.
3. Inspect after every flight.
4. Record BDAR action taken. When mission is
4. Record BDAR action taken. When mission is complete, as soon as practical, repair the equipment/-
complete, as soon as practical, repair the equipment/- system using standard maintenance procedures.
system using standard maintenance procedures.

Section Ill. TAIL ROTOR DRIVESHAFT

8-11. GENERAL. Due to high rotational speeds, housings, gearboxes, and couplings due to “whip” ef-
damage to transmission shafts can induce vibrations fects. Any repair should therefore include the restora-
which will cause failures in bearings, bearing tion of balance.

8-14
 TM 55-1520-244-BD

8-12. DENTS OR BALLISTIC DAMAGE TO LIMITATIONS: Fragments or solid shot must avoid
SHAFTS. the center of a shaft, Figure 8-9. Inspect after every
flight.
GENERAL INFORMATION: After any of the follow-
ing repairs are made, the shaft should be mounted in PERSONNEL/TIME REQUIRED:
its hanger bearings, unconnected and spun by hand ●
1 Soldier
to check for “whipping” deflection. ●
1 Hour

OPTION 1: Tape Patch, Figure 8-8. MATERIALS/TOOLS REQUIRED:

● Drill Motor and Bit

● String or Wire (item 149 or 60, App. C)

LIMITATIONS: Entrance and exit holes 180° apart.
● Ruler
Inspect after every flight.
PROCEDURAL STEPS:
PERSONNEL/TIME REQUIRED:
●
1 Soldier
1. Gain access to the damaged driveshaft.
●
1 Hour

MATERIALS/TOOLS REQUIRED: 2. Straighten the petals around the entrance and

● Green Tape (item 153, App. C)
exit holes.

PROCEDURAL STEPS: 3. Measure arc S, Figure 8-10, by placing one end

of a string or wire on the center of the entrance hole
1. Gain access to the damaged driveshaft. and stretching it across to the center of the exit hole
and mark the string at the mid point of the exit hole.
2. Restore balance in shaft by straightening petals Then measure the string from the entrance hole end
around the entrance/exit hole (i.e., damaged area is to the exit hole mark.
tapped back to a relatively smooth surface).
4. Determine the value of Y, Figure 8-10, by using
3. Wrap tape around the shaft over the holes. Tape the S value found in step 2.b and using the graph in
should be wrapped opposite direction of shaft rotation. Figure 8-11.

4. Record BDAR action taken. When mission is 5. Estimate the amount of material (in square
complete, as soon as practical, repair the equipment/- inches) removed from the entrance and exit holes.
system using standard maintenance procedures. Let a1 equal to the material lost in the entrance hole
and a2 equal to the material lost in the exit hole.
OPTION 2: Drill Balance Hole.
6. Calculate the area A of the counter hole using the
following formula. (“A” will be in square inches.)

"A"= (a1 + a2) X (Y/1 .5)

● Operation of power tools may exceed
recommended noise thresholds. Wear
hearing protection.

. Compressed air can blow dust into eyes.

Wear eye protection. Do not exceed 30
psig air pressure.

8-15
TM 55-1520-244-BD

B. PETAL STRAIGHTENED TO A RELATIVELY SMOOTH SURFACE

Figure 8-8. Damage Passing Through Center of Shaft

8-16
 TM 55-1520-244-BD

Figure 8-9. Damage Not Passing Through Center of Shaft

8-17
TM 55-1520-244-BD

Figure 8-10. Balance Restoring Repair for Damage Not

Passing Through the Center of Shaft

8-18
 TM 55-1520-244-BD

Figure 8-11. Y and S Graph

Figure 8-12. Area and Diameter Graph

8-19
TM 55-1520-244-BD

7. Determine the value ford using the graph in PROCEDURAL STEPS:

Figure 8-12. The valued is the diameter (in inches) of
hole A. 1. Gain access to damaged driveshaft.

8. Calculate the value Z distance from the entrance 2. Straighten petals around the entrance and exit
hole to counter drilled hole by using the following for- holes so that the damaged area has a relatively
mula. smooth surface, Figure 8-13.

a 2S 3. Stop drill any cracks.

z = 4.71- (a1+a2)
4. Fabricate a sheet metal plate to wrap around
The hole is to be of diameter d which was determined over damaged area. The length of the sheet metal
in step 2.f. Drill the hole. plate should be approximately 9-7/16 inches the shaft
circumference. The width of the plate should extend
at least 3 inches beyond each side of the damaged
9. Record BDAR action taken. When mission is
area.
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
5. Wrap the sheet metal plate, fabricated in proce-
dural step 4, around the damaged portion of
OPTION 3: Metal Plate Patch.
driveshaft. The plate ends should come together 180°
opposite the damaged area.
LIMITATIONS: Damaged area not to exceed one-
third of total cross-sectional area. Restrict helicopter
6. Apply a row of rivets, at preferred rivet spacing,
from high speed operation.
across each end of plate and around edges, Figure
8-14.
PERSONNEL/TlME REQUIRED:
1 Soldier
7. Two rows of counter weight rivets are to be
2 Hours
placed 180° opposite the rows which were used to
MATERIALS/TOOLS REQUIRED: secure the edges of the sheet metal plate.
Sheet Metal (items 132, 134, 135,
139, or 142, App. C) 8. Install directly over damaged area a number of
Rivet, Blind (items 98-105, App. C) rivets to compensate for the missing mass in the
Drill Motor and Bit damaged area. See Figure 8-15 and/or Table 8-2 for
data on number of rivets required forgiven shaft area.

9. Record BDAR action taken. When mission is

complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

8-20
 TM 55-1520-244-BD

Figure 8-13. Damaged Shaft; Petals Straightened Smooth

8-21
TM 55-1520-244-BD

Figure 8-14. Repaired Shaft

8-22
 TM 55-1520-244-BD

Figure 8-15. Shaft Area (in2) vs. Number of Rivets

8-23/(8-24 blank)
 TM 55-1520-244-BD

CHAPTER 9

HYDRAULIC SYSTEMS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

9-1. SCOPE. This chapter contains the fault as-

sessment and expedient repair procedures for locat-
ing and fixing damage to the hydraulic systems. A
When checking the armament system, do
functional diagram of the hydraulic system is shown
not apply hydraulic power unless electrical
in Figure 9-1, and pictorially in Figures 9-2, 9-3, 9-4,
power is applied.
and 9-5.
e. No specific assessment procedures are
9-2. ASSESSMENT PROCEDURES.
needed to locate leaks and ruptured lines; therefore,
the fault assessment flow chart, Table 9-1, is rather
a. The hydraulic system is redundant, consisting general in nature.
of two parallel systems. If one system is damaged,
the aircraft can fly with the other system operating,
f. Each area of damage must be carefully
but the components operated by the failed system will
evaluated and classified in order to differentiate be-
not operate.
tween leaks which require immediate repair before
flight and leaks which do not constitute a flight
NOTE hazard. The exact location of a leak shall be deter-
mined and the leak area examined thoroughly.
If the damaged component still operates
satisfactorily and does not leak, repair may 9-3. REPAIR PROCEDURE INDEX.
be deferred. However, the component
should be inspected after every flight to as-
PARA.
sure that operation has not degraded or
that a leak has not developed.
Leaking Hoses . . . . . . . . . . ...9-5
b. BDAR for a hydraulic system is generally con- Leaking Metal Tubing . . . . . . . . .9-7
fined to component replacement, expedient line
repairs, or bypassing damaged circuits. If a hydraulic Lock-Out Valve Stuck Closed . . . . .9-9
circuit cannot be repaired, it may be necessary to iso- No. 1 Hydraulic System
late it (cut it off) from the system to permit operation I Pump Inoperative . . . . . . . . . .9-11
of some other needed hydraulic functions. Damage to No. 2 Hydraulic System
the hydraulic system almost always requires Pump Inoperative . . . . . . . . . .9-12
replenishment of lost fluids. Replacement of Packings . . . . ...9-14
Hydraulic Fluid Substitution . . . . . .9-15

Bring hydraulic system to Zero Pressure

before making repairs.

9-1
TM 55-1520-244-BD
Figure 9-1. Hydraulic System Schematic (Sheet 1 of 2)
9-2
 TM 55-1520-244-BD
Figure 9-1. Hydraulic System Schematic (Sheet 2 of 2)
9-3
TM 55-1520-244-BD

Figure 9-2. Hydraulic System - SYSTEM NO.

9-4
 TM 55-1520-244-BD

1. Pressure Switch
2. Solenoid Valve (sys 2)
P/N 88604-1
3. Hydraulic Modular Unit
4. Relief Valve
5. Check Valve
6. Pump
7. Solenoid Valve P/N 204-076-054-3
P/N 1-U-1025-63 or
P/N 130027-5
8. Solenoid Valve P/N 204-076-504-3
P/N 1-U-1025-63 or
P/N 130027-5
9. Relief Valve
10. Check Valve
11. Flow Regulator
12. Check Valve
13. Pressure Relief Valve
14. Pressure Switch
15. Filter
16. Check Valve
17. Solenoid Valve (SCAS SYS)
P/N 209-076-021-1
PIN 15353
18. Filter
19. Check Valve
20. Check Valve
21. Solenoid Valve (SCAS sys)
P/N 209-076-023-1
P/N 15353
22. Filter
23. Check Valve
24. Reservoir Assembly

Figure 9-2. Hydraulic System - SYSTEM NO. 2 (Sheet 2 of 2)

9-5
TM 55-1520-244-BD
Figure 9-3.
9-6
 TM 55-1520-244-BD

Figure 9-4. Hydraulic System - Armament (Sheet 1 of 2)

9-7
TM 55-1520-244-BD

1. Solenoid Valve (armament)

P/N 204-076-504-3 FSCM 94641
P/N 1-U-1025-63 or
P/N 130027-5
2. Check Valve
3. Servo Actuator
4. Servo Actuator
5. Check Valve (M) Only
6. Cross

Figure 9-4. Hydraulic System - Armament (Sheet 2 of 2)

9-8
 TM 55-1520-244-BD

1. Filler Cap P/N 1-U-1025-63, or

2. Reservoir Assembly P/N 130027-5
3. Solenoid Valve (sys return) 5. Filter
P/N 204-076-504-3, 6. Pressure Relief Valve
P/N 1-7-1025-63, or 7. Pressure Switch
P/N 130027-5 8. Sight Gage
4. Solenoid Valve (sys pressure) 9. Emergency Hydraulic Pump
P/N 204-076-504-3, Package

Figure 9-5. Emergency (Electric Motor Driven) Hydraulic System

9-9
TM 55-1520-244-BD

Table 9-1.

Table 9-1.

PARA 9-11

PARA 9-5, 9-7

PARA 9-14

PARA 9-12

PARAS 9-5,
9-7

PARA 9-14

PARA 9-9

PARA 9-15

9-10
 TM 55-1520-244-BD

Section Il. HOSES

9-4. GENERAL.

a. Replacement hoses maybe manufactured in Prolonged contact with hydraulic fluid or mist
the field if materials are available. It is considered can irritate eyes and skin. Wear rubber gloves
quicker to make a replacement hose using the old fit- when handling liquid. After any prolonged con-
ting, if serviceable, than to repair a damaged hose. tact with skin, immediately wash contacted
There are two types of fittings used. One fitting is a area with soap and water. If liquid contacts
socket and nipple assembly (Figure 9-6), and the eyes, flush immediately with clear water. If liq-
other type is a nipple, o-ring, sleeve, and socket uid is swallowed, do not induce vomiting, get
(Figure 9-7). immediate medical attention. If prolonged ex-
posure with mist is likely, wear an appropriate
b. Replacement hoses need not be routed along respirator. When fluid is decomposed by heat-
the path of the original installation. They maybe ing, toxic gases are released.
routed along any convenient path as long as they do
not interfere with personnel or with operating equip- Compressed air can blow dust into eyes. Wear
ment. Long hoses should be clamped to hard sup- eye protection. Do not exceed 30 psig air pres-
ports at convenient intervals not exceeding 24 inches. sure.
Hose may be used as a substitute for metal tubing.
Extremely high pressure can occur during and
after operation of certain equipment. If this
c. The hydraulic hoses on the AH-1 are braided, pressure is not relieved before working on
wire covered, rubber or Teflon hose. Repair of equipment, serious injury or death may occur.
damage or wear to the wire braids is deferrable for Be sure to open all vents before beginning any
one more flight, provided the inner hose is not leaking disassembly.
under pressure. Kinks in the braided cover should be
gently straightened by hand. If possible, wrap frayed 9-5. LEAKING HOSES. If leaks are not causing
wires with tape. If the inner hose is leaking, replace rapid fluid loss, repair may be deferred.
using BDAR fluid line kit or cannibalized parts. If an
elbow fitting is not available, a hose with a large
OPTION 1: Install New Hose Assembly-BDAR Kit.
gentle loop can be used. MS detachable fittings from
a damaged hose may be reused. Swaged fittings can-
not be reused. LIMITATIONS: None

PERSONNEL/TIME REQUIRED:
1 Soldier
20 Minutes

9-11
 TM 55-1520-244-BD

Figure 9-6. Two-Part Fitting

Figure 9-7. Four-Part Fitting

9-12
 TM 55-1520-244-BD

MATERIAL/TOOLS REQUIRED: 3. Hold in a vice and cut with a finetoothed hack-

● Fluid Line Repair Kit (item 4, App. B) saw. Take care to make square cut. Do not remove
tape.
PROCEDURAL STEPS:
NOTE
1. Remove damaged hose assembly.
If the damage is small, the length of a
2. Install new hose assembly (BDAR kit). It maybe single union may be sufficient to provide a
necessary to splice two or more hose assemblies repair. However, if the damage is longer, a
together using MS unions to replace the damaged replacement hose section will be required.
hose assembly. No harm will be done if the replace-
ment hose is too long. 4. Slip the MS socket over the ends of the hose,
Figure 9-8. Use care not to unravel the wire braids.
3. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/- 5. Insert the MS sleeve between the wire braid
system using standard maintenance procedures.
cover and the inner Teflon hose, Figure 9-8.
OPTION 2: Replace Hose Section. 6. Force sleeve onto hose until the edge of the
sleeve is even with the end of the inner hose liner.
LIMITATIONS: None.
7. Reem inside end of the Teflon hose with a
PERSONNEL/TIME REQUIRED: tapered tool or a wooden plug so that the edge is
Ž 1 Soldier smooth and flared to facilitate insertion of the nipple
● 30 Minutes of the MS female fitting.
MATERIAL/TOOLS REQUIRED:
● Replacement Section of Hose or Tube
8. Slide the MS socket over end of hose as far as it
(if needed) will go and hold in vise. Insert nipple of MS female fit-
● Masking Tape (item 152, App. C)
ting into Teflon inner tube, Figure 9-9.
● Fine Toothed Hacksaw

● MS Fittings (socket, sleeve, and

9. Insert female fitting until threads in socket and
female fitting) female fitting come together.
Ž MS Unions
● Fluid Line Repair Kit (item 4, App. B) 10. Tighten until the gap between the edge of the
socket and the base of the female fitting is ap-
PROCEDURAL STEPS: proximately 0-1/32 inch for rubber and 0.025 to 0.045
inch for Teflon.
1. Wrap masking tape (or other available tape)
around hose over the areas where cuts are to be 11. Prepare the other damaged end of the hose in
made to contain the braided wires from unraveling. the same manner.

2. Mark on tape where the cuts are to be made.

9-13
TM 55-1520-244-BD

Figure 9-8.

Figure 9-9. Assembly of MS Hose Fitting

9-14
 TM 55-1520-244-BD

12. If no replacement section is 14. Refer to steps 4 thru 11 for MS

necessary, connect the MS fittings on fitting installation.
the undamaged ends with an MS union,
Figure 9-16. If a replacement section 15. Install replacement hose section
is needed, obtain replacement section using MS unions.
and cut to desired length. Refer to
step 1 for procedure for cutting hose. 16. Record BDAR action taken. When
No harm will be done if replacement mission is complete, as soon as
section is too long. practical, repair the equipment/system
using standard maintenance procedures.
13. Attach MS fittings to both sides
of the replacement section.

Section III. METAL TUBING

9-6. GENERAL. Metal tubing is subject c. Carefully remove any burrs from
to damage by projectiles and fragments. the inside and outside of the tube.
In BDAR, tubing and hose, AN and MS fit- Use a knife or any other sharp instru-
tings, and other similar components can ment to deburr the tubing.
be substituted one for the other.
Available time, tools, skills, and d. If a tube cutter is not available
materials will determine which repair or if tubing of hard material is to be
option to use. Whenever a line has cut, use a fine toothed hacksaw, pre-
complex bends, replacement of the ferably one having 32 teeth per inch.
damaged section with hose is usually
the quickest fix. e. After sawing, file the end of tube
square, smooth, and remove all burrs.
9-7. LEAKING METAL TUBING. Be sure all cuttings are removed from
Preparation of tube ends. When cutting inside the tubing. Inspect the tubing
tubing, it is of utmost importance to end to verify its roundness, its being
produce a squared end free of burrs. cut square, and that it is clean and
Tubing may be cut with a tube cutter or free from draw marks and scratches.
a hacksaw. The tube cutter (Figure Figure 9-11 illustrates a properly
9-10) is adaptable for use with metal burred tubing end.
tubing such as titanium, stainless
steel, or aluminum alloy. The NOTE
following steps may be used to prepare
tube ends. After tubing has been cut, flush
any residue from the tube end.
a. Place tubing in the cutting tool Flush with any available fluid,
with the cutting wheel at the point or if end connections are diffi-
where the cut is to be made. cult to access, momentary activa-
tion of the system will suffice.
b. Ratchet the cutter around the
tubing applying a light pressure to the OPTION 1: In Line Repair.
cutting wheel by intermittently
tightening the setscrew. Too much LIMITATIONS: None.
pressure on the cutting wheel at one
tightening could deform the tubing or PERSONNEL/TIME REQUIRED:
cause excessive burring. • 1 Soldier
Ž 30 Minutes

9-15
TM 55-1520-244-BD

Figure 9-10.

SECTION A-A

Figure 9-11. Properly Burred Tubing

9-16
 TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED: OPTION 2: Substitute with High Pressure

Fluid Line Repair Kit (item 4, Appx B) Hose.
4 MS Fittings
2 MS Unions LIMITATIONS: None.
Splice Tube
Tubing Cutter PERSONNEL/TIME REQUIRED:
Knife or File 1 Soldier
30 Minutes
1. Cut and remove damaged section of
tubing, Figure 9-12. Tube ends must be MATERIALS/TOOLS REQUIRED:
cut square. Hydraulic Hose Assy Complete with
End Fittings
2. Clean ends of undamaged tubing with MS Unions
knife or file. Tube Cutter
Knife or File
3. Prepare all tubing ends as Fluid Line Repair Kit (item 4, Appx B)
instructed in paragraph 9-7.
PROCEDURAL STEPS:
NOTE
1. Cut and remove damaged section of
Replacement tubing need not be tubing, Figure 9-12. Tube ends must be
routed along the path of the cut square.
original installation. Tubing
may be routed along any conve- 2. Clean ends of undamaged tubing with
nient path as long as it does not knife or file.
interfere with personnel or with
operating equipment. Long lines 3. Install MS tube fittings as shown in
should be clamped to hard sup- Figure 9-13.
ports at convenient intervals not
exceeding 24 inches. 4. Connect MS unions to both tube ends
and complete the repair by connecting a
4. Measure the distance between the two hydraulic hose assembly from one union
undamaged ends and cut a tube splice to the other, Figure 9-15.
replacement section of this length.
5. If the damaged length of tubing is
5. Prepare ends of splice section. long and more than one hose assembly is
required, hose assemblies may be spliced
6. Install a MS fitting on each end together with unions.
of the tubes, Figure 9-13.
NOTE
7. Install splice tube in line along
with 2 unions and tighten, Figure 9-14. No harm will be done if the
replacement hose is too long.
8. Record BDAR action taken. When
mission is complete, as soon as 6. Clamp at convenient intervals, not
practical, repair the equipment/system exceeding 2 feet, to hard supports.
using standard maintenance procedures.
7. Record BDAR action taken. When
mission is comple te, as soon as
practical, repair the equipment/system
using standard ma intenance procedures.

9-17
TM 55-1520-244-BD

Figure 9-12. Damaged Tube Sections

9-18
 TM 55-1520-244-BD

Figure 9-13. MS Tube Fitting Installation

Figure 9-14. Completed Tubing Installation

9-19
TM 55-1520-244-BD

Figure 9-15. Completed High Pressure Hose Substitution

OPTION 3: Repair with MS Union (use to PROCEDURAL STEPS:

fix hole in existing hose).
1. Cut and remove short damaged
LIMITATIONS: None. section of hose.

PERSONNEL/TIME REQUIRED: 2. Clean ends of hose and slip an MS

2 Soldiers socket and sleeve over each end, as
1 Hour shown in Figures 9-8 and 9-9.

MATERIALS/TOOLS REQUIRED: 3. Install and tighten union, Figure

Hydraulic Hose 9-16.
MS Fittings
Tube Cleaner 4. Record BDAR action taken. When
Tube Cutter mission is complete, as soon as
Hacksaw practical, repair the equipment/system
Hand File using standard maintenance procedures.
Fluid Line Repair Kit (item 4, Appx B)
OPTION 4. Repair Return Lines.
(Primarily for low pressure lines.)
Refer to hose and tubing repair options
in Chapter 12.

9-20
 TM 55-1520-244-BD

Figure 9-16.

Section IV. HYDRAULIC COMPONENTS

9-8. GENERAL. Hydraulic components receiving MATERIALS/TOOLS REQUIRED:

ballistic damage are prone to shattering or tearing. l Common Hand Tools
The component will usually require replacement, al- l Packing Assortment (item 71, App. C)
though items such as filters maybe by passed.
PROCEDURAL STEPS:
9-9. LOCK-OUT VALVE STUCK IN CLOSED
POSITION. 1. Remove defective lock-out valve assembly from
aircraft.
GENERAL INFORMATION: If the hydraulic system
is inoperable and the flight controls are binding with NOTE
the pressure on, one reason might be that the lock-
out valve (Figure 9-1 7) is stuck in the closed position. During disassembly, take care not to
Turn one system off. If the other system then damage packings.
operates, the lock-out valve on the turned-off system
probably is the cause for the failure of the combined
system to operate. 2. Disassemble item 1 thru 12, Figure 9-17. Clean
and inspect.
OPTION 1: Disassemble and Clean.
NOTE
LIMITATIONS: Self-recovery or one more mission Replace packing with new packing if possible.
not requiring abrupt maneuvers. Refer to App. D for packing substitutions.

PERSONNEL/TIME REQUIRED: Relube parts before reassembly.

1 Soldier
1 Hour Per Unit

9-21
TM 55-1520-244-BD

Figure 9-17. Lock-Out Valve Assembly

9-22
 TM 55-1520-244-BD

Section V. HYDRAULIC SYSTEM ISOLATION

9-10. GENERAL.
a. Both hydraulic systems jointly operate the three O-rings, wipers, gaskets or other plastic, or
flight control power cylinders: cyclic fore and aft, cyclic rubber parts of the hydraulic system may
lateral, and collective. In addition, each system in- swell or shrink, and for that reason continued
dividually operates a set of several other subsystems. operability of the system cannot be guaran-
b. If the No. 1 system hydraulic pump were to fail, teed. Following such a substitution, instruc-
the tail rotor control hydraulic cylinder and the yaw tions for bringing the system back to normal
stability and control augmentation system SCAS servo- should include checking all moving parts of
actuator would be inoperable. Without the tail rotor the hydraulic system and all hydraulic
hydraulic cylinder, the pedal controls would be very stiff. activated devices for proper operation and
It would be possible but very difficult to fly the aircraft leaks. Where feasible, in critical areas,
through simple maneuvers. Without the services of the plastic and rubber parts should be inspected
yaw SCAS servo actuator, it would be difficult to main- for swelling, deformation, and other damage.
tain control at speeds above 90 knots. Also, without the 9-11. NO. 1 HYDRAULIC SYSTEM PUMP IN-
use of the yaw servo actuator, erratic airframe move- OPERATIVE.
ments such as those caused by strong winds or arma-
ment recoil could cause the aircraft to drift. GENERAL INFORMATION: If the No. 1 hydraulic
pump fails, the system can be altered to isolate the No.
c. If the No. 2 system hydraulic pump were to fail, 1 pump from the hydraulic system. The No. 2 hydraulic
the armament and tow missile launcher systems and the pump will operate all those systems operated by the No.
pitch and roll SCAS servo actuators would be in- 1 system in addition to those systems which it operates
operable. Without hydraulic pressure to the armament under normal usage.
and tow missile launcher systems, these systems will
not operate. Without the services of the pitch and roll OPTION: Isolate No. 1 Pump.
SCAS servo-actuator, it would be difficult to maintain LIMITATIONS: Avoid any abrupt maneuvers. Inspect
control at speeds above 90 knots. Also, without the pitch after every flight.
and roll SCAS actuators working, any erratic airframe
movements such as those caused by strong winds or PERSONNEL/TIME REQUIRED:
armament recoil could cause the aircraft to drift. Ž 2 Soldiers
●3 Hours

MATERIAL/TOOLS REQUIRED:
When handling hydraulic fluid, observe the One Hose Assembly 3/8 X 24 inches
following: Prolonged contact with liquid or One Tee Fitting-MS21912 D6
mist can irritate eyes and skin. After any One No. 6 Steel Plug Fitting MS21913-6
prolonged contact with skin, immediately One No. 6 Steel Cap Fitting MS21914-6
wash contact area with soap and water. If Hydraulic Fluid
liquid contacts eyes, flush them immediately Fluid Line Repair Kit (item 4, App. B)
with clear water. If liquid is swallowed, do not
induce vomiting; get immediate medical PROCEDURAL STEPS:
attention. Wear rubber gloves when handling
1. Drain hydraulic fluid from reservoir system No. 2 by
liquid. If prolonged contact with mist is likely,
disconnecting bypass tube fitting (1, Figure 9-1 8).
wear an appropriate respirator. When fluid is
Leave tube disconnected.
decomposed by heating, toxic gases are
released. 2. Drain hydraulic fluid from reservoir system No. 1 by
disconnecting fluid return tube fitting (11, Figure 9-1 8).
3. Plug elbow fitting by installing steel cap fitting (5,
Figure 9-19).
4. Remove electrical wire clamp from return tube (12,
Figure 9-18).
5. Disconnect tube fitting (5, Figure 9-18).
6. Remove return tube assembly (13, Figure 9-18)
from aircraft.
7. Disconnect tube fitting (6, Figure 9-18).

9-23
TM 55-1520-244-BD

1. Tube Fitting, 5. Tube Fitting 10. Quick Disconnect, Return

Bypass 6. Tube Fitting 11. Tube Fitting
2. Hose Fitting, 7. Quick Disconnect, 12. Electrical Clamp
Return Pressure 13. Tube Return Sys No. 1
3. Elbow Fitting 8. Elbow, Pressure 14. Drain Plug
4. Hose Fitting 9. Union 15. Hose, Return Sys No. 2

Figure 9-18. Hydraulic System, Unaltered

9-24
 TM 55-1520-244-BD

1. Tube Fitting, Bypass 6. Tube Fitting

2. Hose Fitting, Return 7. Tee Fitting
3. Elbow Fitting 8. Hose Assembly
4. Hose Fitting 9. Union
5. Steel Cap 10. Quick Disconnect, Return

Figure 9-19. Hydraulic System, Isolating No. 1 System

9-25
TM 55-1520-244-BD

8. Disconnect hose fitting (2, Figure 9-1 8). 18. Connect the other end of hose to elbow fitting
(3, Figure 9-19).
9. Remove elbow fitting (3, Figure 9-1 8) from sys-
tem No. 2 reservoir. 19. Tighten all connections that have been broken
and remade in procedural steps above.
10. Replace elbow with a “tee” fitting (7, Figure
9-1 9) as shown. Leave tee fitting loose. 20. Refill hydraulic reservoir system No. 2.

11. Remove filter screen from elbow fitting (3, 21. Without disconnecting hydraulic lines, remove
Figure 9-1 9) and connect elbow to tube fitting (6, isolated hydraulic pump No. 1 from drive pad on right
Figure 9-1 9). hand side of transmission sump case and set clear of
transmission, Figure 9-20.
12. Disconnect hose fitting (4, Figure 9-1 8) and con-
nect to “tee” fitting (9, Figure 9-21) as shown. 22. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
13. Connect hose fitting (2, Figure 9-19) to “tee” system using standard maintenance procedures.
fitting (7, Figure 9-19) as shown.
9-12. NO. 2 HYDRAULIC SYSTEM PUMP
14. Reconnect bypass tube fitting (1, Figure 9-19) INOPERATIVE.
as shown.
GENERAL INFORMATION: If the No. 2 hydraulic
NOTE pump fails, the system can be altered to isolate the
No. 2 pump from the hydraulic system. The No. 1
hydraulic pump will operate all those systems
Return quick disconnect (1O, Figure 9-18)
operated by the No. 2 system in addition to those sys-
needs to be pivoted down as shown (1O, tems which it operates under normal usage.
Figure 9-1 8), in order to remove pressure
quick disconnected and elbow fitting.
OPTION: Isolate No. 2 Pump.
15. Disconnect and remove system pressure quick
disconnect (7, Figure 9-18) and elbow fitting (8, LIMITATIONS: Avoid any abrupt maneuvers.
Figure 9-18).
PERSONNEL/TlME REQUIRED:
NOTE ● 2 Soldiers
● 3 Hours

Union (9, Figure 9-18) to remain in module. MATERIALS/TOOLS REQUIRED:

●
Two Hose Assembly 3/8 X 24 inches.
16. Obtain a hose assembly (8, Figure 9-19). This ●
One Tee Fitting MS21912-D6
hose should be 3/8 X 24 inches (two 12 inch hose as- ●
One No. 6 Steel Plug Fitting
semblies may be spliced together with a MS union). MS 21913-6
● One No. 6 Steel Cap Fitting MS21914-6
17. Connect one end of hose assembly (8, Figure ● Hydraulic Fluid (App. D)
9-19) to system pressure union (9, Figure 9-19). ●
Fluid Line Repair Kit (item 4, App. B)

9-26
 TM 55-1520-244-BD

Figure 9-20. Hydraulic Pump and Drive Pad

9-27
TM 55-1520-244-BD

PROCEDURAL STEPS: NOTE

1. Drain hydraulic fluid from reser- Union (9, Figure 9-18) to

voir system No. 1 by removing drain plug remain in module.
(14, Figure 9-18).
Obtain a hose assembly (8, Figure
2. Reinstall drain plug. 9-21). This hose should be 3/8 X 24
inches (two 12 inch hose assemblies may
3. Drain hydraulic fluid from reser- be spliced together with an MS union).
voir system No. 2 by disconnecting Connect one end of hose assembly (8,
bypass tube fitting (1, Figure 9-18). Figure 9-21) to system pressure union
Leave tube disconnected. (9, Figure 9-21).

4. Disconnect hose fitting (2 Figure 13. Connect the other end of hose to
9-18) and remove elbow fitting (3, elbow fitting (3, Figure 9-21).
Figure 9-18).
Remove hose assembly (15, Figure
5. Install steel plug fitting (7, 9-18) .
Figure 9-21).
15. Obtain a hose assembly (2, Figure
6. Reconnect bypass tube fitting (1, 9-21) (two 12 inch hose assemblies may
Figure 9-21). be spliced together with an MS union).

Disconnect tube fitting (6, Figure 16. Connect one end of hose assembly to
9-18) . return quick disconnect (10. Figure
9-21) and the other end to tee fitting
8. Remove filter screen from elbow (11, Figure 9-21) as shown.
fitting (3, Figure 9-21) and connect
elbow to tube fitting (6, Figure 9-21). 17. Tighten all connections that have
been broken and remade in procedural
9. Disconnect tube fitting (4, Figure steps above.
9-18) and hose fitting (5, Figure 9-18)
from elbow fitting attached to bracket 18. Refill hydraulic reservoir system
assembly. No. 1.

10. Connect tube fitting (4, Figure 19. Without disconnecting hydraulic
9-21) and hose fitting (5, Figure 9-21) lines, remove isolated hydraulic pump
to tee fitting (11, Figure 9-21). Tee No. 2 from drive pad on right hand side
fitting is to be placed directly above of transmission sump case and set clear
bracket assembly. of transmission, Figure 9-20.

NOTE 20. Record BDAR action taken. When

mission is complete, as soon as
Return quick disconnect (10, Fig. practical, repair the equipment/system
9-18) needs to be pivoted down as using standard maintenance procedures.
as shown (10, Fig. 9-21), in order
to remove pressure quick disconnect
and elbow fitting.

11. Disconnect and remove system

pressure quick disconnect (7, Figure
9-18) and elbow fitting (8, Figure
9-18).

9-28
 TM 55-1520-244-BD

1. Tube Fitting 5. Tube Fitting 9. Union

2. Hose Assembly 6. Tube Fitting 10. Quick Disconnect,
(from BDR kit) 7. Steel Plug Return
3. Elbow Fitting 8. Hose Assembly 11. Tee Fitting
4. Hose Assembly

Figure 9-21. Hydraulic System, Isolating No. 2 System

9-29
TM 55-1520-244-BD

Section VI. O-RING, PACKING, AND GASKETS

9-13. GENERAL. b. Selection of Proper Packing or

Gasket. Selection of proper packing or
a. O-rings are used in static and gasket for a particular application is
dynamic applications. of the utmost importance. The exact
size, shape, and material composition
(1) In static applications, the must be properly determined in order for
o-ring serves as a gasket when it is various systems to function correctly.
compressed within a recess. Leakage is Packings, gaskets, or seals. Similar
not normally acceptable. to fittings, packings are made to an
AN, MS, or NAS standard.
(2) In dynamic applications, the
sealing action is dependent primarily on 9-14. REPLACEMENT OF PACKINGS. While
the resilience of the o-rings. When packings may look alike in general con-
moving parts are involved, minor seepage struction features and may be of the
may be normal and acceptable. A moist same size, they are not necessarily
surface found on moving parts of a made from the same compound. Refer to
hydraulic unit (piston shaft is an Appendix D for a complete listing of
indication that the seal is being interchangeable packings. The dimen-
properly lubricated. sional relationship between AN6227,
AN6230, and MS 28775 series o-ring
(3) Seal replacement is required packings and gaskets in the various
when the following steps occur: sizes is as follows:

(a) The amount of fluid being .AN6227-B1 through B7 are equivalent

lost will cause system failure. to MS28775-006 through MS28775-012.

(b) The leak creates a hazard. •AN6227-B8 through B14 are equivalent
to MS28775-11O through MS28775-116.
(c) The leak will not permit
the system to function safely for one .AN6227-B15 through B27 are equivalent
more flight. to MS28775-21O through MS28775-222.

NOTE •AN6227-B28 through B52 are equivalent

to MS28775-325 through MS28775-349.
Packings and gaskets are identi-
fied by part number on packages. •AN6227-B53 through B87 are equivalent
Do not remove from package until to MS28775-426 through MS28775-460.
ready for use.
.AN6227B88 is equivalent to MS28775-
425.

.AN6230-B1 through B25 are equivalent

to MS28775-223 through MS28775-247.

9-30
 TM 55-1520-244-BD

Section VII. HYDRAULIC FLUID SUBSTITUTIONS

9-15. GENERAL. If the original specified fluid is a BDAR action as a last resort. Consideration should
lost and standard replacement is not available, a sub- be given to salvaging fluid during repairs. Con-
stitute fluid must be used. Check Appendix D for a taminated fluid may be strained through fine weave
compatible fluid. If a compatible fluid is not available, linen or clothing fabric and reused.
any available non-flammable lubricant can be used in

9-31/(9-32 blank)
 TM 55-1520-244-BD

CHAPTER 10

INSTRUMENT SYSTEMS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

There are no BDAR repairs offered for the instrument systems.

10-1/(10-2 Blank)
 TM 55-1520-244-BD

CHAPTER 11

ELECTRICAL AND AVIONICS SYSTEM

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

11-1. SCOPE. This chapter provides b. Circuit Function. The unit

methods for assessing battle damage, number and circuit designation letter
deferring damage repair, and repairing identify the type of circuits. The wire
electrical and avionics systems. Exten- number consists of one or more digits.
sive repairs to complicated components It is used to distinguish between wires
or Line Replacement Units (LRUs) are in the same circuit. The wire segment
not expected to be made in the field; letter is used to distinguish between
therefore, more emphasis is placed on conductor segments (a wire segment be-
repairs to interconnecting cables and tween two terminals or connections). The
simple electrical and avionic components. wire size number is used to identify the
gage of the wire or cable. The ground,
11-2. ASSESSMENT PROCEDURES. (Refer phase, or thermocouple letter(s) are
to Table 11-1 for assessment logic.) used as suffixes to the wire identifi-
cation code to further identify certain
a. Wire Identification. The most wires. Ground wires are identified with
difficult and time consuming part of an N suffix. Phase letters A, B, or C
electrical and avionics battle damage are added to identify the phase of wires
assessment is wire identification. that are in the three-phase wiring of
Added and repaired wiring should be alternating current (AC) systems. For
identified to aid in troubleshooting. thermocouple wire, the following suffixes
If time permits, tape or sleeving at are added to the identification code:
each end of added wiring of a material AL (Alumel), CR (Chromel), FE (Iron),
suitable for the ambient temperature CN (Constantan), and CU (Copper).
range may be used. Typical wire and
circuit function and designation letters c. Deferral. Repair of systems and
are shown in Figure 11-1 and Table 11-2. subsystems which have adequate redun-
Appendix F lists and depicts the major dancy or are not critical to mission
components, cable routes, and wiring accomplishment may be deferred if safety
terminations for the more complex of flight is not significantly degraded.
avionics systems. Requirements must be examined to deter-
mine if relaxed criteria for repair and
aircraft performance can be accepted.
The commander may defer combat main-
tenance and battle damage repair, even
if doing so places operational limita-
on the aircraft.

11-1
TM 55-1520-244-BD

Table 11-1. Electrical and Avionics Assessment Procedures

PARA 11-5, 11-6,

11-9, 11-19
11-7, 11-9,

PARA 11-10,
11-12, 11-18,

PARA 11-13,
11-14

PARA 11-16

PARA 11-15

11-2
 TM 55-1520-244-BD

Figure 11-1.

Table 11-2.

11-3
TM 55-1520-244-BD

Table 11-2. Function and Designation Letters (Cont)

CIRCUIT CIRCUIT
DESIGNATION DESIGNATION
LETTER CIRCUITS LETTER CIRCUITS

H HEATING, VENTILATING, AND Running, position, navigation

DE-ICING: Passing
Anti-icing (general) Search
Battery heater Taxi
Cabin heater Warning
Cigarette lighter
De-icing (general) M MISCELLANEOUS ELECTRIC:
Windshield defroster Windshield spray
Windshield defogger Windshield wiper
Windshield de-icer Hoist
Heater blanket Enclosure operation
Oil immersion heater Positioner; seat, pedal
Refrigeration Special test equipment
Ventilation
Warning N UNASSIGNED

I In order to avoid confusion with o In order to avoid confusion

the numeral one, the letter “I” with the numeral zero, the
shall not be used for circuit on letter “O” shall not be used
cable identification. for circuit or cable identi-
fication.
J IGNITION:
Booster P DC POWER
Vibrator
Distributor Q FUEL AND OIL:
Electronic Fuel valves
Warning Fuel booster-pump motor
Moisture control
K ENGINE CONTROL: Oil dilution
Blower ratio Engine primer
Starter Fuel-transfer-pump motor
Warning and control
Fuel-loading-pump motor
L LIGHTING: Oil transfer-pump motor
Approach and control
Flasher-coder Oil booster pump
Cockpit Oil scavenge pump
Drift Throttle control
Cabin Fuel-pump motor
Formation Oil diverter
Cargo Oil valves
Interior Warning
Instrument
Section (fuselage)
Landing
Exterior

11-4
 TM 55-1520-244-BD

Table 11-2. Function and Designation Letters (Cont)

CIRCUIT CIRCUIT
DESIGNATION DESIGNATION
LETTER CIRCUITS LETTER CIRCUITS

R RADIO (Navigation and TR-Receivers

communication): TT-Transmitters
RA-Instrument landing TU-Reconnaissance
RC-Command TW-Weather devices
RD-Radio direction finding TZ-Bombing devices
RF-VHF liaison
RH-Homing U MISCELLANEOUS ELECTRONIC:
RL-Liaison Electronic wiring for which no
RM-Marker beacon "R", “S”, or “T” designation has
RN-Navigation been assigned by the procuring
RP-Special systems activity shall have the circuit
RS-SHF command function letter “U” assigned.
RT-Radio teletype Examples of wiring for which
RU-UHF command the circuit function letter. “U”
RV-VHF command will be assigned are common leads
RX-Recorder to electronic equipments and
RZ-Interphone, headphone systems interconnection wiring
such as antenna or power circuits
S RADAR : common to more than one equipment
SA-Altimeter or system.
SF-Intercept
SG-Gunlaying V DC POWER and DC control
SM-Mapping cables for AC systems.
SN-Navigation
SQ-Bombing W WARNING AND EMERGENCY
SR-Recorder Enclosure release and
SS-Search locks
SV-Special systems Fire extinguishers
SW-Warning Flare release
SX-Recognition (IFF) Fire detector
Intercrew buzzer or light
T SPECIAL ELECTRONIC:
TA-Adapter X AC POWER:
TB-Radar control Wiring in the AC power
TC-Radio control system.
TD-Airborne announcing
TE-Electronic countermeasure Y ARMAMENT SPECIAL SYSTEMS:
TF-Repeat back Y*A-Air to air
TG-GM homing Y*B-Air to surface
TH-Infrared Y*C-Multimode
TK-Telemetering Y*M-Missile-guidance
TL-Attitude indicator Y*T-Turret
TM-Chaff dispenser * Armament special
TN-Navigation system number
TP-Beacon (crash and locator)
TQ-Transmitters and receivers Z UNASSIGNED

11-5
TM 55-1520-244-BD

11-3. REPAIR PROCEDURE INDEX.

para 11-5 para 11-12

para 11-6 para 11-13

para 11-7 para 11-14

para 11-8 para 11-15

para 11-16

para 11-9 para 11-18

para 11-10 para 11-19

para 11-11

Section Il. WIRE AND CABLE SPLICING

11-4. GENERAL. reinspected at 100 flight hours. At this time, a per-

manent repair will be performed or an extension of
a. The objective of electrical and avionics system use for the temporary repair will be granted.
battle damage repair is to restore damaged circuits
which are mission essential. It is also used to make 11-5. SPLICING UNSHIELDED WIRES.
non-essential circuits safe. Electrical and avionics
equipment receiving significant battle damage will GENRAL INFORMATION: This procedure
usually not be repairable. Avionics wiring, coaxial provides for repairing damaged unshielded wires.
cables, and general aircraft wiring can be repaired
using a variety of procedures and materials. Appendix
F lists and depicts the major components, cable
routes, and wiring terminations for the more complex
avionics systems. Do not be misled by the term “low volt-
age.” Potentials as low as 50 volts may
b. BDAR wiring repair provides for two types of cause death under adverse conditions.
aircraft electrical wiring repairs which are classified as
“PERMANENT” or “TEMPORARY.”

(1) A permanent repair returns the electrical Ensure aircraft power is OFF. Disconnect
wiring system to full capability, as manufactured, with battery before touching any wires.
no degradation of any system operating charac-
teristics. No periodic inspection or replacement is re-
OPTION 1: Crimp Splice.
quired with a permanent repair.
LIMITATIONS: Only to be used for wire sizes 12-26.
(2) A temporary repair returns the electrical No more than one splice is made per 10 feet of wire.
wiring system to a reduced level of capacity with a This is a permanent repair.
possible slight reduction of system operational
capability. Temporary repairs must be
PERSONNEL/TIME REQUIRED:
● 1 Soldier
● 10 Minutes

11-6
 TM 55-1520-244-BD

MATERIAL/TOOLS REQUIRED: PERSONNEL/TIME REQUIRED:

● Splice (items 130 or 145-148,
● 1 Soldier
App. C) Ž Minutes Per Splice
● Sealing Sleeve (item 53, APP
. . C).
Ž Crimping Tool MATERIALS/TOOLS REQUIRED:
● Strippers ● Terminal Lug (items 154-160, App. C)

● Heat Gun • Insulating Sleeve (item 53, App. C)

● Wire Repair Kit (item 14, App. B) ● Crimp Tool

● Emergency Repair Kit (item 3, App. B) ● Wire (items 170-178, App. C)

● Wire (items 170-178, App. C) ž Emergency Repair Kit (item 3, App. B)

● Wire Repair Kit (item 14, App. B)

PROCEDURAL STEPS:
PROCEDURAL STEPS:
1. Strip wires. Refer to Table 11-3.
1. Select a terminal with a barrel large enough to
Table 11-3. Unshielded Crimp accommodate both wires.
Slice Application
2. Cut off terminal lug tongue.

STRIPPING TEMP. 3. Prepare wire ends.

WIRE LENGTH RATING
SIZE INCH DEG.ÉC 4. Slip an insulating sleeve, 1 inch longer than ter-
20-26 .25-.30 >125 minal lug barrel, over the end of one of the wires, and
16-18 .30-.35 >125 insert wire end into the barrel as shown in Figure 11-3.
12-14 .30-.35 >125
20-26 .25-.30 <105 5. Crimp barrel in center.
16-18 .30-.35 <105
12-14 .30-.35 <105 6. Slide insulating sleeve over the terminal lug bar-
rel splice, and secure in place by using tie wraps or
heating if heat shrink is used.
2. Slide sealing sleeve onto one of the wires, Figure
11-2. On wire rated at 125°C or above, insert one-
prepared wire into small end of sealing sleeve and 7. Record BDAR action taken. When mission is
push crimp barrel out. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
3. Crimp wires with crimp tool.
OPTION 3: Split Bolt Splice.
4. Shrink sealing sleeve over crimp with heat gun,
LIMITATIONS: Only to be used on wire sizes awg
No. 4 through No. 10. This is a permanent repair.
5. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures. PERSONNEL/TIME REQUIRED:
● 1 Soldier
● 10 Minutes
OPTION 2: Terminal Lug Splice.

LIMITATIONS: Only to be used on wire size awg

No. 10 and smaller. This is a temporary repair.

11-7
TM 55-1520-244-BD

Figure 11-2. Crimp Splice

11-8
 TM 55-1520-244-BD

Figure 11-3. Splicing with Terminal Lug Barrel

MATERIAL/TOOLS REQUIRED: NOTE

Strippers or Knife
Heat Shrinkable Tubing (item 53, Conductors maybe folded back one or more
App. C) times to fill the connector opening and provide
Tape (item 151, App. C) firm clamping.
Emergency Repair Kit (item3, App.B)
Wire Repair Kit (item14, App. B) Strip wires 1/2 inch if folding back is not re-
quired.
PROCEDURAL STEPS:
Strip wires 1-1/4 inch if single folding back is
required.
1. Slide a 3 inch length heat shrinkable tubing over
one of the wires to be spliced. Strip wires 2-1/2 inch if double folding back is
required.
2. Strip wires and insert into the connector from op-
posite sides. 3. Tighten nut securely.

11-9
TM 55-1520-244-BD

4. Wrap the splice with heat shrinkable tape. Cover 5. Split all the wire ends.
all metal parts and overlap onto insulation.
6. Split the strands of wire apart and twist the match-
5. Heat the end of the tape to soften the adhesive ing wires together as shown in Figure 11-4.
layer and press it into position while warm.
7. Cover splice area with electrical tape,
6. Heat the tape to shrink it onto the splice and
soften the adhesive layer. 8. If a section of wire needs to be replaced, a
double repair can be made, Figure 11-5.
7. Center the heat shrinkable tubing over the splice.
9. Record BDAR action taken. When mission is
8. Heat the tubing to shrink it onto the splice. Begin complete, as soon as practical, repair the equipment/-
in the middle and work toward the ends. Tubing may system using standard maintenance procedures.
not shrink completely onto the wire insulation, this is
normal. OPTION 5: Casing Splice.

9. Record BDAR action taken. When mission is LIMITATIONS: This is a temporary repair.
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures. PERSONNEL/TIME REQUIRED:
● 1 Soldier
OPTION 4: Twist Wire Splice. Ž10 Minutes

LIMITATIONS: This is a temporary repair. MATERIALS/TOOLS REQUIRED:

●
Metal Tubing such as ball point pen refills,
PERSONNEL/TlME REQUIRED: expended cartridges, hydraulic line
● 1 Soldier ● Insulation Sleeve or Tape (item 53
● 10 Minutes or 151, App. C)
●
Crimp Tool (hammer, pliers, etc.)
MATERIALS/TOOLS REQUIRED: ● Wire (items 170-178, App. C)
● Tape, Electrical (item 151, App. C)

● Strippers or Knife
PROCEDURAL STEPS:

PROCEDURAL STEPS: 1. Fabricate splices approximately 1 to 2 inches

long from small metal casing.
1. Cut ties and work broken wire to the outside of
the bundle. NOTE

2. Pull sufficient slack from the wire run toward the Metal ball point refills or expended
break so that there will be no strain on the splice. cartridge shell casings when cut to length
make excellent splices, Figure 11-6.
3. Wipe wire clean with a clean, dry rag or a rag
dampened with solvent. 2. Strip 1/2 to 1 inch insulation from both ends of
wire to be spliced.
4. Trim broken ends of the wire.

11-10
 TM 55-1520-244-BD

Figure 11-4. Twist Wire Splice

Figure 11-5. Replacement Section; Twist Wire Splice

11-11
TM 55-1520-244-BD

Figure 11-6. Metal Casing Splice

3. Insert wires into casing splice and WARNING

crimp tightly with pliers or a hammer
and small iron bar. Cleaning solvents may be flam-
mable and toxic. Use only in
4. Insulate with tape or use plastic well-ventilated areas. Avoid
and string, tie in place. inhalation of vapor and skin
contact. Do not use solvents
5. Record BDAR action taken. When near open flame or in areas where
mission is complete, as soon as very high temperatures prevail.
practical, repair the equipment/system Solvent flash point must not be
using standard maintenance procedures. less than 100°F.

OPTION 6: Bolted Terminal Lug Splice. LIMITATIONS: This is a temporary

repair.

PERSONNEL/TIME REQUIRED:
1 Soldier
10 Minutes

11-12
 TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED: 5. Strip both wire ends and crimp an insulated ter-
●
Terminal Lugs (items 154-160, App. C) minal lug of the proper size to each wire end.
●
Screw or Bolt (items 7-10, App. C)
● Nut (items 63-70, App. C) 6. Bolt terminal lugs together as shown in Figure
● Washer (items 163-169, App. C) 11-7.
●
Insulating Sleeve or Tape (items 53,
or 151, 153, App. C) 7. Slide the insulating sleeve over the splice so that
●
Solvent (item 7 or 129, App. C) the ends of the insulating sleeve extend at least 3/4 of
an inch beyond the ends of each terminal lug.
PROCEDURAL STEPS:
8. Secure both ends of the insulation with tie wraps
1. Cut ties and work broken wire to the outside of or string ties as shown in the figure.
the bundle.
NOTE
2. Pull sufficient slack from the wire run toward the
break so that there will be no strain on the splice.
If a section of wire needs to be replaced, a
double repair can be made to bridge the
3. Wipe wire clean with a clean, dry rag or a rag ends of the original wire back together.
dampened with solvent.
9. Record BDAR action taken. When mission is
4. Trim broken ends of wire and install an insulating complete, as soon as practical, repair the equipment/-
sleeve over one end of the wire, and slide back and system using standard maintenance procedures.
out of the way for now.

Figure 11-7. Replacement Section; Terminal Lug Repair

11-13
TM 55-1520-244-BD

OPTION 7: Metal Clamp Splice.

LIMITATIONS: This is a temporary

repair.
WIRE RAMMED TOGETHER
PERSONNEL/TIME REQUIRED:
1 Soldier
10 Minutes

MATERIALS/TOOLS REQUIRED:
Screw Clamp, Control Cable Clamp
Insulating Sleeve or Electrical Tape
(item 53 or 151, App. C)
Knife
Cable lies (item 26 or 27, App. C)

PROCEDURAL STEPS: SCREW CLAMP OR EQUIVALENT

1. Cut ties and work broken wire to the

outside of the bundle.
Figure 11-8. Ram Wire Repair
2. Pull sufficient slack from the wire
run toward the break so that there will 11-6. SPLICING SHIELDED CABLE.
be no strain on the splice.
GENERAL INFORMATION: The following pro-
3. Wipe wire clean with a clean, dry cedures may be used to r epair severed
rag or a rag dampened with solvent. shielded cables.

4. Trim broken ends of wire. OPTION 1: Shielded Cab’ e Splice.

5. Remove 2 inches of wire insulation LIMITATIONS: Repair is good for cables

from each end of the damaged wire. rated at 125°C or above.

6. Ram or push the two wire ends PERSONNEL/TIME REQUIRED:

together so that the strands interlink. 1 Soldier
15 Minutes
7. Secure with screw clam, control
cable clamp, safety wire, or other MATERIALS/TOOLS REQUIRED:
suitable means, Figure 11-8. Splice (items 145-148, App. C)
Sealing Sleeve (item 53, App. C)
8. Insulate with tape or insulation Crimping Tool
sleeve. Strippers
Heat Gun
9. Record BDAR action taken. When
mission is complete, as soon as PROCEDURAL STEPS:
practical, repair the equipment/system
using standard maintenance procedures. 1. Prepare cable for splice. Refer to
Figure 11-9 and Table 11-4.

2. Slide the shield sleeve onto one of

the cables.

11-14
 TM 55-1520-244-BD

NOTE: Refer to Table 11-4 for X, Y, and Z.

Figure 11-9. Shielded Cable Repair Preparation

PERSONNEL/TIME REQUIRED:
1 Soldier
1/2 Hour Per Wire
Table 11-4.
MATERIALS/TOOLS REQUIRED:
Insulating Sleeving, Heat Shrinker
Tape (items 53 or 151,153,App. c)
Knife
String, Nylon Braid, or Tie Wrap
3. Slide the inner sealing sleeve onto (to be used if insulating sleeve
the primary wires of one of the cables; is used) (items 149, or 26, 27,
then insert the other primary wire onto App. C)
the other end of the inner sealing sleeve Connectors (item 159 or 160, App.C)
and crimp with AD-1377 crimp tool. Refer Conductor Splice (items 145-148, App. C)
to Figure 11-10. Wire Repair Kit (item 14, App. B)
4. Shrink the inner sleeve of the
splice. Keep hot air away from PROCEDURAL STEPS:
shield sleeve.
1. Select a grounding sheath.
5. Center and shrink the shield over
the splice area so that the solder melts 2. Prepare the severed ends of the
and flows. Shield sleeve braid must cable for application of a grounding
overlap cable braid at both ends. sheath connector, Figure 11-12, step A.
Refer to Figure 11-11.
3. Position sheath connector and
OPTION 2: Sheath Connector Splice. grounding sheath as shown in Figure
11-12, step B. (NOTE: Crimp sheath
LIMITATIONS: This is a temporary connector and grounding sheath only
repair until heat shrink is installed; at one side at this time.)
then it becomes a permanent repair.

11-15
TM 55-1520-244-BD

Figure 11-10.

Figure 11-11. Completed Shielded Cable Splice

4. Slide insulating sleeve over 7. If an insulating sleeve is used,

uncrimped sheath connector as shown slide into place and tie both ends,
in Figure 11-12, step B. (NOTE: If Figure 11-12, step D.
insulating sleeve is not available,
use shrink or alternate insulating 8. If heat shrink is used, slide into
such as electrical tape.) place and shrink into position. Tape
may be used to cover repair.
5* Splice center conductor using a
permanent splice or by using one of the 9. Record BDAR action taken. When
splicing procedures in paragraph 11-5. mission is complete, as soon as
practical, repair the equipment/system
6. Push the free end of the grounding using standard maintenance procedures.
wire into the uncrimped grounding sheath
connector. Crimp securely, Figure
11-12, step C.

11-16
 TM 55-1520-244-BD

Figure 11-12. Sheath Connector Splice

11-17
TM 55-1520-244-BD

OPTION 3: Pigtailed Sheath Splice. PERSONNEL/TlME REQUIRED:

● 1 Soldier

● 1/2 Hour Per Wire

LIMITATIONS: This is a temporary repair.
MATERIAL/TOOLS REQUIRED:
PERSONNEL/TIME REQUIRED:
● Substitute Shielded Braid
● 1 Soldier
● Knife
● 1/2 Hour Per Wire
● Splice (items 145-148, App. C)

Ž Metal Screw Clamp, Sheath Connector,

MATERIALS/TOOLS REQUIRED:
● Knife
or Equivalent
● Emergency Repair Kit (item 3, App. B)
● Insulating Sleeving or Tape

(item 53 or 151, App. C)

PROCEDURAL STEPS:
● String, Nylon Braid, or Tie Wrap

(to be used if insulating sleeve

is used) (items 149 or 26, 27, 1. Prepare severed ends of cable for application of
App. C) repair splice and shielding, Figure 11-14, step A.
● Splice (items 145-148, App. C)

Ž Wire Repair Kit (item 14, App. B) 2. Select suitable shielding material and slide over
● Wire (items 170-178, App. C) one end of severed cable. Shielding must be long
enough to overlap the shielding on both sides of the
PROCEDURAL STEPS: cable being repaired after the center conductor is
repaired. Shielding material can be obtained from
1. Prepare severed ends of cable for pigtail method another shield cable or ground cable material.
of shield terminations, Figure 11-13, step A.
NOTE
2. Splice center conductor, Figure 11-13, step B,
using a permanent splice or by using one of the It is essential that the shielding, as well as
splicing procedures in paragraph 11-5. the inner conductor, be repaired properly
to prevent electromagnetic interference
3. Use two splice connectors to add short length of (EMI) problems.
insulated wire as extension to complete shield con-
nection, Figure 11-13, step B. 3. Splice center conductor using a permanent splice
or by using one of the splicing procedures in para-
4. Insulate repair, Figure 11-13, step C. graph 11-5 and Figure 11-14, step B.

5. Record BDAR action taken. When mission is 4. Slide shielding material over repaired inner con-
complete, as soon as practical, repair the equipment/- ductor and clamp at shielding overlap areas, Figure
system using standard maintenance procedures. 11-14, step C.

OPTION 4: Substitute Shielded Braid. 5. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
LIMITATIONS: This is a temporary repair.

11-18
 TM 55-1520-244-BD

COVER WITH VINYL SLEEVE AND TIE AT BOTH ENDS

Figure 11-13. Pigtail Sheath Splice

11-19
TM 55-1520-244-BD

Figure 11-14. Substitute Shielded Braid Splice

11-20
 TM 55-1520-244-BD

11-7. SHIELDED CABLE REPAIR SEGMENTS. 11-8. SHIELD TERMINATORS.

GENERAL INFORMATION: The electrical wiring kit GENERAL INFORMATION: The BDAR electrical kit
has wire replacement segments for replacement sec- contains various types of shield terminators for
tions up to 9 inches in length. shielded cable.

OPTION: Install Shield Terminators.

Ensure aircraft power is OFF. Disconnect LIMITATIONS: This is a temporary repair.

battery before touching any wires.
PERSONNEL/TlME REQUIRED:
OPTION: Install New Cable Segment. 1 Soldier
15 Minutes
LIMITATIONS: None.
MATERIALS/TOOLS REQUIRED:
Shield Terminator
PERSONNEL/TIME REQUIRED: Heat Gun/Heat Source
1 Soldier Stripper or Knife
1 Hour Insulating Sleeve (item 53, App. C)
Wire Repair Kit (item 14, App. B)
MATERIALS/TOOLS REQUIRED: Wire (items 170-178, App. C)
Stripper or Knife
Splice (items 145-148, App. C) PROCEDURAL STEPS:
Insulation Sleeve (item 53, App. C)
Crimp Tool
1. Prepare cable for repair, Figure 11-15.
PROCEDURAL STEPS:
2. Position shield terminator on cable as shown in
Figure 11-16. (Select the smallest terminator that
1. Cut out damaged cable (up to 9 inches in length).
slides easily over the prepared cable.)
2. Prepare cable for splice. Refer to Figure 11-9.
3. Heat shield terminator until solder melts and
flows into wire strands, red color disappears, and
3. Use one of the OPTIONS of paragraph 11-6 to seals melt and flow at both ends.
splice the ends of the replacement segment onto the
damaged cable.
4. Terminate the ground lead as directed in aircraft
wiring manual.
4. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
5. Record BDAR action taken. When mission is
system using standard maintenance procedures.
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

11-21
TM 55-1520-228-BD

11-9. COAX SPLICING USING WIRING

REPAIR KIT.

GENERAL INFORMATION. There are various

coax splices in the wirinq repair kit
that may be used for the different types
and sizes of coax cable.

OPTION: Splice Coax.

LIMITATIONS: This is a temporary repair.

PERSONNEL/TIME REQUIRED:
1 Soldier
15 Minutes

MATERIALS/TOOLS REQUIRED:
Emergency Repair Kit (item 3, App. B)
Stripper or Knife
Crimp Tool
HeatGun/HeatSource
Wire Repair Kit (item 14, App. B)

PERSONNEL/TIME REQUIRED:
Figure 11-15.

1. Prepare coax cable, Figure 11-9.

Refer to Table 11-4.

2. Slide the shield sleeve and inner

sleeve onto one of the coaxial cables
in the order gi ven.

3. Splice the center conductor. Use

the red cavity of the crimp tool.

4. Shrink the inner sleeve over the

----
splice, Figure 11-10. Keep the hot air
away from shield sleeve.

5. Center and shrink the shield sleeve

over the splice area so that the solder
melts and flows, Figure 11-11. Shield
sleeve braid must overlap coax braid at
both ends.

6. Record BDAR action taken. When

mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

Figure 11-16. Shield Terminator Repair

11-22
 TM 55-1520-244-BD

11-10. COMPONENT BRIDGING AND SPLICING. MATERIALS/TOOLS REQUIRED:

Will be dependent on the type of splice used.
GENERAL INFORMATION: Inmost cases it Wire (items 170-178, App. C)
will be quicker not to replace bulkhead
connectors, junction boxes, or terminal
strips. These circuits can be repaired PROCEDURAL STEPS:
by “bridging” the damaged area with
jumper wires spliced in to eliminate the 1. Identify wires to be bridged
damaged area or component, Figure 11-17. together.

OPTION : Bypass Component. 2. Splice wires and jumper wires

together using one of the splicing
LIMITATIONS: This is a temporary techniques of this chapter.
repair.
3. Secure jumper wires after repair is
PERSONNEL/TIME REQUIRED: made to prevent vibration chaffing.
l Will be dependent on the type of
splice used. 4. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

Figure 11-17. Component Bypass

11-23
TM 55-1520-244-BD

Section III. CONNECTOR REPAIR

11-11. DAMAGED CONNECTOR PINS.

GENERAL INFORMATION: Deformed, crushed,

missing, or otherwise damaged connectors
can be replaced or repaired. If a
replacement connector is not available
to replace a damaged connector, cleanup
fragments of the connector and use
jumper wires to bridge wire ends
together. If only part of the connector
has been damaged and there are unused
pins/sockets on the connector which are
undamaged, wires on both sides of the
connectors can be moved to the unused
good pins/sockets. Any available
undamaged wires on the connector CONNECTOR SOCKET
may be used.

OPTION 1: Replace Damaged Pins or

Sockets; No Damage to Connector. Figure 11-18. Connector Pin and Socket

LIMITATIONS: None NOTE

PERSONNEL/TIME REQUIRED: Superglue or epoxy may be used to

1 Soldier secure the original or replace-
10 Minutes Per Wire ment pin back into place. Avoid
getting glue or epoxy on contact
MATERIALS/TOOLS REQUIRED: surface of pin.
Replacement Pins/Sockets
Insertion/Extraction Tool OPTION 2: Bridge Across Damaged
Knife Connector. Refer to paragraph 11-10,
Connector Repair Kit (item 2, App.B) component bridging and splicing.

PROCEDURAL STEPS: OPTION 3: Cannibalize Connector from

Other Aircraft.
1. Solder or crimp wires to
pin/sockets, Figure 11-18. LIMITATIONS: None.

2. Insert the pins/sockets into the MATERIALS/TOOLS REQUIRED:

connector. Replacement Connector with Wires
Splices (items 145-148, App. C)
3. Record BDAR action taken. When Knife
mission is complete, as soon as Tape (item 151 or 153, App.C)
practical, repair the equipment/system Emergency Repair Kit (item 3, App. B)
using standard maintenance procedures. Wire Repair Kit (item 14 App. B)

11-24
 TM 55-1520-244-BD

PROCEDURAL STEPS: should match the staggered wire of

the replacement connector of step 1,
1. Obtain a replacement connector with Figure 11-19.
a wire. (Replacement may be obtained
from a crash damaged aircraft.) 4. Splice the appropriate wires
together.
2. Cut wire so that splices can be
staggered,
-. Figure 11-19. 5. Record BDAR action taken. When
mission is complete, as soon as
3. Remove damaged connector; stagger practical, repair the equipment/system
the wires being cut to remove the using standard maintenance procedures.
damaged connector. The staggered wires

Figure 11-19.

Section IV. OVERCURRENT PROTECTION DEVICES

11-12. DAMAGED CIRCUIT BREAKER REPAIR. b. Replacing circuit breakers with a

specified number of individual strands
GENERAL INFORMATION: Attempt to main- of No. 38 awg from No. 26 awg wire.
tain a protected system at all times.
Circuits with damage circuit breakers OPTION 1: Circuit Breaker Replacement.
can be repaired as follows:
LIMITATIONS: None
a. Circuit breakers of the same
rating salvaged from other nonflyable PERSONNEL/TIME REQUIRED:
aircraft or removed from other non- 1 Soldier
essential circuits in the aircraft. 20 Minutes

11-25
TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED: PERSONNEL/TIME

Salvaged Circuit Breaker ● 1 Soldier
Electrical Tape (item 151, Appx C) ● 20 Minutes

PROCEDURAL STEPS: MATERIALS/TOOLS REQUIRED:

● No. 8 Terminal Lugs
1. Gain access to area behind circuit ● 1 Ft. of No. 22 Awg Stranded Wire
breaker panel by turning duzs fasteners (item 170, App. C)
counterclockwise.
PROCEDURAL STEPS:
2. Remove screws holding plastic face
plate on circuit breaker panel. 1. Perform steps 1 through 4 of option
1, and remove circuit breaker.
3. Use pliers to remove nut and inside
star lockwasher from damaged circuit 2. Identify the wires hooked to each
breaker. circuit breaker. Typical circuit
breaker is shown in Figure 11-20.
4. Use phillips screw driver to remove
the two screws from the terminals of 3. Determine amperage of damaged
the circuit breaker. circuit breaker(s) to be replaced.
(Amperage is printed on the end of reset
5. Replace bad circuit breaker with button.)
the salvaged circuit breaker.

6. Connect back of circuit breaker to

line and bus bar by reinstalling the
two phillips screws. Bend bus bars as
required to fit size difference of
salvaged breaker.

7. Place lockwasher and nut on front

of circuit breaker and tighten with
pliers.

8. Replace plastic face plate on front

of circuit breaker panel with screws pre-
viously removed.

9. Clean and remove any debris from

inside circuit breaker panel and close
panel.

10. Record BDAR action taken. When

mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

OPTION 2: Individual Strands of No. 38

Awg as Circuit Breaker.

LIMITATIONS: None. Figure 11-20. Typical Original

Circuit Breaker Connection

11-26
 TM 55-1520-244-BD

4. Use Table 11-5 to determine number 11. Insert the other end of No. 38 awg
of strands of No. 38 awg wire needed to strands of wire into the other terminal
replace damaged circuit breaker. into the other terminal lug (supply
side), pull tight against the piece
5. Strip No. 22 awg wire, select num- of insulation and twist tight, insulate
ber of No. 38 awg wire strands (6 to 8 bare end of terminal lugs on both sides
inches long) as per Table 11-5. of 1 inch piece of insulation with tape.

6. Cut salvaged insulation into 1 12. Use 8-32 screw to connect other
inch lengths (one length from each terminal lug to bus side of bus bar.
fuse link required).
13. Use this procedure to replace
7. Cut line side wire 1 inch from damaged circuit breaker.
terminal lug.
14. Secure fuse link to other wiring
8. Strip both ends and crimp an 8-32 with tape to avoid pinching wire when
terminal lug where wire was cut and circuit breaker panel is closed.
stripped. -
15. Clean up damaged area behind cir-
Table 11-5.
cuit breaker panel to remove debris, and
use tape to insul ate any damaged parts
that might cause electrical shorts.

16. Carefully cl ose circuit breaker

panel and secure by turning duzs
fasteners clockw ise.

17. Record BDAR action taken. When

mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

Try to use inner strands of wire

that are not cut or nicked by
knife used to remove insulation.

9. Twist the No. 38 awg strands of

wire, from step 5, together and insert
the end of line side of terminal lug,
wrap and twist as shown in Figure 11-21.

10. Slip 1 inch piece of insulation

over No. 38 awg strands of wire.

11-27
TM 55-1520-244-BD

Figure 11-21. Construction of Fuse Link

11-13. DAMAGED FUSES. CAUTION

GENERAL INFORMATION: If a fuse is bro- If too low a current rating fuse

ken, it may be replaced by another fuse is used, it will blow from the
or a piece of solder or wire. Where the initial turn on surge current.
same current rating fuse is not If too high a current rating
available, one as close to proper as fuse or if the solder or wire
possible should be used. A slow blow is used, the equipment will not
fuse could be replaced by a fast blow be properly protected in case
fuse of higher current rating while a of a short circuit.
fast blow fuse could be replaced by a
slow blow fuse of lower current rating. OPTION 1: Salvaged Fuse Replacement.
The solder or wire should be used only
when no fuse is available. LIMITATIONS: None.

CAUTION PERSONNEL/TIME REQUIRED:

● 1 Soldier
If the fuse is blown, the same 1/2Hour
procedure can be used but the
cause of the overcurrent must be MATERIALS/TOOLS REQUIRED:
fixed. Substituting for the fuse Fuse
without fixing the cause of over- Common Hand Tools
current can cause more damage to
the equipment.

11-28
 TM 55-1520-244-BD

PROCEDURAL STEPS: Replace fuse b. Trim dowel, stick, or pencil piece

with the following: as necessary to fit into end caps, and
hold wire in place. This stiffens the
1. An identical spare fuse from other substitute fuse.
equipment.
c. Wrap dowel, stick, or pencil and
2. An identical fuse from the other wire with electrical tape, but do not
equipment of lower priority. cover end caps.

3. A similar fuse. 4. For type B fuse, connect substitute

No. 38 awg wire strand between two
4. Record BDAR action taken. When points, Figure 11-24. Use Table 11-5 to
mission is complete, as soon as determine the number of No. 38 awg
practical, repair the equipment/system strand to use between points A and B for
using standard maintenance procedures. different size, amperage, and fuses.

OPTION 2: Individual Strands of No. 38 5. Install fuse into equipment.

Awg as Fuse.
6. Record BDAR action taken. When
LIMITATIONS: Temporary use only. mission is complete, as soon as
practical, repair the equipment/system
PERSONNEL/TIME REQUIRED: using standard maintenance procedures.
1 Soldier
1 Hour

MATERIALS/TOOLS REQUIRED:
Wire (item 170, App. C)
Small Dowel or Stick
Electrical Tape (item 151, App. C)

PROCEDURAL STEPS:

1. Remove damaged fuse, Figure 11-22.

2. If type A fuse, break off glass

and salvage end caps. If type B fuse,
break off clear top portion.

3. For type A fuse, cut wire and dowel,

stick or pencil piece to proper length.
Refer to Table 11-5 to determine the
number of No. 38 awg wire strands to use
for the different site, amperage, and
fuses. See Figure 11-23 for fuse
assembly and assemble as follows:

a. Lay wire or wrap piece between

ends of wood.

Figure 11-22. Typical Fuses

11-29
TM 55-1520-244-BD

Figure 11-23. Fabricated Fuse, Type A Figure 11-24. Fabricated Fuse, Type B

Section V. BUS BARS

11-14. POWER BUS BAR REPAIR. LIMITATIONS: Repaired bus bars will have
a somewhat higher resistance than the
GENERAL INFORMATION: Rigid bus bars are original circuit and a higher than nor-
used in the power distribution circuits mal voltage drop may occur. This is a
of the aircraft. Replace damaged bus temporary repair.
bars with aluminum or brass strips of
the same or higher cross-sectional PERSONNEL/TIME REQUIRED:
area. 2 Soldiers
2 Hours
OPTION: Fabricate Bus Bar.

11-30
 TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED:
●
Drill and Bit
●
Nuts (item 63, App. C) ● Ni-Cad batteries use potassium hydroxide, a
●
Bolts (items 8-24, App. C) strong caustic alkali, as the electrolyte. Do not
●
Washers (item 162, App. C) get this electrolyte on your skin or in your eyes.
●
Tape (item 151 or 153, App. C) Use rubber gloves, rubber apron, and protec-
●
Brush, Wire tive goggles when handling the electrolyte. If
●
Hacksaw accidental contact with the electrolyte is made,
use ONLY clean water and immediately
PROCEDURAL STEPS: (seconds count) flush contaminated areas.
Continue flushing with large quantities of clean
1. Cut a section of another bus bar or piece of water and get medical attention as soon as
aluminum scrap to use for splice. possible.

2. Drill matching holes in bus bar sections and

splice, Figure 11-25. ● Cell temperature should never exceed 120°F -
130°F. If steam or spewing electrolyte is ob-
served or the battery is hot to the touch, DO
3. Remove insulation from bus bar only where
needed. Insure contact surfaces of cracked bus bar NOT attempt to remove from the aircraft.
and splice are smooth, and clean to reduce resis-
tance. If necessary, use file and wire brush to dress
and prepare contact surfaces.
Penetration of battery case by small arms
4. Install bolts and washers and tighten. Insure no fire or shrapnel may cause thermal
contact of bolts with aircraft structure. runaway. The battery cells will overheat
and rupture, melt, or explode. Exercise ex-
treme caution when repairing damaged
5. Insulate repair with tape or slit a piece of insulat-
ing tubing. Wrap it around the repair and tie it with battery.
string
OPTION: Jumper Cells.
6. Same repair procedure can be used to lengthen
bus bars, Figure 11-26. LIMITATIONS: Some loss of battery voltage (1.25
to 1.50 V dc per cell removed) and amperage.
7. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/- PERSONNEL/TIME REQUIRED:
system using standard maintenance procedures. ● 1 Soldier
● 30 Minutes
11-15. BATTERY BUS BAR REPAIR.
MATERIALS/TOOLS REQUIRED:
●
Multimeter with Leads
GENERAL INFORMATION: Nickel-Cadmium ●
Rubber Gloves
(Ni-Cad) consists of a number of cells connected in ●
Protective Goggles
series. Damage to a cell which does not result in ● Rubber Apron
destruction of the battery maybe repairable. This pro- ● Torque Wrench
cedure gives instructions for locating and removing ●
Test Equipment Repair
bad Ni-Cad battery cells and creating a bus bar
Kit (item 13, App. B)
jumper around the bad cell.

11-31
TM 55-1520-244-BD

Figure 11-25.

Figure 11-26. Lengthening Bus Bars

11-32
 TM 55-1520-244-BD

PROCEDURAL STEPS: 9. Measure and cut wire to needed

length, strip 1/2 inch of insulation and
1. Disconnect battery and remove from crimp terminal lug to other end of wire.
aircraft if necessary.
10. Install jumper across removed cells
2. Release snap fasteners and remove in place of terminal links. Cells are
cover. connected in series (positive to
negative), Figure 11-27.
3. Use a multimeter to measure voltage
across each cell. Normal readings CAUTION
should be 1.25 to 1.5 V dc per cell.
Remove cells that are dead. Battery terminal threads are soft
brass.

11. Torque terminal screws to between

Be extremely careful when 35 and 50 inch-pounds. If torque wrench
removing or installing battery is not available, tighten firmly with
cells. Bodily injury and equip- wrench or pliers.
ment damage may result if any
metal tools or parts accidentally 12. Replace cover and install battery
cause a short circuit. in aircraft.

NOTE 13. Record BDAR action taken. When

mission is complete, as soon as
For engine cranking loads, cell practical, repair the equipment/system
voltages as low as 0.6 V dc are using standard maintenance procedures.
acceptable. Remove any damaged,
cracked, or extremely hot cells
leaking or spewing electrolyte.

4. To remove bad cells, use a 3/8 inch

socket or equivalent to loosen and
remove terminal screws.

5. Remove washers and terminal links.

6. To remove individual cells screw

terminal screws back into each cell
terminal, grasp these screws with pliers
and lift the cell straight up.

7. Join several removed bus bars

together or prepare jumper from 1 foot
of No. 4 awg and two terminal lugs.

8. Remove 1/2 inch of insulation from

one end of wire and crimp terminal lug
on stripped end of wire.

Figure 11-27. Battery Cell Layout

11-33
TM 55-1520-244-BD

Section VI. Power Relays

11-16. POWER RELAY TEST AND REPAIR.

GENERAL INFORMATION:

a. A power relay is an electrically

operated switch between the main buss
and other electrical components in the
aircraft. The relays are normally
controlled by a switch in the cockpit.

b. To check power relay formalfunc-

tion, locate terminals Xl and X2 on the
relay. With a multimeter set on the
0-50 V dc scale, check the voltage from
terminals Xl and X2 to the aircraft
fuselage (ground), Figure 11-28. One of
the two terminals should have 24-28 V dc
on it when the power relay control
circuit is energized. No dc voltage
indicates damage to the control circuit
wiring. Repair control circuit wiring.
With 24-28 V dc applied to terminals
Xl or X2 of the power relay, check the
voltage between terminals Al, A2, and
the aircraft fuselage (ground), Figure
11-28. The voltage on terminals A1 and
A2 should be identical. If there is no
voltage on either one of the two
terminals A1 or A2 with the relay
energized, the relay should be
considered defective and replaced
or jumped.

Figure 11-28. Block Diagram Power

Relay, Check, and Test

11-34
 TM 55-1520-244-BD

OPTION 1: Salvaged Power Relay Installation. OPTION 2: Jumper Damaged Power Relays, Figure
11-33.
NOTE
LIMITATIONS: Temporary repair. No control over
Identical P/N or NSN (Figures 11-29 thru jumpered power relays, circuit cannot be turned on or
11-32) denotes interchangeability. If off .
damage is extensive, salvaged relays may
be difficult to attach to bulkheads.
Do not jumper battery relay on any aircraft.
LIMITATIONS: None
This procedure is to be used only for one time
PERSONNEL/TIME REQUIRED: emergency evacuation and recovery of AH-1
1 Soldier helicopters.
30 Minutes
PERSONNEL/TIME REQUIRED:
MATERIALS/TOOLS REQUIRED: 1 Soldier
Salvaged Power Relay 20 Minutes
Test Equipment Repair Kit
(item 13, App. B) MATERIALS/TOOLS REQUIRED:
Wire (items 170-178, App. C)
PROCEDURAL STEPS: Terminal Lugs (items 154-160, App. C)
Test Equipment Repair Kit
1. Obtain salvaged power relay. (item 13, App. B)
Wire Repair Kit (item 14, App. B)
2. Disconnect battery. PROCEDURAL STEPS:

3. Remove damaged power relay as follows: 1. Disconnect battery.

NOTE 2. Figure 11-33 shows two typical power relay con-

figurations with jumper. This may be used as an aid in
Note the position of wires/bus bar and performing steps 3 through 7.
what terminals they are connected to.
NOTE
a. Remove attaching hardware, wires, and bus
bar. Use wire with the same gage or larger
than the one being replaced.
b. Remove attachment bolts, and lift relay free
from compartment. 3. Prepare a jumper wire, Figure 11-34. (A 1/2 to 1
foot length of appropriate size wire with appropriate
4. Position salvaged power relay, and install mount- size terminal lugs crimped on each end.)
ing hardware.
4. Locate terminals marked Al and A2 on power
5. Install wires and bus baron correct terminals and relay. Power relay terminals should be marked on
secure with hardware. case of relay, If markings are illegible, Al and A2 ter-
minals will be the ones with the largest diameter ter-
minal studs.

11-35
TM 55-1520-244-BD

Figure 11-29. AH-1 PROD Battery Compartment, Forward View (Sheet 1 of 2)

11-36
 TM 55-1520-244-BD

Figure 11-29 AH-1 PROD Battery Compartment, Forward View (Sheet 2 of 2)

11-37
TM 55-1520-244-BD

Figure 11-30. AH-1 PROD Battery Compartment, Side View (Sheet 1 of 2)

11-38
 TM 55-1520-244-BD

Figure 11-30. AH-1 PROD Battery Compartment, Side View (Sheet 2 of 2)

11-39
 - ------------.---

110-128-l 1 .-.l” 3&

110-128-l 3Ki

IlO-111-l JK$ -. Relay, ,Iwerter Three Phase

: ~/ '-
110-111-1 -.3K6
_. Relay; Inverter Select
_ '.I_
214-075-150-l 3K5 '_ Relay, Main AC Fail
i
214-075-150-l 3K7 ': Relay, Standby AC Fail
:-
110-127-l 2K7' '- delay, Bus Control

MS24140-Dl lOK2.. Relaj fs Heater Control

212-075-236-15 lOS5 Sensor, TOW Overload

06-649/A 2BTl Battery

P&543()/A Inver *ter, Standby

Figure 11-30.
 v >” ,; .y ,,.,, <.. .e T-.’ “l,,, c “_ ._ j- ._. ,;*s-,._
i .?,,.” _‘, _ -a _\. .,
-. .‘i‘” --
:_ .’ _, ..::‘,. -
:’ ,^ ”
., : :. .- i,
3’. ,.

TM 55-152012;44-BD
.

r
_
:

.:
: .' ‘. .,-, .I

. q&q‘ ,' * *_',*,_ -; ' i ~~~~~~~~~ : ' ~

/ NUB8fR ~~S~~~AT~OM ,Ftit&QN.~. ' _' .- *"

‘. "*
2BT1 '5! . ,' B&tery -.
BB-649/A
IlO-lib! .2K16 4telay (Ext Pwr Cant)

110-111-1 26 Retay (RVS Cur.Gont)

iubili-1 2K15 ' Relay, (TRU Cant)-

/
.- l~~fJ-,lll-l ,2K21 Relay

-'~&27-l 2K8 Relay (Bat Gontf

110-127-l 2Kl7 Relay (Armt Cant) )I_

<
,110-$28-l‘ 2K3 Relay (Bat Cont)

t l,O-i28-11 -. 3K2' +elay (AC Cont)

I&2545?-Df. 2K6 :Rhiy '(Gen Field)

.
209-075-572-3 3PSl lnverter
.a (
2Q$i-075~&l-2 3PS2 Unit, Transformer
ReCtffier
r
ZiM6OlBA2OAl 3CB6 Ckt- l3kr TRU (WQ 77-22763
to '?8-23092)

SM6OlBA2OAlX 3CB6 Ckt Bky TRU- (78-23093 & Sub)

M6106/9-002 _ 3Kl Relay (AC Source)

M21480/16-5 x3 Cur XFMR

209-075-998-l 3VRl Control; Alternatori

M81714/5-1 2TBl Terminal Board; Relay

Intei-face

_)

Figure II-3i. AH-IS ECkS and MC Battery Compartment, (Sheet 2 of 2)

-11-41
TM 55-1520-244-BD

Figure 11-32. AH-lS ECAS and MC Battery Compartment (Sheet 1 of 3)

11-42
 TM 55-1520-244-BD

PART DRAWING
NUMBER DESIGNATION FUNCTION

MS??!??-D? 3Yl
LhA
Dal a\\I , External
I\L Iuy Pwr

MS24142-D2 2K4 Relay, Non-Essential

MS24142-D2 2K9 Relay, Essential

MS24142-D2 2Klcl Relay, (TRU) Essential

MS24142-D2 2K13 Relay, Armament

MST" 1 Q-J-01
LT A"& lK3 Dnlzit~
,\r,tuy, starter

MS24183-Dl 2Kll Relay, (TRU) Non-Essential

MS24183-Dl 2K12 Relay, (TRU) Armament

MS24183-Dl 19K7 Relay, Turrent Pwr

MS24140-D2 lK4 Relay, EMG. Hyd. Pump

212-075-236-17 lS24 Switch, EMG. Hyd. Pump Sensor

AN2552-3A 251 Receptacle, EXT. Pwr

209-175-200-l 2K2 Relay, Battery

205-075-642-101 2K5 Relay, Reverse Current

204-675-152-l 2Rl Shunt

209-075-228-l 2VRl Regulator, Voltage

M83383/02-09 3CB7 Ckt Bkr Inverter (RCCB)

M8805/1-008 8S6 Switch, External Pwr Door

MS24140-51 lOK2 Relay, Tow Blower

212-075-236-15 lOS5 Sensor, Tow Blower Overload

M83383!01-10 3426Kl RCCB

212-075-236-27 19S18 Sensor

Figure 11-32. AH-1S ECAS and MC Battery Compartment (Sheet 2 of 3)

11-43
TM 55-1520-244-BD

PART DRAWING
NUMBER DESIGNATION FUNCTION
209-175-357-101 2K20 Reverse Current in Action,
Relay

MS3320-5 2CBl DC VM

MS3320-5 2CB2 DC VM

MS3320-5 2CB6 Battery Relay

MS3320-5 2CB7 EXT. Pwr

MS3320-5 2CB8 ESNTL BUS

MS3320-5 2cl39 TRU BUS

MS3320-5 2CBlO REV CUR

MS25244-5 8CBll XMSN Oil Level Lt.

MS25244-10 19CB126 AMMO Load

MS25244-10 2OCB2 TSGMS Pwr

MS25244-35 2OCBl TOW Pwr

Figure 11-32. AH-IS ECAS and MC Battery Compartment (Sheet 3 of 3)

11-44
 TM 55-1520-244-BD

Figure 11-33. Block Diagram, Typical Power Relays

Figure 11-34. Jumper Wire Fabrication

11-45
TM 55-1520-244-BD

5. Remove hardware from terminals Al and A2. 8. Remove jumper as soon as emergency evacua-
tion flight is completed.
6. Install jumper from terminal Al to terminal A2.
Reference Figure 11-33. 9. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
7. Install hardware on terminals Al and A2. Tighten system using standard maintenance procedures.
hardware to hold jumper in place.
Section VII. ANTENNAS

11-17. GENERAL. This section contains ex- PROCEDURAL STEPS:

pedient repair procedures to restore radio communica-
tion needed to complete the mission. 1. Determine length of wire needed for the radiating
element by using Figure 11-35. Example:

FM radio with frequency range of 30 to 69.95 MHz.

Avoid contact with expedient antennas.
Bare wires could cause severe burns and Center of frequency range is 50 MHz.
electrocution hazard.
Using Figure 11-35, look under frequency column
for 50 MHz on the wave length side of the Table, 6
11-18. SUBSTITUTE EMERGENCY ANTENNA. M is shown.

GENERAL INFORMATION: This procedure gives Use Figure 11-35 to convert meters to feet. Six
Instructions for construction of a replacement antenna meters multiplied by 3.280 = 19.68 feet for one
that can be used to transmit and receive radio mes- wave length.
sages.
Divide the one wave length by 8, for a 1/8 wave
length antenna, 19.68 = 2.46 feet.
OPTION: Fabricate Antenna. 8
Multiply the 1/8 wave length by a .95 correction fac-
LIMITATIONS: Some loss of antenna gain and tor: 2.46 ft. X .95= 2.34 feet. This is the length of
radio transmitter power. the radiating element.

PERSONNEL/TlME REQUIRED: 2. Cut the coax cable to the length of the required
1 Soldier radiating element. Remove the outer insulation and
1 Hour shield from the piece of coax cable and then strip a 1
inch piece of insulation from each end exposing the
MATERIALS/TOOLS REQUIRED: center conductor, Figure 11-36.
Cable, Coax RG-58U or Other Available
Coax 3. Wrap and solder the 51 Ω resistor to one end of
Tape (item 151 or 153, App, C) the radiating element as per Figure 11-36. This com-
Resistor, Carbon, 1 Watt 51 Ω ±5% pletes the fabrication of the radiating element of the
(item 87, App. C) antenna.

11-46
 TM 55-1520-244-BD

Figure 11-35. Frequency vs. Wave Length Figure 11-36. Preparation of Coax

11-47
TM 55-1520-244-BD

4. Next, remove the structural panel on 9. Ground the pigtail from the coax
the right-hand side just forward of the antenna by wrapping and twisting it
tailboom, Figure 11-37. around the plug where the coax was
disconnected.
5. At the tailboom quick disconnect,
locate coax cable marked 1 ARC 114-105A 10. Secure with tape to hold the
and disconnect it. antenna and coax in place inside the
tailboom. Replace the structural panel
6. Remove the coax connector and pre- and secure with screws.
pare a 4 inch pigtail termination on the
end of the coax cable as shown in Figure NOTE
11-38.
Antenna must be at right angle
7. Pass the radiating element of the (90°) to aircraft skin to radiate
antenna, from step three, with the resis- R.F. energy. Do not tape antenna
tor end down into the drain hole in the to skin of aircraft.
bottom of the tailboom where it joins the
fuselage, Figure 11-37. 110 Tape a one to two ounce weight,
using tape, below the 51 Ω resistor as
8. Twist the center conductor from the shown in Figure 11-36.
radiating element of the antenna to the
center conductor of the coax. Make a
good mechanical joint and insulate with
tape.

11-48
 TM 55-1520-228-BD

Figure 11-37. Installation of Field Expedient Antenna

11-49
TM 55-1520-244-BD

Figure 11-38. Pigtail Termination for Shielded Wire

Section VIII. ELECTRICAL WIRE INSULATION

11-19. GENERAL. Aircraft wiring may CAUTION

sustain minor damage to the electrical
wiring such that splicing repair tech- Ensure aircraft power is OFF.
niques are not required. The fixes Disconnect battery before
described herein will be the most expe- touching wires,
dient under minor repair circumstances.
OPTION 1: Apply Heat Shrinkable Reps r
11-20. DAMAGED WIRE INSULATION. Tape.

GENERAL INFORMATION: If the wire insu- LIMITATIONS: This is a temporary

lation is damaged but the wire itself is repair.
not, repair of the insulation may be
accomplished by installing heat PERSONNEL/TIME REQUIRED:
shrinkable tape, a transparent sleeve of 1 Soldier
flexible tubing, and securing with nylon 10 Minutes
braid or some other means.

11-50
 TM 55-1520-244-BD

MATERIALS/TOOLS REQUIRED: PROCEDURAL STEPS:

● Heat Shrinkable Tape

● Heat Gun/Heat Source 1. Remove damaged insulation and examine to in-

● Wire Repair Kit (item 14, App. B) sure conductor strands are not damaged.

PROCEDURAL STEPS: 2. Prepare a sleeve of flexible tubing one and one-

half times the outside diameter of the wire and 2
1. Start wrapping at one end of area to be covered. inches longer than the damaged portion of the insula-
tion.
2. Overlap each turn about one-third of tape width.
Overlap of more than 50 percent or multiple wraps 3. Split lengthwise and wrap one and one-half times
are not recommended. Excess thickness prevents around the wire at the damaged section.
heat transfer to the inner layer. Refer to Figure 11-39.
4. Tie with string or other suitable material at each
3. Apply heat to end of last lap to soften the mel- end and at 1 inch intervals over the entire length,
table adhesive and press it into position while warm. Figure 11-40.

4. Heat the tape to shrink it and melt the adhesive 5. Record BDAR action taken. When mission is
layer. complete, as soon as practical, repair the equip-
ment /system using standard maintenance procedures.
5. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/- OPTION 3: Apply Tape Insulation.
system using standard maintenance procedures.
LIMITATIONS: This is a temporary repair.
OPTION 2: Apply Insulation Sleeve.
PERSONNEL/TIME REQUIRED:
LIMITATIONS: This is a temporary repair. ● 1 Soldier

● 5 Minutes Per Wire

PERSONNEL/TlME REQUIRED:
●
1 Soldier MATERIALS/TOOLS REQUIRED:
● 10 Minutes ● Tape (item 151 or 153, App. C)

● Knife

MATERIALS/TOOLS REQUIRED: PROCEDURAL STEPS:

●
Insulation Sleeving or Rubber Hose
(item 53, App. C) 1. Remove damaged insulation and examine to in-
●
Knife sure center conductor is not damaged.
●
String or Cable Ties
(item 26 or 27, App. C) 2. Wrap tape over exposed center conductor of
wire. Tape should extend 2 inches beyond the wire in-
sulation at each end of the area to be covered.

3. Record BDAR action taken. When mission is

complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

11-51
TM 55-1520-244-BD

OPTION 4: Apply Potting Compound PROCEDURAL STEPS:

Insulation.
1. Remove damaged insulation and
LIMITATIONS: This is a temporary examine to insure center conductor is
repair. is not damaged.

PERSONNEL/TIME REQUIRED: 2. Apply a thin coat of potting

1 Soldier compound over the exposed center
1-3 Hours Per Wire (depending on which conductor.
potting compound is used)
3. Allow time to dry. If compound
MATERIALS/TOOLS REQUIRED: coating does not seem to be sufficient,
Potting Compound (item 85, App.C) apply additional layers as needed.
Tape, Electrical (item 151 or 153,
App. C) 4. Record BDAR action taken. When
Knife mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.

Wrap only tight enough to hold tape in place.

The tape will shrink tightly when heated.

Figure 11-39. Heat Shrinkable Tape

Figure 11-40. Insulation Repair with Sleeving

11-52
 TM 55-1520-244-BD

CHAPTER 12

FUEL SYSTEM

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

12-1. SCOPE. This chapter contains the a leak shall be determined and the leak
fault assessment and expedient repair area examined thoroughly. Refer to
procedures for locating and fixing Table 12-1 assessment logic.
damage to the fuel system. The system
is shown pictorially in Figure 12-1. 12-3. REPAIR PROCEDURE INDEX.

12-2. ASSESSMENT PROCEDURES. Each fuel PARA.

system must be carefully evaluated and
PARA. 12-5
classified, both in confined areas and
PARA. 12-6
in open areas exposed to the airstream,
in order to differentiate between leaks Aft Fuel Cell Isolation. . . . 12-7
which require immediate repair before Forward Fuel Cell Isolation. . 12-8
flight and leaks which do not constitute Fuel Boost Pumps (General) 12-9
a flight hazard. The exact location of External Fuel Filter Clogged 12-10
Fuel Filter Bypass . . . . . . 12-11

Section II. LINES AND HOSES

12-4. GENERAL. (2) If hose assemblies from kits

are not available, damage may be cut
a. Replacement lines and hoses need out and replaced with a small section
not be routed along the path of the ori- (refer to repair procedures), or a
ginal installation. They may be routed replacement hose may be manufactured if
along any convenient path as long as a long enough hose section and MS fit-
they do not interfere with personnel or tings are available (refer to repair
with operating equipment. Long lines procedures in Chapter 9).
and hoses should be clamped to hard sup-
ports at convenient intervals not c. In the event of o-ring damage,
exceeding two feet. refer to Chapter 9, paragraph 9-13.
The same criteria that applies to
b. Fuel System Metal Tubes and Hoses. hydraulic o-rings also applies to
o-rings in the fuel system.
(1) Damaged metal tubes will nor-
mally be replaced with hose assemblies d. If the standard fuel is not
from BDAR kits. available, a substitute fuel must be
used. Check Appendix D for a compatible
fuel.

12-1
TM 55-1520-244-BD

1. Hose Assembly 9. Engine Drain Coupling 17. Seal

2. Pressure Switch 10. Filter 18. Boost Pump
3. Check Valve Manifold 11. Engine Fuel Supply Hose 19. Forward Fuel Cell
4. Plug 12. Governor Bleed Coupling 20. Fuel Receiver
5. Pressure Switch 13. Boost Pump 21. Fuel Vent Fitting
6. Fuel Quantity Probe 14. Crossover Hose 22. Fuel Quantity Probe
7. Fuel Shutoff Valve 15. Fuel Hose 23. Vent Lines
8. Aft Fuel Cell 16. Drain Valve 24. Check Valve

Figure 12-1. Fuel System

12-2
 TM 55-1520-244-BD

Table 12-1. Fuel System Assessment Procedure

PARA 12-5

PARA 9-13

PARA 12-9

PARA 12-7
PARA 12-8

PARA 12-10 PARA 12-11

12-3
TM 55-1520-244-BD

OPTION 1: Hose Splice Tubing Repair.

● Battle damaged areas should be inspected for LIMITATIONS: Inspect after every flight.
unexploded ordnance before attempting
repairs. Disposal of unexploded ordnance PERSONNEL/TIME REQUIRED:
should be accomplished by qualified personnel. ● 1 Soldier

● 1 Hour

● Cleaning solvents may be flammable and

toxic. Use only in well-ventilated areas. Avoid MATERIALS/TOOLS REQUIRED:
inhalation of vapors and skin contact. Do not ●
String or Wire (item 149 or 61,
use solvents near open flame or in areas App. C)
where very high temperatures prevail. Solvent ● Sealant or Epoxy (Optional)
flash point must be less than 100°F. (items 4 or 123-127, App. C)
● Adhesive (item 5 or 6, App. C)
● When refueling helicopter, the refueling vehicle ● Hose
must be parked a minimum of 20 feet from the ● Two Hose Clamps (items 54-59, App. C)
helicopter. Before starting the fueling opera- ● Tube Cutter
tion, always insert fueling nozzle ground cable ● Hacksaw
of fuel truck into GROUND HERE receptacle. ● Tube Cleaner
Refer to FM 10-68. When defueling, turn off all ●
Hand File
electrical switches and disconnect external
power from the helicopter. The helicopter must PROCEDURAL STEPS:
be electrically grounded.

● Fuel line and tank repairs often involve han- 1. Cut out damaged area of tubing.
dling of highly inflammable material. Mishan-
dling can result in serious injury or death. 2. Clean and smooth newly cut ends.

● The helicopter should be electrically grounded 3. Make an improvised bead by wrapping string or a
when parked to dissipate static electricity. Turn soft wire around the tube as shown in Figure 12-2. (If
off all power switches before making electrical time permits, coat the string or wire with sealant or
connections of disconnections. hardening epoxy and let it dry.)
12-5. METAL TUBE AND HOSE LEAKS.
4. Cut a piece of hose which fits tightly over the
tubing and extends 1-1/2 to 2 inches over each end,
GENERAL INFORMATION: This paragraph Figure 12-2 and 12-3.
describes procedures for the expedient repair of low
pressure (i.e., fuel lines not hydraulic lines) tubing.
New hoses can be manufactured by following the pro-
cedures in Chapter 9.

12-4
 TM 55-1520-244-BD

Figure 12-2. Use of String Bead

Figure 12-3. Long Replacement Tube Section

12-5
TM 55-1520-244-BD

5. Slip the hose over both ends of 2. Split the hose lengthwise.
the tube, and secure it with two hose
clamps. 3. Coat the inside of the tube with
sealant.
6. Record BDAR action taken. When
mission is complete, as soon as 4. Install the hose over the leak with
practical, repair the equipment/system the split opposite the leak, Figure
using standard maintenance procedures. 12-4.

OPTION 2: Patch Metal Tubing. 5. Secure the hose with at least three
clamps, the center one directly over the
LIMITATIONS: Inspect after every flight. leak.

PERSONNEL/TIME REQUIRED: NOTE

• 1 Soldier
• 1 Hour If a rubber hose is not available,
use a piece of patch material,
MATERIALS/TOOLS REQUIRED: rubber (piece of innertube),
• Hose or Other Patch Material gasket, or poncho material. If a
(item 52 or 116, App. C) hose clamp is not available, use
• Sealant (items 123-128,App. C) tape, lacing wire, or copperware.
Hose Clamps, Tape, or Wire Check the system fuel level fre-
(items 54-62,153, App. C) quently.

PROCEDURAL STEPS: 6. Record BDAR action taken. When

mission is complete, as soon as
1. Use a piece of reinforced hose with practical, repair the equipment/system
an inside diameter equal to the outside using standard maintenance procedures.
diameter of the damaged tube.

Figure 12-4. Repair of Small Hole in Tube

12-6
 TM 55-1520-244-BD

OPTION 3: Manufacture a New Hose. Refer to PROCEDURAL STEPS:

Chapter 9, repair procedures on installing MS fittings
to a hose section. 1. Cut out the damaged section of the hose. Wrap
the hose with tape at the location of intended cuts.
OPTION 4: Replacement of Damaged Hose
Section. 2. Cut each end of the damaged section, take care
to make a square cut.
LIMITATIONS: None.
3. Clean loose particles from ends of hose; remove
PERSONNEL/TIME REQUIRED: tape.
● 1 soldier
● 30 Minutes
4. Measure distance between cut ends of damaged
hose.
MATERIAL/TOOLS REQUIRED:
●
Hydraulic Tubing
5. Take a piece of tubing with an outside diameter
●
Tube Cutter
equal to the inside diameter of the hose and cut a
●
Hacksaw length 6 inches longer than the distance measured in
●
Hand File step 4, above.
●
Safety Wire (items 60-62, App. C)
●
Adhesive (items 4-6, App. C)
6. Make an improvised bead by wrapping string or
● Hose Clamps (items 54-59, App. C)
safety wire around the tube. (If time permits, coat the
●
Tape (items 151-153, App. C)
string or wire with sealant or hardening epoxy and let
●
String (item 149, App. C)
it dry.)

7. Position tube inside each end of cut hose, and

secure in place with four clamps, Figures 12-5, 12-6.

8. Record BDAR action taken. When mission is

complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

Section Ill. FUEL CELLS

12-6. FUEL CELL PATCHING. b. One-Time or Emergency Flight Capability

Repair:
GENERAL INFORMATION: The fuel cells restrict
the catastrophic loss of fuel in survivable crashes. Mechanical Clamp Repair (option 1).
The repairs specified in this section, however, will
not necessarily return the cells to their original crash c. 100 Flight Hour Capability Repair:
resistant level. Fuel cell damage can be categorized
as follows:
(1) Adhesive repair (option 2).

a. Non-Repairable:
(2) Flat panel repair, one plane (option 3).

(1) Damage to tank wall which exceeds 3

(3) Two plane repair (option 4).
inches.

(4) Three plane repair (option 5).

(2) Damage within 2 inches of metal fittings,

12-7
TM 55-1520-244-BD

Figure 12-5. Expedient Repair of Damaged Hose

Figure 12-6. Replacement of Damaged Hose Section

12-8
 TM 55-1520-244-BD

NOTE 5. Position the plate so the hole is entirely within the

gasket area.
Nonrepairable damage to one fuel cell
may be isolated if the other cell is operable 6. Slip the top plate over the threaded stud and
or repairable. hand tighten the wing nut. Refer to Figure 12-8.

OPTION 1: Mechanical Clamp Repair.

LIMITATIONS: Emergency flight repair. Excessive mechanical tightening of the

wing nut can result in failure of the clamp.
PERSONNEL/TIME REQUIRED: The wing nut shall be finger tightened and
1 Soldier the maximum torque on the wing nut shall
30 Minutes not exceed 10 to 12 inch-pounds.

MATERIAL/TOOLS REQUIRED: 7. Refuel the aircraft.

Fuel Cell Repair Kit
(item 5, App. B) 8. Record BDAR action taken. When mission is
Sealant (item 125, App. C) complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
PROCEDURAL STEPS:
OPTION 2: Adhesive Repair.

LIMITATIONS: Inspect after every flight.

Ground aircraft during defueling and fuel-
ing procedures. PERSONNEL/TIME REQUIRED:
1 Soldier
1. Defuel aircraft by disconnecting inlet to fuel con- 30 Minutes
trol and using fuel boost pumps to pump out fuel,
Figure 12-7. MATERIALS/TOOLS REQUIRED:
Knife
2. Locate the damage (i.e., hole or tear) on the cell. Solvent (item 7 or 129, App. C)
Sandpaper (items 118-120, App. C)
NOTE Adhesive (item 5 or 6, App. C)

For holes less than 2 inches across, use PROCEDURAL STEPS:

the 3 inch clamp. For holes greater than 2
inches across, but less than 3 inches 1. Defuel the aircraft. Refer to option 1, step 1.
across use the 5 inch clamp. For larger
holes consider cell isolation. 2. Once step 1 (above) has been completed, trim
only the outer exposed damage area to provide a
3. Use the knife to enlarge the hole 3/4 to 2 inches reasonably smooth exterior surface. DO NOT
maximum for a 3 inch clamp and 1 to 3 inches maxi- ENLARGE HOLE.
mum for the 5 inch clamp.
3. Abrade and solvent wash the area surrounding
4. Insert the bottom plate of the clamp through the the damage using solvent at least 4 inches beyond
hole and pull up using the cord. the damage.

12-9
 TM 55-1520-244-BD

Figure 12-7. Inlet Line to Fuel Control

12-10
 TM 55-1520-244-BD

Figure 12-8. Emergency Mechanical Clamp Repair

12-11
TM 55-1520-244-BD

4. Cut a fabric patch to overlap the MATERIALS/TOOLS REQUIRED:

damaged area by a minimum of 1 inch all Knife or Scissors
the way around. Solvent (item 7 or 129, Appx C)
Sandpaper (items 118-120, Appx C)
5. Soak the patch in solvent. (NOTE: Fuel Cell Repair Kit (item 5, Appx B)
No hole is required in the center of
the patch.) PROCEDURAL STEPS:

6. Prepare the adhesive. 1. Defuel the aircraft. Refer to

option 1, step 1.
7. Apply adhesive to the wound opening
for at least 1-1/2 inches around the 2. Once step 1 of this section has been
damaged area or enough to accept the completed, enlarge the wound in the tank
patch cut in step 4 (above). to no more than 3 inches in diameter by
using a knife or scissors. Remove all
8. Apply and smooth out the applied frayed fabric and damaged inner lines.
adhesive and solvent soaked fabric patch
to the damaged area. 3. Abrade the inner lines or inner
surface at least 1/2 inch beyond the
9. Apply adhesive if required to seal enlarged hole, preferably more if con-
the patch to the tank and smooth out ditions permit.
the surface.
4. Abrade the outer surface to a
CAUTION minimum of 4 inches from the enlarged
area. (NOTE: If the fraying fibers
The patch will tend to slip when are too-numerous, retrim the fiber
applying additional adhesive and with scissors.)
smoothing. Be sure to recenter
the patch. 5. Clean the abraded areas using towels
soaked in solvent.
10. Maintain the patch position until
the adhesive sufficiently sets. (NOTE: 6. Cut a fabric patch 4 inches in
Allow the adhesive to cure before diameter or large enough to extend at
refueling.) least 1 inch beyond the damaged area and
add a 1/2 inch hole in the center.
11. Refuel the aircraft.
7. Soak the patch in solvent.
12. Record BDAR action taken. When
mission is complete, as soon as 8. Prepare the adhesive.
practical, repair the equipment/system
using standard maintenance procedures. 9. Apply adhesive to inner liner using
finger to swab cement around the wound.
OPTION 3: Flat Panel Repair (One
10. Apply adhesive to concave surface
of the rubber plug (this is the surface
LIMITATIONS: Inspect after every the cord is attached to). Refer to
flight. Figure 12-9 for rubber plug assembly.

PERSONNEL/TIME REQUIRED:
1 Soldier
3 Hours

12-12
 TM 55-1520-244-BD

Figure 12-9.

NOTE 16. Smooth the patch into the adhesive.

Use adhesive as required, retain 17. Pull the cord and tape to the
some for finishing the outside of structure keeping a slight tension.
the cell repair.
18. Do not disturb the repair for a
11. Fold the rubber plug and insert it minimum of 30 minutes and let cure two
through the hole in the cell. (NOTE: hours before refueling.
Retain cord to prevent loss of plug in
the cell.) 19. Cut the string and plug stem
without distributing the repair.
12. Pull the plug into position and
rotate it in position to smooth out the 20. Refuel the aircraft.
adhesive interface.
21. Record BDAR action taken. When
13. Center the plug on the wound. mission is complete, as soon as
practical, repair the equipment/system
14. Apply a layer of adhesive 4 inches using standard maintenance procedures.
in di ameter around the wound on the out-
side and fill in the wound with adhe- 0PTION 4: Two Plane Repair. Damage to a two
sive (There must be a minimum of a 1/2 plane area will be repaired in the same manner
inch bond.) described in OPTION 3 except the hole should not be
enlarged to more than 1/2 by 2-1/2 inches.
15. Apply the solvent soaked fabric
patch to the outside surface by passing
the cord through the hole in the patch-
and position the patch over the wound.

12-13
TM 55-1520-244-BD

OPTION 5: Three Plane (Corner) Repair. Damage OPTION: Isolate Fuel Cell.
to a three plane area will be repaired in the same
manner as described in OPTION 3 except the hole LIMITATIONS:
should not be enlarged to more than 1/2 by 2-1/2
inches and the rubber plug will be cut as shown in Fig- 1. The aircraft center of gravity will
ure 12-10. This will allow the plug to assume the con- be changed after the removal of the aft
tour of the tank when pulled into place. fuel cell. The aircraft will be nose
heavy.

CAUTION
12-7. AFT FUEL CELL ISOLATION.
Weight and balance consideration:
GENERAL INFORMATION: If battle damage forward cell capacity 143 gallons,
to the aft fuel cell is too severe to located at FS 173.
repair, alterations can be made to the
system to isolate the damaged aft cell 2. The fuel supply will be one-half of
from the fuel system. The forward fuel the normal supply which results in less
cell will become the sole fuel reservoir flight time.
for the aircraft.

Figure 12-10. Plug Modification for Three Plane (Corner) Repair

12-14
 TM 55-1520-244-BD

3. No more than one-half of the rounds on the 5. Cut out a section of the rubber material that the
20mm turret gun can be carried with a full forward cell. fuel cells are constructed of. Cut the section of fuel
cell material to the shape of the crossover line flange
PERSONNEL/TlME REQUIRED: use template, Figure 12-12.
● 2 Soldiers

● 3 Hours 6. Drill ten bolt holes on the cutout section as shown

on the template. These bolt holes are to match the
MATERIALS/TOOLS REQUIRED: ten bolt holes on the crossover line flange. This part
●
Knife or Scissors will be used as a gasket.
●
Plywood or Sheet Metal (items 136-138,
App. C) 7. Obtain a piece of thick sheet metal, plywood, or
● Drill Bit – 1/4 in. and Drill Motor some other solid plate and cut out two plates to the
● Ten 1/4 in. nuts (items 63-70, App. C) shape of the cutout made in step 5.
●
Ten 1/4 in. washers (item 168 or 169,
App. C) 8. Drill ten bolt holes on each of these plates to
● Ten 1/4 in. bolts match those made on the cutout section in step 5.
●
Sealant (items 123-128, App. C)
●
Gasket Material (item 52, App. C)
9. Obtain ten 1/4 inch nuts, washers, and bolts.
PROCEDURAL STEPS:
10. Place the cell material plate cutout in step 5 and
one of the rigid plates cutout in step 7 against the
1. Defuel the aircraft. Refer to option 1, step 1.
crossover flange to block off the crossover line.
2. Remove the right and left side access panels (1,
11. Bolt the pieces together using the bolts,
Figure 12-1 1) to gain access to the crossover line (14,
washers, and nuts. Refer to Figure 12-13.
Figure 12-1 ). (Either panel will give access to the
crossover line; however, having both panels open will
make working easier.) 12. If available, apply a bead of sealant around the
flange assembly and over the bolts.
3. Remove the ten bolts which connect the aft end
flange of the crossover line to the aft fuel cell and 13. Place the other rigid plate cut out in step 5
detach the aft end of the crossover line from the aft against the aft fuel cell opening which is where the
cell. crossover line was previously attached.

4. Gain access to the damaged aft cell. A damage 14. Bolt or seal in place. (This will help to isolate the
hole opening on the fuel cell panel may be used as fuel vapors in the empty fuel compartment and
an access port. reduce the amount of fuel vapors escaping into the
aircraft.)

15. Disconnect and remove the hose assembly (1,

Figure 12-14) from the check valve fuel manifold (2).

12-15
TM 55-1520-244-BD

Figure 12-11. Aft Cell Isolation Access Panels

12-16
 TM 55-1520-244-BD

Figure 12-12. Crossover Line Flange Template

12-17
TM 55-1520-244-BD

NOTE

IF AVAILABLE, APPLY A BEAD OF

SEALANT AROUND FLANGE AND OVER
BOLTS.

Figure 12-13. Blocked Off Crossover Line

12-18
 TM 55-1520-244-BD

1. Aft Fuel Cell Inlet

2. Fuel Manifold
3. Forward Fuel Cell Inlet

Figure 12-14. Fuel Manifold

12-19
TM 55-1520-244-BD

16. Disconnect the aft end of the elbow which con- LIMITATIONS:
nects to the fuel cell then disconnect the fitting which
attaches to the manifold. The fuel control linkage (not 1. The aircraft center of gravity will be changed after
shown) and the pressure switch connections (5, the removal of the forward fuel cell. The aircraft will
Figure 12-1 ) may need to be removed to allow access. be tail heavy.

17. OPTIONAL - Cap off the check valve fuel NOTE

manifold with a 3/4 inch cap fitting. (The cap fitting is
attached where the hose assembly, removed in step Weight and balance consideration:
13, previously connected.)
aft fuel cell capacity 117 gallons,
located at FS 230.
NOTE
2. The fuel supply will be one-half of the normal
Turn off circuit breaker for aft fuel boost supply, which results in less flight time.
pump. Aft boost pump light will illuminate
when breaker is switched off. Ignore the
PERSONNEL/TIME REQUIRED:
light or disable segment by removing
● 2 Soldiers
lamps.
● 3 Hours

18. Reinstall the panels (1, Figure 12-11) removed MATERIALS/TOOLS REQUIRED:
in step 2. ●
Knife or Scissors
● Plywood or Sheet Metal (items 136-138,
19. Refuel the aircraft. Only the forward cell will con- App. C)
tain fuel. ● Drill Bit - 1/4 in. and Drill Motor
● Ten 1/4 in. Nuts (items 63-70, App. C)
20. Record BDAR action taken. When mission is ● Ten 1/4 in. Washers (item 168 or 169,
complete, as soon as practical, repair the equipment/- App. C)
system using standard maintenance procedures. ● Ten 1/4 Bolts (items 8-24, App. C)
● Sealant (items 123-128, App.C)
12-8. FORWARD FUEL CELL ISOLATION.
● Gasket Material (item 52, App.C)

PROCEDURAL STEPS:
GENERAL INFORMATION: If the battle damage to
the forward fuel cell is too severe to repair, alterations
can be made to the system to isolate the damaged 1. Defuel the aircraft. Refer to option 1, step 1.
forward fuel cell from the fuel system. The aft fuel cell
will become the sole fuel reservoir for the aircraft. 2. Remove the right and left side access panels (1,
Figure 12-11) to gain access to the crossover line (14,
OPTION: Isolate Fuel Cell. Figure 12-1). (Either panel will give access to the
crossover line; however, having both panels open will
make working easier.)

12-20
 TM 55-1520-244-BD

3. Remove the ten bolts which connect 12. Place the other rigid plate cutout
the aft end flange of the crossover line in step 7 against the fuel cell opening,
to the aft fuel cell and detach the aft which is where the crossover line was
end of the crossover line from the aft previously attached and bolt or seal in
cell. DO NOT discard bolts, they will place. This will help to isolate the
be used later. fuel vapors in the empty fuel compart-
ment and reduce the amount of fuel vapor
4. Gain access to the damaged forward escaping into the aircraft.
fuel cell. A damage hole opening on the
fuel cell panel may be used as an access 13. Block off the check valve fuel
port. manifold (2, Figure 12-14) by discon-
necting fitting (3).
5. Cut out a section of the fiberous
rubber material that the fuel cells are 14. OPTIONAL - Cap off the check valve
constructed of. Cut the section of fuel fuel manifold with a 3/4 inch cap
cell material to the shape of the fitting. (The cap fitting is attached
crossover line flange, see template, where the hose assembly, removed in step
Figure 12-12. 12, previously connected.)

6. Drill ten bolt holes on the cutout NOTE

section, as shown on the template.
These bolt holes are to match the ten Turn off circuit breaker for for-
bolt holes on the crossover line flange. ward boost pump. Forward boost
pump light will illuminate when
7. Obtain a piece of sheet metal, breaker is switched off. Ignore
plywood, or some other solid plate and light.
cut out two plates to the shape of the
cutout made in step 5. 15. Reinstall the panels (1, Figure
12-11) removed in step 2.
8. Drill ten bolt holes on each of
these plates to match those made on the 16. Refuel the aft fuel cell by the
cutout section in step 5. following procedure:

9. Obtain ten 1/4 inch nuts, washers, a. Open the transmission cowl
and bolts (bolts removed in step 3 assembly panel (4, Figure 12-11).
should be used), and place the cell
material plate cutout in step 5 and one b. Remove the floor baffle panel by
of the rigid plates cutout in step 7 removing all screws and fasteners
against the aft fuel cell flange, which which attach to it (Figure 12-16).
had previously been used to connect with (The tube assembly going through baffle
the flange of the crossover line, see panel will have to be disconnected as
Figure 12-15. indicated.)

10. Bolt the assembly together as NOTE

shown.
Label electrical connectors
11. If available, apply a bead of before removal to assure correct
sealant around the flange assembly and reassembly.
over the bolts.

12-21
TM 55-1520-244-BD

Figure 12-15. Blocked Off Fuel Cell

12-22
 TM 55-1520-244-BD

c. Remove the four bolts and the two electrical NOTE

connectors, which attach the fuel quantity probe (6,
Figure 12-1 ) to the aft fuel cell. DO NOT discard Close circuit refueling is not possible
probe cap, bolts, or o-ring (1 through 3, Figure 12-17). through this opening.

d. Remove the fuel quantity probe by gently lifting f. Once the cell has been refueled, replace the
the probe cap up and out as necessary. probe cap with o-ring attached and reconnect the
electrical leads.
e. Refuel the aircraft by pouring in fuel to the aft
cell through the opening provided. 16. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

Section IV. FUEL BOOST PUMPS

12-9. GENERAL. the engine driven pump provided that the boost pump
damage is not causing any fuel leakage and that the
a. Each of the two fuel cells has an electrically helicopter not fly above 4600 feet altitude. If the en-
operated boost pump which feeds fuel into the fuel gine driven pump should fail, regardless of whether or
manifold. The fuel then goes through a shutoff valve not the boost pumps are still functioning, the helicop-
and through the engine driven fuel pump. ter is not operable until the engine driven pump is
repaired or replaced.
b. If one or both of the fuel boost pumps be-
comes inoperable, the engine can still operate on

Section V. FUEL FILTERS

12-10. EXTERNAL FUEL FILTER CLOGGED.

The first indication of a clogged or frozen fuel filter will MATERIALS/TOOLS REQUIRED:
be a failure of the engine to start or degraded perfor- Compressed Air Source
mance because of insufficient fuel. Use this proce- Common Hand Tools
dure if a replacement fuel filter is not available. Solvent (item 7 or 129, App. C)
Towels (item 161, App. C)
OPTION 1: Clean Filter.
PROCEDURAL STEPS:
LIMITATIONS: None
1. Open the left engine access panel to gain access
PERSONNEL/TIME REQUIRED: to the external fuel filter, Figure 12-18.
1 Soldier
30 Minutes 2. Remove filter sump bowl, along with filter ele-
ment (3 and 5, Figure 12-18), from the fuel filter as-
sembly.

12-23
TM 55-1520-244-BD

Figure 12-16. Floor Baffle Assembly

12-24
 TM 55-1520-244-BD

1. Probe Cap
2. Bolt
3. O-Ring

Figure 12-17. Fuel Quantity Probe; Fuel Inlet

12-25
TM 55-1520-244-BD

1. V-Band Trunnion Clamp

2. Packing
3. Filter Element
4. Packing
5. Filter Sump Bowl
6. Packing

Figure 12-18. External Fuel Filter Assembly

12-26
 TM 55-1520-244-BD

3. Blow dirt out of filter element using compressed 4. Start engine.

air. If frozen, thaw out first then proceed to blow dirt
out using compressed air. 5. Record BDAR action taken. When mission is
complete, as soon as practical, repair the equipment/-
4. Place filter element back inside of filter sump system using standard maintenance procedures.
bowl and reinstall back onto the filter assembly.
OPTION 2: Ballistic Damage, Bowl Perforated
5. Start engine. Bypass.

6. Record BDAR action taken. When mission is LIMITATIONS: Possible fuel control clogging if filter
complete, as soon as practical, repair the equipment/- is bypassed.
system using standard maintenance procedures.
PERSONNEL/TIME REQUIRED:
12-11. FUEL FILTER BYPASS. ● 1 Soldier
● 30 Minutes

GENERAL INFORMATION: If the main filter is

bypassed, filtering of fuel will be accomplished by MATERIALS/TOOLS REQUIRED:
● Common Hand Tools
strainers inside the engine fuel control. However, the
strainer will clog and require frequent cleaning if the
fuel is heavily contaminated. PROCEDURAL STEPS:

OPTION 1: Bypass Filter. 1. Open left engine access panel to gain access to
external fuel filter, Figure 12-18.
LIMITATIONS: Possible fuel control clogging if filter
is by passed. 2. Disconnect hose fitting (1, Figure 12-19) from
breakaway fitting (2).
PERSONNEL/TlME REQUIRED:
1 Soldier 3. Loosen and remove the four mounts that attach
30 Minutes the filter assembly to the bracket and gently lift upon
the filter assembly just enough to provide enough
MATERIAL/TOOLS REQUIRED: deck clearance to remove the elbow (3) and
● Common Hand Tools
breakaway fitting (2) from the filter assembly. Do not
● Towels (item 161, App. C)
remove breakaway fitting from elbow.

PROCEDURAL STEPS: 4. Disconnect hose fitting (4) from coupling assemb-

ly (5).
1. Open the left engine access panel to gain access
to external fuel filter, Figure 12-18. 5. Bypass the filter assembly by connecting hose fit-
ting (1, Figure 12-20; also 4, Figure 12-19) to elbow
2. Remove filter sump bowl along with filter element fitting (2, Figure 12-20; also 3, Figure 12-19).
(3 and 5, Figure 12-18).
6. Record BDAR action taken. When mission is
3. Remove filter element from filter sump bowl, and complete, as soon as practical, repair the equipment/-
reinstall filter sump bowl without the filter element system using standard maintenance procedures.
back into the filter assembly.

12-27
TM 55-1520-244-BD

1. Hose Fitting
2. Breakaway Fitting
3. Elbow Fitting
4. Hose Fitting
5. Coupling Assembly

Figure 12-19. External Fuel Filter

12-28
 TM 55-1520-244-BD

1. Hose Fitting
2. Elbow Fitting

Figure 12-20. Bypassing External Fuel Filter

12-29/(12-30 Blank)
 TM 55-1520-244-BD

CHAPTER 13

FLIGHT CONTROLS SYSTEM

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

13-1. SCOPE. This chapter contains the c. Control Rods. If any control
fault assessment and expedient repair rods, bell-cranks, or linkages con-
procedures for locating and fixing necting gunner controls to pilot
damage to the flight control system. controls break or otherwise become
The system is depicted in Figures 13-1 inoperable, pilot may assume full
and 13-2. control for the particular function
which has been damaged, provided that
13-2. ASSESSMENT PROCEDURES. There are the damaged part does not become jammed
various subsystems and assemblies within in the surrounding aircraft structure.
the flight control system that are vital Once the aircraft is on the ground, if
for combat maneuverability and control, no replacement parts are available,
but are not necessarily essential for damaged control tube may be splice
basic flight capabilities. Refer to repaired or removed to avoid any possi-
Table 13-1 for assessment logic chart. bility of the control tube getting
jammed. If the tube is removed, the
a. Stability Control and Augmentation pilot assumes full control of the func-
System (SCAS). If the entire SCAS or a tion that has been lost to the gunner.
particular phase of the SCAS is inoper-
able, it may be bypassed and the If the Armament Compensator Unit
aircraft will still be flyable but with (ACU) is not functioning properly, the
the following limitations: aircraft is still flyable; however, the
armament is not to be used.
(1) The aircraft speed should not
exceed 100 knots. 13-3. REPAIR PROCEDURE INDEX.

(2) The aircraft armament should PARA.

not be used.
Severed or Bent Control Tubes. 13-4
b. Force Trim System. If the force
trim system is malfunctioning, the air-
craft is still fully mission capable
with no limitation presented.

13-1
TM 55-1520-244-BD
Figure 13-1. Flight Controls
13-2
 TM 55-1520-244-BD

Yaw Servo-Actuator 7. Roll Control Motion Transducer

Roll Servo-Actuator 8. Pitch Control Motion Transducer
3. Pitch Servo-Actuator 9. Yaw Hydraulic Solenoid Valve
4. Sensor Amplifier Unit 10. Roll Hydraulic Solenoid Valve
5. Three-Axis Rate Sensor 11. Pitch Hydraulic Solenoid Valve
6. Yaw Control Motion Transducer 12. Armament Compensation Unit

Figure 13-2. Stability and Control Augmentation System (SCAS)

13-3
TM 55-1520-244-BD

Table 13-1. Flight Control System Assessment Procedures

PARA 13-4

13-4
 TM 55-1520-244-BD

Section II. FLIGHT CONTROL TUBES

13-4. SEVERED OR BENT CONTROL TUBES. MATERIALS/TOOLS REQUIRED:

Metal Sleeve
GENERAL INFORMATION. Angle Stock (items 35-47, App. C)
Fasteners (items 7-24,63-70,
98-115, App. C)
Cotter Pins (item 35, App. C)

The standards contained herein allow PROCEDURAL STEPS:

aircraft to be flown with battle damage
substantially in excess of peacetime limits. 1. Measure center to center distance between rod
Under no cirumstances shall this manual ends or clevis eye bolts before removing damaged
be used entirely or in part for peacetime control tube. This step will allow repaired tube length
maintenance of the aircraft. Repair of flight to be matched to original, eliminating the need to
control damage requires extreme care and re-rig flight controls. If damage has completely
diligence and strict adherence to the severed original tube, center to center distance may
instructions and standards contained in be determined using Table 13-2.
this manual.
2. Disconnect and remove damaged control tube
a. The following repair procedures maybe used from aircraft.
to accomplish repairs to flight control tubes. Flight
control tubes connect the gunner’s and pilot’s cyclic, 3. Trim damaged area.
collective, and tail rotor controls to the aft flight control
components. See Figure 13-1 for a complete detail of
4. Using Table 13-2 and Figures 13-3 through 13-6,
the system and refer to Figures 13-3 through 13-6 for
a complete detail on each individual tube, see Table select a metal splice either inner or outer, whichever
is more suitable.
13-1.
5. Drill at least two bolt/rivet holes on each end of
b. Make all necessary repairs on all flight control
the tube, see Table 13-3. Holes should go through the
tubes by splicing. Insure that splice repairs do not
splicer and the damaged tube and should be posi-
cause any interference at bulk-head lighting holes or
tioned in a cross pattern. Refer to Figure 13-7. Make
adjacent components.
sure that the original center to center, Length b, Table
13-2 is maintained.
OPTION 1: Splice Control Tube.
6. Reinstall tube after repair is accomplished, and
LIMITATIONS: Inspect after every flight. check for binding or interference by manually moving
the appropriate controls: cyclic, collective, or pedals.
PERSONNEL/TIME REQUIRED:
1 Soldier 7. Record BDAR action taken. When mission is
2 Hours complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.

OPTION 2: Fabricate Flight Control Tube.

13-5
TM 55-1520-244-BD

Figure 13-3. Collective Flight Controls

13-6
 TM 55-1520-244-BD

Figure 13-4. Cyclic Lateral Controls

13-7
TM 55-1520-244-BD

Figure 13-5. Cyclic, Fore and Aft Controls

13-8
 TM 55-1520-244-BD

Figure 13-6. Tail Rotor Controls

13-9
TM 55- 1520-244-BD

Table 13-2. Control Tube Dtmensions

(Refer to figtys 13-3 thru 13-6)

SIZE
INCHES WALL
CENTER TO
CENTER
IDESIRED SPLICE
' TUBE S: E IN
1
g :IGURE NSN 0.1). 1 I.D. (IN) b m 7-w
UT IDE

1 13-6 3040-00-931-8282 5/8 9/16 si35 8-l/8 112 314

2 13-6 3040-00-931-8279 7/8 13J16 ,035 22-l/8 3J4 1

3 13-6' 3040-00-932-1195 718 13/16 .035 25-l/8 3J4 1

4 13-6 3040-00-977-2663 518 9316 .035. 12-3/i l/i 3/4

5 13-6 3040-00-931-8304 l-3/8 l-5116 ,035 44-3/4 l-114 l-112

6 13-6 3040-00-931-8273 518 9116 .035 12-l/16 l/2 3/4

7 t3-6 3040-00-932-1194 l-3/8' l-5/16 ,035 49-314 l-1/4 l-112

8 L3-6 3040-00-410-6334 l-318 l-5/16 .035 44-3f4 l-114 l-112

9 13-6 1560-00-446-4478 l-3/-8 l-5116 .035 29-l/8 l-114 l-1/2

10 13-6 3040-01-031-9151 l-l/4 l-3/16 .035 86-13J16 l-l/8 l-318

11 13-6 3040-01-031-1200 l-114 l-3116 .035 89-9116 l-1/8 l-3/8

12 13-6 3040-01-031-9152 t l-3/8 l-5/16 .035 67-13JlS I-114 l-112

13 13-3 3040-DO-931-$274 l-3/% l-5/16 .035 63-3J16 l-114 l-112

14 13-3 3040-00-878-4915 l-3/8 l-5/16 .035 64-314 l-314 l-112

15 13-3 3040-00-103-9485 l-1/4 L-3116 .035 22-15/16 l-1/8 l-318

16 13-3 3040-00-931-8281 l-1/4 l-3/16 .035 60-l/16 l-l-J8 l-318

17 13-3 3040-00-971-6295 l-114 l-3/16 . ~ .035 20-318 l-1/8 l-318

18 13-5 3040-00-931-8288 314 11116 .035 24-l/2 5J8 718

13-10
 TM 55-1520-244-Bd

Table 13-2. Control Tube D im iensif

SIZE DESIREt S P L I C E
INCHES WALL E (IN),
NO. FIGURE
- NSN . D.D. I.D. (IN) TER :i5:D;1 OUTSIDE.
19 13-5 1560-00-089-9824 l-114 l-3116 .035 24-7116 l-1/8 l-318
20 13-5 3040-00-089-9825 l-1/4 l-3/16 .035 23-11116 l-1/8 l-318
21 13-5 3040-00-877-0102 1 15/16 .035 12-15/16 7/8 l-1/8
22 13-5 3040-00-446-4436 l-3/8 l-5116 .035 29-l/8 l-1/4 l-1/2
23 13-5 3040-00-971-6295 l-1/4 l-3116 ,035 20-3/8 l-l/8 l-3/8
24 13-4 3040-00-931-8292 1 15/16 ,035 39-l/2 718 l-1/8
I
25 13-4 3040-00-931-8291 1 15116 .035 12 718 l-1/8
26 13-4. 3040-00-931-8290 l-1/4 l-3/16 .035 30-9/16 l-118 l-318
27 13-4 3040-00-103-4630 5/8 9116 .035 14-3/8 l/2 314'
28 13-4 3040-00-446-4436 l-318 l-5/16. .035 29-118 l-l/4 l-1/2
29 13-4 3040-00-932-1190 l-1/4 l-3/16 .035 21-7116 l-1/8 l-3/8
30 13-5 3040-00-877-6573 l-1/2 l-5/16 .083 58-9116 l-318 l-518'
31 13-5 3040-00-931-8266 314 lllI6 .035 2f-9/16 518 718
32 13-5 3040-00-931-8289 314 11/16 ,035 21-7116 5/8 7/8
33 13-5 3040-00-931-8276 5/8 9116 ,035 12-9/16 l/2 314
34 13-5 3040-00-931-8275 l-1/8 l-1116 .035 45-l/4 1 l-1/4
35 13-6 3040-01-028-0016 7/8 13/16 .035 107-91'16 3/4 1
- I I

Table 13-3. Reconvnended'Bolts and Dr111 Hale

13-11
TM 55-1520-244-BD

Figure 13-7. Control Tube Splice

13-12
 TM 55-1520-244-BD

LIMITATIONS: Inspect after every flight. 5. Drill a hole through the tube and install the bolt.

PERSONNEL/TIME REQUIRED: 6. From Table 13-2, determine the correct distance

1 Soldier between holes of the flight tube. Mark this distance.
3 Hours
7. Drill the hole and install the bolt.
MATERIAL/TOOLS REQUIRED:
Drill and Bit
8. On the other end where the clevis arms would
Structures repair Kit (ieem 12, App. B) normally fit, mash the tube only enough to fit over the
PROCEDURAL STEPS: bearing assembly with some clearance.

9. Round off the end of the tube, Figure 13-11.

1. Put aircraft flight control system into neutral rig.

10. Drill proper size holes.

2. Remove damaged flight control tube, Figure 13-8,
11. Install bolts.
3. On the end that fits into the clevis bolt, mash the
tube so that it fits into the arms of the bell crank or
clevis. A small amount of clearance between the 12. Record BDAR action taken. When mission is
clevis fork should be allowed, Figure 13-9. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
4. Round off the end of the mashed tube, Figure
13-10.

13-13
TM 55-1520-244-BD

Figure 13-8. Control Rod with Bearing and Clevis Assemblies

13-14
 TM 55-1520-244-BD

Figure 13-9.

Figure 13-10.

Figure 13-11. Bell Crank or Lever Assembly

Connection of Fabricated Flight Control

13-15/(13-16 Blank)
 TM 55-1520-244-BD

CHAPTER 14

UTILITY SYSTEMS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

14-1. SCOPE. This chapter describes damage to the aircraft can be catas-
the fault assessment procedures and trophic. Repairs to the system wiring
references the expedient repairs may be accomplished using procedures
useful in fixing damages to the contained in Chapter 11.
utility systems.
14-5. RAIN REMOVAL SYSTEM. This is a
14-2. ASSESSMENT PROCEDURES. subsystem of the environmental control
Assessment procedures are simplified in system. Damage to the system will not
this chapter. They are contained in impair helicopter operation. Failure of
Table 14-1 and reference fixes described the system during heavy rain may affect
in other chapters of this manual. full mission capability. If damaged and
system is determined unnecessary, defer
14-3. REPAIR PROCEDURE INDEX. repair or cap off metal tubing supplying
nozzles. If system function is to be
PARA. restored, refer to Chapter 15 for bleed
air line repair. Nozzles may be fabri-
Fire Detection System (Gen). . 14-4 cated from common AN “T” fittings.
Rain Removal System (Gen). . . 14-5
Defroster System (Gen) . . . . 14-6 14-6. DEFROSTER SYSTEM. This is a sub-
system of the environmental control
14-4. FIRE DETECTION SYSTEM. The system. Damage to the system will not
detection system is not vital to the impair helicopter operation. Failure of
function of the aircraft in reference to the system may affect full mission capa-
its flight capabilities; however, in the bility. If system function must be
event that the fire detection system is restored, refer to Chapter 15 for bleed
inoperative and a fire should occur in air line and duct repair procedures.
the engine compartment, the resulting

14-1
TM 55-1520-244-BD

Table 14-1.

PARA 14-4

PARA 14-5

PARA 14-6

14-2
 TM 55-1520-244-BD

CHAPTER 15

ENVIRONMENTAL CONTROL SYSTEM

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

15-1. SCOPE. This chapter contains the reduced visibility caused by loss of
fault assessment and expedient repair rain removal or defroster systems opera-
procedures for locating and fixing tion. Refer to Table 15-1 for
damage to the environmental control assessment logic.
system. The system is depicted in
Figure 15-1. 15-3. REPAIR PROCEDURE INDEX.

15-2. ASSESSMENT PROCEDURES. The PARA.

environmental control system is pri-
marily designed for crew comfort, but Surface of ECU Damaged . . . . 15-5
damage assessment and repair must be Ducting Torn or Perforated . . 15-6
based on the possibility of lost engine Holes in Bleed Air Lines . . . 15-7
performance due to leaking bleed air or

Section II. ENVIRONMENTAL CONTROL UNIT (ECU)

15-4. GENERAL. The ECU is the heart of

the cooling and heating system. If
damage has not occured to the ECU’s Compressed air can blow dust into
cooling turbine, the unit can normally eyes. Wear eye protection. Do
be repaired and put back in operation. not exceed 30 psig air pressure.
The cooling turbine operates at high
speed and is accordingly very sensitive Cleaning solvents may be flam-
to damage. mable and toxic. Use only in
well-ventilated areas. Avoid
15-5. SURFACE OF ECU DAMAGED. inhalation of vapors and skin
contact. Do not use solvents
near open flame or in areas
where very high temperatures
Adhesives, resins, fillers, and prevail. Solvent flash point
sealants contain toxic substances. must not be less than 100°F.
Wear protective equipment. Work
with adequate ventilation. GENERAL INFORMATION: Some damage, holes,
or cracks to the external surface of
Sanding or reinforced laminated the ECU housing can be repaired provided
glass produces fine dust that may no critical internal damage is incurred,
cause skin and lung irritations. Figure 15-2.
Observe necessary protective
measures. OPTION 1: Plastic Patch Holes or Cracks
on ECU Housing.

15-1
TM 55-1520-244-BD

1. Ram Air Inlet 11. Drain Valve

2. Bleed Air Line 12. Gunner Air Outlets
3. Pressure Regulator and 13. Rain Removal Manifold
Shutoff Valve 14. Gunner Cushion Air Valve
4. Blower 15. Pilot Air Outlets
5. Ram Air Outlet 16. Heat or Vent Air Pull Control
6. Environmental Control Unit 17. Duct
7. Defog Outlet 18. Pilot Cushion Air Valve
8. Duct 19. Vent Air Control Valve
9. Rain Removal Valve 20. Inlet Duct
10. Air Control Valve

Figure 15-1. Environmental Control System

15-2
 TM 55-1520-244-BD

Table 15-1.

PARA 15-6

PARA 15-7

PARA 15-5

15-3
TM 55-1520-244-BD

Figure 15-2. ECU Housing

15-4
 TM 55-1520-244-BD

LIMITATIONS: Only areas accessible without 9. Allow time for resin to cure.
removing the ECU will be repairable.
10. Record BDAR action taken. When mission is
PERSONNEL/TlME REQUIRED: complete, as soon as practical, repair the equipment/-
1 Soldier system using standard maintenance procedures.
3 Hours
OPTION 2: Metal Patch Holes or Cracks on ECU
MATERIAL/TOOLS REQUIRED: Housing.
Solvent (item 7 or 129, App. C)
Sandpaper (items 117-121, App. C)
LIMITATIONS: Inspect after every flight.
Repair Material (items 50,51,97, App. C)
Drill Bit and Drill
PERSONNEL/TIME REQUIRED:
PROCEDURAL STEPS: 1 Soldier
1 Hour
1. Locate hole on housing.
MATERIAL/TOOLS REQUIRED:
Sheet Metal Patch (item 133, App. C)
2. Stop drill any cracks which might be extending Green or Aluminum Tape
from hole. (item 153 or 150, App. C)

3. Clean surface to be repaired with solvent. PROCEDURAL STEPS:

4. Sand surface around hole. Sanded surface 1. Locate damaged area and remove panels and/or
should extend at least 1-1/2 inches from the edge of other items as necessary to gain access to the sur-
the hole at all points. face to be required.

5. Cut a piece of patch material that will overlap the 2. Cut a patch out of sheet stock.
hole by 1-1/2 inches at all points.
3. Tape into place.
6. Apply resin to the sanded area around the hole.
4. Record BDAR action taken. When mission is
7. Press patch over hole. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
8. Apply resin over the patch and all around the
edge of the patch.

15-5
TM 55-1520-244-BD

Section Ill. DUCTING

15-6. DUCTING TORN OR PERFORATED. PROCEDURAL STEPS:

GENERAL INFORMATION: The ducting maybe 1. Locate damaged area and remove panels and/or
repaired using almost any patching material since this other items as necessary to gain access to the duct to
is a noncritical area of the helicopter. be repaired. Refer to Figure 15-4 for locations of rigid
plastic ducts.
OPTION 1: Flexible Duct Patch.
2. Cut a patch out of sheet stock. Patch should
LIMITATIONS: None. extend 1-1/2 inches from the edge of the hole at all
points.
PERSONNEL/TIME REQUIRED:
●
1 Soldier 3. Stop drill any cracks which might be extending
● 15 Minutes from hole.

MATERIALS/TOOLS REQUIRED: 4. Sand both the bottom sufface of the patch and
● Green Tape or Equivalent the surface area around the hole to be covered by the
(item 153 or 150, App. C) patch.

PROCEDURAL STEPS: 5. Clean surface with solvent.

1. Locate damaged area and remove panels and/or 6. Apply sealant to patch and on the surface area
other items as necessary to gain access to the duct to that will be covered by the patch.
be repaired. Refer to Figure 15-3 for locations of
flexible plastic ducts.
7. Press patch in place and wrap tape around patch
and duct to hold the repair in position.
2. Wrap tape several turns around duct to cover
hole or tear. Tape should extend beyond damaged
8. Record BDAR action taken. When mission is
area 3 to 4 inches in each direction.
complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
OPTION 2: Plastic Patch Rigid Duct.
OPTION 2: Metal Patch Rigid Duct.
LIMITATIONS: None.
LIMITATIONS: Inspect after every flight.
PERSONNEL/TIME REQUIRED:
● 1 Soldier
PERSONNEL/TIME REQUIRED:
1 Hour
● 1 Soldier
● 1 Hour
MATERIAL/TOOLS REQUIRED:
● Sheet Metal Patch (item 133, App. C)
MATERIAL/TOOLS REQUIRED:
● Sealant (items 123-128, App. C)
● Sheet Metal Patch (item 133, App. C)
● 400 Grit Sandpaper (item 117, App. C)
● Green or Aluminum Tape
● Green or Aluminum Tape

(item 153 or 150, App. C) (item 153 or 150, App. C)

● Solvent (item 7 or 129, App.C)

15-6
 TM 55-1520-244-BD

Figure 15-3. Ducts, Flexible Plastic

15-7
TM 55-1520-244-BD

Figure 15-4. Ducts, Rigid Plastic

15-8
 TM 55-1520-244-BD

PROCEDURAL STEPS: 3. Tape into place.

1. Locate damaged area and remove panels and/or 4. Record BDAR action taken. When mission is
other items as necessary to gain access to the duct to complete, as soon as practical, repair the equipment/-
be repaired. Refer to Figure 15-4 for location of rigid system using standard maintenance procedures.
plastic ducts.

2. Cut a patch out of sheet stock.

Section IV. BLEED AIR LINES

15-7. HOLES IN BLEED AIR LINES. 2. Cut patch from sheet metal to cover hole or other
damage. Patch should extend approximately 1 inch
GENERAL INFORMATION: Damage to some bleed from the edge of the hole or damage at all points if
air lines routed to the ECU and rain removal system possible.
may be repairable. There may be loss of engine
torque and/or high engine oil temperature if damage 3. Apply sealant around the hole area to be covered
is not repaired, Figure 15-5. by the patch.

OPTION: Line Patching. 4. Place patch in position, make sure patch fits the
contour of the line.
Limitations: Inspect after every fright.
5. Wrap aluminum tape around the repair. Tape
PERSONNEL/TIME REQUIRED: should cover at least 2 inches beyond the edge of
1 Soldier repair. (If hose clamps are not available, secure in
1 Hour place with safety wire. Turn pigtail to line.)

MATERLALS/TOOLS REQUIRED: 6. Secure metal patch in place using hose clamp.

Sheet Metal Patch (item 133, App. C) Refer to Figure 15-6.
Sealing Compound (items 123-128, App. C)
Aluminum Tape (item 150, App. C) 7. Record BDAR action taken. When mission is
Clamps or Safety Wire (items 54-62, complete, as soon as practical, repair the equipment/-
App.C) system using standard maintenance procedures.
PROCEDURAL STEPS:

1. Locate damaged area and remove panels and

other items as necessary to gain access to the line to
be repaired.

15-9
TM 55-1520-244-BD

Figure 15-5. Bleed Air Lines

15-10
 TM 55-1520-244-BD

Figure 15-6. Bleed Line Patch Repair

15-11/(15-12 Blank)
 TM 55-1520-244-BD

CHAPTER 16

MISSION EQUIPMENT

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. Introduction

16-1. SCOPE. This chapter contains the

fault assessment and expedient repair
procedures for locating and fixing Lifting or moving heavy equipment
damage to the mission equipment. incorrectly can cause serious injury
Mission equipment on the attack heli- Do not try to lift or move more than
copter consists of the armament systems. 50 pounds by yourself. Get an assis-
tant. Bend legs while lifting. Do
16-2. ASSESSMENT PROCEDURES. not support heavy weight with your
back. Always use assistants during
lifting operations. Use guide ropes
to move hanging assemblies. Lack of
Loaded weapons, or weapons being attention or being in an improper
loaded or unloaded, shall be position during lifting operations
pointed in a direction which can result in serious injury. Pay
offers the least exposure to close attention to movements of
personnel or property in the assemblies being lifted. Do not
event of accidental firing. stand under lifted assembly or in a
position where you could be pinned
YOU can be blinded if you look against another object. Watch your
into a laser beam when you are footing.
not wearing laser safety goggles.
Never aim the laser range finder a. The armament systems are dependent
(LRF) at personnel. on the following functional equipment in
order to be 100 percent mission capable.
Prior to any helicopter main- Use Table 16-1 to assess vital system
tenance functions that require functions:
external stores be removed,
JETTISON cartridge shall be Telescopic Sight Unit (TSU)
removed. To prevent injury Helmet Sight Subsystem (HSS)
to personnel and damage to Universal Turret Subsystem
equipment, remove jettison Rocket Management Subsystem (RMS)
cartridges from pylon stores TOW Missile Subsystem
ejection device prior to placing Air Data Subsystem (ADS) (MC only)
helicopter in a hangar. Laser Range Finder (MC only)
Head-Up Display System (HUD) (MC only)
Collective Transducer
Airborne Laser Tracker (ALT) (MC only)
Attitude Reference Gyro
Magnetic Compass Set
Radar Altimeter

16-1
 TM 55-1520-244-BD
Torquemeter operate normally with those launchers that remain
Doppler Navigation System (DNS) operable to enable the directed launching of whatever
Fire Control Computer (FCC) (MC only) rockets remain.
M73 Reflex Sight (ECAS and PROD only)
f. The AH-1 armament system is very complex.
b. If the HUD (MC) is nonoperational, the gun It consists of numerous electronic units with intercon-
and rocket system can still be fired. If the laser necting cabling, optical sighting systems, lasers, and
rangefinder (if installed) (MC) is also nonoperational, mechanical components. The armament systems do
the HUD unit is switched to STAD and a stadiametric not operate independently but interface with each
reticle is displayed for rocket firing. other, with the helicopter avionics and navigation sys-
tems, and with transducers monitoring the engine and
c. If the TSU or HSS are nonoperational, the tur- flight controls. In most cases, however, the armament
ret gun can be fired by the pilot in the fixed forward system will continue to function when the interface or
mode by maneuvering the helicopter and aiming input from other systems is not functional. Most of the
through the HUD (MC) or the M73 Pilot Reflex Sight subsystems have a built-in test (BIT) feature which
(ECAS and PROD). will indicate if there is a malfunction. The following
systems have BIT systems:
d. If normal turret subsystem operating power is
lost or removed for any reason, the emergency stow Air Data System (ADS)
control unit will automatically position the Ml 97 Rocket Management System (RMS)
(ECAS and MC) gun at the emergency stow position Helmet Sight System (HSS)
to permit the helicopter to be landed safely. If the gun Head-Up Display (HUD).
turret will not return to a position pointed straight Fire Control Computer
ahead with the aircraft, it can be brought back manual- M65 TOW Guided Missile System
ly (on the ground). To raise or lower the gun manually, Infrared Countermeasure System
release the brake toggle on the end of the elevation Radar Countermeasure System
drive motor (Figure 16-1 ) and position the gun by
hand. To position the gun in azimuth (Figure 16-1), g. Assessment of battle damage will also require
open the panel on the right side of the aircraft nose a visual inspection to determine damage to wiring
shroud behind the turret and release the brake toggle harnesses, evidence of damage due to fragment
on the end of the azimuth drive motor; then, position penetration, and any damage to the mechanical sys-
the gun manually to a straight ahead position. tems of the TOW launchers, rocket launchers, and
the 20mm turret gun with its ammunition feed system.
e. The RMS uses 2.75 inch FFAR as a light
antipersonnel/assault weapon. Should one or more 16-3. REPAIR PROCEDURE INDEX.
launchers be disabled, the subsystem will cause the
corresponding launcher on the opposite side of the PARA
aircraft fuselage to become inactive in order to main-
tain inflight stability of the aircraft by equalizing the 16-5
load of unfired rockets. Thereafter, the subsystem will
Hydraulic Hose Damage . . . . . .16-7
Damaged Pneumatic Lines . . . . . .16-8

16-2
 TM 55-1520-244-BD

Table 16-1.

Table 16-1.

Section II. WIRING

16-4. GENERAL. Due to the highly

complex and intergrated design of the
wiring, loss of an area of system func- Do not be misled by the term "low volt-
tion may be caused by simple wiring age." Potentials as low as 50 volts may
damage. Since most of the mission cause death under adverse conditions.
equipment is electronic, not many
battlefield type repairs can be made.
Components such as black boxes or 16-5. WIRE DAMAGE. Damage to wires,
control panel equipment containing which has not caused any further damage
integrated circuits, circuit cards, and to other units within the mission equip-
other electronic equipment, which can- ment, may be repaired by the wire repair
not be battlefield repaired, will be procedures described in Chapter 11.
replaced if available. Components must
be replaced with new parts or with parts
cannibalized from other helicopters.

16-3
TM 55-1520-244-BD

Figure 16-1. Turret Gun Brake Toggle (ECAS and MC)

16-4
 TM 55-1520-244-BD

Section Ill. HYDRAULICS

16-6. GENERAL. The outboard wing stores pylon 16-7. HYDRAULIC HOSE DAMAGE. In the event
is equipped with a hydraulically controlled actuator that the hydraulic pressure lines which lead to the
which adjusts the trajectory angle of the TOW or actuator sustain battle damage, they may be repaired
rocket launchers, Figure 16-2. by using procedures in Chapter 9.

Section IV. AIR DATA SUBSYSTEM

16-8. GENERAL. The air data subsystem may be 4. Record BDAR action taken. When mission is
disabled by leaks in its pneumatic lines. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
16-9. DAMAGED PNEUMATIC LINES.
OPTION 2: Tape and Sealant Repair.
GENERAL INFORMATION: This procedure is used
to repair damaged tubing running from the ADS sen- LIMITATIONS: None.
sor. Refer to Figure 16-3 for location of pneumatic
lines. These are low pressure air lines. PERSONNEL/TIME REQUIRED:
1 Soldier
OPTION 1: Splice Tubing. 30 Minutes

LIMITATIONS: None. MATERIALS/TOOLS REQUIRED:

Tape (item 153 or 150, App. C)
Sealant (items 123-127, App. C)
PERSONNEL/TlME REQUIRED:
1 Soldier PROCEDURAL STEPS:
30 Minutes

MATERIALS/TOOLS REQUIRED: 1. Straighten damaged tubing and remove

Fluid Line Repair Kit obstructions to airflow.
(item 4, App. B)
Sealant (items 123-128, App. C) 2. Wrap damaged area with tape.

PROCEDURAL STEPS: 3. Apply sealant over tape to effect an airtight seal.

1. Straighten damaged tubing and remove portion of 4. Record BDAR action taken. When mission is
tube that would obstruct air flow. complete, as soon as practical, repair the equipment/-
system using standard maintenance procedures.
2. Install a length hose over each end of tube.

3. Secure with hose clamps if available. Due to low

pressure levels, tight fitting tubing may not need
clamps.

16-5
TM 55-1520-244-BD

Figure 16-2. Outboard Wing Stores Pylon

16-6
 TM 55-1520-244-BD

1. Pitot Union Tee 9. Support Assembly

2. Static Union Tee 10. Grounding Strap
3. Screw 11. Screw
4. Washer 12. Pitot Union Connector
5. Canopy Channel Support 13. Static Union Connector
6. Screw 14. Electrical Connector 18A2J1
7. Mounting Bracket 15. Washer
8. Tube Assembly 16. Bolt
17. AADS

Figure 16-3. ADS Pneumatic Lines

16-7/(16-8 Blank)
 TM 55-1520-244-BD

CHAPTER 17

EMERGENCY EQUIPMENT

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

There are no BDAR repairs offered for the emergency equipment.

17-1/(17-2 Blank)
 TM 55-1520-244-BD

APPENDIX A

REFERENCES

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.
The following references of the issue in effect are required for use by repair personnel to accomplish the instruc-
tions set forth in this TM.

PUBLICATION
NUMBER TITLE

AR95-1 . . . . . . . . . . . . . . . . . . . . . Army Aviation Flight Regulations

AR 385-11. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . Ionizing Radiation Protection
AR708-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Catalog Supply and Management Data

DA Form 2028 . . . . . . . . . . . . . . . . . Recommend Changes to Publications

DA Form 2408-13 . . . . . . . . . . . . . . . . Aircraft Inspection and Maintenance Record
DA Form 2408-18 . . . . . . . . . . . . . . . . Equipment Inspection List
DA Pam 738-751 . . . . . . . . . . . . . . . . The Army Maintenance Management System (TAMMS)

FM 1-500 . . . . . . . . . . . . . . . . . . . . Army Aviation Maintenance

FM 3-5 . . . . . . . . . . . . . . . . . . . . . NBC Decontamination
FM 10-68 . . . . . . . . . . . . . . . . . . . . Aircraft Refueling
FM 21-11 . . . . . . . . . . . . . . . . . . . . First Aid for Soldiers

SF 368 . . . . . . . . . . . . . . . . . . . . . Quality Deficiency Report

TB MED 501 . . . . . . . . . . . . . . . . . . Occupational and Environmental Health

Hearing Conservation

TB 43-0108 . . . . . . . . . . . . . . . . . . . Handling, Storage, and Disposal of Army

Aircraft Components Containing Radioactive
Materials

TM 1-1500-328-25 . . . . . . . . . . . . . . . . Aeronautical Equipment Maintenance

Management Policies and Procedures

TM 3-261 . . . . . . . . . . . . . . . . . . . . . Handling and Disposal of Unwanted Radioactive

Materials

TM 55-1500-204-25/1 . . . . . . . . . . . . . General Aircraft Maintenance Manual

TM 55-1520-236-23 . . . . . . . . . . . . Aviation Unit and Intermediate Maintenance

Manual: Model AH-1S (PROD), AH-1(ECAS)
AH-1S (Modernized Cobra) Helicopters

A-1/(A-2 Blank)
 TM 55-1520-244-BD

APPENDIX B

SPECIAL OR FABRICATED TOOLS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. GENERAL

B-1. SCOPE. This appendix lists spe- and durable supplies not listed in other
cial tools and test equipment. Several appendices. Each kit contains its own
special tools are contained in the BDAR inventory list and tool usage instruc-
kits listed on the next page. The kits tions. There are no fabricated tools
also contain small quantities of parts associated with this BDAR manual.

Section II. TOOLS

B-2. SPECIAL TOOL LISTINGS. The items accomplish battlefield damage assessment
listed in this appendix will enhance crew and repairs.
members and mechanics at all levels to

B-1
TM 55-1520-244-BD

SPECIAL OR FABRICATED TOOLS

ITEM
NO. NSN DESCRIPTION

1 Not Assigned Composite Structures Repair Kit

2 5935-01-161-5883 Connector Repair Kit (Special Tools
(11851) DMC658 for Electrical Connector Repair)
3 4920-01-266-7535 Emergency Repair Kit (Special and
(11851) DMC895 Common Tools for Electrical Repair,
including Repair Parts)
4 4920-01-266-7534 Fluid Line Repair Kit (Special and
(78286) Common Tools for Tubing and Hose
70700-20900-041 Repair, Including Repair Parts)
5 Not Assigned Fuel Cell Repair Kit
6 Not Assigned High Energy Laser Damage Analysis
Test Kit
7 Not Assigned Optical Component Repair Kit
8 5120-00-017-2849 Riveter, Blind, Hand
(1 0054) 200
9 5120-00-224-9296 Riveter, Blind, Hand
(25472) C6000-10-32
10 5120-00-979-7601 Riveter, Blind, Hand
(03481 ) C6000-4-40
11 3540-01-117-7870 Sealing Iron, Electric
(19836) 50-T
12 Not Assigned Standard Structures Repair Kit
13 4920-01-266-7536 Test Equipment Repair Kit (Electrical
(78286) Test Equipment)
70700-20638-041
14 5935-01-254-1688 Wire Repair Kit (Special Tools Used
(06090) MK-0015-1 for Electrical Wiring Repair,
Including Repair Parts)
15 3455-00-222-3792 Wing Milling Cuter
(72295) F508
16 4920-01-035-0319 Wing Router, Electric
(84955) K747-409-1
17 4920-01-035-0324 Wing Router Kit
(84955) K747-401 -1

B-2
 TM 55-1520-244-BD

APPENDIX C

EXPENDABLE/DURABLE SUPPLIES AND MATERIALS LIST

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY
STANDARD PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

C-1. SCOPE. This appendix lists expendable sup- b. National Stock Number. This is the National
plies and materials needed to make BDAR fixes on stock number assigned to the item; use it to request
the AH-1 attack helicopter. Items are listed alphabeti- or requisition the item.
cally by the item shown in the description column.
These items are authorized to you by CTA 50-970, Ex- c. Description. Indicates the Federal item name
pendable Items (Except Medical, Class V, Repair and, if required, a description to identify the item. The
Parts, and Heraldic Items) or CTA 8-100. last line for each item indicates the Commercial and
Government Entity Code (CAGEC) in parentheses fol-
C-2. EXPLANATION OF COLUMNS. Iowed by the part number.

a. Item Nuber. This number is assigned to the d. Unit of Issue (U/I). Is the abbreviation of the
entry in the listing and is referenced in the narrative in- types of units under which material is issued.
structions to identify the material (e.g., “Use cleaning
compound, item 5, Appendix C“).

C-1
 z-3
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699It-3-1IW (EOtrOL) ‘;‘-.
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90LI8-3-1IW (BPZY f="'nn'"'
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VSIHELTNV (tP0813) alO8 1X64'-901-00-90&S Et.
V9HELtNV .(PPO81 3). 7108 E&42-9sx-00-90&9 z z
OWCLTNV (PPO883 2109 E806iOH-OO-90f.S
VPtlELtNV (t47088) 7108 P8Z8-t62-00-90ES ::
OX-SOClS@N (SO2081 7108 8t60-9X8-00-90&9
OETSVN (SOZO8) 7109 EZLS-Z8S-OO-90ES ii:
:':OUSVN (SOZOE1) 7lb8 9X68-t'LL-OO-90ES LX
P-9OETSVN (SOZOE1)‘ 71oa L69L:908-l%t-90ES
OI-tOET4VN-(;SOZOS) ,710a TLt9-919-00-90Es t:
8-PQCISWN 'iSOZO8) 2lW &ttL-S99-00-90&9
9-WEXSVN (StiZO8) 3108 884X-ZZL-00-90&S ;I
HP-00CISVN (SOZOi 1 7109 896Z-L08-00-90&S ZT
OX-cot:KiVN (SOZOS) 7109 SLOZ-PfO-lo-9O&s
_ .i!l ,(I,-EO&t?MN (SOZOS 1 ,3lQ8 8LXZ-6X9-00-90&S i:
9-&O&XSWN (SOZOS) 3108 98Zi-il8!i-iiP9OC9
tr-EJ.MS\iN hOtO UQa PZZI-LOT-IO-9OES ii
jPN 3cWdctv . 6 X X8-8EZ-OO-OT89 L
F-IIW (tDZO8)
1 au034 11s ‘wsawv ~866-w6-Oo-oPo8 9
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J a j *iApaqQjj *X98-S9X-OO-0+08 S
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----_- -- ----_
(~2.edad apel8) Axodj ‘anbsaqpv &L06-680-TO-0908
NOIldIW30 NSN tl39WnN
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 TM 55-1520-244-BD

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)

NUMBER NSN DESCRIPTION ISSUE

33 8030-00-231-2345 Corrosion Preventive Compound CN

(80244) MIL-C-16173
34 5310-00-297-3751 Cotter Pin Assortment (81348) KT
35 9540-00-140-2401 Extrusion Angle 2X1X0.125 FT
(81348) QQ-A-200/9
36 9540-00-140-2417 Extrusion Angle 1-1/2Xl 1/2 0.125 FT
(81348) QQ-A-200/11
37 9540-00-145-4524 Extrusion Angle 1-1/4X3/4 0.063 FT
(81348) QQ-A-200/3
38 9540-00-145-5716 Extrusion Angle 1-3/4Xl 1/2 0.156 FT
(81348) QQ-A-200/11
39 9540-00-145-7542 Extrusion Angle 2X1X0.156 FT
(81348) QQ-A-200/11
40 9540-00-145-7543 Extrusion Angle 2X1 1/2 0.125 FT
(81348) QQ-A-200/3
41 9540-00-230-2338 Extrusion Angle 1-1/2Xl 1/2 0.188 FT
(81348) QQ-A-200/11
42 9540-00-236-5240 Extrusion Angle 3X1 1/2 0.250 FT
(81348) QQ-A-200/11
43 9540-00-596-3006 Extrusion Angle 1-1/2 X 1/4 0.094 FT
(81348) QQ-A-200/11
44 9540-00-854-6554 Extrusion Angle 2X2 0.250 FT
(81348) QQ-A-200/
45 9540-00-931-7261 Extrusion Angle 2X2 0.188 FT
(81348) QQ-A-200/3
46 9540-00-933-9650 Extrusion Angle 1-1/2X1 1/2 0.094 FT
(81348) QQ-A-200/3
47 9540-00-596-3016 Extrusion, L Angle 2024T-4 FT
0.063 (81348) QQ-A-267
48 9540-00-555-1172 Extrusion, T Angle 2024T-4 FT
0.063 (81348) QQ-A-200/3
49 5940-00-296-5326 Ferrul, Electrical, 22-14 Wire EA
Gage size (10 ea) (59730)
50 8305-00-530-0109 Fiberglass Cloth (81349) RO
MIL-C-9084
51 8305-00-530-0111 Fiberglass Resin (81349) CN
MIL-C-9084
52 5330-00-467-3615 Gasket, Material 1/32 in. SH
(81348) HH-P-96
53 5970-00-032-0291 Heat Shrink Sleeve Assortment KT
(61521) DI-295-MS-1
54 4730-00-203-3131 Hose Clamp (66295) EA
AN737TW57-66
55 4730-00-278-9200 Hose Clamp (66295) EA
AN737TW22

C-3
TM 55-1520-244-BD

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)

NUMBER NSN DESCRIPTION ISSUE

56 4730-00-279-0065 Hose Clamp (08484) QS200M1200 EA

57 4730-00-541-7747 Hose Clamp (66295) EA
AN737TW74-91
58 4730-00-720-0167 Hose Clamp (88044) EA
AN737TW30
59 4730-00-908-6292 Hose Clamp (88044) EA
AN737RM98
60 9505-00-596-5101 Lockwire, Steel 0.020 (81348) RO
QQ-W-423
61 9505-00-293-4208 Lockwire, Steel 0.032 (81348) RO
QQ-W-423
62 9505-00-331-3275 Lockwire, Steel 0.041 (81348) RO
QQ-W-423
63 5310-00-297-3751 Nut Assortment (81348) FFN836 PG
64 5310-00-807-1467 Nut (80205) NAS1291X3 BX
65 5310-00-807-1469 Nut (21450) 503443 BX
66 5310-00-807-1474 Nut (80205) NAS679A3 BX
67 5310-00-807-1475 Nut (96906) MS21042L4 BX
68 5310-00-680-7105 Nut, Self-Lock Steel 5/16 EA
(80205) NAS 679C5M
69 5310-00-807-1474 Nut, Self-Lock Steel 3/16 in HD
(80205) NAS679A3
70 5310-00-844-4872 Nut, Self-Lock Steel 1/4 in HD
(80205) NAS67904
71 5330-00-966-8657 Packing, Preformed Assortment PG
(51808) MAOK311
72 1615-01-089-0437 Parts Kit, Rotor (84955) EA
K747-201-119
73 1615-01-041-7060 Patch Kit (84955) K747-201-1 EA
74 1615-01-041-7061 Patch Kit (84955) K747-201-3 EA
75 1615-01-041-7062 Patch Kit (84955) K747-201-5 EA
76 5340-01-161-2806 Patch Kit, Erosion (84955) EA
K747-204-11
77 1615-01-042-9466 Patch Kit, Trial Spline EA
(84955) K747-201-113
78 9150-00-250-0926 Petrolatum, Technical (81349) CN
VV-P-236
1615-01-041-7063 Plug Kit (84955) K747-201-7 EA
1615-01-041-7064 Plug Kit (84955) K747-201-9 EA
1615-01-041-7065 Plug Kit (84955) K747-201-1O1 EA
1615-01-041-7067 Plug Kit (84955) K747-201-1O5 EA
1615-01-041-7069 Plug Kit (84955) K747-201-1O9 EA
1515-01-042-9467 Plug Kit (84955) K747-201-111 EA
8030-00-616-7696 Potting Compound, Electrical KT
(81349) MIL-S-8516

C-4
 TM 55-1520-244-BD

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)

ITEM UNIT OF
NUMBER NSN DESCRIPTION ISSUE

86 8030-00-664-4968 Putty, Chromate (81349) RO

MIL-P-8116
87 5905-00-901-9520 Resistor, Fixed Composition EA
51 ohm (81349) 63A5A68-51O
88 1560-01-161-2805 Repair Kit, Erosion (84955) EA
K747-207
89 1560-01-161-7591 Repair Kit, Erosion (84955) EA
K747-206
90 1615-01-126-9449 Repair Kit, Rotor, 3 X 1/4 in. EA
(78286) 70092-15001-016
91 1615-01-126-9450 Repair Kit, Rotor, 3 X 7/8 in. EA
(78286) 70072-15001-017
92 1615-01-126-9451 Repair Kit, Rotor, 6 X 1/4 in. EA
(78286) 70072-15001-018
93 1615-01-126-9452 Repair Kit, Rotor, 6 X 7/8 in. EA
(78286) 70072-15001-020
94 1615-01-128-1748 Repair Kit, Rotor 3 X 1/4 in. EA
(78286) 70072-15001-015
95 1615-01-128-4408 Repair Kit, Rotor, 6 X 1/2 in. EA
(78286) 70072-15001-019
96 4920-01-035-0324 Repair Kit, Rotor (84955) EA
K747-401-1
97 6810-00-995-4804 Resin Activator (22527) 4573T KT
98 5320-00-006-4912 Rivet, Blind (92215) RV11OO-4-3 BX
99 5320-00-117-6826 Rivet, Blind (96906) MS2040AD4-4 BX
100 5320-01-033-8177 Rivet, Blind, Cherry Max 5-2 EA
(81349) MIL-R-7885/6
101 5320-01-033-8178 Rivet, Blind, Cherry Max 5-6 EA
(81349) MIL-R-7885/6
102 5320-01-033-8179 Rivet, Blind (81349) MIL-R-7885/6 BX
103 5320-01-041-6454 Rivet, Blind (11815) EA
CR3553-5-2
104 5320-01-041-6458 Rivet, Blind, CR3553-6-6 EA
(96906) MS7885/8-6-6
105 5320-01-042-2891 Rivet, Blind (7652) EA
CR3553-5-6
106 5320-01-042-8250 Rivet, Blind (F7652) EA
CR3553-6-4
107 5320-01-042-8893 Rivet, Blind (F7652) EA
CR3553-6-2
108 5320-01-043-6694 Rivet, Blind (F7652) EA
CR35553-5-4
109 5320-01-084-9234 Rivet, Blind, Cherry Max 6-6 EA
(81349) MIL-R-7885/2

C-5
TM 55-1520-244-BD

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)

NUMBER NSN DESCRIPTION ISSUE

110 5320-01-084-9235 Rivet, Blind (81349) EA

MIL-R-7885/2-6-05
111 5320-01-084-9236 Rivet, Blind (11815) EA
CR3213-6-11
112 5320-01-135-7319 Rivet, Blind, Cherry Max 6-3 EA
(81349) MIL-R-7885/2
113 5320-01-136-1782 Rivet, Blind, Cherry Max 6-4 EA
(81349) MIL-R-7885/2
114 5320-00-408-6073 Rivet, Pop, Aluminum, 3/16 in. dia., HD
1/8 in. long (81349) MIL-R-24243
115 5320-00-510-7823 Rivet, Pop, Aluminum (05693) EA
AAP-4-2
116 9320-00-291-8468 Rubber Sheet SH
(22337) PF1OO56
117 5330-00-224-7201 Sand Paper 400 Grit (81348) P-P-101 SH
118 5350-00-224-7203 Sand Paper 320 Grit (81348) P-P-101 SH
119 5350-00-619-9167 Sand Paper 80 Grit (81348) P-P-101
120 5350-00-721-8117 Sand Paper 180 Grit (81348) P-P-101 SH
121 5330-01-060-8212 Sand Paper 600 Grit (98747) SH
7530179-50
122 5305-00-206-2036 Screws, Wood (81348) FF-S-85 BX
123 8030-00-881-5238 Sealant and Puttying Compound KT
(81349) MI L-S-8516
124 8030-00-935-1083 Sealant, Asphalt Base (81349) CN
125 8030-00-965-2004 Sealant, Synthetic Rubber (81349) KT
MIL-S-8802
126 8030-00-656-1426 Sealing Compound, Gasket Non- PT
Hardening (81349) MIL-S-45180
127 8030-00-723-2746 Sealing Compound, Pro-Seal 890 QT
(81349) MIL-S-7502
128 8040-00-828-7385 Silicon Sealant TU
129 6850-00-264-9038 Solvent, Cleaning, P-D-680 (81348) GL
130 5940-00-500-8723 Splice, Conductor, Crimp Style, EA
Wire Gage 10 (96906) MS25181-3
131 9515-00-231-8601 Sheet Metal, 0.032 Stainless SH
(81349) MIL-S-5059
132 9515-00-596-1728 Sheet Metal, 0.040 Stainless SH
(81349) MIL-S-5059
133 9515-00-995-0731 Sheet Metal, 0.016 Stainless SH
(81349) MIL-S-5059
134 9535-00-167-2280 Sheet Metal, 0.040 2024-T3 SH
(81348) QQ-A-250/5
135 9535-00-232-0383 Sheet Metal, 0.071 2024-T3 SH
(81348) QQ-A-250/5

C-6
 \
TM 55-1520-244-BD

;,APPENDIX C
Section II. EXPEND1SBLE'SUPPLIES AND MATERIALS LIST (Cont)
i .
ITEM UNIT OF
NUMBER NSN DESCRIPTIOtj ISSUE

136 9535-00-232-0405 Sheet Metal, 0.090 2024-T3 SH

.I (81348) QQ-A-250/5
137 9535-00-232-0529. Sheet Metal, 0.063 2024-T3 SH
1813481 O-A-250/5
\---‘-I -- .- --

138 9535-00-232-0569 Sheet Metal, 0. 050 2024-T3 SH

(81348) CjQ-A-250/5
139 9535-00-232-7540 Sheet Mei:al, 0.063 7075-T6 SH
(81348) CIQ-A-250/13
140 9535-00-236-7075 .Sheet Met;al, 0.125 7075-T6 SH
(81348) C, IO-A-25O/i3
._ __
141 9535-00-249-5808 Sheet Metal, 0. 040 7075-T6 SH
181348) 00-A-25 o/13
142 9535-00-249-5809 ' - het(;l, 0, 050.7075-T6
Sheet SH
(81348)- QQ-A-25O/l3 *'\
143 5305-00-854-6689 Sheet Metal Screws BX
1969061
\-----a MS24617-21
5305-00-883-0628 Sheet Mel:a1 Screws BX
(96906) b4S24617-21
5940-01-079-1375 Spli-ce, 114/16 AWG Blue EA
t-----n MIL-T-7$28/3
f&1349\
146 5940-01-079-1646 Splice, 2?4/26 AWG Ye1 low EA
(81349)’ 1yIIL-T-7928/3
147 5940-01-079-1647 Splice, I18/20 AWG Red EA
(81349) bI I L - T - 7 9 2 8 / 5 I
148 5940-01-079-1936 Splice, 312/10 AWG Yellow EA
(81349) bIIL-T-7928/3
149 4020-00-753-6555 String (f31349) MIL-T-43435 RO
150 7510-00-473-9855 Tape, Aluminum RO
(81349) 'IlL'I
VT’ TA397
3
151 5970-00-419-4291 Tape, Elfxtrfcal (81349) RO
MIL-I-24: 191
152 7510-00-680-2450 Tape, Ma:iking RO
(80244) b1IL-T-21595
153 7510-00-074-5124 Tape, Green (58536) A-A-1586 RO
154 5940-00-143-4777 Tkrminal, Lug (81349) MIL-T-7928 BX
155 5940-00-115-0776 Terminal, Lug, 2 AWG 3/8 in. Hole EA
696906) ~MS20659-114
156 5940,-00-115-4992 -’ Terminpl, Lug, 6 AWG 3/8 in. Hole EA
(96906) M$Z0659-110
157 5940-00-143-4771 Terminal, Lug, 10 AWG 18/20 EA
(96906) MS25036-103
158 5940-00-143-4780 Terminal, Lu,g, Crimp Style Stud, BX
Size 10, Wi-re Gage 16-14
(81349) MIL-T-7928
..

c-7
TM 55-1520-244-BD

APPENDIX c

Section II. -EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)

UNIT OF
NUMBER NSN DESCRIPTION ISSUE

159 5940-00-804-9184 Terminal, Quick Disconnect, PG i

Wire Size 14-16 (96906)
MS27429-2
160 5940-00-804-9185 Terminal, Quick Disconnect, PG
Wire Size 18 (96906)
MS27429-1
161 8305-00-753-2967 Towel, Wiping BX
(81348) CCCC46 ~.
162 5310-00-275-4290 Washer Assortment PG
(81349) MEL-W:1085
163 $310-00-167-0765 Washer, Flat (88044) AN970-3
164 5310-00-167-0766 Washer, Flat (88044) AN970-4 Iii
165 5310-00-167-0801 Washer,'Flat Steel, 3/16 \, EA
(88044) AN960ClO
166 531Q-00-167-0812 Washer,,Flat ( 8 8 0 4 4 ) EA
AN960ClW
167 5310-00-205-8924 Washer, Flat'(88044) EA
AN960C416L
168 5310-00-209-0027 Washer, Flat Steel, l/4 EA
( 8 0 2 0 5 ) NAS143-4
169 5310-00-883-3049 Washer, Flat Steel 5/16 EA
(80205) NAS1587-51,
170 6145-00-14470231 Wire, Electrical, 22 AWG FT
(81349) MIL-W-81044/11
171 6145-00-192-0680 Wire, Electrical, 14 AWG FT
(81349) MIL-W-81044/2
172 6145-00-578-6595 Wire, Electrica+, 4 AWG FT
to1 -Ban\ ,171
'-' '08662
( 0 1 3 4 5 ) RIL-w-3
173 6145-00-917-6378 Wire, Electrica 1, 20 Gage FT
(81349) MIL-W-2 2759/5
174 6145-00-989-3723 Wire,
,nm...#N\Electrica
L.-l .* 1 1, 1.2 Gage RO
lUlJ4Y) MlL-W-Z2759/5
175 6145-00-9.93-5490 iire, bectrical, 18 (;age FT
(81349) MIL-W-2---- .-
2759J5
176 6145-01-081-1~73 Wire, Electric-a 1, 10. Gage t FT
/07m7\ #‘ILL,
h4777*415,10,g
\“L”“, , u.d,

177 6145-01-122-3317 Wire. Electrica 1, 2 Gag‘e FT

(81349) MIi-W-2 275913
178' 6145-01-203-5399 Wire,
.-....a.Electrica
..-. . . - 1, 16 Gage FT
(81.34~) MIL-W-z2759/3

C-8
 TM 55-1520-244-BD

APPENDIX D

SUBSTITUTE MATERIALS/PART

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

D-1. GENERAL. This appendix lists substitute/- packing, and gasket substitute information. Section IV
alternate materials and parts. Section II contains contains petroleum, oil, lubricant (POL) substitute,
prime National stock number (NSN) interchangeability and blending information. Section V contains a sub-
cross-references for spare and repair parts from other stitute table for structural metal alloys.
models of helicopters. Section III contains O-ring,

Section Il. INTERCHANGEABLE PARTS

D-2. SCOPE. This section lists and cross- b. All parts which have the same NSN can be
references AH-1 spare and repair parts to other sys- used on the AH-1 without making any modification
terns having these same parts. prior to installation.

D-3. GENERAL. c. All subcomponents of the major components

may be substituted; however, the level of disassembly
a. Parts pertaining to the aircraft mechanical and must be consistent with field tools and skill levels
electrical functions are listed on Table D-1. For cross- available.
reference to aircraft armament parts use Table D-2.
d. These table listings maybe used to cross-
-reference parts and components provided from
cannibalized aircraft.

D-1
TM 55-1520-244-BD

Table D-1

D-2
 TM 55-1520-244-BD

Table D-1

D-3
TM 55-1520-244-BD

Table D-1

D-4
 TM 55-1520-244-BD

Table D-1

D-5
TM 55-1520-244-BD

Table D-1

D-6
 TM 55-1520-244-BD

Table D-1

D-7
TM 55-1520-244-BD

Table D-1

D-8
 TM 55-1520-244-BD

Table D-1

D-9
TM 55-1520-244-BD

Table D-2.

D-10
 TM 55-1520-244-BD

Section III. O-RING, PACKINGS, AND GASKETS

D-4. SCOPE. This section lists and to higher temperatures or fluids not in
cross-references packings and o-rings its range. The degradation process will
in the military part number series to not occur rapidly enough to affect the
commercial or other military series. helicopter mission except in instances
where low temperature packings or seals
D-5. GENERAL. Use of substitute or are used in high temperature applica-
alternate packings may limit the opera- tions on the engine or bleed air system.
tional life of the packing when exposed

D-11
TM 55-1520-244-BD
Table D-3
D-12
 TM 55-1520-244-BD
Table D-3
D-13
TM 55-1520-244-BD
Table D-3
D-14
 TM 55-1520-244-BD

Section IV. PETROLEUM, OIL, AND LUBRICANT (POL)

D-6. SCOPE. This appendix lists various types of (2) Alternate product. These are products
substitute fuels, lubricants, and hydraulic fluids which that closely match the primary product and may result
can be used on the AH-1 attack helicopter. Contained in some reduced performance with no effect on sys-
in this appendix is general information concerning tem durability. There are no limitations on duration of
types, uses, and effects of such POL substitutes. use.

D-7. GENERAL. (3) Emergency/expedient products. These

are products that can be used for only short periods
a. Some substitute products are made up of of time. These products are to be used as a last
chemical ingredients which are not compatible with resort. These products will cause poor performance
products used on an AH-1 aircraft. Some fuels, oils, or system damage after prolonged use,
and hydraulic fluids can have an adverse effect on
systems and components compatible with the AH-1
systems; therefore, it is advisable to properly identify
the product by specification number and name for The helicopter shall not be flown when
cross-reference with primary and expedient products emergency fuel has been used for a total
available. cumulative time of 50 hours unless a hot
section inspection is performed.
b. National stock numbers are used in conjunc-
tion with specification numbers to distinguish them e. Table D-4 lists some possible U.S. fuels, in
from foreign products. The identification of (NATO) proper priority, that may be used. Table D-5 lists
product numbers relate directly to U.S. Military primary or standard fuel sources and alternate fuel
Specification Numbers and thus are considered direct sources for various foreign countries. Table D-6 lists
replacements. some commercial fuel sources that may be sub-
stituted for the primary or standard JP-4.
c. In some situations, POL substitute products of
friendly or enemy nations can be used; however, f. Substitute fuels, which cannot be used alone
CAUTION should be exercised due to the possibility on the AH-1, can be blended with a primary fuel and
of sabotage. If there is no other alternative but to use can then be utilized for engine operation.
enemy products, check for signs of contamination, dis-
coloration, smell, and thickness. (1) When using substitute fuels, it is preferable
to premix the fuels in a container for better blending
d. Once a product under consideration is iden- before pouring into tank. This method of mixing the
tified, as described above, it will fall in one of three primary fuel with a substitute fuel insures that the
categories. These categories are defined as follows: fuels mix completely. The best expedient fueling
method is to add both fuels at the same time from two
(1) Primary products. These are basic separate fuel lines. Table D-7 lists alternate and
products for which the system was designed. The expedient fuel blends.
system will function without limitation.

D-15
TM 55-1520-244-BD

(2) There is no special limitation on the use of (1) They may not allow proper efficient opera-
Army standard fuel or alternate fuel. When using an tions because of improper viscosity.
emergency fuel, a fuel mixture which contains over 10
percent leaded gasoline is considered to be all leaded (2) They may allow an increase in wear be-
fuel. When using an emergency fuel, an entry on the cause of improper viscosity.
faults and remarks column of DA Form 2408-13, In-
spection Record, should be made. The entry should
(3) They may cause seals to swell or create
annotate the type of fuel, additives, and duration of
deposits because of improper composition.
operation.
h. Table D-8 lists the primary lubricants and
(3) Fuels having the same NATO code number
hydraulic fluids for use as alternate and expedients
are interchangeable, and fuels conforming to ASTM-
on the AH-1 helicopter.
D-l 655 specification may be used when standard
fuel, MIL-T-5624 JP4, is not available.

g. The lubricants and hydraulic fluids used in the

AH-1 systems and components must have a com- Lubricating oil MIL-L-23699 shall not be
patible base composition, as well as good additive used in ambient temperatures below
level. The purpose of lubricants and hydraulic fluids is minus 32°C/25°F.
to reduce wear, support bearing loads, and provide
cooling; their chemical composition must be com- It is not advisable to mix MIL-L-7808 and
patible. In addition to lubricating, hydraulic fluids must MIL-L-23699 oils, except during an emer-
transmit power and motion. If two incompatible gency. If oils are mixed, the system
hydraulic fluids are mixed, there is a tendency of a gel should be flushed within six hours.
substance forming within the system. Some lubricants Hydraulic oils MIL-L-83282 and
will not withstand AH-1 temperatures or loads for ex- MIL-L-5606 should not be mixed except
tended periods of time. These type of lubricants do during an emergency. When these oils
not contain the necessary base properties for are mixed with each other or any other
withstanding long term use, therefore they are recom- oil, a DA Form 2408-13 entry is required.
mended only as a last resort. Expedient lubricants
can cause one of three problems:

D-16
 TM 55-1520-244-BD

Table D-4

D-17
TM 55-1520-244-BD

Table D-5

D-18
 TM 55-1520-244-BD

Table D-6

D-19
TM 55-1520-244-BD

Table D-7. Alternate and Expedient Fuel Blends

BASE FUEL EXTENDER (50% MAXIMUM)

NOTE

Fuel may be extended on an alternate basis with the following

blends up to a half and half mixture.

Any Primary Fuel Any Alternate Fuel

I
Any Primary Fuel Any Alternate Fuel

Any Primary or Alternate Fuel MIL-F-815 Distillate

I
Any Primary or Alternate Fuel NATO-F-76 Navy Distillate

Any Alternate or Primary Fuel Dry Cleaning Solution:

P-D-680 (Type I and II)

Dry Cleaning Solution:

AMSTM-D-484 (K, I, II, III, IV)

Petroleum Spirits: ASTM-D-235

(I, II, III, IV)

CAUTION

The helicopter shall not be flown when emergency fuel has

been used for a total cumulative time of 50 hours.

D-20
 TM 55-1520-244-BD
Table D-8
D-21
TM 55-1520-244-BD
Table D-8
D-22
 TM 55-1520-244-BD

Section V. STRUCTURAL METAL ALLOYS

D-8. SCOPE. This section lists and b. Locate the substitute material in
cross-references substitute structural the vertical columns.
metal alloys.
c. To obtain the minimum thickness
D-9. GENERAL. Due to the short term of the substitute material, multiply
of use, weight and dissimilar metal the thickness of the material to be
corrosion considerations can be replaced by the factor shown at the
overlooked during BDAR structural intersection of the line and column
repairs. Metal selection should be found in step A & B, substitute stan-
based only on strength requirements. dard gage equal to this thickness or
Refer to Table D-9 and use the nearest standard gage.
following steps to locate substitute
metal alloy types:

a. Locate the material to be

replaced on the line in the left-hand
column.

D-23
TM 55-1520-244-BD
Table D-9
D-24
 TM 55-1520-244-BD

APPENDIX E

BDAR FIXES AUTHORIZED FOR TRAINING

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

NOTE

The procedures listed below are authorized for sustainment

training. They do not permanently alter aircraft or components.
These procedures duplicate those highlighted in each system’s
chapter, Repair Procedure Index, surrounded by a box.

All BDAR fixes contained in this manual are trainable if scrap

or beyond economical repair (BER) components are available for
practice repair and such training is approved by the unit
commander. Many of the other procedures not listed in this
appendix will permanently alter or damage the equipment.

REPAIR PROCEDURE PARA NO.

POWER PLANT INSTALLATION

Low Oil Pressure, Defective Indicator/Transmitter. . . 6-5

Fuel Filter Clogged. . . . . . . . . . . . . . . . . . 6-6

ROTOR

Lateral Vibrations . . . . . . . . . . . . . . . . . . 7-6

DRIVE TRAIN SYSTEM

Oil Pressure Switch Leak... . . . . . . . . . . . . 8-5

Oil Pressure Transmitter Leak. . . . . . . . . . . . . 8-6
Oil Filter Leak. . . . . . . . . . . . . . . . . . . . 8-7
Sump Outlet Hose Leak. . . . . . . . . . . . . . . . . 8-8

HYDRAULIC SYSTEM

Lock-Out Valve Stuck Closed . . . . . . . . . . . . . 9-9

No. 1 Hydraulic System Pump Inoperative. . . . . . . . 9-11
No. 2 Hydraulic System Pump Inoperative. . . . . . . . 9-12

E-1
TM 55-1520-244-BD

BDAR FIXES AUTHORIZED FOR TRAINING (Cont)

REPAIR PROCEDURE PARA NO.

ELECTRICAL AND AVIONICS SYSTEM

Splicing Unshielded Wires. . . . . . . . . . . . . . . 11-5

Splicing Shield Cable . . . . . . . . . . . . . . . . . 11-6
Shield Cable Repair Segments . . . . . . . . . . . . . 11-7
Shield Terminators . . . . . . . . . . . . . . . . . . 11-8
Coax Splicing Using Wiring Repair Kit. . . . . . . . . 11-9
Damaged Connector Pins... . . . . . . . . . . . . . 11-11
Damaged Circuit Breaker Repair . . . . . . . . . . . . 11-12
Damaged Fuses. . . . . . . . . . . . . . . . . . . . . 11-13
Battery Bus Bar Repair. . . . . . . . . . . . . . . . 11-15
Power Relay Test and Repair. . . . . . . . . . . . . . 11-16
Substitute Emergency Antenna . . . . . . . . . . . . . 11-18
Damaged Wire Insulation . . . . . . . . . . . . . . . 11-19

FUEL SYSTEM

Aft Fuel Cell Isolation . . . . . . . . . . . . . . . 12-7

Forward Fuel Cell Isolation. . . . . . . . . . . . . . 12-8
Fuel Boost Pumps (General) . . . . . . . . . . . . . . 12-9
External Fuel Filter Clogged . . . . . . . . . . . . . 12-10
Fuel Filter Bypass. . . . . . . . . . . . . . . . . . 12-11

MISSION EQUIPMENT

Wire Damage. . . . . . . . . . . . . . . . . . . . . . 16-5

E-2
 TM 55-1520-244-BD

APPENDIX F

AVIONICS CONFIGURATIONS

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING

AT THE DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

F-1. SCOPE. This appendix lists and depicts the The Figures F-1 thru F-16 show typical location of
major components, cable routes, and wiring termina- avionics and their associated components in relation
tions pertaining to the AH-1 series helicopter avionics. to the helicopter and lists the component part number.
This information is furnished as an aid to expedient Each figure also has a table associated with the
repair techniques described in Chapter 11. avionics system which contains a complete wire list-
ing to be used as an aid in rapid wire splicing. This in-
F-2. GENERAL. The actual configurations may cludes the wire number, type (shielded, not shielded,
vary depending on particular requirements or or pair twisted with shield), end connectors and the
changes incorporated through modification work pin numbers on each connector.
order (MWO) action and special purpose alterations.

F-1
TM 55-1520-244-BD
Figure F-1. UHF Command Communication System
AN/ARC-1160 or AN/ARC-164 (Sheet 1 of 2)
F-2
 /,- . *iv
_ ‘_ .__ . d :
I: ._ .,.’
.

TM 55-1520-244-B6

..I r
>"

DRAWING P A R T
DESIGNATION N U M B E R DESCRIPTION

1 209-975-132-5 Bracket, Mounting

2 209~07.7-097-107 Xable Assembly, Spec Pr USBL

EFF 78-23093 and subsequent.

3 tiFP40-0lT 2 Filter, High Pass

4 209-0772097-105' Cabl'e Assembly, Spec PR USBL

: , EFF 77-23093 and SubSeQUent

= 5 20&077-043-5' Cable,Assembly, Special Purpose USBL

EFF 76-22567 thru 77-23092.

6 269-077-043-5 Cable Assembly, Coax &SBi

EFF 76-2256 thru 77-23092

209-077-097~105 --Cable Assembly, Special Purpose USBL

EFF 77-23093 and SUbSeQUent.

7 AN/ARC-116 Radid set USBL EFi 76-22567 thru

77-23092 ,

RT-11671ARG164(V) Receiver-Transmitter U.S@L 78-23093 ' ~

and subsequent.

8 209-077-043-3 Cable Assembly, ARC 116 USBL

EFF 76-22567 thru 77-23092.

9 AT-256AfARC Antenna

10 209-077-043-7 Cable Assembly, UHF Antenna USBL

EFF,P&22587 thw 77-2309'2.

Figtire-F-l. l$iF C~~~.~~~~cat~o~ System

~#WAR@~~lG() or ANfjkR@l-ti4: (Sheet 2 of 2)
',
;
_t F-3

‘.

_
TM 55-1520-244-BD

Table F-1

Table F-2

F-4
 TM 55-1520-244-BD
Figure F-2. VHF Command Communication System
AN/ARC-115 (Sheet 1 of 2)
F-5
TM 55-1520-244-BD

Figure F-2

Table F-3

F-6
 TM 55-1520-244-BD
Figure F-3
F-7
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 BPF 40-03P Filter, Band Pass

2 209-077-096-105 Cable Assembly, Special Purpose

3 209-077-096-107 Cable Assembly, Special Purpose

4 209-077-096-109 Cable Assembly, ARC-115

5 VFS 10-90-6 Antenna UBL EFF 78-23093 thru

78-23125, 79-23253

AS-3204/ARC Antenna USBL EFF 79-23187 thru

79-23252

6 AN/ARC-115 Radio Set Direct Replacement:

AN/ARC-186

AN/ARC-186 Radio Set Direct Replacement:

AN/ARC-115

7 209-077-096-105 Cable Assembly, Special Purpose

8 209-077-096-103 Cable Assembly, Special Purpose

Figure F-3. VHF Command Communication System

AN/ARC-115 or AN/ARC-186 (Sheet 2 of 2)

Table F-4. VHF Command Communication System

AN/ARC-115 or AN/ARC-186 Wire Chart

NOTE

See wire chart, Table F-3. AN/ARC-186 uses same wiring harness
and connectors.

F-8
 TM 55-1520-244-BD
Figure F-4. FM Liaison Communication System AN/ARC-l14 (Sheet 1 of 3)
F-9
TM 55-1520-244-BD
Figure F-4. FM Liaison Communication System AN/ARC-114 (Sheet 2 of 3)
F-10
 TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 AN/ARC-114A Radio Set

2 LPF 40-02B Filter, Low Pass

3 209-077-042-3 Cable Assembly, ARC-114

4 8157-ARC Control, Indicator

5 209-077-042-21 Cable Assembly, Homing

6 209-077-042-25 Cable Assembly, Homing

7 M39014/05-2219 Capacitor, Fixed, Cer

8 209-077-062-1 Filter Assembly, Avionics

9 209-077-042-23 Cable Assembly, Homing

10 209-077-062-1 Filter Assembly, Avionics

11 209-077-042-19 Cable Assembly, Homing

12 AS-3205/ARC Antenna, F.M. Homing

13 209-077-042-15 Cable Assembly, ARC-114

14 TSEC/KY-28 Communications, Security

15 209-077-042-19 Cable Assembly, Homing

16 209-077-042-23 Cable Assembly, Homing

17 209-077-042-9 Cable Assembly, ARC-114

18 209-077-042-13 Cable Assembly, ARC-114

19 MS3474L16-26PW Connector Receptacle

20 MS3474L12-1OP Connector Receptacle

21 209-077-202-3 Antenna

22 209-077-042-27 Cable Assembly, ARC-114

23 209-077-042-11 Cable Assembly

Figure F-4. FM Liaison Communication System AN/ARC-l14 (Sheet 3 of 3)

F-11
TM 55-1520-244-BD

Table F-5

F-12
 TM 55-1520-244-BD

Table F-5.

F-13
TM 55-1520-244-BD
Figure F-5.
F-14
 TM 55-1520-244-BD
Figure F-5. FM Liaison Communication System AN/ARC-114A (Sheet 2 of 3)
F-15
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 209-077-093-107 Cable Assembly, Coaxial

2 209-077-093-105 Cable Assembly, Coaxial

3 209-077-093-109 Cable Assembly, Coaxial

4 209-077-093-117 Cable Assembly, Coaxial

5 AN/ARC-114A Radio Set

6 209-077-062-1 Filter Assembly, Avionics

7 M39014/05-2219 Capacitor Fixed Cer

8 209-077-062-1 Filter Assembly, Avionics

9 209-077-042-25 Cable Assembly, Homing

10 209-077-042-21 Cable Assembly, Homing

11 209-077-093-111 Cable Assembly, Coaxial

12 LPF 40-02B Filter, Low Pass

13 TSEC/KY-28 Communication Security

14 MS3474L12-1OP Connector, Receptacle

15 209-077-042-13 Cable Assembly, ARC-114A

16 MS3474L16-26PW Connector, Receptacle

17 . . . Antenna

18 209-077-093-113 Cable Assembly, ARC-114

Figure F-5. FM Liaison Communication System AN/ARC-l14A (Sheet 3 of 3)

F-16
 TM 55-1520-244-BD

Table F-6

F-17
TM 55-1520-244-BD

Table F-6

F-18
 TM 55-1520-244-BD
Figure F-6. Gyromagnetic Compass System AN/ASN-43 (Sheet 1 of 2)
F-19
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 C-6347()/ASN-43 Controller, Compass

2 MS3476L1O-6S Connector, Plug Elec

3 MS3474L1O-6P Connector, Receptacle

4 T-611A/ASN Transmitter, Induction

5 CN-405/ASN Compensator, Transmitter

6 209-077-048-5 Cable Assembly ASN-43, USBL

EFF 76-22567 thru 77-23092.

209-077-095-105 Cable Assembly ASN-43, USBL

EFF 78-23093 and subsequent.

7 CN-998B/ASN-43 Gyroscope, Displacement

8 209-077-048-3 Cable Assembly, Branch USBL

EFF 76-22567 thru 77-23092

209-077-095-103 Cable Assembly, Branch USBL

EFF 78-23093 and subsequent.

Figure F-6. Gyromagnetic Compass System AN/ASN-43 (Sheet 2 of 2)

F-20
 TM 55-1520-244-BD

Table F-7.

F-21
TM 55-1520-244-BD

Table F-7

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair Twisted, W/Shield

*Wires Not Used On (MC)AH-1

**Denotes Difference In Wiring For (MC) AH-1

F-22
 TM 55-1520-244-BD
Figure F-7. Automatic Direction Finder AN/ARN-89B (Sheet 1 of 2)
F-23
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 7392A/ARN-89 Control, Radio Set

2 9-077-041-13 Cable Assembly, Loop Antenna

3 -2108A/ARN-89 Antenna

4 9-077-041-15 Cable Assembly, Loop Antenna

5 9-077-041-5 Cable Assembly, ADF

6 1496A/ARN-89 Receiver, Radio

7 9-077-041-9 Cable Assembly, Spec Pr USBL

EFF 76-22567 thru 77-22762.

9-077-041-19 Cable Assembly, Spec Pr USBL

EFF 77-22763 and subsequent.

8 -4859A/ARN-89 Amplifier, Impedance

9 9-030-133-7 Sense Antenna Panel

10 9-077-041-11 Cable Assembly, Spec Pr USBL

EFF 76-22567 thru 77-22762

9-077-041-21 Cable Assembly, Spec Pr USBL

EFF 77-22763 and subsequent.

11 9-075-108-101 Cover, Instl Wiring, USBL

EFF 78-23093 and subsequent.

12 9-077-041-17 Cable Assembly, ADF

13 9-077-041-7 Cable Assembly, ADF

Figure F-7. Automatic Direction Finder AN/ARN-89B (Sheet 2 of 2)

F-24
 TM 55-1520-244-BD

Table F-8

F-25
TM 55-1520-244-BD

Table F-8

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair Twisted, W/Shield

3 Wires Vary Between AH-1 Models

F-26
 TM 55-1520-244-BD
Figure F-8
F-27
TM 55-1520-244-BD
Figure F-8. VOR/MB/GS Recieving Set Radio AN/ARN-123(V)3 (Sheet 2 of 3)
F-28
 TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 30-015-13 Track, Terminal

2 CR07G333JS Resistor Fixed, Comp

3 09-077-094-119 Cable Assembly, VOR GLID

4 D-2105/A Indicator, Radio-Magnetic

5 09-077-094-119 Cable Assembly, VOR GLID

6 09-077-081-5 Control, Navigation Select

7 D-2404/A Indicator, Attitude

8 D-3103/A Indicator, Horizontal

9 -10048/ARN-123(V) Control, Receiver

10 S-3188/ARN Antenna

11 209-077-094-113 Cable Assembly, GS Antenna

12 M39012/16-0004 Connector Plug, Elec

13 AT-640/ARN Antenna

14 209-077-094-111 Cable Assembly, MB Antenna

15 209-077-094-111 Cable Assembly, MB Antenna

16 209-077-094-107 Cable Assembly, ARN-123

17 5995-00-858-6552 Spider, Coax Assembly (05211)

18 AS-1304 ( )/ARN Antenna

19 R-2023/ARN-123(V) Receiver, Radio

20 209-077-094-109 Cable Assembly, ARN-123

21 209-077-094-105 Cable Assembly, ARN-123

22 209-077-094-113 Cable Assembly, GS Antenna

Figure F-8. VOR/MB/GS Receiving Set Radio AN/ARC-123(V)3 (Sheet 3 of 3)

F-29
TM 55-1520-244-BD

Table F-9

F-30
 TM 55-1520-244-BD

Table F-9

F-31
TM 55-1520-244-BD

Table F-9

F-32
 TM 55-1520-244-BD

Table F-9

F-33
TM 55-1520-244-BD

Table F-9

F-34
 TM 55-1520-244-BD

Table F-9

F-35
TM 55-1520-244-BD

Table F-9

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair. Twisted. W/Shield

F-36
 TM 55-1520-244-BD
Figure F-9. Doppler Navigation System AN/ASN-128(MC) (Sheet 1 of 2)
F-37
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 CP-1252/ASN-128 Computer, Display Unit

2 209-077-091-117 Cable Assy, Spec Purpose

3 209-077-091-115 Cable Assy, ASN-128

4 209-077-091-119 Cable Assy, ASN-128

5 CV-3338()/ASN-128 Converter, Signal Data

6 RT-1193()/ASN-128 Receiver, Transmitter

7 209-077-091-117 Cable Assy, Spec Purpose

Figure F-9. Doppler Navigation System AN/ASN-128 (MC) (Sheet 2 of 2)

F-38
 TM 55-1520-244-BD

Table F-10

F-39
TM 55-1520-244-BD

Table F-10

F-40
 TM 55-1520-244-BD

Table F-10

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair. Twisted, W/Shield
TWT/S--Three Wire Twisted, W/Shield
S/CABLE--Shielded Cable/Multi-Pair

F-41
 TM 55-1520-244-BD
Figure F-10. Radar Altimeter System AN/APN-209 (Sheet 1 of 2)
F-42
 TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 209-077-051-3 Cable Assy, Spec Pur

2 209-077-051-5 Cable Assy, APN-209 USBL

EFF 76-22567 Thru 77-23092

209-077-051-103 Cable Assy, APN-209 USBL

EFF 78-23093 and Subq.

3 209-077-051-7 Cable Assy, APN-209 USBL

EFF 76-22567 thru 77-23092

209-077-051-105 Cable Assy, APN-209 USBL

EFF 78-23093 and Subq.

4 RT-1115/APN-209 Receiver-Transmitter

5 AS-2595/APN-194V Antenna

6 209-077-051-5 Cable Assy, APN-209 USBL

EFF 76-22567 thru 77-23092

209-077-051-103 Cable Assy, APN-209 USBL

EFF 78-23093 and Subq.

7 AS-2595/APN-194V Antenna

8 209-077-051-7 Cable Assy, APN-209 USBL

EFF 76-22567 thru 77-23092

209-077-051-105 Cable Assy, APN-209 USBL

EFF 78-23093 and Subq.

Figure F-10. Radar Altimeter System AN/APN-209 (Sheet 2 of 2)

F-43
TM 55-1520-244-BD

Table F-11

1 Underlined Pin Numbers Denote Lower Case.

2 Denotes: NO/S--No Shield

F-44
 TM 55-1520-244-BD
Figure F-11. IFF System AN/APX-72 (Sheet 1 of 2)
F-45
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 209-077-045-3 Cable Assembly, APX-72 USBL

EFF 76-22567 thru 77-22762

209-077-045-103 Cable Assembly, APX-72 USBL

EFF 77-22763 thru 77-23092

2 M83723-75R2255N Connector Plug, Elec

3 TS-1843( )/APX Test Set, Transponder

4 MT-3513/APX Mount, Receiver

5 MT-3949A/U Mounting Base, Elec

6 209-077-045-7 Cable Assembly, APX-72

7 KIT-lA/TSEC Transponder Computer

8 RT-859 A/APX-72 Receiver-Transmitter

9 MT-3809/APX-72 Mount, Transponder

10 209-077-045-9 Cable Assembly, APX-72

11 AT-884 ( )/APX-44 Antenna

12 DPJM-59C1O-34SA Connector, Body Rece

13 C-6280 (P)/APX Control, Transponder

Figure F-11. IFF System AN/APX-72 (Sheet 2 of 2)

F-46
 TM 55-1520-244-BD

Table F-12

F-47
TM 55-1520-244-BD

Table F-12

F-48
 TM 55-1520-244-BD

Table F-12

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

F-49
TM 55-1520-244-BD
Figure F-12. IFF System AN/APX-100(V) (Sheet 1 of 2)
F-50
 TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 KIT-lA/TSEC Transponder Computer

2 RT-1157()/APX-100 Receiver-Transmitter

3 209-077-090-107 Cable Assy., APX-1OO

4 AT-741B/A Antenna

5 C-10533/APX-100 Control, Transponder

6 209-077-090-111 Cable Assy., Branch

7 MT-4811/APX-100 Mounting Base, Elect.

8 AT-884( )/APX-100 Antenna

9 209-077-090-109 Cable Assy., APX-1OO

Figure F-12. IFF System AN/APX-100(V) (Sheet 2 of 2)

F-51
TM 55-1520-244-BD

Table F-13

F-52
 TM 55-1520-244-BD

Table F-13

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair, Twisted, W/Shield

F-53
TM 55-1520-244-BD
Figure F-13. Radar Warning System AN/APR-39(V)l (Sheet 1 of 2)
F-54
 TM 55-1520-244-BD

DRAW&, PART
DESIGt&~LON NUMBER DESCRIPTION
1 R-183&() /&R-39 Recefver, Radar

2 209-077-050-3 . " Cable Assy., APR-39, USBL

EFF 76-22567 thru 77-23092
209-077-050 -105 Cable'Assy., A P R - 3 9 , USBL
EFF 78-23093 and subsequent
3 IP-1150()/APR-39 IndScator, Radar Signal
4 C-9326 APR-39V Control, Detecting Sfgnal
B
5 R-f .&38(j./APR-39 Receiver, Radar
6 1538-8252-1 Cable Assy., Radio
-7‘ AS-2891/APR Antefma, Right Spiral

aa AS-2892/APR -39(V) Antenna, Left Spiral

1538-8252-3 -Cable Assy., Radio

RT-1157()/APX-la MOD AH-S

RT-859()/APX-72 PROD, ECAS, AH-IS
11 209-077-050-15 &ble Assy., APR-39, USBL
EFF 76-22567 thru 77-23092
209-077-a:i0-10f Cable Assy., APR-39, USBL
EFF 77123093 and subsequent
12 CM-440JAPR-39(v) Comparator
,
13 209-077-053-l Bracket, Support

14 209-077-050-i Ca.b?e Assy., Blade Antenna

1 5 AS-2890/APR-39(V) Antenna
16 AS-2891/APR-39(V) Antenna, Right Spiral
17 1538-8252-5 Cable Assy., Radio

1% 1538-8252-7 Cable Assy., Radio

19 AS-2892/APR-39(V) Antenna, Left Spiral ,

Figure F-13. Radar Warning System AN/APR-39(V)I (Sheet 2 of 2)

'
j.- ',-:. 1
TM 55-1520-244-BD

Table F-14

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

PR/S--Pair, Twisted, W/Shield

F-56
 TM 55-1520-244-BD

Figure F-14. Countermeasures Set AN/ALQ-136 (MC) (Sheet 1 of 2)

F-57
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 MS24140-D1 Relay, Electromagnetic

2 6TC14-2 Circuit Breaker

3 DSK-9-01752-501 Wire Harness Assy.

4 AS-3007/ALQ-136(V) Antenna Assy.

5 C-9576/ALQ-136 Control Unit

6 10620 AEL2-7 Indicator, Light, PB 19544

7 AS-307/ALQ-136(V) Antenna Assy.

8 CSK-9-01926 Cable Assy, Coax, XMT.

9 020372 Fan, Vanaxial

10 RT-1149/ALQ-136 Receiver, Transmitter

11 CSK-9-01927 Cable Assy., Coax RCV.

Figure F-14. Countermeasures Set AN/ALQ-136 (MC) (Sheet 2 of 2)

Table F-15. AN/ALQ-136 Wire Chart

NOTE

Information is classified.

F-58
 TM 55-1520-244-BD
Figure F-15. Countermeasures Set AN/ALQ-144(V) (NC) (Sheet 1 of 2)
F-59
TM 55-1520-244-BD

DRAWING PART
DESIGNATION NUMBER DESCRIPTION

1 209-077-092-109 Cable Assembly, Branch

2 C-10280/ALQ-144V Control, Countermeasures

3 T-1360(V)2/ALQ Transmitter, Counter, I.R.

4 209-077-092-113 Cable Assembly

5 209-077-092-111 Cable Assembly, I.R. Jammer

Figure F-15. Countermeasures Set AN/ALQ-144(V) (MC) (Sheet 2 of 2)

F-60
 TM 55-1520-244-BD

Table F-16

1 Underlined Pin Numbers Denote Lower Case

2 Denotes: NO/S--No Shield

F-61/(F-62 Blank)
 TM 55-1520-244-BD

GLOSSARY

NOTE

● The terms and acronyms listed herein are defined in relation to

BDAR, and accordingly may not be used in the same manner in other
manuals.

● Additional definitions of terms, markings, and acronyms used

during BDAR assessment procedures will be found under chapter
1, paragraph 1-10, Tagging and Identifying BDAR Repairs.

ABRASION Roughened surface, varying from light to severe.

ALLOWANCE A prescribed difference between the maximum condition of

mating parts. The minimum clearance or maximum inter-
ference between such parts.

API Armor piercing incendary armament round.

ASSEMBLY A group of two or more physically connected and related

parts, capable of disassembly, and when combined with
other assemblies and parts, creates a component.

ASSEMBLY CLEARANCE The actual fit between two or more mating parts with
respect to the amount of clearance or interference
between them.

ASSESSMENT A procedure to rapidly determine what is damaged,

whether it is repairable, what assets are required,
who can perform the repair, and where the repair
can made.

ASSOCIATED PARTS A group of parts which could contain one or more

unrelated parts of a subassembly, one or more sub-
assemblies, and attaching hardware.

AXIAL Related to an axis. Describes the linear distance a

shaft or gear moves.

BATTLEFIELD DAMAGE Any incident such as combat damage, random failures,

operator errors, accidents, and wear-out failures
which occur on the battlefield and which prevent the
equipment/end item from accomplishing its mission.

BEAM A primary structural element designed to carry heavy

loads by resisting bending in one direction. Usually
constructed with a channel, tee, or “I” cross section.

BEND Any change in an intended configuration.

BORE Inside measurement of the interior diameter of a hole

or tube. Also used to describe the hole itself.

GLOS-1
TM 55-1520-244-BD

GLOSSARY (Cont)

BOWED Curved or gradual deviation from original line or plane.

BOX BEAM A primary structural element designed to carry heavy

loads by resisting bending in at least two directions
characterized by a square or rectangular hollow cross
section.

BRAID Machine woven wire strands.

BREAK Separation of a part or substance from itself.

BRIDGING Jumping or bypassing of a part or component.

BRINELLED Circular indentations on bearing surfaces.

BULKHEAD The primary vertical structural element. Often called

frames or walls.

BUCKLE Wrinkle or crease damage to sheet metal structural

elements.

BURN Loss of metal resulting from overheating.

BURNISHING The smoothing of a metal surface by mechanical action

without loss of material. Generally found on plain
bearing surfaces. Surface discoloration is sometimes
present around outer edges of a burnished area.

BURR A rough edge or sharp projection.

CANNIBALIZATION The removal of needed parts or assemblies from other

aircraft, equipment, or from non-essential systems
on the helicopter undergoing repair.

CAP A continuous structural element (angle, tee, or

channel shape) fastened to the top and bottom of
a beam or web.

CATASTROPHIC A sudden and disastrous event caused by equipment

failure which endangers human life.

CHAFED Functional wear. A rubbing action between two parts

having relative motion.

CHECK An examination for verifying.

CHIPPING Breaking away of small metallic particles.

CHORDLINE An imaginary line running perpendicular to the leading or

trailing edge of a rotor blade.

GLOS-2
 TM 55-1520-244-BD

GLOSSARY (Cont)

CLOCKWISE A circular motion in the direction the hands of a clock

rotate when viewed from the front.

COATING, PROTECTIVE An external surface treatment, such as paint, anodizing,

electroplating or chemical film, used to delay the
effects of corrosive or atmospheric elements upon metals.

COMBAT CAPABLE The ability of the helicopter to perform the MINIMUM

combat mission assignments.

COMBAT EMERGENCY The ability of the helicopter to perform LIMITED

CAPABLE specific tactical mission assignments.

COMPONENT A group of physically connected assemblies or parts.

CONSUMABLE ITEMS Parts or materials which are consumed by usage or which

have a one-time usage in depot maintenance activity.

CORE The inner layer of material used to construct

honeycomb structural panels.

CORROSION Surface chemical action which results in surface

discoloration, a layer of oxide, rust, or removal of
surface metal.

COUNTER-CLOCKWISE The direction opposite to the direction the hands of a

clock rotate, when viewed from the front.

CRACK A break in some type of material.

CRIPPLE Damage to a load carrying structural member which

would cause degradation of the helicopters full
mission capability.

CRITERIA Standards or rules used to judge.

DATA A group of facts.

DECONTAMINATION To make an item safe for unprotected personnel by

removing, neutralizing, or destroying any harmful
substance. A function of Nuclear, Biological, and
Chemical (NBC) Warfare.

DENT Indentation in metal surface produced by an object

striking with force.

DISASSEMBLY The operations necessary to reduce an assembly to its

separate components and parts.

GLOS-3
TM 55-1520-244-BD

GLOSSARY (Cont)

DISTORTION A change from an original shape.

EROSION Wearing away of metal.

EVACUATION A combat service support function which involves the

movement of recovered helicopters from a main supply
route, maintenance collection point, or maintenance
activity to higher categories of maintenance.

EXPEDIENT A rapid and often non-standard method of repairing

an item (repair technique).

FAILURE MODE The specific cause of failure, relating to categories

such as cracks, corrosion, ballistic impact, etc.

FATIGUE FAILURE Sharp indentations, cracks, tool marks, or inclusions

that result in progressive yielding of one or more local
areas of material.-

FIX Any rapid action that returns a damaged part or

assembly to full or an acceptabl y degraded operating
condition (repair technique).

FLANGE A broad ridge or pair of ridges projecting from the

edge of a structural element, pr oviding additional
strength or a place for attachment.

FLAKING Loose particles of metal or evidence of separation of a

surface covering material.

FLUORESCENT PENETRANT A test for locating cracks and fissures in non-

magnetic material, making use of radiation properties
of fluorescent particles when exposed to ultraviolet
light.

FORMER A curved structural element which gives the fuselage

its even aerodynamic shape. Normally longerons and
stringers are attached and the skin is fitted
tightly over all these elements.

FRACTURE Separation of a part or piece of material from itself.

FRAYING Loose or raveled threads and fibers.

FULLY MISSION The ability of the helicopter to perform ALL its combat
CAPABLE (FMC) mission assignments. “

FUNCTIONAL GROUP Major helicopter subsystems identified in and

corresponding to functional groups in TM 55-1520-236-23.

FUSELAGE The central main body of the helicopter.

GLOS-4
 TM 55-1520-244-BD

GLOSSARY (Cont)

GALLING Aggravated condition of wear, generally caused by a

rubbing action with little or no lubrication.

GAP Clearance between faying surfaces, measurement of which

is used to determine thickness of shims.

GOUGING Removal of surface metal because of mechanical contact

with foreign material.

HEAT DISCOLORATION A change in color or appearance of a part, caused by

excessive temperature.

HEI High explosive incendiary armament round.

HOUSING A frame support or cover, used to hold parts of

machinery in place. Also used as a protective cover.

INDENTATION A cavity with smooth bottom or sides, which can occur

on rolling contact surfaces.

INSPECTION A critical examination of parts to determine their use-

fulness or condition.

INTERFACE The joining point of two flat surfaces.

JURY-RIGGING A rapid non-standard method of repairing an item

(repair technique).

LIMIT An established point or boundary, in time, speed, or

space, beyond which something may not go or is not
permitted to go.

LOAD PATH The route taken by a mechanical force traveling through

an airframe structure.

LONGERON A principle longitudinal (fore and aft), structural

element (angle or tee shape) continuous across several
points of support.

LRU Line replaceable unit (electronic circuit board).

MAINTENANCE COLLECTION A point operated by AVIM units for the collection of

POINT equipment for repair.

MAINTENANCE SUPPORT A team consisting of AVUM and AVIM mechanics and technical
TEAM (MST: specialist who are trained in assessing battle damage in
addition to their routine speciality.

GLOS-5
TM 55-1520-244-BD

GLOSSARY (Cont)

MAINTENANCE TEAM A team consisting of organizational mechanics who may

(MT) be trained in assessing-battle damage and field repair
Procedures.

MISSION FUNCTION The ability of the helicopter to perform the MINIMUM

COMBAT CAPABLE combat mission assignments.
(MFCC)

MODIFICATION An alteration and/or integral change affecting the

configuration of equipment or its respective parts,
components, subassemblies, or assemblies.

NATIONAL STOCK NUMBER The assigned identifying number for an item of

(NSN) supply, consisting of the four-digit Federal Supply
Class (FSC), and the nine-digit National Stock
Identification Number (NIIN).

NICK A local break or notch in the edge of material.

OPERATION Performance of a practical, functional action.

OPTION A specific BDAR repair technique often non-standard

in nature.

OVERHAUL The process of repairing or adjusting a machine to

restore, improve, or lengthen its useful life.

PEELING A breaking away of surface finishes such as coatings

or platings, or flaking of large pieces of such material.

PIGTAIL A group of electrical wire strands twisted together.

PITTING Small holes or indentations, generally caused by rust,

corrosion, high compressive stresses, or metal-to-metal
pounding.

PRACTICE A repeated or customary action.

PRIMARY STRUCTURE The major structural load carrying elements of an

airframe without which helicopter flight safety would
be compromised.

PROCEDURE A particular course of action.

PROCESS A series of actions conducive to an end.

PYLON The box shaped structural area surrounding the helicopter

main transmission. This area carries several primary
structural loads.

GLOS-6
 TM 55-1520-244-BD

GLOSSARY (Cont)

REASSEMBLY The assembling and aligning of all subassemblies and

parts into a complete assembly to affect a serviceable
item of equipment.

RECOVERY The retrival of immobile, inoperative, or abandoned

helicopters from the battlefield or immediate vicinity
and its movement to a maintenance collection point, main
supply route, or a maintenance activity for disposition,
repair, or evacuation.

REMOVE To move by lifting, pulling or pushing.

REPAIR To restore a defective part, component, subassembly, or

assembly to a usable condition in accordance with the
instructions contained in this manual.

REPLACE To supply an equivalent for.

REWORK To work over again.

RUPTURE The breaking of an airframe structural element or skin

due to overstress/hostile fire.

SCORING Very deep scratches caused by foreign particles between

surfaces that are moving, or between one moving and
one stationary surface. Scores follow the travel
direction of the part.

SCRATCHING Narrow, shallow lines resulting from movement of

foreign particles across a surface.

SECONDARY STRUCTURE The non-flight safety structural elements of an airframe.

SELF-RECOVERY The ability of the helicopter to fly at reduced airspeed

and altitude from the battlefield or immediate vicinity
to a maintenance collection point, the main supply route,
or maintenance activity for disposition, repair or
evacuation.

SEMIMONOCOQUE A structural design which relies on strength of the skin

to carry a large portion of the load. The skin is nor-
mally reinforced by longerons and vertical bulkheads
(walls), but has no diagonal bracing, leaving the interior
basicly hollow.

SERVICING The lubrication, treating, cleaning, or preservation

necessary to maintain the equipment and other respective
parts in serviceable condition.

SKIN The aerodynamic exterior covering of the helicopter.

GLOS-7
TM 55-1520-244-BD

GLOSSARY (Cont)

SPALLING Chipped or flaked surface caused by the breaking away of

the hardened metal and separation of the case from the
core.

SPANWISE The location of a point or direction of movement parallel

to the leading or trailing edge of a rotor blade.

SPAR A primary structural element designed to carry weight

and resist bending loads in wings and rotor blades.
Spars typically extend the full length of the wing, and
taper down to a smaller cross section toward the tip
of the wing.

STIFFENER A longitudinal (fore and aft) structural element use in

semimonocoque design which stiffens the skin. Often
called a stringer.

STOP HOLE A hole intentionally drilled at the end of a crack, or saw

cut which normally will prevent further propagation
of the crack.

STRINGER A longitudinal (fore and aft) structural element used in

semimonocoque design which stiffens the skin. Often
called a stiffener.

TEST As used herein, the checking or operation of equipment

to determine that the unit functions properly within the
limits set forth in this manual.

TOLERANCE The difference between two limiting sizes as a

means of specifying the degree of accuracy.

TOXIC A poisonous substance.

TWIST The damage of a structural element by turning or torque

forces causing permanent deformation.

VISCOSITY The property of a fluid that tends to resist the force

trying to make it flow such as gravity or applied
pressure.

WARPAGE The bending or twisting damage causing a structural

element to weaken and permanently loose its original
shape.

WEB The sheet metal membrain connecting the upper and lower
flanges of a beam or spar. Provides overall rigidity to
the airframe structure.

WHIP The tendency of a bent shaft to rotate away from its

original center as the shaft RPM is increased, thus
causing severe vibration.

GLOS-8
 TM 55-1520-244-BD

INDEX

Subject Paragraph

Aft Fuel Cell Isolation. . . . . . . . . . . . . . . . . . . . . . . . 12-7

Air Data Subsystem, General. . . . . . . . . . . . . . . . . . . . . . 16-8
Airframe Assessment Procedures . . . . .. . . . . . . . . . . . . . . 4-2
Airframe Repair Procedure Index. . . . . . . . . . . . . . . . . . . . 4-3
Airframe Repairs, General . . . . . . . . . . . . . . . . . . . . . . 4-4
Alighting Gear Assessment Procedures . . . . . . . . . . . . . . . . . 5-2
Alighting Gear Repair Procedure Index. . . . . . . . . . . . . . . . . 5-3
Antenna Substitution . . . . . . . . . . . . . . . . . . . . . . . . . 11-18
Antennas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7

Battery Bus Bar Repair . . . . . . . . . . . . . . . . . . . . . . . . 11-15

BDAR Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Bleed Air Line Holes . . . . . . . . . . . . . . . . . . . . . . . . . 15-7
Bus Bar Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-14

Cap/Longeron, Damage . . . . . . . . . .. . . . . . . . . . . . . . . 4-7

Circuit Breaker Repair . . . . . . . . . . . . . . . . . . . . . . . . 11-12
Coax Splicing Using Wiring Repair Kit. . . . . . . . . . . . . . . . . 11-9
Component Bridging and Splicing. . . . . . . . . . . . . . . . . . . . 11-10
Connector Pin Damage . . . . . . . . . .. . . . . . . . . . . . . . . 11-11
Control Tubes Bent or Severed. . . . . . . . . . . . . . . . . . . . . 13-4

Damaged Circuit Breaker Repair . . . . . . . . . . . . . . . . . . . . 11-12

Damaged Connector Pins . . . . . . . . . . . . . . . . . . . . . . . . 11-11
Damaged Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-13
Damaged Pneumatic Lines. . . . . . . . . . . . . . . . . . . . . . . . 16-9
Damaged Wire Insulation. . . . . . . . . . . . . . . . . . . . . . . . 11-20
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Defroster System . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6
Dents or Bailistic Damage to Shafts. . . . . . . . . . . . . . . . . . 8-12
Driveshafts, Dents, or Ballistic Damage . . . . . . . . . . . . . . . 8-12
Drive Train Assessment Procedures . . . . . . . . . . . . . . . . . . 8-2
Drive Train Repair Procedure Index . . . . . . . . . . . . . . . . . . 8-3
Ducting Torn or Perforated . . . . . . . . . . . . . . . . . . . . . . 15-6

INDEX 1
TM 55-1520-244-BD

INDEX (Cont)

Subject Paragraph

Electrical Component Bridging and Splicing . . . . . . . . . . . . . . 11-10

Electrical/Avionics Assessment Procedures. . . . . . . . . . . . . . . 11-2
Electrical/Avionics Repair Procedure Index . . . . . . . . . . . . . . 11-3
Electrical Wire Insulation, General. . . . . . . . . . . . . . . . . . 11-19
Environmental Control System Assessment Procedures . . . . . . . . . . 15-2
Environmental Control Svstem Repair Procedures Index . . . . . . . . . 15-3
Environmental Control Unit, General. . . . . . . . . . . . . . . . . . 15-4
Environmental Control Unit (ECU) Surface Damaged . . . . . . . . . . . 15-5
External Fuel Filter Clogged . . . . . . . . . . . . . . . . . . . . . 12-10

Fire Detection System . . . . . . . . . . . . 14-4

Flight Controls System Assessment Procedures . . . . . . . . . . . . 13-2
Flight Controls System Repair Procedure Index. . . . . . . . . . . . . 13-3
Former Damage, Airframe. . . . . . . ... . . . . . . . . . . . . . . 4-5
Forward Fuel Cell Isolation. . . . . ... . . . . . . . . . . . . . . 12-8
Frame or Bulkhead Damage, Airframe . ... . . . . . . . . . . . . . . 4-8
Fuel Boost Pumps, General. . . . . . ... . . . . . . . . . . . . . . 12-9
Fuel Cell Isolation, Aft . . . . . . ... . . . . . . . . . . . . . . 12-7
Fuel Cell Isolation, Forward . . . . ... . . . . . . . . . . . . . . 12-8
Fuel Cell Patching . . . . . . . . . ... . . . . . . . . . . . . . . 12-6
Fuel Filter Bypass, General. . . . . ... . . . . . . . . . . . . . . 12-11
Fuel Filter Clogged. . . . . . . . . ... . . . . . . . . . . . . . . 6-6
Fuel Filters, External Fuel Filter Clogged . . . . . . . . . . . . . . 12-10
Fuel System Assessment Procedures. . . . . . . . . . . . . . . . . . . 12-2
Fuel System Repair Procedure Index . . . . . . . . . . . . . . . . . . 12-3
Fuse Damage . . . . ... . . . . . . . . . . . . . . . . . . . . . . 11-13

Gearbox Damage . . . ... . . . . . . . . . . . . . . . . . . . . . . 8-10

Holes in Bleed Air Lines . .. . ... . . . . . . . . . . . . . . . . . . 15-7

Honeycomb Core Floor/Panel Damage. . . . . . . . . . . . . . . . . . . 4-9
Hoses, General . . . . ..... . ... . . . . . . . . . . . . . . . . . . 9-4
Hoses, Leaking ... . . ..... . ... . . . . . . . . . . . . . . . . . . 9-5
Housing Cracks-Fuel Control and Accessory Gearbox. . . . . . . . . . . 6-7
Hydraulic Components . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8
Hydraulic Fluid Substitutions, General . . . . . . . . . . . . . . . . 9-15
Hydraulic Hose Damage. . . . . . . . . . . . . . . . . . . . . . . . . 16-7
Hydraulic System Assessment Procedures . . . . . . . . . . . . . . . . 9-2
Hydraulic System Repair Procedure Index. . . . . . . . . . . . . . . . 9-3
Hydraulic System Isolation . . . . . . . . . . . . . . . . . . . . . . 9-10
Hydraulics, General. . . . . . . . . . . . . . . . . . . . . . . . . . 16-6

INDEX-2
 TM 55-1520-244-BD

INDEX (Cont)

Subject Paragraph

Instrument System Assessment Procedures. . . . . . . . . . . . . . . . 10-2

Instrument System Repair Procedure Index . . . . . . . . . . . . . . . 10-3
Instruments, General . . . . . . . . . . . . . . . . . . . . . . . . . 10-4

Jump Start Engine . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

Lateral Vibrations. . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

Leaking Hoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
Leaking Metal Tubing. . . . . . . . . . . . . . . . . . . . . . . . . 9-7
Lines and Hoses, General . . . . . . . . . . . . . . . . . . . . . . . 12-4
Lock-Out Valve Stuck in Closed Position. . . . . . . . . . . . . . . . 9-9
Low Oil Pressure Indicator/Transmitter, Defective. . . . . . . . . . . 6-5

Main Rotor Blade Damage, Hole Larger Than 1 Inch; 1-1/2 Inches
Wide X 4 Inches Lon Max . . . . . . . . . . . . . . . . . . . . . . 7-5
Main Rotor Blade, Hole 1 Inch or Less, Through Both Skins. . . . . . . 7-4
Metal Tube and Hose Leaks . . . . . . . . . . . . . . . . . . . . . . 12-5
Metal Tubing, General. . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Mission Equipment Assessment Procedures. . . . . . . . . . . . . ... 16-2
Mission Equipment Repair Procedure Index . . . . . . . . . . .... . . 16-3

No. 1 Hydraulic System Pump Inoperative . . . . . . . . . . . . . . . . . 9-11

No. 2 Hydraulic System Pump Inoperative . . . . . . . . . . . . . . 9-12

Oil Fi lter (External Assembly Area Leak) . . . . . . . . . ... ........ ... 8-7
Oil Pressure Low, Defective Indicator/Transmitter. . . . . . . . . . . 6-5
Oil Pressure Switch Leak. . . . . . . . . . . . . . . . . . . . . . . 8-5
Oil Pressure Transmitter Leak. . . . . . . . . . . . . . . . . . . . . 8-6
Oil Tank, Punctured . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Operating Characteristics. . . . . . . . . . . . . . . . . . . . . . . 1-8
O-Ring, Packing, and Gaskets, General. . . . . . . . . . . . . . . . . 9-12

INDEX 3
TM 55-1520-244-BD

INDEX (Cont)

Subject Paragraph

Packings, Replacement ......... . . . . . . . . . . . . . . . . . . 9-13

Poser Bus Bar Repair . . . . . . . . .. . . . . . . . . . . . . . . . 11-14
Power Plant Assessment Procedures. . . . . . . . . . . . . . . . . . . 6-2
Power Plant Repair Procedure Index . . . . . . . . . . . . . . . . . . 6-3
Power Relay Test and Repair. . . . . . . . . . . . . . . . . . . . . . 11-16
Pump (Hyd)-Inoperative, - No. 1 System . . . . . . . . . . . . . . . . . 9-11
Pump (Hyd) Inoperative, No. 2 System . . . . . . . . . . . . . . . . . 9-12
Pump, Fuel Boost . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9

Quality Deficiency Report/Equipment Improvement Recommendation

(QDR/EIR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Rain Removal System . . . . . . . . . . . . . . . . . . . . . . . . . 14-5

Repair Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Replacement of Packings. . . . . . . . . . . . . . . . . . . . . . . . 9-14
Reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Rotors Assessment Procedures . . . . . . . . . . . . . . . . . . . . . 7-2
Rotors Repair Procedures Index . . . . . . . . . . . . . . . . . . . . 7-3

Severed or Bent Control Tubes. . . . . . . . . . . . . . . . . . . . . 13-4

Shield Terminators . . . . . . . . . . .. . . . . . . . . . . . . . . 11-8
Shielded Cable Repair Segments . . . . . . . . . . . . . , . . . . . . 11-7
Skid Shoe Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Skid Tube Damage . . . . . . . . . . . . . . . . . . . . , . . . . . . 5-4
Skin/Stiffener Damage. . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Splicing Shielded Cable. . . . . . . . . . . . . . . . . . . . . . . . 11-6
Splicing Unshielded Wires. . . . . . . . . . . . . . . . . . . . . . . 11-5
Substitute Emergency Antenna . . . . . . . . . . . . . . . . . . . . . 11-18
Sump Outlet Hose Leak. . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Surface or ECU Damaged . . . . . . . . . . . . . . . . . . . . . . . . 15-5

Tagging/Identifying BDAR Repairs . . . . . . . . . . . . . . . . . . . 1-10

Tail Rotor Blade Damage. . . . . . . . . . . . . . . . . . . . . . . . 7-8
Tail Rotor Driveshaft, General . . . . . . . . . . . . . . . . . . . . 8-11
Training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Transmission Ballistic Damage. . . . . . . . . . . . . . . . . . . . . 8-9
Transmission, General. . . . . . . . . . . . . . . . . . . . . . . . . 8-4
Tubing and Hose Leaks. . . . . . . . . . . . . . . . . . . . . . . . . 12-5
Tubing, Leaking. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7

INDEX 4
 TM 55-1520-244-BD

INDEX (Cont)

Subject Paragraph

Utility Systems Assessment Procedures. . . . . . . . . . . . . . . . . 14-2

Utility Systems Repair Procedure Index . . . . . . . . . . . . . . . . 14-3

Waiver of Precautions. . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Windshield/Window, Damage. . . . . . . . . . . . . . . . . . . . . . . 4-10
Wire and Cable Splicing, General . . . . . . . . . . . . . . . . . . . 11-4
Wire Damage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-4
Wire Insulation Repair . . . . . . . . . . . . . . . . . . . . . . . . 11-19
Wiring, General. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-4

XYZ

INDEX 5/(INDEX 6 Blank)

 TM 55-1520-244-BD

By Order of the Secretary of the Army:

CARLE.VUONO
General, United States Army
Official: Chief of Staff

THOMAS F. SIKORA
Brigadier General, United States Army
The Adjutant General

DISTRIBUTION :
To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance
requirements for AH-lP/E/F Helicopter, Attack.

U.S. GOVERNMENT PRINTING OFFICE: 1991 554-122/21092

PIN: 064982-000
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