ALERT SERVICE BULLETIN 429-23-60
PSL #1511
28 August 2023
MODEL AFFECTED: 429
SUBJECT: TAIL ROTOR SHAFT ASSEMBLY 429-044-201-107,
INSPECTION OF AND INTRODUCTION OF
AIRWORTHINESS LIMITATION SCHEDULE.
HELICOPTERS AFFECTED: Serial numbers 57001 through 57447, 57449,
57450, 57452 through 57460, and 57462 through
57464.
[Serial numbers 57448, 57451, 57461, 57465 and
subsequent will have the intent of this bulletin
accomplished prior to delivery.]
COMPLIANCE: PART I - At next scheduled periodic inspection.
PART II – Prior to, or upon reaching, 10,000 flight
hours component Total Time In Service (TTIS) of the
fan shaft assembly 429-044-201-109.
DESCRIPTION:
Bell has been informed that certain tail rotor shaft assemblies 429-044-201-107 may
have been improperly manufactured with Monel rivets instead of the required Corrosion
Resistant Steel (CRES) rivets. This Alert Service Bulletin (ASB) will require a one-time
inspection of the shaft assembly to determine the type of rivets installed. If any of the
rivets are Monel, the shaft assembly will be re-identified as a 429-044-201-109
assembly and assigned an Airworthiness Limitation Schedule (ALS) retirement life of
10,000 flight hours which will be added to the Chapter 4 (Table 1) of the 429-MPI
Maintenance Planning Information. Electronic versions of the Chapter 4 will be made
available on the www.bellcustomer.com and www.mybell.com websites.
Tail rotor shaft assemblies 429-044-201-107 with all CRES rivets can remain in service
with no ALS retirement life assigned.
Applicability of this bulletin to any spare part shall be determined prior to its installation
on an affected helicopter.
ASB 429-23-60
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APPROVAL:
The engineering design aspects of this bulletin are Transport Canada Civil Aviation
(TCCA) approved.
CONTACT INFO:
For any questions regarding this bulletin, please contact:
Bell Product Support Engineering
Tel: 1-450-437-2862 / 1-800-363-8023 / productsupport@bellflight.com
MANPOWER:
Approximately 1.5 man-hour is required to complete PART I of this bulletin.
Approximately 4.0 man-hours are required to complete PART II of this bulletin.
This estimate is based on hands-on time and may vary with personnel and facilities
available.
WARRANTY:
Owners / Operators of Bell Helicopters who comply with the instructions in this bulletin
will be eligible to receive replacement part and labor as applicable, listed in the bulletin.
The www.mybell.com portal allocates specific warranty entitlement for an aircraft by
serial number. The Product Service Letter (PSL) number which will be listed below the
bulletin number on the introduction page. This is going to be a required field when
submitting a claim on the Bulletins Tab for replacement parts, labor, and/or freight. If
you receive an ASB or TB that does not have a PSL number, then there is no warranty
entitlement for that bulletin.
Labor entitlement: Yes
PART I $142.50
PART II $380.00
To receive parts, labor, under warranty:
• If there is a PSL number identified in the bulletin you will be
required to enter this PSL number which will validate warranty
entitlement for the selected aircraft. Please ensure that you use
the Bulletin tab on the warranty section on www.mybell.com
portal to file your claim.
• Claims must be submitted no later than 28 August 2024.
NOTE: A user guide on how to submit a claim can be found here:
How to Submit PSL Bulletin Claims.
ASB 429-23-60
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MATERIAL:
Required Material:
The following material is required for the accomplishment of this bulletin and may be
obtained through your Bell Supply Center.
Part Number Nomenclature Qty (Note)
429-044-200-107S TAIL ROTOR SHAFT 1 (1,2,3,4)
ASSEMBLY
NOTES:
1. Only required if inspection of the tail rotor shaft assembly identifies that Monel
rivets are installed.
2. A one-time policy pricing of the 429-044-200-101S tail rotor shaft assembly will
be provided to owners/operators requiring to accomplish PART II, after Product
Support Engineering (PSE) has received the requested information in step 8 of
PART I.
3. The tail rotor shaft assembly 429-044-200-107S will include the 429-044-201-
107 shaft assembly (1, Figure 2, sheet 2 of 2), two impellers 206-061-432-127
(2), nuts (3), bolts (4), and washers (5 and 6) and will be dynamically balanced.
4. This tail rotor shaft assembly will be an “on-condition” component/part and not
have an Airworthiness Limitation Schedule (ALS) retirement life assigned to it.
Consumable Material:
The following material is required to accomplish this bulletin, but may not require
ordering, depending on the operator’s consumable material stock levels. This material
may be obtained through your Bell Supply Center.
Part Number Nomenclature Qty (Note) Reference *
2100-09016-02 CORROSION PREVENTIVE 1 PT (1) C-104
COMPOUND (GRADE 2)
2000-00697-00 Devcon 2-Ton (Clear Coat) 1 OZ (1) C-298
2110-00010-00 ALIPHATIC NAPHTA 1 GAL (1) C-305
2100-06673-00 ISOPROPYL ALCOHOL 1 GAL (1) C-385
1650-03297-00 SAFETY WIRE (0.032”) ROLL 1 LB (1) C-405
COMMERCIAL CHEESECLOTH AR (2) C-486
2010-05970-00 SEALANT 1 PT (1) C-559
* C-XXX numbers refer to the consumables list in the BHT-ALL-SPM, Standard Practices Manual
ASB 429-23-60
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NOTES:
1. Quantity indicated is the format that the product is delivered in. Actual quantity
required to accomplish the instructions in this bulletin may be less than what has
been delivered.
2. AR represents a quantity of “as required” dependent on amount required for the
accomplishment of the procedures of this bulletin.
SPECIAL TOOLS:
Part Number Nomenclature Qty (Note) Reference
429-244-001-101 Wrench 1
429-244-002-101 Holding Plate 1
OCT No. 1025 (or equivalent) Bearing Puller 1 (1)
Item No. 1 Workaid No. 1 1(2) Figure 5
Item No. 4 Workaid No. 4 1(2) Figure 5
NOTES:
1. Commercially available at OTC Service Solutions, 28635 Mound Road, Warren,
MI 48092 USA (www.otctools.com).
2. Manufacture locally. Refer to Figure 5 for details of dimensions required.
WEIGHT AND BALANCE:
Not affected.
ELECTRICAL LOAD DATA:
Not affected.
REFERENCES:
429-MPI Maintenance Planning Information, Chapter 4 and 5.
429-MM Maintenance Manual, Chapters 53, 71, and 79.
PUBLICATIONS AFFECTED:
429-MPI Maintenance Planning Information, Chapter 4.
429-MM Maintenance Manual, Chapter 65.
429-IPB Illustrated Parts Breakdown, Chapter 65.
ASB 429-23-60
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ACCOMPLISHMENT INSTRUCTIONS:
PART I – Tail rotor shaft assembly 429-044-201-107 one-time inspection.
1. Prepare the helicopter for maintenance.
2. Remove the following panels on the left and right sides to access the shaft assembly:
a. Aft engine cowl assemblies (700CL and 700CR) (DMC-429-A-53-00-00-49A-
520A-A).
b. Forward exhaust fairings (700GL and 700GR) (DMC-429-A-53-00-00-51A-520A-
A).
-NOTE-
The part number and serial number of the fan shaft assembly
will be vibro-etched on the flange of the forward adapter
(Figure 1).
3. Verify part number of the tail rotor shaft assembly.
a. If the part number is 429-044-201-105 go to step 9.
b. If the part number is 429-044-201-107 go to step 4.
-NOTE-
If required to allow improved inspection of the tail rotor shaft
assembly rivets, use cheesecloth (C-486), or equivalent,
wetted with aliphatic naphtha (C-305) or isopropyl alcohol (C-
385) to clean the areas to be inspected. The use of a bright
light and magnifying glass may also be required in
identification of the rivet type.
4. Inspect rivet head markings of all rivets (8, Figure 2) used to attach the forward and
aft adapters (7) to the tube (1) of the shaft assembly.
a. If any rivet has an “M”, for Monel (Figure 3), stamped on the rivet head go to step
5.
b. If all rivets have a “C”, for CRES, stamped on the rivet head go to step 9.
5. Using a fine tipped permanent ink marker strike through the last three digits of the
part number (-107) of the tail rotor shaft assembly and add “-109” as follows:
429-044-201-107 -109
ASB 429-23-60
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6. Seal the areas marked in step 5 with one coat of clear epoxy (C-298) and let cure.
-NOTE-
Blank Historical Service Record (HSR) cards can be
downloaded from the Technical Publications website at
www.mybell.com (RECORD CARDS).
7. Create a Historical Service Record (HSR) card for the 429-044-201-109 tail rotor
shaft assembly, that will become a sub assembly of the 429-044-200-107 fan shaft
assembly, identifying the part number of the shaft assembly, serial number of the
shaft assembly, the date, Total Time In Service (TTIS) of the shaft assembly, the
helicopter serial number on which it is installed, adding an airworthiness limitation
schedule retirement life of 10,000 flight hours, and how many hours left before
requiring removal.
a. Insert the HSR that has been created in the helicopter log books.
8. Send an email to Product Support Engineering (PSE) at
productsupport@bellflight.com with the following information:
(1) In the subject line of the email, include the following information:
(a) The helicopter model.
(b) The helicopter serial number.
(c) The text ASB 429-23-60.
(d) The name of the operator.
(e) The tail rotor shaft assembly serial number.
(f) The Total Time In Service (TTIS) of the tail rotor shaft assembly.
(g) The text AFFECTED.
Example email subject line:
429 (57001) – ASB 429-23-60 - Bell Textron Inc – S/N BH000000 (TTIS 5400
hours) - AFFECTED
9. Install aft engine cowl assemblies (700CL and 700CR) (DMC-429-A-53-00-00-47A-
720A-A).
10. Install forward exhaust fairings (700GL and 700GR) (DMC-429-A-53-00-00-49A-
720A-A).
ASB 429-23-60
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11. Make an entry in the helicopter logbook and historical service records indicating
compliance with PART I of this Alert Service Bulletin.
PART II – Replacement of 429-044-201-109 tail rotor shaft assembly.
-NOTE-
Ensure that a 429-044-200-107S tail rotor shaft assembly and
required tools/workaids are available prior to accomplishment
of the instructions below.
1. Prepare the helicopter for maintenance.
2. Remove fan shaft assembly 429-044-200-107 (DMC-429-A-65-10-00-02A-520A-A).
3. Disassemble fan shaft assembly as follows:
a. Remove the retaining ring (1, Figure 4) and the lockwasher (2) from the nut (3).
b. Remove the retaining ring (35) and the lockwasher (34) from the nut (33).
c. Remove the nuts (3 and 33) from the shaft assembly (17) as follows:
(1) Install the Holding Plate Set (429-244-002-101) on the splined adapter (2,
Figure 5).
(2) Loosen and remove the nut (1) from the shaft assembly (3) with the Wrench
(429-244-001-101).
(3) Loosen and remove the nut (4) from the shaft assembly (3) with the Wrench
(429-244-001-101).
(4) Remove the Holding Plate Set (429-244-002-101) from the splined adapter
(2).
-NOTE-
The splined adapter (4, Figure 4) is installed on helicopters
S/N 57001 through 57080. The splined adapter (36) is
installed on helicopters S/N 57081 and subsequent.
d. Remove the splined adapters (4 or 36, and 32, Figure 4), as applicable, from the
shaft assembly (17).
e. Remove the sealed bearing (6) and forward hanger (8) assembly from the shaft
assembly (17) as follows:
ASB 429-23-60
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(1) Put Workaid (Item No. 1, Figure 5) in position on the end of the shaft assembly
(3).
(2) Pull out and remove the sealed bearing (6) and forward hanger (5) assembly
from the shaft assembly (3) with the Bearing Puller (OTC No. 1025).
f. Repeat the previous step to remove the sealed bearing (30, Figure 4) and aft
hanger (29) assembly from the shaft assembly (17).
g. Remove the forward blower housing (9) from the shaft assembly (17) as follows:
(1) Unscrew and remove the screws (15) and washers (14) from the inlet (13).
(2) Carefully remove the forward blower housing (9) from the shaft assembly (17).
h. Remove the aft blower housing (16) from the shaft assembly (17) as follows:
(1) Unscrew and remove the screws (27) and washers (26) from the inlet (25).
(2) Carefully remove the inlet (25) and aft blower housing (16) from the shaft
assembly (17).
-NOTE-
The following step is optional to remove impellers 206-061-
432-127 from the tail rotor shaft assembly 429-044-201-109,
as replacement impellers will be included with the 429-044-
200-107S tail rotor shaft assembly.
i. Remove impellers (12 and 22) as follows:
(1) Loosen and remove the nuts (19), washers (11 and 18), and bolts (10) from
the forward impeller (12). If removed hardware is serviceable, return to
inventory.
(2) Carefully remove the forward impeller (12) and inlet (13) from the shaft
assembly (17). If removed impeller is serviceable, return to inventory.
(3) Loosen and remove the nuts (24), washers (21 and 23), and bolts (20) from
the aft impeller (22). If removed hardware is serviceable, return to inventory.
(4) Carefully remove the aft impeller (22) from the shaft assembly (17). If removed
impeller is serviceable, return to inventory.
j. Discard tail rotor shaft assembly 429-044-201-109.
ASB 429-23-60
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CAUTION
PROTECT THE FAN SHAFT ASSEMBLY DURING THE
ASSEMBLY PROCESS OR DAMAGE COULD OCCUR.
4. Assemble tail rotor shaft assembly 429-044-200-107 as follows:
-NOTE-
The washers (18) are used to balance the shaft and impellers
assembly.
a. Temporarily remove the forward impeller (12) from the 429-044-200-107S tail
rotor shaft assembly as follows:
(1) On the forward flange of the shaft assembly (17), record the location and
quantity of washers (18) and the orientation of the forward impeller (12) to the
shaft assembly (17).
(2) Loosen and remove the nuts (19), washers (11 and 18), and bolts (10) from
the forward impeller (12).
(3) Carefully remove the forward impeller (12) from the shaft assembly (17).
b. Install the aft blower assembly on the shaft assembly (17, Figure 4) as follows:
(1) Install the aft blower housing (16) in position over the aft impeller (22).
(2) Install the inlet (25) on the aft blower housing (16) with the screws (27) and
washers (26). Tighten the screws.
c. Install the forward blower assembly on the shaft assembly (17) as follows:
(1) Put the inlet (13) in position on the shaft assembly (17).
-NOTE-
Location and quantity of washers (18) must be the same as
recorded in Step 4.a.(1).
(2) Install the nuts (19), washers (11 and 18), and bolts (10). Torque the nuts (19)
50 to 70 inch-pounds (5.65 to 7.9 Nm).
(3) Put the forward blower housing (9) in position over the forward impeller (12).
ASB 429-23-60
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(4) Install the inlet (13) on the forward blower housing (9) with the screws (15)
and washers (14). Tighten the screws.
d. Install the sealed bearing (6) and forward hanger (8) assembly on the shaft
assembly (17) as follows:
CAUTION
DO NOT ALLOW SOLVENTS OR COMPOUNDS TO MAKE
CONTACT WITH PARTS MADE OF ELASTOMERIC
MATERIAL OR DAMAGE WILL OCCUR.
(1) Apply one coat of Corrosion Preventive Compound (C-104) to the inner
diameter of the sealed bearing (6) and bearing mating surface on the shaft
assembly (17).
-NOTE-
Orientation of the sealed bearing (6) and forward hanger (8)
assembly must be such that the hanger flange is pointing aft
(i.e., towards the shaft tube).
(2) Install the sealed bearing (6) and forward hanger (8) assembly on the shaft
assembly (17) with the Workaid (Item No. 4, Figure 5) and an arbor press.
e. Install the sealed bearing (30, Figure 4) and aft hanger (29) assembly on the shaft
assembly (17) as follows:
CAUTION
DO NOT ALLOW SOLVENTS OR COMPOUNDS TO MAKE
CONTACT WITH PARTS MADE OF ELASTOMERIC
MATERIAL OR DAMAGE WILL OCCUR.
(1) Apply one coat of Corrosion Preventive Compound (C-104) to the inner
diameter of the sealed bearing (30) and bearing mating surface on the shaft
assembly (17).
-NOTE-
Orientation of the sealed bearing (30) and aft hanger (29)
assembly must be such that the hanger flange is pointing
forward (i.e., towards the shaft tube).
ASB 429-23-60
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(2) Install the sealed bearing (30) and forward hanger (29) assembly on the shaft
assembly (17) with the Workaid (Item No. 4, Figure 5) and an arbor press.
-NOTE-
The forward splined adapter (4, Figure 4) is installed on
helicopters S/N 57001 through 57080. The forward splined
adapter (36) is installed on helicopters S/N 57081 and
subsequent.
f. Install the forward splined adapter (4 or 36) on the forward end of the shaft
assembly (17).
g. Install the aft splined adapter (32) on the aft end of the shaft assembly (17).
h. Install the nuts (3 and 33) on the shaft assembly (17) as follows:
(1) Apply one coat of Corrosion preventive compound (C-104) to the threads on
both ends of the shaft assembly (17, Figure 4).
(2) Install the Holding Plate Set (429-244-002-101) on the splined adapter (2,
Figure 5).
(3) Install the nut (1) on the shaft assembly (3) with the Wrench (429-244-001-
101). Torque the nut 82 to 98 foot-pounds (112 to 132 Nm).
(4) Install the nut (4) on the shaft assembly (3) with the Wrench (429-244-001-
101). Torque the nut 82 to 98 foot-pounds (112 to 132 Nm).
(5) Remove the Holding Plate Set (429-244-002-101) from the splined adapter
(2).
i. Install the lockwasher (2, Figure 4) on the nut (3). Secure the lockwasher with the
retaining ring (1).
j. Install the lockwasher (34) on the nut (33). Secure the lockwasher with the
retaining ring (35).
5. Install fan shaft assembly 429-044-200-107 to helicopter (DMC-429-A-65-10-00-
02A-720A-A).
6. Make an entry in the helicopter logbook and historical service records indicating
compliance with PART II of this Alert Service Bulletin.
ASB 429-23-60
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Figure 1 – Location of Fan Shaft Assembly Part and Serial Numbers
ASB 429-23-60
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Figure 2 – Fan Shaft Assembly 429-044-200-107 (sheet 1 of 2)
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Figure 2 – Fan Shaft Assembly 429-044-200-107 (sheet 2 of 2)
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Figure 3 – Example of Identification Marking (“M”) on Monel Rivet Head
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Figure 4 – Fan shaft Assembly 429-044-200-107 (sheet 1 of 2)
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Figure 4 – Fan shaft Assembly 429-044-200-107 (sheet 2 of 2)
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Figure 5 – Tools and Workaids Required for Disassembly/Assembly of Fan Shaft
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