RECOMMENDED
SERVICE BULLETIN
Beech
TITLE: ENGINE - REPLACEMENT OF REAR GOVERNOR HEATED AIR PRESSURE TUBE (PY)
ASSEMBLY
1. Planning Information
A. Effectivity
(1) Airplanes with engine Model Numbers, PT6A-21, PT6A-27, PT6A-28, PT6A-34 PT6A-135, and
PT6A-135A installed and Serial Numbers listed in Pratt & Whitney Canada Service Bulletin No.1595
(attached).
(a) Civil
Beech Model C90 King Air, Serials LJ-585, LJ-590, LJ-592, LJ-593, LJ-601, LJ-604, LJ-612, LJ-
619, LJ-620, LJ-622, LJ-652 when modified per Beech Kit Drawing 90-9066).
Beech Model C90 King Air, Serials LJ-668, LJ-669, and LJ-671 through LJ-1062;
Beech Model C90A King Air, Serials LJ-1063 through LJ-1546;
Beech Model E90 King Air, Serials LW-1 through LW-347;
Beech Model F90 King Air, Serials LA-2 through LA-236;
Beech Model 99, 99A, A99, A99A Airliner, Serials U-1 through U-49, U-51 through U-145 and U-
147 with PT6A-27/-28 engines;
Beech Model B99 Airliner, Serials U-146, U-148 through U-164;
Beech Model C99 Airliner, Serials U-50, U-165 through U-203;
Beech Model 100 King Air, Serials B-2 through B-89, and B-93;
Beech Model A100 King Air, Serials B-1, B-90 through B-92, B-94, B-100 through B-161.
(b) Military
Beech Model 65-A90-2 (RU-21B), Serials LS-1 through LS-3;
Beech Model 65-A90-3 (RU-21C), Serials LT-1 and LT-2;
Exported under the authority of license exception: TSU. "These commodities, technology or (a) RAC Authorized Service Centers.
software were exported from the United States in accordance with Export Administration (b) Owners of record on the FAA Aircraft Registration Branch List and the RAC
Regulations. Diversion contrary to U.S. law prohibited."
International Owner Notification/Registration Service List.
Raytheon Aircraft Company (RAC) issues Service Information for the benefit of owners and (c) Those having a publications subscription.
fixed base operators in the form of two classes of Service Bulletins. The first class, Mandatory Information on Owner Notification Service or subscription can be obtained through any RAC
Service Bulletins (red border) includes changes, inspections and modifications that could Authorized Service Center. As Mandatory Service Bulletins and Service Bulletins are issued,
affect safety or crashworthiness. RAC also issues Service Bulletins with no red border which temporary notification in the Service Bulletin Master Index should be made until the index is
are designated as either recommended or optional in the compliance section within the revised. Warranty will be allowed only when specifically defined in the Service Bulletin and in
bulletin. In the case of recommended Service Bulletins, RAC feels the changes, accordance with the RAC Warranty Policy.
modifications, improvements or inspections will benefit the owner/operator and although
highly recommended, Recommended Service Bulletins are not considered mandatory at the Unless otherwise designated, RAC Mandatory Service Bulletins, Service Bulletins and RAC
time of issuance. In the case of Optional Service Bulletins, compliance with the changes, Kits are approved for installation on RAC airplanes in original or RAC modified configurations
modifications, improvements or inspections is at the owner/operator’s discretion. Both only. RAC Mandatory Service Bulletins, Service Bulletins and Kits may not be compatible with
classes are mailed to: airplanes modified by STC installations or modifications other than RAC approved kits.
Issued: April, 2001
SB 72-3461
1 of 5
RECOMMENDED
SERVICE BULLETIN
Beech Model A100 (U-21F), Serials B-95 through B-99.
If you are no longer in possession of the airplane, please forward this information to the present
owner.
(2) Spares
None.
B. Reason
This Service Bulletin is being issued to announce Pratt and Whitnery Canada (P&WC) Service Bulletin No.
1595 (Replacement of Engine Rear Governor Heated Air Pressure Tube PY Assembly), and Service
Information Letter No. PT6A-092 regarding the proper handling and installation of engine P3 and PY
pneumatic lines.
C. Description
This Service Bulletin contains the information from P&WC needed to replace the engine rear governor
heated air pressure (PY) tube providing more clearance. It also provides instructions regarding the
handling and installation practices regarding P3 and PY engine pneumatic lines.
D. Compliance
(1) Civil Airplanes
Raytheon Aircraft Company recommends that this Service Bulletin be accomplished at the next
scheduled inspection.
(2) Military Airplanes
For compliance information on military airplanes affected by this Service Bulletin, contact the
appropriate headquarters.
E. Approval
The engineering data contained in this Service Bulletin is FAA approved.
F. Manpower
The following information is for planning purposes only:
Estimated man-hours: 2 hours.
Suggested number of men: 1 man.
The above is an estimate based on experienced, properly equipped personnel complying with this Service
Bulletin. Occasionally, after work has started, conditions may be found which could result in additional
man-hours.
G. Weight and Balance
None.
Issued: April, 2001 SB 72-3461
2 of 5
RECOMMENDED
SERVICE BULLETIN
H. Electrical Load Data
Not changed.
I. Software Accomplishment Summary
Not applicable.
J. References
Chapter 71-10 of the applicable maintenance manual;
Pratt and Whitney Canada Service Bulletin No. 1595 (attached);
Pratt and Whitney Canada Service Information Letter No. PT6A-092 (attached).
K. Publications Affected
Chapter 71-00 of the applicable P&WC maintenance manual;
Chapter 71-10 of the applicable maintenance manual.
L. Interchangeability of Parts
Not applicable.
M. Warranty Credit
None.
2. Material Information
A. Materials - Price and Availability
Contact a Raytheon Aircraft Authorized Service Center for information.
B. Industry Support
Not applicable.
C. Airplanes
The following parts required for this modification may be ordered through a Raytheon Aircraft Authorized
Service Center or RAPID:
Quantity Per
Part Number Description
Airplane
3045999-01 PY Heated Air Pressure Tube (P&WC) 2
D. Spares
Not applicable.
Issued: April, 2001 SB 72-3461
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RECOMMENDED
SERVICE BULLETIN
E. Reidentified Parts
None.
F. Tooling - Price and Availability
Not applicable.
3. Accomplishment Instructions
This Service Bulletin shall be accomplished as follows:
NOTE
Should any difficulty be encountered in accomplishing this Service Bulletin,
contact Raytheon Aircraft Company at 1-800-429-5372 or 316-676-3140 for
commercial aircraft, and appropriate headquarters for military aircraft.
A. Airplane
Observe all Warnings and Cautions contained in the aircraft manuals
referred to in this Service Bulletin.
Whenever any part of this system is dismantled, adjusted, repaired or
renewed, detailed investigation must be made on completion to make sure
that distortion, tools, rags or any other loose articles or foreign matter that
could impede the free movement and safe operation of the system are not
present, and that the systems and installations in the work area are clean.
(1) Check airplane records to determine if the engine serial numbers are on the effectivity list of P&WC
Service Bulletin No. 1595. If engine serials are within the effectivity, proceed with Step 3.A.(2). If the
airplanes (engines) are not affected, return to service.
(2) Perform an acceleration check (both engines) per the applicable PT6A maintenance manual,
Chapter 71-00, prior to accomplishing P&WC Service Bulletin No. 1595.
(3) Remove all power from the airplane and disconnect the battery. Display warning notices prohibiting
reconnection of airplane electrical power.
(4) Remove the engine upper cowl, access doors/panels per Chapter 71-10 of the applicable
maintenance manual to gain access to the PY rear governor heated air pressure tube assembly.
(5) Accomplish Pratt and Whitney Canada Service Bulletin No. 1595 (attached). During the
accomplishment of the Service Bulletin pay particular attention to the installation of the PY tube per
instructions of Service Information Letter No. PT6A-092 (attached).
(6) Install the engine upper cowling, access doors/panels that were removed per Chapter 71-10 of the
applicable maintenance manual.
(7) Reconnect the airplane battery, remove warning notices and restore power.
Issued: April, 2001 SB 72-3461
4 of 5
RECOMMENDED
SERVICE BULLETIN
(8) Ensure all work areas are clean and clear of tools and miscellaneous items of equipment.
(9) Perform an acceleration check (both engines) per the applicable PT6A maintenance manual, after
accomplishing P&WC Service Bulletin No. 1595. Compare the data gathered from both checks to
determine if there are any leaks in the PY system. Make any repairs if necessary.
(10) Place copy of Service Information Letter No. PT6A-092 in Chapter 71-00 of the applicable
maintenance manual and Chapter 73-10 of the applicable PT6A Technical Manual.
(11) Return airplane to service.
B. Spares
Not applicable.
C. Record of Compliance
Upon completion of this Service Bulletin, make an appropriate maintenance record entry.
Issued: April, 2001 SB 72-3461
5 of 5
PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 1595
BULLETIN INDEX LOCATOR
73-10-00
TURBOPROP ENGINE
REAR-GOVERNOR HEATED-AIR-PRESSURE TUBE ASSEMBLY - REPLACEMENT OF
MODEL APPLICATION
PT6A-21, PT6A-27, PT6A-28, PT6A-34, PT6A-34AG, PT6A-36, PT6A-114, PT6A-114A, PT6A-135,
PT6A-135A, and PT6D-114A
Compliance: CATEGORY 6, 8
Summary: The rear governor heated air pressure tube (PY) can touch the fuel control unit and
the P2.5 air bleed adapter because the tube profile does not provide sufficient
clearance for other components. Introduce a new heated air pressure tube with an
additional bend to provide more clearance with engine components.
Aug 21/2000 PT6A-72-1595
Cover Sheet
24-Hour Global Service USA & CANADA........................ 1-800-268-8000 Other .......................................... 1-450-647-8000
HELP DESK International .................... (IAC*)+8000-268-8000 Fax ............................................. 1-450-647-2888
Toll free where available (SIL GEN-027) * International Access Code Web Site .................................. www.pwc.ca
PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 1595
TURBOPROP ENGINE
REAR-GOVERNOR HEATED-AIR-PRESSURE TUBE ASSEMBLY - REPLACEMENT OF
1. Planning Information
A. Effectivity
PT6A-21 Engines which are before and include Serial No. PCE-PE0208.
PT6A-27 Engines which are before and include Serial No. PCE-PG 0067 and Serial No.
PCE-40001 thru PCE-42771, PCE-47001 thru PCE-47015 and all engines converted
to Engine Model PT6A-27 (Ref. P&WC engine conversion SB1214).
PT6A-28 Engines which are before and include Serial No. PCE-52696 and all engines
converted to Engine Model PT6A-28 (Ref. P&WC engine conversion SB1120).
PT6A-34 Engines which are before and include Serial No. PCE-RB0035 and Serial No.
PCE-57001 thru PCE-57521 and all engines converted to Engine Model PT6A-34
(Ref. P&WC engine conversion SB1499).
PT6A-34AG Engines which are before and include Serial No. PCE-PH0164 and Serial
No. PCE-57001 thru PCE-57528 and all engines converted to Engine Model
PT6A-34AG (Ref. P&WC engine conversion SB1252).
PT6A-36 Engines which are before and include Serial No. PCE-38215 and all engines
converted to Engine Model PT6A-36 (Ref. P&WC engine conversion SB1405).
PT6A-114 Engines which are before and include Serial No. PCE-PB0527 and Serial No.
PCE-17001 thru PCE-17497.
PT6A-114A Engines which are before and include Serial No. PCE-PC0654 and Serial
No. PCE-19101 thru PCE-19423 and all engines converted to Engine Model
PT6A-114A (Ref. P&WC engine conversion SB1453).
PT6A-135 Engines which are before and include Serial No. PCE-RE0002 and Serial No.
PCE-92001 thru PCE-92772.
PT6A-135A Engines which are before and include Serial No. PCE-PZ0023 and Serial
No. PCE-92001 thru PCE-92772.
PT6D-114A Engines which are before and include Serial No. PCE-RJ0001
B. Concurrent Requirements
None.
C. Reason
(1) Problem
The rear governor heated air pressure tube can touch the fuel control unit and the
P2.5 air bleed adapter.
(2) Cause
The clearance between the air tubes and the fuel control unit is minimal.
(3) Solution
Introduce a new heated air pressure tube which provides more clearance.
P&WC No. B6936B
Aug 21/2000 PT6A-72-1595
© 2000 Pratt & Whitney Canada Corp. Page 1 of 4
PRINTED IN CANADA
PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 1595
TURBOPROP ENGINE
REAR-GOVERNOR HEATED-AIR-PRESSURE TUBE ASSEMBLY - REPLACEMENT OF
1. Planning Information (Cont’d)
D. Description
Replace the air pressure tube with a new one
E. Compliance
For PT6A-21 Engines:
CATEGORY 6 - P&WC recommend to do this service bulletin when the subassembly
(i.e. module, accessories, components, or build groups) is disassembled
and access is available to the necessary part. Do all spare
subassemblies.
For PT6A-27, PT6A-28, PT6A-34, PT6A-34AG, PT6A-36, PT6A-114, PT6A-114A,
PT6A-135, PT6A-135A, and PT6D-114A Engines:
CATEGORY 8 - This service bulletin is optional and can be done at the decision of the
operator.
F. Approval
D.O.T./D.A.A. approved.
G. Weight and Balance
None.
H. Electrical Load Data
Not changed.
I. Software Accomplishment Summary
Not applicable.
J. References
Applicable PT6A Technical Manuals
K. Publications Affected
Applicable PT6A Technical Manuals
L. Interchangeability and Intermixability of Parts
Interchangeability - Refer to Para. 2.D.
Aug 21/2000 PT6A-72-1595
Page 2 of 4
PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 1595
TURBOPROP ENGINE
REAR-GOVERNOR HEATED-AIR-PRESSURE TUBE ASSEMBLY - REPLACEMENT OF
1. Planning Information (Cont’d)
Intermixability - Not changed.
2. Material Information
A. Industry Support Information
Not applicable.
B. Material - Cost and Availability
You can get the procurable parts listed in Para. 2.D. from any Pratt & Whitney Canada
Parts Distribution Center.
The estimated total cost of new parts needed to replace old parts is $3,159.00 (US,
2000).
C. Manpower
No more man-hours are necessary to include this service bulletin at overhaul.
D. Material Necessary for Each Engine
The quantity of materials listed in this section is on a per engine basis.
Est. Unit
List Price
($US, Instructions
New P/N Keyword Old P/N Qty 2000) Disposition
3045999-01 Tube Assembly, Heated Air 3027974 1 3,159.00 (A)(B)
Pressure Governor, Rear
(A) TWO WAY INTERCHANGEABLE - (ATA 200 Explanation Code 02):
The old or the new part can replace the old or the new part.
(B) Discard the old part if it is unserviceable.
E. Reidentified Parts
None.
F. Tooling - Price and Availability
Not applicable.
3. Accomplishment Instructions
A. Remove the parts listed under Old P/N in Para. 2.D., Material Information, per the
applicable maintenance or overhaul manual instructions.
Aug 21/2000 PT6A-72-1595
Page 3 of 4
PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 1595
TURBOPROP ENGINE
REAR-GOVERNOR HEATED-AIR-PRESSURE TUBE ASSEMBLY - REPLACEMENT OF
3. Accomplishment Instructions (Cont’d)
B. Install the parts listed under New P/N in Para. 2.D., Material Information, per the
applicable maintenance or overhaul manual instructions.
C. Write accomplishment of P&WC S.B. No. 1595 in the applicable engine module log
book.
4. Appendix
Not applicable.
Aug 21/2000 PT6A-72-1595
Page 4 of 4
