# BULLETIN INDEX LOCATOR 

# 49-21-02

AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF MODEL APPLICATION PW901A Compliance: CATEGORY 3 Summary: Modify the rear gas generator case, exhaust duct support, and the turbine exhaust duct flanges and introduce additional flange retaining hardware to prevent potential flange separation in conditions of extreme distress. 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Cover Sheet

24-Hour Global Service USA & CANADA........................ **1-800-268-8000** Other .......................................... **1-450-647-8000** 

### CFIRST CENTRE 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**WARNING - PROPRIETARY RIGHTS & EXPORT CONTROLS NOTICE This bulletin contains proprietary information of Pratt & Whitney Canada Corp. (′′P&WC′′), which P&WC provides in confidence and solely for the purposes of supporting engine certification and providing applicable information regarding the proper use, maintenance, inspection, repair, servicing and parts application of P&WC products and services, as directed therein. Neither this bulletin nor any information in it may be disclosed to others, or used for any other purpose, including, without limitation, to design, create, develop, reproduce, manufacture or derive any design, part, product, material, process, modification, configuration change or repair, or obtain FAA or other government approval to do so. Possession and use of this bulletin is also subject to the restrictions set out in P&WC’s Technical Data Agreement (a copy of which may be obtained by contacting P&WC Technical Publications). The contents of this bulletin may be subject to export control laws. Unauthorized export or re-export of the bulletin, or parts thereof, is prohibited. By accepting and possessing this bulletin, you agree to be bound by the foregoing terms. If a Government agency or department intends to disclose any information, written notice should be given to: VP - Legal Services, Pratt & Whitney Canada Corp., 1000 Marie-Victorin (01BE5), Longueuil, Quebec J4G 1A1.REVISION TRANSMITTAL SHEET AUXILIARY POWER UNIT MODEL PW900

SUBJECT: Pratt & Whitney Canada Service Bulletin No. 3910001-49-A16255, Rev. No. 2, dated Mar 01/2011 (P&WC S.B. No. A16255R2) EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF

Replace your existing copy of this service bulletin with the attached revised bulletin. Destroy the superseded copy.

Please retain this Revision Transmittal Sheet with the revised bulletin.
SUMMARY: This revision is being issued to change the compliance code from 4 to 3 and to update pricing to 2011 catalog pricing.

EFFECT OF REVISION ON PRIOR ACCOMPLISHMENT: None.
NOTE: A black bar in the left margin indicates a change in that line of text or figure.

REVISION HISTORY: Original Issue: Dec 12/2007 Revision No. 1: Sep 12/2008 Revision No. 2: Mar 01/2011 Pratt & Whitney Canada Corp. 1000, Marie-Victorin Longueuil, Québec, Canada J4G 1A1 Tél. 450-677-9411

01 March 2011
P&WC S.B. No. A16255R21. Planning Information A. Effectivity PW901A Engines which are before and include Serial No. PCE-900776. B. Concurrent Requirements None. C. Reason (1) Problem The rear gas generator case, exhaust duct support, and the turbine exhaust duct can separate at their flanges in conditions of extreme distress. (2) Cause The strength of the current flange and attaching bolt design can be improved to prevent flange separation at all distress conditions. (3) Solution Introduce flange retainer segments, a mating spacer ring, and an additional bolt and nut arrangement to strengthen a redefined flange design. The flange redesign makes it necessary to introduce new rear gas generator and exhaust duct insulation blanket segments. D. Description Remove and replace the exhaust duct support, exhaust duct insulation blankets, and the rear gas generator case insulation blankets. E. Compliance CATEGORY 3 - P&WC recommends to do this service bulletin the first time the engine or module is at a maintenance facility than can do the procedures, regardless of the scheduled maintenance action or reason for engine removal prior to June 1, 2015. F. Approval D.O.T./D.A.A. approved. G. Manpower No more man-hours are necessary to include this service bulletin at overhaul. P&WC No. D7219B, D7219G, D7219G/1 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 1 of 12 © 2007 Pratt & Whitney Canada Corp. PRINTED IN CANADA AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF1. Planning Information (Cont’d) H. Weight and Balance The engine weight will increase by 3.05 pounds (1.38 kgs). The effect of weight change on the center of gravity is negligible. I. Electrical Load Data Not changed. J. Software Accomplishment Summary Not applicable. K. References Component Maintenance Manual P/N 3900283 (PW901A) L. Publications Affected Component Maintenance Manual P/N 3900283 (PW901A) Illustrated Parts Catalog P/N 3900282 (PW901A) M. Interchangeability and Intermixability of Parts Interchangeability - Refer to Para. 2.C 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.C. from any Pratt & Whitney Canada Parts Distribution Center. The estimated total cost of new parts needed to replace old parts is $39668.70 (US, 2011). The new parts are available. 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 2 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OFC. Material Necessary for Each APU The quantity of materials listed in this section is on a per APU basis.

New P/N Keyword Old P/N Qty Est. Unit NET Price ($US, 2011) Instructions Disposition **Exhaust Duct Support and Mounting Hardware:** 3902607-01 Support Assy, Exhaust Duct 3910323-01 1 12714.00 (A)(B)

Ê Insert, Flange Jacking 3101309-01 7 (A) ST3287-01 Ê Insert, Flange Jacking 4 44.21 (A) MS9696-08 Bolt, Machine, Dbl Hex ST3860-19 24 10.63 (A) Washer, Flat MS9321-09 24 (A) Spacer, Sleeve 3900940-01 24 (A)(B) 3902643-01 Ring, Spacer Assy 1 5794.20 (A) 3902604-01 Ê Ring, Spacer 1 NP (A) ST3020-010 Ê Pin, Shouldered, Headless 1 43.55 (A) 3902606-01 Retainer Segment 3 4740.00 (A) MS9697-14 Bolt, Mach, Dbl Hex 23 20.16 (A) AS3554-10 Nut, Self-Locking, Dbl Hex 23 60.30 (A) **Insulation Blankets for the Rear Gas Generator Case:** 3902611-01 Blanket Segment, Insulation, Gas Generator, Rear 3911319-01 1 1525.80 (A)
3902612-01 Blanket Segment, Insulation, Gas Generator, Rear 3911076-01 1 892.20 (A)

**Insulation Blankets for the Turbine Exhaust Duct:** 3902613-01 Blanket Segment, Insulation, Exhaust Duct 3910309-01 1 1208.40 (A) 3902614-01 Blanket Segment, Insulation, Exhaust Duct 3910308-01 1 1208.40 (A) 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 3 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OFNew P/N Keyword Old P/N Qty Est. Unit NET Price ($US, 2011) Instructions Disposition (A) RESTRICTED INTERCHANGEABILITY - (ATA 200 Explanation Code 07): All the old parts must be replaced by all the new parts as an assembly. (B) Discard. Do not use again in any application.
D. Reidentified Parts None. E. Tooling - Price and Availability

Tool No. Nomenclature Est. Price ($US,) Delivery PWC30114-61 Wrench PWC64241-3 Alignment Pin 3. Accomplishment Instructions A. Remove the parts listed under Old P/N in Para. 2.C., Material Information, per the applicable component maintenance manual instructions. B. Install the parts listed under New P/N in Para. 2.C., Material Information, per the applicable component maintenance manual instructions except for the differences that follow: NOTE: During the assembly of this new configuration, the turbine exhaust duct is installed on the rear gas generator case before the exhaust duct support. (1) Install the spacer ring assembly P/N 3902643-01 as follows (Ref. Fig. 1): (a) With a (PWC05-018B) blue marking pencil, put an X mark on the spacer ring assembly in line with the offset hole (Ref. View A). (b) Put the spacer ring assembly in an oven at 250 to 300 °F (121-149 °C) for 15 minutes minimum. (c) Install the two (PWC64241-3) alignment pins on the rear gas generator case. (d) Remove the spacer ring assembly from the oven, and install it on the rear gas generator case with the X mark at BDC facing out. (2) Install the turbine exhaust duct as follows: 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 4 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF3. Accomplishment Instructions (Cont’d) (a) Apply (PWC06-011) assembly fluid to the No. 4 bearing rollers inside the rear gas generator case, to load the rollers inward to make sure they will clear the carbon seal when the turbine exhaust duct is installed (Ref. Section D-D). **CAUTION:** LOWER THE TURBINE EXHAUST DUCT CAREFULLY INTO THE REAR GAS GENERATOR CASE TO AVOID DAMAGE TO THE NO. 4 BEARING CARBON SEAL. (b) With the turbine exhaust duct pre-assembled per the applicable component maintenance manual instructions, align the offset hole on the turbine exhaust duct with the offset hole at BDC on the spacer ring assembly P/N 3902643-01, and install the turbine exhaust duct (Ref. Views A and B). (c) Remove the two (PWC64241-3) guide pins from the rear gas generator case. (d) Apply (PWC03-001) engine oil on the threads of the 24 bolts P/N MS9696-08. (e) Install the 24 bolts to attach the turbine exhaust duct and spacer ring assembly P/N 3902643-01 to the rear gas generator case. (f) Torque the 24 bolts in a star pattern 36 to 40 lbf.in. (4.0-4.5 Nm). (3) Install the exhaust duct support P/N 3902607-01 and three retainer segments P/N 3902606-01 as follows: (a) Align the X mark on the exhaust duct support with the shouldered pin on the spacer ring assembly P/N 3902643-01, and install the exhaust duct support (Ref. View E). (b) Apply (PWC03-001) engine oil on the threads of the 23 bolts P/N MS9697-14. (c) Install the three retainer segments on the forward side of the spacer ring assembly P/N 3902643-01, starting with the large slot in the middle of a retainer segment aligned with the offset hole at BDC, with the 23 bolts and self-locking nuts P/N AS3554-10 finger tight (Ref. View F). (d) Measure the gap all around between the three retainer segments and the rear gas generator case and make sure the gap is per F&C Ref. No. 1830 (Ref. Fig. 2, Section H-H). (e) Use the (PWC30114-61) wrench to hold the 23 self-locking nuts and torque the 23 bolts in a star pattern 85 to 95 lbf.in. (9.6-10.7 Nm) (Ref. Fig. 1). (f) Measure the gap again all around between the three retainer segments and the rear gas generator case and make sure the gap is per F&C Ref. No. 1830 (Ref. Fig. 2, Section H-H). 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 5 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF3. Accomplishment Instructions (Cont’d) C. Write accomplishment of P&WC S.B. No. 16255 in the APU log book. 4. Appendix A. Refer to Table 1 and Figure 2 for the changes to the fits and clearances. 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 6 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF**RETAINER SEGMENT (QTY. 3) P/N 3902606−01**  **SELF−LOCKING NUT (QTY. 23) P/N AS3554−10**  **SPACER RING ASSY. P/N 3902643−01**  **REAR GAS GENERATOR CASE (REF.)**  **TURBINE EXHAUST DUCT (REF.)**  **BOLT (QTY. 23) P/N MS9697−14** 

**EXHAUST DUCT SUPPORT P/N 3902607−01** 

**BOLT (QTY. 24) P/N MS9696−08** 



## C **A B** 

**ALIGNMENT PIN PWC64241−3** 

C127892 Exhaust Duct Support - Installation of Figure 1 (Sheet 1 of 3) 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 7 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF**VIEW** 

## A **BDC** X **OFFSET HOLE** 

**VIEW**

## C **E**

**(SHOWN ASSEMBLED)** 

## D D

**F**

**SECTION** 

## D−D **VIEW**

## B **OFFSET HOLE**  **No. 4 BEARING ROLLERS (REF.)** 

**TURBINE EXHAUST DUCT (REF.)**  **X MARK SHOULDER PIN**  **P/N ST3020−010 SPACER RING ASSY.**  **P/N 3902643−01**

C127893 Exhaust Duct Support - Installation of Figure 1 (Sheet 2) 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 8 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF**VIEW**

## F **VIEW** 

## E

**LARGE SLOT RETAINER SEGMENT**  **P/N 3902606−01** X **SHOULDER PIN P/N ST3020−010** 

**X MARK EXHAUST DUCT SUPPORT**  **P/N 3902607−01**

C127894 Exhaust Duct Support - Installation of Figure 1 (Sheet 3) 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 9 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF4. Appendix (Cont’d) TABLE 1, Changes to the Fits and Clearances Dim. for Ref. inches (mm) Limits inches (mm) REF. NO. IFR Name Min. Max. Min. Max. Replace **Pre-SB** 1190 C Duct-Turbine Exhaust, Assy of 15.528 (394.411) 15.530 (394.462) 0.012 0.018 (0.305) (0.457) Support-Exhaust Duct, Assy of 15.542 (394.767) 15.546 (394.868) **Post-SB** 1190 C Duct-Turbine Exhaust, Assy of 15.528 (394.411) 15.530 (394.462) 0.012 0.018 (0.305) (0.457) Ring-Spacer, Assy of 15.542 (394.767) 15.546 (394.868) **Pre-SB** 1192 B Case-Gas Generator Rear, Assy of 16.478 (418.541) 16.480 (418.592) 0.020T 0.016T (0.508T) (0.406T) Support-Exhaust Duct, Assy of 16.460 (418.084) 16.462 (418.135) **Post-SB** 1192 C Case-Gas Generator Rear, Assy of 16.478 (418.541) 16.480 (418.592) 0.020T 0.016T (0.508T) (0.406T) Ring-Spacer, Assy of 16.460 (418.084) 16.462 (418.135) **Post-SB** 1281 C Pin-Shouldered, Headless 0.0620 (1.575) 0.0621 (1.577) 0.0000 0.0011T (0.000) (0.028T) Ring-Spacer, Assy of 0.0610 (1.549) 0.0620 (1.575) **Post-SB** 1282 C Pin-Shouldered, Headless 0.0773 (1.962) 0.0778 (1.975) 0.0013 0.0058 (0.032) (0.146) Support-Exhaust Duct, Assy of 0.0790 (2.007) 0.0830 (2.108) 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 10 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF4. Appendix (Cont’d) TABLE 1, Changes to the Fits and Clearances (Cont’d) Dim. for Ref. inches (mm) Limits inches (mm) REF. NO. IFR Name Min. Max. Min. Max. Replace **Post-SB** 1283 C Ring-Spacer, Assy of 17.178 (436.321) 17.182 (436.423) 0.012 0.018 (0.305) (0.457) Support-Exhaust Duct, Assy of 17.194 (436.728) 17.196 (436.778) **Post-SB** 1830 C Minimum gap 0.010 in. (0.254 mm) between retainer segment and gas generator case all around. 

### PRATT & WHITNEY CANADA 

# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 11 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF

## G

**J VIEW** 

## G

**VIEW** 

## J **SECTION** 

## H−H

**SECTION** 

## K−K **H H** 

**K**

**K L** 

**DETAIL**

## L **1830**

**1283 1282**  **1281**

**1190**

**1192 SPACER RING**  **ASSEMBLY P/N 3902643−01** 

**REAR GAS GENERATOR**  **CASE (REF.)** 

C127896 Changes to the Fits and Clearances Figure 2 

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# ALERT SERVICE BULLETIN
P&WC S.B. No. A16255R2

P&WC Proprietary Information. Subject to the restrictions on the back of the locator. Dec 12/2007 **3910001-49-A16255** Revision No. 2: Mar 01/2011 Page 12 of 12 AUXILIARY POWER UNIT EXHAUST DUCT SUPPORT AND INSULATION BLANKETS - REPLACEMENT OF