### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-53A1214**  Original Issue: June 17, 1999 Revision 4: December 16, 2011 ATA System: 5311 **SUBJECT:** FUSELAGE - Body Station 1016 Aft Pressure Bulkhead Web Cracks - Inspection and Repair Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws.9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1999 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 1 of 73 5.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 2 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 37 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 39 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 39 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 FIGURE 1: LFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM STRINGER S-15L TO S-15R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 FIGURE 2: HFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM STRINGER S-15L TO S-15R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 FIGURE 3: ONE-TIME NDT INSPECTION OF WEB AT THE OUTER CIRCUMFERENTIAL TEAR STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 FIGURE 4: NDT INSPECTION OF WEB AT THE "Y" CHORD IN THE LOWER BULKHEAD FROM STRINGER S-15LTO S-15R. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 FIGURE 5: DETAILED INSPECTION FOR OIL-CAN DAMAGE IN THE BULKHEAD WEB. . . . . . 56 FIGURE 6: NDT INSPECTION OF THE DOME CAP AT THE CENTER OF THE BULKHEAD. . . . . 58 FIGURE 7: NDT INSPECTION OF THE FORWARD FLANGE OF THE "Z" STIFFENER AT THE DOME CAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 3 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**Appendix A: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 3 OR 737-300/400/500 53-80-08 REPAIR 1 - TYPICAL REPAIR FOR DAMAGE TO WEB AND STRAP. . . . . . . . . . . . . . . . . . 63 Appendix B: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 3 OR 737-300/400/500 53-80-08 REPAIR 1 - TYPICAL REPAIR FOR DAMAGE TO WEB. . . . . . . . . . . . . . . . . . . . . . . . . 65 Appendix C:OBSOLETE 737-100/200 SRM 53-10-4, FIGURE 5 OR 737-300/400/500 SRM 53-80-08 REPAIR 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Appendix D:OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 12 OR 737-300/400/500 SRM 53-80-08 REPAIR 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Appendix E:OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 13 OR 737-300/400/500 SRM 53-80-08 REPAIR 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 4 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Revision Transmittal Sheet**  **Number: 737-53A1214** Original Issue: June 17, 1999 Revision 4: December 16, 2011 ATA System: 5311 **SUBJECT:** FUSELAGE - Body Station 1016 Aft Pressure Bulkhead Web Cracks - Inspection and Repair This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on the airplanes changed in accordance with Revision 3 of this service bulletin. **REASON FOR REVISION** This revision is sent to change the compliance time for Detailed Inspection for Oil-Cans and to delete incorrect paragraph reference in Paragraph 3.B., Work Instructions, Part VI. These sections were changed: 1. Summary Background: FAA Airworthiness Directive statement deleted. SIIA and SRP statements added. 2. Paragraph 1.C., Reason: FAA Airworthiness Directive statement deleted. 3. Paragraph 1.E., Compliance: Table 4, Compliance Time changed. Table 8 SRM reference corrected. 4. Paragraph 1.J.1., Existing Data: Revised. 5. Paragraph 3.A., General Information: Note 5 revised. Note 9 and 10 added. 6. Paragraph 3.B., Work Instructions: Part I, step 5. note, SRM reference corrected. 7. Paragraph 3.B., Work Instructions: Part VI, step 1.b. and 1.c., incorrect paragraph reference removed. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** June 17, 1999 Original Issue: June 22, 2000 Revision 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 5 of 73May 24, 2001 Revision 2: January 19, 2011 Revision 3: December 16, 2011 Revision 4:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 6 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **Number: 737-53A1214** Original Issue: June 17, 1999 Revision 4: December 16, 2011 ATA System: 5311 **SUBJECT:** FUSELAGE - Body Station 1016 Aft Pressure Bulkhead Web Cracks - Inspection and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None **BACKGROUND** Cracks have been reported in four general areas on the aft pressure bulkhead: cracks in the web at the web-to-"Y" chord interface; cracks in the web at the outer circumferential tear strap; cracks in the web near the dome cap; and cracks in the "Z" stiffeners near the dome cap. Undetected cracking could result in loss of ability to maintain cabin pressure, rapid decompression of the airplane, and significant structural damage to the aft fuselage. Cracks reported in the web at the web-to-"Y" chord interface occurred in the aft row of fasteners connecting the web to the "Y" chord. In all of the cases, the cracks ran in the circumferential direction. Most of the cracks have been at Stringer S-6L and S-6R, but there have been reports of cracks at other locations. The airplanes had accumulated between 22,966 and 68,000 flight cycles and between 45,500 and 61,000 flight hours. There have been two reports of cracking in the bulkhead web at the outer circumferential tear strap. The airplanes had 21,246 and 26,162 flight cycles and 17,500 and 24,132 flight hours respectively. Since revision 2 of this service bulletin, there have been reports of cracking in the center of the web near the dome cap. The cracks occurred at the center of the bulkhead at the end of the web gore sections. The airplanes had accumulated more than 30,000 flight cycles and 36,000 flight hours. There have also been two reports of cracks located on the "Z" stiffeners forward flange at the attach location to the dome cap pan. The cracks extended from the outboard fastener hole and ran circumferentially. Boeing Structural Item Interim Advisory (SIIA) SIIA 737-52 and SIIA 737-269 are related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0109, 737-SRP-53-0116, and 737-SRP-53-0155 are related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 7 of 73**ACTION (PRR 35005-229R)** Get access to the forward or aft side of the aft pressure bulkhead and do a Non-Destructive Test (NDT) inspection for any cracking in the web at the "Y" chord. If damage is found from the aft side, get access to the forward side of the bulkhead and do a High Frequency Eddy Current (HFEC) inspection for any cracking in the web at the "Y" chord for the section of web where the damage was found. If any cracking is found, repair the crack(s) in accordance with the Structural Repair Manual (SRM) or contact Boeing for repair instructions. From either side of the bulkhead, do a NDT inspection for any cracking in the web at the outer circumferential tear strap for 360 degrees. Also, do an inspection for oil-canning in the web of the entire bulkhead and do repeat inspections at the times shown in the Compliance Section. If you find any cracking, repair the crack(s) in accordance with the SRM or contact Boeing. From the aft side of the bulkhead, do a NDT inspection for any cracking in the bulkhead web at the lap joints. Do the inspection from the edge of the gore section at the center of bulkhead to approximately ten inches outboard of the center. Do repeat inspections at the times shown in the Compliance Section. If you find any cracking, contact Boeing or repair the crack(s) in accordance with the SRM. **EFFECTIVITY** All 737-100/-200/-200C/-300/-400/-500 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directive AD 99-08-23, is related to this service bulletin. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 8 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 9 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 10 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-53A1214**  Original Issue: June 17, 1999 Revision 4: December 16, 2011 ATA System: 5311 **SUBJECT:** FUSELAGE - Body Station 1016 Aft Pressure Bulkhead Web Cracks - Inspection and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 35005-229R for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** All 737-100/200/200C/300/400/500 Series Airplanes, Line Numbers 1-3132. - 1

Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 **Group Variable Number**  1 PA001 - PA022 1 PA099 1 PA231 - PA232 1 PC001 - PC005 1 PG001 - PG075

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 11 of 73**Group Variable Number**  1 PG199 1 PG201 - PG230 1 PG251 - PG255 1 PG271 - PG279 1 PG301 - PG314 1 PG331 - PG332 1 PG351 - PG356 1 PG375 1 PG401 - PG403 1 PG431 - PG442 1 PG471 - PG475 1 PG501 - PG505 1 PG571 - PG586 1 PG621 - PG630 1 PG651 - PG652 1 PG701 - PG705 1 PH001 1 PH011 - PH013 1 PH021 - PH024 1 PH701 - PH715 1 PH731 - PH732 1 PH741 - PH743 1 PJ001 - PJ009 1 PJ031 - PJ032 1 PJ071 - PJ072 1 PJ101 - PJ119 1 PJ201 - PJ219 1 PJ301 - PJ302 1 PJ551 - PJ561 1 PJ601 - PJ615 1 PJ811 1 PJ816 - PJ817 1 PK026 - PK029

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 12 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PK041 - PK053 1 PK061 - PK070 1 PK081 - PK082 1 PK091 - PK099 1 PK101 - PK103 1 PK111 - PK120 1 PK141 - PK146 1 PK201 - PK204 1 PK211 - PK223 1 PK231 - PK241 1 PK251 - PK258 1 PK271 - PK274 1 PK281 - PK289 1 PK291 1 PK301 - PK318 1 PK341 1 PK351 - PK361 1 PK391 1 PK431 - PK433 1 PK451 - PK452 1 PK461 - PK469 1 PK495 1 PK501 - PK504 1 PK511 - PK515 1 PK519 1 PK521 - PK528 1 PK541 - PK565 1 PK581 1 PK591 - PK599 1 PK601 - PK617 1 PK621 - PK637 1 PK641 - PK642 1 PK661 - PK666

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 13 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PK671 - PK681 1 PK691 - PK697 1 PK711 - PK716 1 PK731 - PK765 1 PK771 - PK779 1 PK801 - PK804 1 PK819 - PK827 1 PK830 1 PK861 - PK863 1 PK871 - PK874 1 PK881 - PK884 1 PK901 - PK938 1 PK971 - PK974 1 PL001 - PL028 1 PL061 1 PL081 1 PL101 - PL113 1 PL151 1 PL171 - PL172 1 PL201 - PL203 1 PL221 1 PL401 - PL417 1 PL421 1 PL441 1 PL451 - PL456 1 PL471 1 PL491 1 PL501 - PL506 1 PL551 - PL562 1 PL581 1 PL601 - PL603 1 PL611 1 PL621 - PL626

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 14 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PL631 - PL632 1 PL711 - PL712 1 PL716 - PL747 1 PL756 1 PL758 1 PL761 - PL770 1 PL781 - PL788 1 PL793 1 PL801 - PL803 1 PM001 - PM006 1 PM016 - PM017 1 PM021 - PM023 1 PM051 - PM066 1 PM101 - PM119 1 PM141 - PM142 1 PM171 1 PM181 1 PM251 - PM255 1 PM281 - PM283 1 PM381 - PM399 1 PM401 - PM417 1 PM541 - PM564 1 PN001 - PN002 1 PN021 - PN043 1 PN081 - PN086 1 PN101 - PN117 1 PN131 - PN163 1 PN401 - PN420 1 PN431 - PN433 1 PN451 - PN456 1 PN471 - PN474 1 PN481 1 PN491 - PN493

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 15 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PN501 - PN502 1 PN511 - PN512 1 PN521 1 PP001 - PP054 1 PP101 - PP169 1 PP181 - PP199 1 PP201 - PP205 1 PP221 1 PP231 - PP243 1 PP281 - PP286 1 PP301 - PP305 1 PP351 - PP353 1 PP376 - PP384 1 PP391 - PP393 1 PP401 - PP440 1 PP471 - PP475 1 PP501 - PP522 1 PP631 - PP634 1 PP651 - PP652 1 PP671 - PP699 1 PP701 - PP733 1 PP771 - PP779 1 PP801 - PP808 1 PP821 - PP827 1 PP831 - PP848 1 PP851 - PP852 1 PP861 - PP877 1 PP891 - PP899 1 PP901 - PP936 1 PP946 - PP948 1 PP951 - PP952 1 PP961 - PP967 1 PP981 - PP991

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 16 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PP993 1 PQ001 - PQ016 1 PQ026 - PQ041 1 PQ051 - PQ092 1 PQ101 - PQ199 1 PQ201 - PQ202 1 PQ221 - PQ237 1 PQ241 - PQ243 1 PQ251 - PQ267 1 PQ281 - PQ299 1 PQ301 - PQ307 1 PQ331 - PQ332 1 PQ341 - PQ348 1 PQ361 - PQ373 1 PQ391 - PQ395 1 PQ401 - PQ418 1 PQ421 1 PQ431 - PQ438 1 PQ447 - PQ448 1 PQ451 1 PQ454 1 PQ471 - PQ475 1 PQ479 - PQ481 1 PQ486 - PQ487 1 PQ491 - PQ493 1 PQ771 - PQ772 1 PQ791 - PQ793 1 PQ801 - PQ805 1 PQ931 - PQ935 1 PQ951 1 PQ971 - PQ997 1 PR001 - PR017 1 PR021 - PR034

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 17 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PR041 - PR045 1 PR061 - PR072 1 PR077 - PR082 1 PR091 - PR092 1 PR096 1 PR101 1 PR121 - PR122 1 PR131 - PR132 1 PR141 - PR143 1 PR161 - PR172 1 PR181 1 PS601 - PS631 1 PS636 - PS638 1 PS641 - PS644 1 PS651 - PS657 1 PS666 - PS669 1 PS691 - PS692 1 PS701 - PS706 1 PS751 - PS799 1 PS811 1 PS836 - PS837 1 PS841 - PS846 1 PS851 - PS852 1 PS856 1 PS861 - PS863 1 PS866 - PS868 1 PS871 - PS874 1 PS896 - PS897 1 PS901 - PS941 1 PS956 - PS957 1 PS961 - PS963 1 PS971 - PS978 1 PT001 - PT015

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 18 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PT021 - PT031 1 PT041 - PT064 1 PT101 - PT105 1 PT121 - PT138 1 PT146 - PT148 1 PT161 - PT170 1 PT181 - PT188 1 PT211 - PT220 1 PT295 1 PT301 - PT309 1 PT331 - PT360 1 PT381 - PT399 1 PT401 - PT438 1 PT501 - PT517 1 PT561 - PT565 1 PT581 - PT586 1 PT611 - PT621 1 PT641 - PT644 1 PT651 - PT656 1 PT671 - PT672 1 PT681 - PT685 1 PT701 - PT703 1 PT716 - PT717 1 PT721 - PT725 1 PT801 - PT834 1 PT851 - PT854 1 PT871 - PT886 1 PT901 - PT930 1 PT971 - PT973 1 PT981 - PT985 1 PT996 1 PU001 - PU025 1 PU301

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 19 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PU311 - PU313 1 PV001 - PV055 1 PV201 - PV209 1 PV226 - PV229 1 PV231 - PV237 1 PV271 - PV272 1 PV281 - PV287 1 PV296 1 PV301 - PV302 1 PV351 1 PV356 - PV357 1 PW001 - PW054 1 PW061 - PW068 1 PW072 1 PW086 - PW088 1 PW091 - PW094 1 PW101 - PW102 1 PW106 1 PW111 - PW120 1 PW156 - PW157 1 PW161 - PW171 1 PW201 - PW252 1 PW261 - PW268 1 PW271 - PW276 1 PW278 1 PW281 - PW293 1 PW296 1 PW301 - PW327 1 PW401 - PW408 1 PW411 - PW418 1 PW421 - PW424 1 PW431 - PW435 1 PW441 - PW450

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 20 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PW461 - PW467 1 PW501 - PW504 1 PW511 - PW522 1 PW524 - PW550 1 PW556 - PW557 1 PW561 - PW564 1 PW571 - PW576 1 PW591 - PW596 1 PW611 - PW622 1 PW631 - PW637 1 PW661 - PW662 1 PW681 - PW683 1 PW701 - PW702 1 PW711 - PW717 1 PW741 - PW742 1 PW761 1 PW771 1 PW831 1 PW851 - PW856 1 PX071 1 PX701 1 PY001 - PY008 1 PY021 - PY022 1 PY031 1 PY036 - PY037 1 PY046 - PY048 1 PY051 - PY053 1 PY056 - PY057 1 PY101 - PY103 1 PY111 - PY113 1 PY131 - PY135 1 PY141 - PY143 1 PY151 - PY154

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 21 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Group**  **Variable Number** 1 PY156 - PY157 1 PY161 - PY162 1 PY166 1 PY191 1 PY201 1 PY221 - PY222 1 PY231 1 PY241 - PY244 1 PY270 - PY275 1 PY281 1 PY286 1 PY301 - PY304 1 PY321 - PY323 1 PY341 - PY346 1 PY361 - PY362 1 PY381 1 PY401 1 PY409 - PY411 1 PY421 - PY422 1 PY441 1 PY451 1 PY461 - PY463 1 PY591 - PY595 1 PY611 - PY612 1 PY621 1 PY631 1 PY651 1 PY671 - PY672 1 PY721 1 PY741 2. Spares Affected None

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 22 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT B. Concurrent Requirements**  None **C. Reason** Cracks have been reported in four general areas on the aft pressure bulkhead: cracks in the web at the web-to-"Y" chord interface; cracks in the web at the outer circumferential tear strap; cracks in the web near the dome cap; and cracks in the "Z" stiffeners near the dome cap. Undetected cracking could result in loss of ability to maintain cabin pressure, rapid decompression of the airplane, and significant structural damage to the aft fuselage. As of the initial release of this service bulletin, six operators had reported finding cracks in the aft pressure bulkhead web of sixteen 737-200 and -300 airplanes. In all of the cases, the cracks ran in the circumferential direction along the aft row of fasteners connecting the web assembly to the bulkhead "Y" chord. Fifteen airplanes had cracks at Stringer (S)-6L and one airplane had cracks at S-6L and S-6R. The airplanes had accumulated between 25,500 and 68,000 flight cycles and between 45,500 and 61,000 flight hours. Since the initial release of this bulletin, there have been additional reports of cracking. The cracks were similar to the previously reported cracks. Cracks have been reported on airplanes with a range of between 22,966 and 67,937 flight cycles. Also, there have been two reports of cracking in the bulkhead web at the outer circumferential tear strap. The first report happened in 1978 and resulted in the release of a Structural Item Interim Advisory (SIIA) SIIA 737-52. In that event, the airplane experienced a sudden cabin pressure drop as a result of a 42 inch crack in the bulkhead web. The crack ran along the outer circumferential tear strap from S-15R to S-21, turned 90 degrees inwards and ran along the radial stiffener at S-21R, stopping at the middle circumferential tear strap. The second report happened in January of 1999 and resulted in the release of SIIA 737-269. The operator discovered an eight inch crack during a heavy maintenance check. The crack ran along the outer circumferential tear strap from S-15R to S-18R. The airplanes had 21,246 and 26,162 flight cycles and 17,500 and 24,132 flight hours respectively. Since revision 2 of this bulletin, there have been reports of cracking in the web near the dome cap. The cracks occurred at the center of the bulkhead at the edge of web gore sections. The airplanes had accumulated more than 30,000 flight cycles and 36,000 flight hours. There have also been reports of cracking in the radial "Z" stiffeners where they attach to the dome cap. The cracks extended from the outboard fastener hole and ran circumferentially. Revision 1 was sent to: — Modify Industry Support Information. — add an SRM repair reference for repairing cracking in the web periphery at S-6L or S-6R. — add a visual inspection for oil-canning for the entire bulkhead web. — add an NDT inspection for cracking in the web at the outer circumferential tear strap around the entire bulkhead. — add an inspection for cracking in the web at the "Y" chord below S-15L and S-15R. Revision 2 was sent to: — Clarify the inspection threshold in the compliance section. — Change two SRM figure references and add a note. The note states that more work is required if an operator used the wrong SRM figure to do a web crack repair.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 23 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**Revision 3 was sent to: — Add an inspection for cracking in the web joints in the center of the aft pressure bulkhead. — Add inspections for cracking in the radial "Z" stiffeners where they attach to the dome cap. — Add repeat inspections for oil cans. — Add Appendices A to D to show post repair inspections for repairs that have been deleted from the SRM. — Add Appendix E to show the removal and replacement of a repair that has been deleted from the SRM. — Add SRM references for new oil can repairs and repairs for web cracking at the center of the bulkhead. — Change the Industry Support Information statement. — Clarify the inspection in Figure 1, step 2. Revision 4 is sent to change the compliance time for Detailed Inspection for Oil-Cans and to delete incorrect paragraph reference in Paragraph 3.B., Work Instructions, Part VI. Boeing Service Related Problem (SRP) 737-SRP-53-0109, 737-SRP-53-0116, and 737-SRP-53-0155 are related to this service bulletin. **D. Description** Inspect the web for cracking at the "Y" chord in the upper bulkhead from S-15L to S-15R: — Get access to the aft side of the aft pressure bulkhead and do a Low Frequency Eddy Current (LFEC) inspection for any cracking in the web periphery. Do the inspection for circumferential cracking in the web where it attaches to the "Y" chord along the aft row of fasteners. Do the inspection in the upper fuselage from S-15L to S-15R. Also do a Detailed Inspection for any cracking in the web and for any incorrectly drilled or elongated fastener hole(s). — If either cracking, incorrectly drilled fastener hole or elongated fastener hole is found, you must get access to the forward side of the bulkhead and do a High Frequency Eddy Current (HFEC) inspection for any cracking and a Detailed Inspection from the forward side. Do the HFEC inspections for circumferential cracking along the aft row of fasteners at the "Y" chord for the section of web where the cracking, incorrectly drilled fastener hole or elongated fastener hole was found. It is not necessary to do the HFEC inspection beyond the web splices of the web section containing the cracking, incorrectly drilled fastener hole or elongated fastener hole. Do the Detailed Inspection for any cracking in the web and for any incorrectly drilled or elongated fastener hole(s). If you find damage at S-6L or S-6R, repair it as shown in the 737-100/200 or 737-300/400/500 SRM as applicable. If you install the SRM repair, there are future inspection requirements as defined in the SRM repair. If you find any cracking in the web periphery that is not covered by the SRM, contact Boeing for repair instructions and install the repair. — As an option to doing the inspections on the aft side of the bulkhead, you can do the HFEC and Detailed Inspection from the forward side of the bulkhead directly at less frequent intervals. — Do repeat inspections at the times shown in Paragraph 1.E., Compliance. Once the SRM repair is accomplished, subsequent inspections become less frequent. Inspect the web for cracking at the "Y" chord in the lower bulkhead from S-15L to S-15R: — This inspection is identical to the inspection above stringers S-15L and S-15R (upper lobe) and is done using a LFEC, HFEC, and Detailed Inspection procedures from the forward and the aft side. The compliance time for this inspection is different than the compliance time for the upper-lobe inspection. Refer to Paragraph 1.E., Compliance for compliance information. — Do repeat inspections at the times shown in Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 24 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**— If you find any cracking in this area, contact Boeing for repair instructions and install the repair. Inspect the web for any cracking at the outer circumferential tear strap: — From the aft side of the bulkhead, do a LFEC inspection for any cracking in the web at the outer circumferential tear strap around the entire bulkhead. As an option, you can do a HFEC inspection from the forward side of the bulkhead. Refer to Paragraph 1.E., Compliance for compliance information. — If you find any cracking in this area, repair in accordance with the SRM or contact Boeing for repair instructions and install the repair. Inspect the web for oil-cans: — From the aft side of the bulkhead, do a Detailed Inspection for oil-cans. — If you find oil-cans beyond SRM allowable limits, repair it as shown in the SRM. — If you find an oil-can within SRM allowable limits, repair as shown in the SRM, OR if the oil can is within the SRM allowable limits you can monitor the condition with repeat inspections and repair as shown in the SRM within the time shown in Paragraph 1.E., Compliance. — Do repeat inspections at the times shown in Paragraph 1.E., Compliance. Inspect the web for any cracking at the dome cap at the center of the bulkhead: — From the aft side of the bulkhead, do a NDT inspection for any cracking in the bulkhead web near the dome cap. — If you find any cracking in this area, repair as shown in the SRM. — Do repeat inspections at the times shown in Paragraph 1.E., Compliance. Inspect the forward flange of the "Z" stiffeners for any cracking at the dome cap at the center of the bulkhead: — From the fwd side of the bulkhead, do a NDT inspection for any cracking in the forward flange of the "Z" stiffeners at the dome cap. Do the inspection at both fastener rows common to the dome. — If you find any cracking in this area, contact Boeing for repair instructions and install the repair. — Do repeat inspections at the times shown in Paragraph 1.E., Compliance. Revision 3: — More work is necessary on airplanes that have repairs installed in accordance with 737-100/200 SRM 53-10-4, Figures 3, 5, and 12, or 737-300/400/500 SRM 53-80-08, Repair 1, 2, and 4: Repeat inspections must be performed at the times shown in Paragraph 1.E., Compliance. — More work is necessary on airplanes that have repairs installed in accordance with 737-100/200 SRM 53-10-4, Figure 13 or 737-300/400/500 SRM 53-80-08, Repair 5. Repairs must be replaced at the time shown in Paragraph 1.E., Compliance. **NOTE:** Service Bulletins 737-53A1075 and 737-53-1123 have common access and can be done concurrently with this bulletin. 1.

2. If any cracking, incorrectly drilled holes or elongated holes are found that are not within the repairable limits of applicable repairs, write to Boeing for repair instructions. Give the size and location of the damage. When possible, send sketches and photographs. If the damage includes corrosion, send data on the length, width, and largest depth of clean up.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 25 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**Send to: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT Revision 4 - No more work is necessary on airplanes changed in accordance with Revision 3 of this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 7-1, 2-20 737-100, 737-200, 737-200C **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 220, 701 737-300, 737-400, 737-500 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directive AD 99-08-23, is related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 26 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT TABLE 1: INSPECTION REQUIREMENTS - NDT INSPECTION OF WEB AT "Y" CHORD IN THE UPPER**  **BULKHEAD FROM S-15L TO S-15R Repeat Interval Flight Cycles (Not**  **to Exceed) (a) Compliance Time** **(whichever occurs lat er) (a)**  **Action Condition** 

**Above S-15L to S 15R except S-5L**  **to S-7L and S-5R to S-9R**  **S-5L to S-7L and S-5R to S**  **9R Upper Fuselage from S**  **15L to S-15R**

6,000 Flight Cyclesfrom last LFEC Inspection,1,200 Flight Cycles from lastLFEC Inspection, Within 375 Flight Cycles of the effective date of AD 99-08-23, OR Eddy Current Inspection and Detailed Inspection for any cracking and anyincorrectly drilled or elongated fastener hole(s) inaccordance with Paragraph 3.B., Work Instructions, PART I. 25,000 Total Flight Cycles or more OR12,000 Flight Cycles from last HFEC Inspection. OR3,800 Flight Cycles from the lastHFEC Inspection. WIthin 1,200 flight cycles or within 12 months afterthe last inspection accomplished in accordance with Paragraph (a)(2) of AD 99-08-23, whichever occurs first. OR Within 1,200 flight cycles after the last LFEC (aft side) inspection, OR Within 3,800 flight cycles after the last HFEC (fwd side) inspection.

- - Before Further Flight HFEC Inspection and De- tailed Inspection from the forward side for anycracking and any incorrectly drilled or elongated fastener hole(s). (b) Any cracking or incorrectly drilled fastener hole orelongated fastener hole is found

- - - Repeat inspections at specified intervalsNo cracking or incorrectly drilled orelongated fastener hole(s) found

- - Before Further Flight Repair in accordance with the Structural Repair Manual Any cracking or any incorrectlydrilled or elongated fastener hole(s) found at S-5L to S-7L or at S-5R to S-9R

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 27 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT TABLE 1: INSPECTION REQUIREMENTS - NDT INSPECTION OF WEB AT "Y" CHORD IN THE UPPER**  **BULKHEAD FROM S-15L TO S-15R Repeat Interval Flight Cycles (Not**  **to Exceed) (a) Compliance Time** **(whichever occurs lat er) (a)**  **Action Condition** 

**Above S-15L to S 15R except S-5L**  **to S-7L and S-5R to S-9R**  **S-5L to S-7L and S-5R to S**  **9R Upper Fuselage from S**  **15L to S-15R**

- - Before Further Flight Contact Boeing for repair instructions and install the repair. Any cracking or any incorrectlydrilled or elongated fastener hole(s) found atS-15L to S-7L, S15R to S-9R orabove S-5L to S5R (a) If you install the SRM repair doubler at S-6L or S-6R in accordance with 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Repair 7 or 737-400 SRM 53-80-08, Repair 7 or 737-500 SRM 53-80-08, Repair 7, refer to the SRM for Inspection threshold and repeat Inspection intervals for the area of the web covered by the repair doubler. (b) Do the HFEC Inspection for any cracking in the section of web where the cracking or incorrectly drilled or elongated fastener hole was found. It is not necessary to do the HFEC Inspection beyond the web splices of the web section containing the cracking, incorrectly drilled fastener hole or elongated fastener hole.**Table 2: Inspection Requirements - NDT Inspection of Web at "Y" Chord in the Lower Bulkhead from S 15L to S-15R**  **Repeat Interval Flight Cycles (Not to Exceed)**  **Compliance Time Action**  **Condition** 6,000 Flight Cycles from the last LFEC Inspection (aft side). (a) Before 30,000 Total Flight Cycles.Eddy Current Inspection and Detailed Inspection for any cracking and for any incorrectly drilled orelongated fastener hole(s) or corrosion in accordance with Paragraph 3.B., Work Instructions, PART III. Less than 24,000 Total Flight Cycles OR 12,000 Flight Cycles from the last HFEC Inspection (forward side). (a) 6,000 Flight Cycles from the last LFEC Inspection (aft side). (a)Within 6,000 Flight Cycles or Two years, whichever comes first,from the date of Revision 3 of this service bulletin.Eddy Current Inspection and Detailed Inspection for any cracking and for any incorrectly drilled orelongated fastener hole(s) or corrosion in accordance with Paragraph 3.B., Work Instructions, PART III. 24,000 Total Flight Cycles or more OR 12,000 Flight Cycles from the last HFEC Inspection (forward side). (a)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 28 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 2: Inspection Requirements - NDT Inspection of Web at "Y" Chord in the Lower Bulkhead from S**  **15L to S-15R Repeat Interval Flight**  **Cycles (Not to Exceed) Compliance Time**  **Action Condition** 

- Before Further Flight Contact Boeing for repair instructions and install the repair. Any cracking, any incorrectly drilled or elongated fastener hole(s) or corrosion found (a) In many areas the access is limited and you can do an inspection from only one side: either the forward side (HFEC) or the aft side (LFEC). In these areas, do the inspection from the side which provides access. **Table 3: Inspection Requirements - NDT Inspection under Tear Strap Repeat Interval**  **Flight Cycles (Not to Exceed)**  **Compliance Time Action**  **Condition**

One-time inspection only. Before 16,200 Total Flight Cycles Eddy Current Inspection for any cracking in accordance with Paragraph 3.B., Work Instructions, PART II, Step 1. Less than 15,000 Total Flight Cycles

One-time inspection only. Within 1,200 Flight Cycles or six months, whichever comes first, after the date of Revision 1 to this Service Bulletin Eddy Current Inspection for any cracking in accordance with Paragraph 3.B., Work Instructions, PART II, Step 1. 15,000 Total Flight Cycles or more

- Before Further Flight Contact Boeing for repair instructions and install the repair. Any cracking found

**Table 4: Inspection Requirements - Detailed Inspection for Oil-Cans Repeat Interval**  **Flight Cycles (Not to Exceed)**  **Compliance Time Action**  **Option Condition** 

- Before 15,000 Total Flight CyclesDetailed Inspection for OilCans in accordance withParagraph 3.B., Work Instructions, PART II, Step 2. - Initial Inspection for Oil-Cans OR Within 1,200 Flight Cycles after the date of Revision 1 to this Service Bulletin, Whichever comes later.

- Before further flight. Contact Boeing for repair in-structions and install the repair. - Any cracking is found.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 29 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 4: Inspection Requirements - Detailed Inspection for Oil-Cans**  **Repeat Interval Flight Cycles**  **(Not to Exceed) Compliance Time**  **Action Option**  **Condition**

6,000 Within 6,000 Flight Cycles from prior Inspection.Detailed Inspection for OilCans in accordance withParagraph 3.B., Work Instructions, PART II, Step 2. - No Oil-Cans on Initial Inspectionor Repeat Inspections. OR Within 1,200 Flight Cycles after the date of Revision 3 to this Service Bulletin, Whichever comes later.

- Before further flight. Contact Boeing for repair in-structions and install the repair. - Any cracking is found. 1,200 (a) Before further flight. Detailed and NDT Inspection in accordance with Paragraph 3.B., Work Instructions, PART II, Step 2.Option 1 (defer repair) Oil-Cans foundwithin limits defined in SRM.

- Within 12,000 Flight Cycles from the time when the oil can is found.Install the repair in accordance with Paragraph 3.B., Work Instructions, PART II, Step 2.

- Before Further Flight. Install the repair in accor- dance with Paragraph 3.B., Work Instructions, PART II, Step 2.Option 2 (repair immediately)

- Before further flight. Contact Boeing for repair in-structions and install the repair. - Any cracking is found.

- Before further flight. Install the repair in accor- dance with Paragraph 3.B., Work Instructions, PART II, Step 2. - Oil-Cans foundoutside of allowable limits defined in SRM. (a) Repeat inspections are terminated when the repair is installed. **Table 5: Inspection Requirements - NDT Inspection of the Dome Cap at the Center of the Bulkhead Repeat Interval**  **Flight Cycles (Not to Exceed)**  **Compliance Time Action**  **Condition**

6,000 Before 30,000 Total Flight Cycles. Eddy Current Inspection of the Dome Capfor any cracking in accordance with Paragraph 3.B., Work Instructions, PART IV. Less than 24,000 Total Flight Cycles

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 30 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 5: Inspection Requirements - NDT Inspection of the Dome Cap at the Center of the Bulkhead**  **Repeat Interval Flight Cycles (Not**  **to Exceed) Compliance Time**  **Action Condition** 

6,000 Within 6,000 Flight Cycles or 2 years, whichever comes first, after the date of Revision 3 to this Service Bulletin. Eddy Current Inspection of the Dome Capfor any cracking in accordance with Paragraph 3.B., Work Instructions, PART IV. 24,000 Total Flight Cycles or more

- Before Further Flight.Install the repair in accordance with Paragraph 3.B., Work Instructions, PART IV. Any cracking found

**Table 6: Inspection Requirements - NDT Inspection of the Forward Flange of the "Z" Stiffeners at the Dome Cap**  **Repeat Interval Flight Cycles**  **(Not to Exceed) Compliance Time**  **Action Condition** 

12,000 Before 30,000 Total Flight Cycles. HFEC Inspection of the forward flanges of the "Z" stiffener for anycracking in accordance with Paragraph 3.B., Work Instructions, PART V. Less than 24,000 Total Flight Cycles

12,000 Within 6,000 Flight Cy- cles or 2 years, whichever comes first,after the date of Revision 3 to this Service Bulletin. HFEC Inspection of the forward flanges of the "Z" stiffener for anycracking in accordance with Paragraph 3.B., Work Instructions, PART V. 24,000 Total Flight Cycles or more

- Before Further Flight. Contact Boeing for repair instructions and install the repair Any cracking found

**Table 7: Inspection Requirements - Inspection for Existing Repairs Compliance Time**  **Action Condition**  Within 4,500 flight cycles after the date of Revision 3 to this Service Bulletin. Do a detailed inspection of the bulkhead web and stiffeners to find existing repairs on the bulkhead in accordance with Paragraph 3.B., Work Instructions, Part VI. All Airplanes

At the applicable time in accordance with Table 8.Do Eddy Current Inspections or repair replacement as necessary, in accordance with Paragraph 3.B., Work Instructions, PART II.Obsolete SRM repair installed. At the applicable time in accordance with the SRM. Do Eddy Current Inspections in accordance with Paragraph 3.B., Work Instructions, PART II. Current SRM repair installed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 31 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 7: Inspection Requirements - Inspection for Existing Repairs**  **Compliance Time Action**  **Condition** At the time in accordance with the FAAapproved Damage Tolerance Inspections.Do the FAA approved Damage Tolerance Inspections.Non SRM repair installed and the repair has FAA approved DamageTolerance Inspections. Within 4,500 flight cycles after the date of Revision 3 to this Service Bulletin.Contact Boeing for FAA approved Damage Tolerance Inspections.Non SRM repair installed and the repair does not have FAA approved Damage Tolerance Inspections. At the time in accordance with the FAAapproved Damage Tolerance Inspections.Do the FAA approved Damage Tolerance Inspections.

**Table 8: Requirements for Obsolete SRM Repairs Repeat Interval**  **Flight Cycles (Not to Exceed)**  **Compliance Time (Whichever Occurs**  **Later) Action**  **Condition Reference** 

12,000 for HFEC Inspection. 6,000for LFEC Inspection. Within 12,000 FlightCycles after the repair was installed, OR Do a HFEC inspection of the web at fastener locations not common to a tear strap in accordance with APPENDIX A 737-300 SRM 53-80-08, Repair 1 or 737-400 SRM 53-80-08, Repair 1 or 737-500 SRM 53-80-08, Repair 1 installed (obsolete - older SRM) or 737-100/200 SRM 53-10-4, Figure 3repair installed (obsolete - older SRM) APPENDIX A - Repair For Damage to Web and Strap Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. OR At the operators option, do a LFEC inspection of the webin accordance with APPENDIX A 12,000 for HFEC Inspection. 6,000for LFEC Inspection. Within 12,000 FlightCycles after the repair was installed, OR Do a HFEC inspection of the web at fastener locations common to a tear strap in accordance with APPENDIX A Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. OR At the operators option, do a LFEC inspection of the webin accordance with APPENDIX A

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 32 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 8: Requirements for Obsolete SRM Repairs**  **Repeat Interval Flight Cycles**  **(Not to Exceed) Compliance Time**  **(Whichever Occurs Later)**  **Action Condition**  **Reference**

12,000 for HFEC Inspection. 6,000for LFEC Inspection. Within 12,000 FlightCycles after the repair was installed, OR Do a HFEC inspection of theweb and repair plate in accordance with APPENDIX B OR 737-300 SRM 53-80-08, Repair 1 or 737-400 SRM 53-80-08, Repair 1 or 737-500 SRM 53-80-08, Repair 1 installed (obsolete - older SRM) or 737-100/200 SRM 53-10-4, Figure 3repair installed (obsolete - older SRM) APPENDIX B - Repair For Damage to Web Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. At the operators option, do a LFEC inspection of the webin accordance with APPENDIX B

12,000 for HFEC Inspection. 6,000for LFEC Inspection. Within 12,000 FlightCycles after the repair was installed, OR Do a HFEC inspection of theweb in accordance with APPENDIX C OR 737-300 SRM 53-80-08, Repair 2 or 737-400 SRM 53-80-08, Repair 2 or 737-500 SRM 53-80-08, Repair 2 installed (obsolete - older SRM) or 737-100/200 SRM 53-10-4, Figure 5repair installed (obsolete - older SRM) APPENDIX C - Repair For Oil Can in Web. Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. At the operators option, do a LFEC inspection of the webin accordance with APPENDIX C

6,000 Within 12,000 FlightCycles after the repair was installed, Do a LFEC inspection of theweb in accordance with APPENDIX D 737-300 SRM 53-80-08, Repair 4 or 737-400 SRM 53-80-08, Repair 4 or 737-500 SRM 53-80-08, Repair 4 installed (obsolete - older SRM) or 737-100/200 SRM 53-10-4, Figure 12repair installed (obsolete - older SRM) APPENDIX D - Repair For Oil Can in Web (Not at Strap) OR Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. 12,000 Within 12,000 FlightCycles after the repair was installed, Do a HFEC inspection of theweb in accordance with APPENDIX D OR Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 33 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 8: Requirements for Obsolete SRM Repairs**  **Repeat Interval Flight Cycles**  **(Not to Exceed) Compliance Time**  **(Whichever Occurs Later)**  **Action Condition**  **Reference**

- Within 6,000 Flight Cycles after the date of Revision 3 to this Service Bulletin. Remove the existing repair and replace in accordance with 737-100/200 SRM 53- 10-4, Figure 3A repair, or737-300 SRM 53-80-08, Repair 11 or 737-400 SRM 53- 80-08 , Repair 11 or 737-500 SRM 53-80-08, Repair 11 as applicable. 737-300 SRM 53-80-08, Repair 5 or 737-400 SRM 53-80-08, Repair 5 or 737-500 SRM 53-80-08, Repair 5 installed (obsolete - older SRM) or 737-100/200 SRM 53-10-4, Figure 13repair installed (obsolete - older SRM) APPENDIX E - Repair For Oil Can in Web and Strap.

**F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. The Manager of the FAA Seattle Aircraft Certification Office has approved the inspection methods, locations, and repetitive inspection intervals as specified in Revision 4 of this service bulletin as an alternate method of compliance to paragraphs (a)(1), (a)(2), (c), (d)(1), (d)(2), and (g) of AD 99-08-23, Amendment 39-11132. All provisions of the AD that are not specifically referenced in the preceding sentence remain fully applicable and must be complied with. Operators should be aware that a number of SRM repairs which pertain to this Service Bulletin do not have AMOC approval statements for AD 98-11-04 R1, AD 99-08-23, AD 2008-08-23, and AD 2008-09-13. Until these SRMs are revised to include the appropriate AMOC approval statements, operators should request approval from the Boeing Company. When this Service Bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph (e) of AD 99-08-23, paragraph (i) of AD 98-11-04 R1, paragraph (l) of AD 2008-08-23, or paragraph (l) of AD 2008-09-13, as applicable. **G. Manpower** The table below shows an estimate of the man-hours necessary to do the inspections and modifications. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator man-hour data if necessary. The estimate does not include lost time. These are some examples of lost time:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 34 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**— Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. **Table 1A: Web Inspection at "Y" Chord - Option A: LFEC Inspection from the Aft Side of the Bulkhead**  **Elapsed Time (Hours)**  **Man-Hours Number of Persons**  **Task**

4 8 2 LFEC Inspection 4 8 TOTAL FOR EACH AIRPLANE
**Table 1B: Web Inspection at "Y" Chord - Option B: HFEC Inspection from the Forward Side of the Bulkhead**  **Elapsed Time (Hours)**  **Man-Hours Number of Persons**  **Task**

13 26 2 Access 1 (a) 2 (a) 2 HFEC Inspect Web 16 32 2 Close Access 30 60 TOTAL FOR EACH AIRPLANE (a) Adding the NDT inspection below S-15 would take an additional 24 hours.

**Table 2: Web Inspection under Outer Circumferential Tear Strap and Detailed Inspection for Oil-Cans**  **Elapsed Hours Task-Hours**  **Number of Persons Task**  7 14 2 LFEC Inspection and Detailed Inspection (a) 4 (b) 8 (b) 2 Optional HFEC Inspection and Detailed Inspection (a) 7 14 TOTAL FOR EACH AIRPLANE - LFEC OPTION 4 8 TOTAL FOR EACH AIRPLANE - HFEC OPTION (a) The repeat oil-can Detailed Inspections would take 1 person 0.5 hours. (b) This estimate does not include access and close access for the forward side of the web. Refer to Table 1B for an estimate of the man-hours needed to get access and close access for the forward side of the bulkhead.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 35 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 3:**  **NDT Inspection of Bulkhead Lap Splices at the Center of the Bulkhead Elapsed Hours**  **Task-Hours Number of Persons**  **Task** 3 (a) 6 (a) 2 Inspection 3 6 TOTAL FOR EACH AIRPLANE (a) This estimate does not include access and close access for the forward side of the web. Refer to Table 1B for an estimate of the man-hours needed to get access and close access for the forward side of the bulkhead.
**Table 4: NDT Inspection of "Z" Stiffeners at the Dome Cap**  **Elapsed Hours Task-Hours**  **Number of Persons Task**  4 (a) 8 (a) 2 Inspection 4 8 TOTAL FOR EACH AIRPLANE (a) This estimate does not include access and close access for the forward side of the web. Refer to Table 1B for an estimate of the man-hours needed to get access and close access for the forward side of the bulkhead. **H. Weight and Balance Changes** None **I. Electrical Load Data** Not applicable **J. References** 1. Existing Data: a. Engineering Change Memo PRR 35005-229R b. Boeing Service Bulletin 737-53-1123, 737-53A1075 c. Boeing Service Related Problem (SRP) 737-SRP-53-0109, 737-SRP-53-0116, 737-SRP-53-0155 d. Boeing Structural Item Interim Advisory (SIIA) 737-269, 737-52 e. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2008-08-23, 2008-09-13, 98-11-04, 99-08-23 f. Service Bulletin Index D6-19567

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 36 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**g. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Part 6, 53-10-41, Part 6, 53-10-54, Part 6, 53-10-64, Part 6, 53-30-00 h. 737-100/200 Aircraft Maintenance Manual (AMM) 25-31-61, 25-40-0, 38-11-11 i. 737-100/200 Structural Repair Manual (SRM) 53-10-1, 53-10-11, 53-10-4 j. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-31-41, 25-40-01, 38-11-11 k. 737-300 Structural Repair Manual (SRM) 53-80-08 l. 737-400 Structural Repair Manual (SRM) 53-80-08 m. 737-500 Structural Repair Manual (SRM) 53-80-08 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  Bulkhead Installation - STA 1016 65-46568 Support Installation - Toilet Compartments Section 46 65-46812

These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS and new DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. **L. Interchangeability and Intermixability of Parts** None

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 37 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 38 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None **B. Industry Support Information** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts: None 2. Parts and Materials Supplied by the Operator: None. 3. Parts Modified and Reidentified: None 4. Parts Removed and Not Replaced: None **D. Parts Necessary to Change Spares** None **E. Special Tooling - Price and Availability** None **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 39 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 40 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:**KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 8. Boeing Service Letter 737-SL-51-042, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 41 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**9. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. **B. WORK INSTRUCTIONS PART I - NDT INSPECTION OF THE WEB AT THE "Y" CHORD - UPPER BULKHEAD FROM S-15L**  **TO S-15R:** 1. Do a Detailed Inspection and LFEC inspection of the aft side of the bulkhead web in accordance with Figure 1. As an option, you can do an inspection of the forward side of the bulkhead web in accordance with PART I - Step 3 (below). 2. If you find any cracking, or incorrectly drilled fastener hole or elongated fastener hole while you are doing the LFEC inspection and Detailed Inspection, you must get access to the forward side of the bulkhead and do a HFEC and Detailed Inspection of the section of web where the cracking, incorrectly drilled fastener hole or elongated fastener hole was found. Do the inspection in accordance with FIGURE 2 except the inspection can be limited to only the section of web with the damage. It is not necessary to do the inspection beyond the web splices of the web section containing the damage. 3. As an option to doing the LFEC inspection from the aft side of the bulkhead, you can do an inspection from the forward side of the bulkhead as follows: a. Get access to the forward side of the bulkhead by removing these items as necessary: (1) Remove the galley. Refer to 737-100/200 AMM 25-31-61 or 737-300/400/500 AMM 25-31-41 as an accepted procedure. (2) Remove the lavatory. Refer to 737-100/200 AMM 25-40-0 or 737-300/400/500 AMM 25-40-01 as an accepted procedure. b. Do an inspection of the forward side of the bulkhead in accordance with FIGURE 2. 4. If no cracking, incorrectly drilled fastener holes or elongated fastener holes are found, put the airplane back to a serviceable condition by replacing the aft galley and aft lavatory. Refer to the applicable AMM sections called out in PART I - Step 3 (above). **NOTE:**You can install the repair in accordance with 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Repair 7 or 737-400 SRM 53-80-08, Repair 7 or 737-500 SRM 53-80-08, Repair 7 as a preventive modification. If the SRM repair is installed, do inspections at the times given in the SRM. 5. If you find any cracking, incorrectly drilled fastener holes or elongated fastener holes at S-6L or S-6R, cut out the damage and install a repair doubler in accordance with 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Repair 7 or 737-400 SRM 53-80-08, Repair 7 or 737-500 SRM 53-80-08, Repair 7. If you find any cracking, incorrectly drilled fastener holes or elongated fastener holes in the web periphery at a location other than at S-6L or S-6R, contact Boeing for repair instructions and install the repair.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 42 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT NOTE:** – More work is required on airplanes with any web cracking repaired in accordance with 737-100/200 SRM 53-10-4 , Figure 3 or 737-300 SRM 53-80-08, Repair 1 or 737-400 SRM 53-80-08, Repair 1 or 737-500 SRM 53-80-08, Repair 1. If web cracking at the "Y" Chord was repaired using one of these figures, contact Boeing within 90 days of the release date of Revision 2 of this Service Bulletin to find out what additional work will be required. Please provide repair details when contacting Boeing. – If you install the repair in accordance with 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Repair 7 or 737-400 SRM 53-80-08, Repair 7 or 737-500 SRM 53-80-08, Repair 7, do inspections at the times given in the SRM. 6. If you find any cracking, report it to the Boeing company. Include the crack location, length, and the airplane flight cycles and flight hours. Send the information to: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT 7. Do repeat inspections of unrepaired structure at the times shown in Paragraph 1.E., Compliance. **NOTE:**If you installed the repair in accordance with 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Repair 7 or 737-400 SRM 53-80-08, Repair 7 or 737-500 SRM 53-80-08, Repair 7, do inspections at the times given in the SRM. **PART II - NDT INSPECTION UNDER CIRCUMFERENTIAL TEAR STRAP AND DETAILED INSPECTION FOR OIL-CANNING:**  1. ONE-TIME NDT INSPECTION UNDER THE TEAR STRAP: a. From the aft side of the bulkhead, do a one-time LFEC inspection of the web under the outer circumferential tear strap in accordance with FIGURE 3. b. As an option to doing the LFEC inspection from the aft side, you can do a one-time HFEC inspection from the forward side in accordance with FIGURE 3. c. If you find any cracking under the outer circumferential tear strap, contact Boeing for repair instructions and repair. Do not repair in accordance with the SRM. 2. DETAILED INSPECTION FOR OIL-CANNING: a. At the times shown in Paragraph 1.E., Compliance, Table 4, accomplish a Detailed Inspection for oil canning from the aft side of the Bulkhead in accordance with FIGURE 5. b. If oil canning is found, accomplish the additional NDT inspections in accordance with the Allowable Damage Section in 737-100/200 SRM 53-10-1, Figure 1 or 737-300 SRM 53-80-08, Figure 101 or 737-400 SRM 53-80-08, Figure 101 or 737-500 SRM 53-80-08, Figure 101. If any cracking is found when inspecting the oil canning, or if any of the structural requirements listed in the SRM Notes cannot be met (for example: proximity to fasteners, damage to adjacent structure etc.), then contact Boeing for repair instructions and install the repair. c. Measure the depth and width of the oil can in accordance with the SRM Allowable Damage Section. If the oil can is within the limits of Graph I (lower curve) where repairs can be deferred, then choose one of the options that follow:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 43 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**(1) Option 1: Install the appropriate repair in accordance with Graph I of the SRM Allowable Damage Section in 737-100/200 SRM 53-10-1, Figure 1, or 737-300 SRM 53-80-08, Figure 101 or 737-400 SRM 53-80-08, Figure 101 or 737-500 SRM 53-80-08, Figure 101, within the time shown in Paragraph 1.E., Compliance. Repeat inspections are required until the repair is installed. Accomplish the inspection program in accordance with the SRM Allowable Damage Section. (2) Option 2: Install the appropriate repair in accordance with Graph I of the SRM Allowable Damage Section, before further flight. d. If the oil canning exceeds the limits of Graph I (lower curve) of the Allowable Damage Section in 737-100/200 SRM 53-10-1, Figure 1 or 737-300 SRM 53-80-08, Figure 101 or 737-400 SRM 53-80-08, Figure 101 or 737-500 SRM 53-80-08, Figure 101, then install the appropriate repair in accordance with Graph I, before further flight. e. Note that Graph I of the SRM Allowable Damage Section refers to two repairs, dependent upon the severity of the oil canning. These repairs are detailed below in Table 1. **Table 1: SRM Repairs for the Aft Pressure Bulkhead**
**737-300 SRM 53- 80-08**  **737-400 SRM 53- 80-08**  **737-500 SRM 53- 80-08**  **737-100/200 SRM 53-10-4**  **Subject**

Repair 11 Figure 3A BS 1016 Bulkhead Cutout Repair Repair 12 Figure 5A Oil Can Doubler Repair f. If an oil-can repair is installed as listed in Table 1 above, do inspections of the repair at the times given in the SRM. g. After you install the SRM oil-can repair(s), verify that remaining oil-cans (if any) are within the allowable damage limits of the SRM. h. If you find any oil canning, report it to the Boeing company. Report the oil canning even if you are going to repair it in accordance with the SRM. Include the location, depth, size, orientation, and the airplane flight cycles and flight hours. Send the information to: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT i. Do repeat inspections for oil canning at the times shown in Paragraph 1.E., Compliance. **PART III - NDT AND DETAILED INSPECTION OF THE WEB AT THE "Y" CHORD BELOW S-15** 1. Get access to the forward side of the bulkhead by removing these items as necessary: a. Remove the galley. Refer to 737-100/200 AMM 25-31-61 or 737-300/400/500 AMM 25-31-41 as an accepted procedure.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 44 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**b. Remove the lavatory. Refer to 737-100/200 AMM 25-40-0 or 737-300/400/500 AMM 25-40-01. c. Remove the potable water tank. Refer to 737-100/200 AMM 38-11-11 or 737-300/400/500 AMM 38-11-11. 2. Do an inspection of the web from the forward or aft side of the bulkhead in accordance with FIGURE 4. **NOTE:**In many areas the access is limited and you can do an inspection from only one side: either the forward side (HFEC) or the aft side (LFEC). In these areas, do the inspection from the side which provides access. 3. If no cracking or no incorrectly drilled fastener holes or no elongated fastener holes are found, put the airplane back to a serviceable condition by replacing the galley, lavatory, and potable water tank, as necessary. Refer to the applicable AMM sections called out in PART III - Step 1 (above). If any cracking, incorrectly drilled fastener holes or elongated fastener holes are found, contact Boeing for repair instructions and install the repair. Report all cracking to the Boeing Company. Include the crack location, the length, and the airplane flight cycles and flight hours. Send the report to: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT **NOTE:**The 737-100/200 SRM 53-10-4, Figure 15 or 737-300 SRM 53-80-08, Figure 7 or 737-400 SRM 53-80-08, Figure 7 or 737-500 SRM 53-80-08, Repair 7 repair for cracking at S-6L and S-6R cannot be used at other stringer locations. 4. Do repeat inspections at the times shown in Paragraph 1.E., Compliance. **PART IV - NDT INSPECTION OF THE DOME CAP AT THE CENTER OF THE BULKHEAD** 1. Do an inspection of the dome cap at the center of the bulkhead in accordance with FIGURE 6. a. If any cracking in the web is found, install the appropriate SRM repair, in accordance with Table 3, below. **Table 3: SRM Repairs for the Apex Region of the Aft Pressure Bulkhead**
**737-300 SRM 53- 80-08**  **737-400 SRM 53- 80-08**  **737-500 SRM 53- 80-08**  **737-100/200 SRM 53-10-11**  **Subject**

Repair 9 Figure 13 BS 1016 Pressure Bulkhead Web Repair - Single Gore Web Repair 10 Figure 14 BS 1016 Pressure Bulkhead Web Repair - All Gore Webs

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 45 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**b. Do inspections of the repair at the times given in the SRM. 2. If no cracking is found do repeat inspections at the times shown in Paragraph 1.E., Compliance. **PART V - NDT INSPECTION OF THE FORWARD FLANGE OF THE "Z" STIFFENERS AT THE DOME CAP**  1. Do an inspection for any cracking in the "Z" stiffener flanges at the dome cap in the center of the bulkhead as in accordance with FIGURE 7. a. If any cracking in a "Z" stiffener flange is found, contact Boeing for repair instructions and install the repair. 2. If no cracking is found do repeat inspections at the times shown in Paragraph 1.E., Compliance. **PART VI - DETAILED INSPECTION FOR EXISTING REPAIRS ON THE BULKHEAD** 1. Do a detailed inspection of the bulkhead web and stiffeners to find existing repairs on the bulkhead. a. If no existing repair is found then no additional work is necessary. b. If an obsolete SRM repair is found then do eddy current Inspections or repair replacement as necessary, in accordance with Paragraph 1.E., Compliance, Table 8. **NOTE:**Refer to Appendices A through E to identify Obsolete SRM repairs. c. If a repair is installed in accordance with the SRM then Do Eddy Current Inspections in accordance with the SRM. d. If a non SRM repair is installed and the repair has FAA approved Damage Tolerance Inspections do the FAA approved Damage Tolerance Inspections. e. If a non SRM repair is installed and the repair does not have FAA approved Damage Tolerance Inspections contact Boeing for FAA approved Damage Tolerance Inspections and do the inspections. 2. Do an inspection of the aft pressure bulkhead to identify any SRM repairs installed that are listed in Table 2 below. a. If a SRM repair is installed that is listed in Table 2 below, do the inspections or repair replacement in accordance with Appendices A through E, at the times given in Paragraph 1.E., Compliance. Refer to Table 2 below or replace the repair in accordance with Table 1 above.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 46 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Table 2: Obsolete SRM Repairs for the Aft Pressure Bulkhead**  **Appendix 737-300 SRM 53-**  **80-08 737-400 SRM 53-**  **80-08 737-500 SRM 53-**  **80-08 737-100/200 SRM**  **53-10-4 Subject** 

A and B Repair 1 Figure 3 BS 1016 Bulkhead Cutout Repair C Repair 2 Figure 5 OIL CAN REPAIR D Repair 4 Figure 12 OIL CAN REPAIR BETWEEN TEAR STRAPS E Repair 5 Figure 13 OIL CAN REPAIR ACROSS TEAR STRAP

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4: December 16, 2011 47 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 1: LFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM**  **STRINGER S-15L TO S-15R (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 48 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  From the aft side, inspect the web at the aft fastener row of the "Y" chord/web interface in the upper fuselage from S-15L to S-15R. It is not necessary to inspect the web in the area of the steel straps. In accordance with 737 NDT Part 6, 53- 10-54. Low Frequency Eddy Current Web Inspect 1

Wherever you are doing the NDT inspection, visually inspect along both fastener rows of the "Y" chord. Look for any cracking and incorrectly drilled or elongated fastener holes. - Detailed Inspec- tion "Y" chord Inspect 2

**FIGURE 1: LFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM STRINGER S-15L TO S-15R**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 49 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 2: HFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM**  **STRINGER S-15L TO S-15R (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 50 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  From the forward side, inspect theweb at the aft fastener row in the upper fuselage from S-15L to S-15R. In accordance with 737 NDT Part 6, 51- 00-00, Figure 4 or 23. High Frequency Eddy Current Web Inspect 1

NOTE: 1. Where a radial stiffener overlaps the "Y" chord at the perimeter of the web, you cannotget access to the web to inspect the fastener holes. Instead, use the reference NDT procedure to inspect the web along the edge of the radial stiffener adjacent to the fastener holes that need to be inspected. Inspect the web for a distance of one inch each side of the fastener row. 2. Where the fin terminal fitting doublers overlap the web, use the reference NDT procedure to inspect the web along the edge of the doublers.Wherever you are doing the NDT inspection, visually inspect along both fastener rows of the web. Look for any cracking and any incorrectly drilled or elongated fastener hole(s). - Detailed Inspec- tion Web Inspect 2

**FIGURE 2: HFEC INSPECTION OF THE WEB AT THE "Y" CHORD IN THE UPPER BULKHEAD FROM STRINGER S-15L TO S-15R**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 51 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 3: ONE-TIME NDT INSPECTION OF WEB AT THE OUTER CIRCUMFERENTIAL TEAR STRAP**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 52 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
MORE DATA REFERENCES PROCEDURE NAME TASK STEP From the aft side, inspect under the outer circumferential tear strap for any cracking in the web. As an option to doing this LFEC procedure, you can do the HFEC procedure shown in Step 2. In accordance with 737 NDT Part 6, 53- 10-41. Low Frequency Eddy Current Web Inspect (a) 1

Step 2 is optional to Step 1. From the forward side, inspect the web at the fasteners that attach the outer circumferential strap. In accordance with 737 NDT Part 6, 51- 00-00, Figure 4 or 23 High Frequency Eddy Current Web Inspect (b) 2

The NDT subject referenced in step 1 is an inspection of the web at the lap splices and at all three tear straps. You only need to inspect the outer tear strap. For airplanes, Line no. 1 - 24, use Reference Standard 389A. (a)

For airplanes, Line no. 25 - 3132, use Reference Standard 389B. Contact Boeing if existing oil can repairs or bulging of the tear strap between fasteners prevents you from doing the LFEC inspection. Contact Boeing if existing oil can repairs prevent you from doing the HFEC inspection. (b)

**FIGURE 3: ONE-TIME NDT INSPECTION OF WEB AT THE OUTER CIRCUMFERENTIAL TEAR STRAP (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 53 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 4: NDT INSPECTION OF WEB AT THE "Y" CHORD IN THE LOWER BULKHEAD FROM STRINGER**  **S-15LTO S-15R (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 54 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  From the forward side, do a HFEC inspection of the web at the aft fastener row where possible. (a) The inspection from the forward side is not possible at: -the "Y" chord splice angle -the intersection of the floor structure and the "Y" chord -the bottom of the bulkhead where there is leveling compound covering the fasteners. In accordance with 737 NDT Part 6, 51- 00-00, Fig. 4 or 23 High Frequency Eddy Current (HFEC) Web Inspect 1

At these locations, do Step 3 and 4 instead. The LFEC inspection in Step 3 from the aft side is optional to a HFEC inspection from the forwardside. However, the inspection intervals will be more frequent. Refer to Paragraph 1.E., Compliance. In accordance with 737 NDT Part 6, 53- 10-54. Low Frequency Eddy Current (LFEC)

Wherever possible, visually inspect the forward side of the bulkhead along both fastener rows of the web. Look for any cracking, any incorrectly drilled or elongated fastener hole(s), or corrosion. - Detailed Inspec- tion Web Inspect 2

Wherever the HFEC inspectionfrom the forward side is not possible, do the LFEC inspection on the aft side of the bulkhead. In accordance with 737 NDT Part 6, 53- 10-54 Low Frequency Eddy Current Web Inspect 3

NOTE: 1. It is possible that the NDT manual shows an inspection area that is different than what is shown in this bulletin. Use the inspection area shown in this bulletin. 2. It is not possible to inspect the web adjacent to the stringer end-fittings because the NDT probe cannot fit under the fittings. Inspect the web along the edge of the leveling compound. - Detailed Inspec- tion Web Inspect 4 (a) Where a radial stiffener overlaps the "Y" chord at the perimeter of the web, you cannot get access to the web to inspect the fastener holes. Instead, use the reference NDT procedure to inspect the web along the edge of the radial stiffener adjacent to the fastener holes that need to be inspected. Inspect the web for a distance of one inch each side of the fastener row.

**FIGURE 4: NDT INSPECTION OF WEB AT THE "Y" CHORD IN THE LOWER BULKHEAD FROM STRINGER S-15LTO S-15R**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 55 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 5: DETAILED INSPECTION FOR OIL-CAN DAMAGE IN THE BULKHEAD WEB**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 56 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
MORE DATA REFERENCES PROCEDURE NAME TASK STEP Do a Detailed Inspection from the aft side of the bulkhead for any cracking. Use a flashlight held parallel to the web surface to highlight surface irregularity. - Detailed Inspec- tion Web Inspect 1

**FIGURE 5: DETAILED INSPECTION FOR OIL-CAN DAMAGE IN THE BULKHEAD WEB (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 57 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 6: NDT INSPECTION OF THE DOME CAP AT THE CENTER OF THE BULKHEAD**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 58 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  Inspect the web from the aft side for any cracking. In accordance with 737 NDT Part 6, 53- 10-64, Figure 2 Eddy Current Web Inspect 1

**FIGURE 6: NDT INSPECTION OF THE DOME CAP AT THE CENTER OF THE BULKHEAD (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 59 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 7: NDT INSPECTION OF THE FORWARD FLANGE OF THE "Z" STIFFENER AT THE DOME CAP**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 60 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT FIGURE 7: NDT INSPECTION OF THE FORWARD FLANGE OF THE "Z" STIFFENER AT THE DOME CAP**  **(SHEET 2 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 61 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  Inspect the forward flanges of the "Z" stiffener for any cracking at both fastener rows common to the dome pan. In accordance with 737 NDT Part 6, 51-00-00, Figure 4 or 23. High Frequency Eddy Current"Z" Stiffener Inspect 1

**FIGURE 7: NDT INSPECTION OF THE FORWARD FLANGE OF THE "Z" STIFFENER AT THE DOME CAP (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 62 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**INSPECTION THRESHOLD 12,000 Flight Cycles from the time the repair is installed or 6,000 Flight Cycles after Revision 3 to this Service Bulletin is released, whichever is later. REPEAT INSPECTIONS 1. At fastener locations not common to a tear strap, High Frequency Eddy Current (HFEC) inspect the web from the forward side of the pressure bulkhead every 12,000 Flight Cycles. Do the HFEC inspections in accordance with 737 NDT Part 6, 51-00-00 Figure 4 or 23.

**Appendix A: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 3 OR 737-300/400/500 53-80-08 REPAIR 1 - TYPICAL REPAIR FOR DAMAGE TO WEB AND STRAP**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 63 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**At the operators option, Low Frequency Eddy Current (LFEC) inspect the web from the aft side of the pressure bulkhead every 6,000 flight cycles. Do the LFEC inspection in accordance with 737 NDT Part 6, 53-30-00 Figure 5, using reference standard ANDT1049 for calibration. 2. At fastener locations common to a tear strap, HFEC inspect the web from the forward side of the bulkhead between the radial 'Z' stiffeners every 12,000 Flight Cycles. Do the HFEC inspections in accordance with 737 NDT Part 6, 51-00-00 Figure 4 or 23. At the operators option, LFEC inspect the web from the aft side of the pressure bulkhead every 6,000 Flight Cycles. Do the LFEC inspection in accordance with 737 NDT Part 6, 53-10-41 at location C using the relevant reference standard that matches the thickness of the tear strap and repair strap. **NOTE:**For 737-100/200 aircraft: this repair was removed from SRM 53-10-4, Figure 3, and replaced by Figure 3A which installs the repair plate on the forward side of the web. For 737-300/400/500 aircraft: this repair was removed from SRM 53-80-08, Repair 1, and replaced by Repair 11 which installs the repair plate on the forward side of the web.

**Appendix A: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 3 OR 737-300/400/500 53-80-08 REPAIR 1 - TYPICAL REPAIR FOR DAMAGE TO WEB AND STRAP**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 64 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**INSPECTION THRESHOLD 12,000 Flight Cycles from the time the repair is installed or 6,000 Flight Cycles after Revision 3 to this Service Bulletin is released, whichever is later. REPEAT INSPECTIONS 1. High Frequency Eddy Current (HFEC) inspect the web from the forward side of the pressure bulkhead and the repair plate from the aft side of the pressure bulkhead every 12,000 Flight Cycles. Do the HFEC inspections in accordance with 737 NDT Part 6, 51-00-00 Figure 4 or 23. At the operators option, Low Frequency Eddy Current (LFEC) inspect the web from the aft side of the pressure bulkhead every 6,000 Flight Cycles. Do the LFEC inspection in accordance with 737 NDT Part 6, 53-30-00 Figure 5, using reference standard ANDT1049 for calibration. **NOTE:**For 737-100/200 aircraft: this repair was removed from SRM 53-10-4, Figure 3, and replaced by Figure 3A which installs the repair plate on the forward side of the web. For 737-300/400/500 aircraft: this repair was removed from SRM 53-80-08, Repair 1, and replaced by Repair 11 which installs the repair plate on the forward side of the web.

**Appendix B: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 3 OR 737-300/400/500 53-80-08 REPAIR 1 - TYPICAL REPAIR FOR DAMAGE TO WEB**  **(SHEET 1 OF 1)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 65 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Appendix C: OBSOLETE 737-100/200 SRM 53-10-4, FIGURE 5 OR 737-300/400/500 SRM 53-80-08 REPAIR**  **2 (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 66 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**INSPECTION THRESHOLD 12,000 Flight Cycles from the time the repair is installed or 6,000 Flight Cycles after Revision 3 to this Service Bulletin is released, whichever is later. REPEAT INSPECTIONS 1. High Frequency Eddy Current (HFEC) inspect the web from the forward side of the pressure bulkhead every 12,000 Flight Cycles. Do the HFEC inspections in accordance with 737 NDT Part 6, 51-00-00 Figure 4 or 23. At the operators option, Low Frequency Eddy Current (LFEC) inspect the web from the aft side of the pressure bulkhead every 6,000 Flight Cycles. Do the LFEC inspection in accordance with 737 NDT Part 6, 53-30-00 Figure 5, using reference standard ANDT1049 for calibration. **NOTE:**For 737-100/200 aircraft: this repair was removed from SRM 53-10-4, Figure 5, and replaced by Figure 5A which installs the repair plate on the forward side of the web. For 737-300/400/500 aircraft: this repair was removed from SRM 53-80-08, Repair 2, and replaced by Repair 12 which installs the repair plate on the forward side of the web.

**Appendix C: OBSOLETE 737-100/200 SRM 53-10-4, FIGURE 5 OR 737-300/400/500 SRM 53-80-08 REPAIR 2**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 67 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Appendix D: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 12 OR 737-300/400/500 SRM 53-80-08 REPAIR**  **4 (SHEET 1 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 68 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Appendix D: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 12 OR 737-300/400/500 SRM 53-80-08 REPAIR**  **4 (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 69 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**INSPECTION THRESHOLD 12,000 Flight Cycles from the time the repair is installed or 6,000 Flight Cycles after Revision 3 to this Service Bulletin is released, whichever is later. REPEAT INSPECTIONS Repeat inspections at the intervals shown on the first page of this Appendix D. **NOTE:**This repair was removed from the 737-100/200 SRM 53-10-4, Figure 12 or the 737-300 SRM 53-80-08, Repair 4 or 737-400 SRM 53-80-08, Repair 4 or 737-500 SRM 53-80-08, Repair 4 .

**Appendix D: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 12 OR 737-300/400/500 SRM 53-80-08 REPAIR 4**  **(SHEET 3 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 70 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Appendix E: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 13 OR 737-300/400/500 SRM 53-80-08 REPAIR**  **5 (SHEET 1 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 71 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT Appendix E: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 13 OR 737-300/400/500 SRM 53-80-08 REPAIR**  **5 (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 72 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**ACTION Remove the repair and replace with the 737-100/200 SRM 53-10-4, Figure 3A repair, or 737-300 SRM 53-80-08, Repair 11 or 737-400 SRM 53-80-08, Repair 11 or 737-500 SRM 53-80-08, Repair 11 within 6,000 Flight Cycles after Revision 3 to this Service Bulletin is released. **NOTE:**This repair was removed from the 737-100/200 SRM 53-10-4, Figure 13 or 737-300 SRM 53-80-08, Repair 5 or 737-400 SRM 53-80-08, Repair 5 or 737-500 SRM 53-80-08, Repair 5.

**Appendix E: OBSOLETE 737-100/200 SRM 53-10-4 FIGURE 13 OR 737-300/400/500 SRM 53-80-08 REPAIR 5**  **(SHEET 3 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 17, 1999 737-53A1214 Revision 4 December 16, 2011 73 of 73 **BOEING SERVICE BULLETIN 737-53A1214 ALERT**  **ALERT**