# Boeing Alert Service Bulletin 737-53A1279: Revision 1 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2011-1162; AD 2011-23-05 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-53A1279](https://openairdocs.org/service-documents/boeing/737-53a1279.md) - Title as filed: Boeing - Service Bulletin - Pages: 227 - PDF: https://openairdocs.org/files/sha256/33/f8/33f8cce2fb292abfed6a72d8ef5641487dee50c37c02fe378fcbeadb48092b3b - Page: https://openairdocs.org/service-documents/boeing/737-53a1279/file/33f8cce2fb29 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1279 Original Issue: December 18, 2007 Revision 1: September 02, 2011 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 21 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole 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all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2007 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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: December 18, 2007 737-53A1279Revision 1: September 02, 2011 1 of 159 3.0 ### Page 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 2 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 Summary ...................................................... 7 1. PLANNING INFORMATION ........................................ 1 1 A. Effectivity ............................................... 1 1 1. Airplanes ............................................ 1 1 2. Spares Affected ........................................ 1 7 B. Concurrent Requirements ...................................... 1 7 C. Reason ................................................ 1 8 D. Description .............................................. 1 9 E. Compliance .............................................. 2 0 F. Approval ............................................... 2 4 G. Manpower .............................................. 2 5 H. Weight and Balance Changes .................................... 2 6 I. Electrical Load Data ......................................... 2 7 J. References .............................................. 2 7 1. Existing Data: ......................................... 2 7 2. Data supplied with this Service Bulletin: ........................... 2 7 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 2 7 K. Publications Affected ........................................ 2 8 L. Interchangeability and Intermixability of Parts ........................... 2 8 2. MATERIAL INFORMATION ........................................ 2 9 A. Material - Price and Availability ................................... 2 9 B. Industry Support Information .................................... 2 9 C. Parts Necessary For Each Airplane ................................. 2 9 1. Kits/Parts: ........................................... 2 9 2. Parts and Materials Supplied by the Operator: ........................ 2 9 3. Parts Modified and Reidentified: ............................... 2 9 4. Parts Removed and Not Replaced: .............................. 2 9 D. Parts Necessary to Change Spares ................................. 2 9 E. Special Tooling - Price and Availability ............................... 2 9 F. Special Tooling Necessary to do this Service Bulletin ....................... 3 0 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 1 A. GENERAL INFORMATION ..................................... 3 1 B. WORK INSTRUCTIONS ....................................... 3 1 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL [Group 1] ............................................ 4 1 FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL [Group 3] ............................................ 4 5 FIGURE 3: FORWARD CARGO BAY - AFT BULKHEAD PANELS - REMOVAL ............ 4 9 FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 1] .................................................. 5 1 FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 2] .................................................. 5 6 FIGURE 6: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 3] .................................................. 6 1 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 3 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 4 FIGURE 7: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 1] ................... 6 6 FIGURE 8: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 2] ................... 7 3 FIGURE 9: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 3] ................... 8 0 FIGURE 10: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 1] .................. 8 7 FIGURE 11: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 2] .................. 9 5 FIGURE 12: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 3] ................. 1 0 3 FIGURE 13: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 1] ................. 1 1 1 FIGURE 14: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 2] ................. 1 1 9 FIGURE 15: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 3] ................. 1 2 7 FIGURE 16: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 1 ] ................................................ 1 3 5 FIGURE 17: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 2 ] ................................................ 1 4 0 FIGURE 18: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 3 ] ................................................ 1 4 5 FIGURE 19: FORWARD CARGO BAY - AFT BULKHEAD PANELS - INSTALL ............ 1 5 0 FIGURE 20: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - INSTALL [Group 1] ............................................ 1 5 2 FIGURE 21: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - INSTALL [Group 3] ............................................ 1 5 6 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 4 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-53A1279Original Issue: December 18, 2007 Revision 1: September 02, 2011 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 21 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-02-06 R1 is related to this service bulletin. No More work is necessary on the airplanes changed in accordance with the original issue of this service bulletin. REASON FOR REVISION This revision is sent to update Paragraph 1.E.Compliance with new inspection thresholds and separate compliance tables by airplane group. More background information is added and other references are updated throughout. These sections were changed: 1. Paragraph 1.C.Reason - added background information 2. Paragraph 1.D.Description - added request for information from operators 3. Paragraph 1.E.Compliance - updated and added new table, added DTI information 4. Paragraph 1.F.Approval - added AD information 5. Paragraph 1.J.References - added AD and SRP information 6. Paragraph 1.K.Publications Affected - added DTI statement 7. Minor text updates throughout 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. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 5 of 159 ### Page 6 REVISION HISTORY December 18, 2007Original Issue: September 02, 2011Revision 1: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 6 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 7 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-53A1279Original Issue: December 18, 2007 Revision 1: September 02, 2011 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 21 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole 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 This service bulletin gives instructions to inspect a wire penetration hole for cracking in the forward cargo compartment frames and frame reinforcements, between Stringer S-20 and S-21, on both left and right sides of the airplane. It also provides repair instructions for cracking at the wire penetration hole and instructions for a preventative modification. Undetected cracking in fuselage frames at the wire penetration hole intended for wire routing will reduce the frames structural capability below fail-safe load limits. Undetected cracking in the frames could lead to cracking in the skin and could result in rapid depressurization of the airplane. Boeing has received reports of cracking in the frame, or in the frame and frame reinforcement, common to the 1.04 inch nominal diameter wire penetration hole intended for wire routing, between S-20 and S-21, on both left and right sides of the airplane. The cracked frames are located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes. Cracking is occurring at the 1.04 inch nominal diameter wire penetration hole due to the effect of operating loads in combination with the stress concentration at the 1.04 inch nominal hole. Boeing received a report of frame cracking from an operator at the 1.04 inch nominal diameter wire penetration hole on a 737-400 airplane. The airplane had one cracked frame. Boeing has since received reports of more than fifty cracked frames at the 1.04 inch nominal diameter wire penetration hole on more than twenty airplanes, all either 737-300 or 737-500 airplanes. The airplanes had accumulated between 35,832 and 66,694 flight cycles. The cracking initiated at the 1.04 inch nominal diameter wire penetration hole and grew towards the inner chord. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 7 of 159 ### Page 8 Boeing received a report of four cracked frames at BS 500B, BS 500C, BS 500D and BS 520 in the forward cargo compartment between S-20L and S-21L on a 737-300 airplane. The cracks at BS 500B and BS 500C were completely through the frame and fail-safe chord. The BS 500B frame was also cracked on the right hand side. The airplane had 44,535 flight cycles and 44,876 flight hours. Though the airplane was above the AD and service bulletin threshold of 32,000 flight cycles, the cracking was discovered before the airplane had reached the compliance time of the AD and of the original issue of this service bulletin. In total, Boeing has received more than 50 reports of frame cracking at the 1.04 inch nominal diameter wire penetration hole on 24 airplanes. Details of the cracking are as follows: — The cracking occurred at three frame stations on 737-300 airplanes, on four frame stations on 737-500 airplanes, and at one frame station on one 737-400 airplane. — Sixteen airplanes had cracking on multiple frames. — 10 frames had cracking at adjacent frames. — 43 frames had cracking only at the inboard side of the 1.04 inch nominal diameter wire penetration hole in the frame inner chord or in the frame and frame reinforcement inner chord. — 3 frames had cracking at the outboard side of the 1.04 inch nominal diameter wire penetration hole in the frame and the frame reinforcement. 2 of these frames were severed. — Some frames had additional cracking at either the standoff/tooling holes or at the 0.50 inch diameter hole positioned below the 1.04 inch nominal diameter wire penetration hole. This service bulletin gives instructions to inspect the 1.04 inch nominal diameter wire penetration hole for cracking in the frame and frame reinforcement, between S-20 and S-21, on both left and right sides of the airplane. It also provides repair instructions for cracking at the wire penetration hole and instructions for a preventative modification. An Inspection for cracking of the area and any necessary repair will assure the structural integrity of the fuselage. Boeing Service Related Problem (SRP) 737-SRP-53-0289 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0377 is related to this service bulletin. ACTION Get access to the forward cargo bay. Remove the cargo handling system, if installed. Remove the wire shrouds, sidewall linings, aft bulkhead panels and insulation blankets, on both sides of the airplane to get access to frames STA 500B - STA 520 on 737-300 and -400 airplanes and STA 482 - STA 520 on 737-500 airplanes. Unscrew the power feeder cable guides as required, and move them away from the hole. Do a High Frequency Eddy Current (HFEC) inspection of the frame and frame reinforcement between S-20 and S-21 for cracking. If cracking is found at the 1.04 inch nominal diameter wire penetration hole, do additional HFEC inspections for cracking at the 0.50 inch diameter hole between S-20 and S-21 and all standoff/tooling hole locations between S-19 and S-22. If no additional cracking is found at the 0.50 inch or standoff/tooling holes, repair cracking at the wire penetration hole as given in this Service Bulletin. If additional cracking is found at the 0.50 inch or standoff/tooling holes, contact Boeing for repair instructions. Repair all cracking damage. If no cracking is found at the 1.04 inch nominal diameter wire penetration hole, either accomplish the preventative modification as given in this service bulletin, or restore access, put the airplane back to a serviceable condition and do repeat inspections at the intervals given in Paragraph 1.E., Compliance . EFFECTIVITY 737-300/400/500 Series Airplanes. Refer to Paragraph 1.A.1 Airplanes, for the list of affected airplanes. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 8 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 9 COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-02-06 R1 is related to this service bulletin. 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. See Service Bulletin Paragraph 1.E., for compliance information. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. MANPOWER See Service Bulletin Paragraph 1.G., for manpower information. MATERIAL INFORMATION Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability . BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 9 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 10 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT SEE S-19R TYPICAL CRACKING AT OUTBOARD AND INBOARD SIDE OF 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE. IF NO CRACKING IS FOUND AT THE 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE IS FOUND, EITHER DO REPEAT INSPECTIONS AS GIVEN IN PARAGRAPH I.E. COMPLIANCE, OR ACCOMPLISH THE PREVENTATIVE MODIFICATION AS GIVEN IN THIS SERVICE BULLETIN. INSPECT THE 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE FOR CRACKING. S-22R S-20R IF CRACKING AT THE 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE IS FOUND, INSPECT THE 0.50 INCH DIAMETER HOLE AND ALL STANDOFF/TOOLING HOLES BETWEEN STRINGER 19 AND STRINGER 22. IF NO CRACKING IS S-21R FOUND AT THE 0.50 INCH OR STANDOFF/TOOLING HOLES, REPAIR CRACKING AT THE WIRE PENETRATION HOLE AS GIVEN IN UP THIS SERVICE BULLETIN. IF ADDITIONAL CRACKING IS FOUND INBD < AT THE 0.50 INCH OR STANDOFF/TOOLING HOLES, CONTACT BOEING FOR REPAIR INSTRUCTIONS. VIEW LOOKING FORWARD (TYPICAL FRAME SECTION) RIGHT SIDE SHOWN 1339121 LEFT SIDE OPPOSITE Original Issue: December 18, 2007 Revision 1: September 02, 2011 737-53A1279 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 159 ### Page 11 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1279 Original Issue: December 18, 2007 Revision 1: September 02, 2011 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 21 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole 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 Document D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. DESCRIPTIONCONFIGURATIONGROUP 737-300 Series Airplanes, Line numbers 1001-3130.-1 737-400 Series Airplanes, Line numbers 1487-3132.-2 737-500 Series Airplanes, Line numbers 1718-3116.-3 Airplane Models: 737-300, 737-400, 737-500 GroupVariable Number 2PJ301 - PJ302 2PJ551 - PJ561 2PJ601 - PJ615 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 11 of 159 ### Page 12 GroupVariable Number 2PJ811 2PJ816 - PJ817 1PM381 - PM399 1PM401 - PM417 1PM541 - PM550 2PM551 - PM564 1PP001 - PP054 1PP101 - PP169 1PP181 - PP199 1PP201 - PP205 1PP221 1PP231 - PP243 1PP281 - PP286 1PP301 - PP305 1PP351 - PP353 1PP376 - PP384 1PP391 - PP393 1PP401 - PP440 1PP471 - PP475 1PP501 - PP522 1PP631 - PP634 1PP651 - PP652 1PP671 - PP699 1PP701 - PP733 1PP771 - PP779 1PP801 - PP808 1PP821 - PP827 1PP831 - PP848 1PP851 - PP852 1PP861 - PP877 1PP891 - PP899 1PP901 - PP936 1PP946 - PP948 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 12 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 13 GroupVariable Number 1PP951 - PP952 1PP961 - PP967 1PP981 - PP991 1PP993 1PQ001 - PQ016 1PQ026 - PQ041 1PQ051 - PQ092 1PQ101 - PQ199 1PQ201 - PQ202 1PQ221 - PQ237 1PQ241 - PQ243 1PQ251 - PQ267 1PQ281 - PQ299 1PQ301 - PQ307 1PQ331 - PQ332 1PQ341 - PQ348 1PQ361 - PQ373 1PQ391 - PQ395 1PQ401 - PQ418 1PQ421 1PQ431 - PQ438 1PQ447 - PQ448 1PQ451 1PQ454 1PQ471 - PQ475 1PQ479 - PQ481 1PQ486 - PQ487 1PQ491 - PQ493 1PQ771 - PQ772 1PQ791 - PQ793 1PQ801 - PQ805 1PQ931 - PQ935 1PQ951 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 13 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 14 GroupVariable Number 1PQ971 - PQ997 1PR001 - PR017 1PR021 - PR034 1PR041 - PR045 1PR061 - PR072 1PR077 - PR082 1PR091 - PR092 1PR096 1PR101 1PR121 - PR122 1PR131 - PR132 1PR141 - PR143 1PR161 - PR172 1PR181 1PS601 - PS631 1PS636 - PS638 1PS641 - PS644 1PS651 - PS657 1PS666 - PS669 1PS691 - PS692 1PS701 - PS706 1PS751 - PS799 1PS811 1PS836 - PS837 1PS841 - PS846 1PS851 - PS852 1PS856 1PS861 - PS863 1PS866 - PS868 1PS871 - PS874 1PS896 - PS897 1PS901 - PS941 1PS956 - PS957 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 14 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 15 GroupVariable Number 1PS961 - PS963 1PS971 - PS978 3PT001 - PT015 3PT021 - PT031 3PT041 - PT064 3PT101 - PT105 3PT121 - PT138 3PT146 - PT148 3PT161 - PT170 3PT181 - PT188 3PT211 - PT220 3PT295 3PT301 - PT309 3PT331 - PT360 3PT381 - PT399 3PT401 - PT438 3PT501 - PT517 3PT561 - PT565 3PT581 - PT586 3PT611 - PT621 3PT641 - PT644 3PT651 - PT656 3PT671 - PT672 3PT681 - PT685 3PT701 - PT703 3PT716 - PT717 3PT721 - PT725 3PT801 - PT834 3PT851 - PT854 3PT871 - PT886 3PT901 - PT930 3PT971 - PT973 3PT981 - PT985 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 15 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 16 GroupVariable Number 3PT996 3PU001 - PU025 3PU301 3PU311 - PU313 2PV001 - PV055 2PV201 - PV209 2PV226 - PV229 2PV231 - PV237 2PV271 - PV272 2PV281 - PV287 2PV296 2PV301 - PV302 2PV351 2PV356 - PV357 2PW001 - PW054 2PW061 - PW068 2PW072 2PW086 - PW088 2PW091 - PW094 2PW101 - PW102 2PW106 2PW111 - PW120 2PW156 - PW157 2PW161 - PW171 2PW201 - PW252 2PW261 - PW268 2PW271 - PW276 2PW278 2PW281 - PW293 2PW296 2PW301 - PW327 2PW401 - PW408 2PW411 - PW418 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 16 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 17 GroupVariable Number 2PW421 - PW424 2PW431 - PW435 2PW441 - PW450 2PW461 - PW467 2PW501 - PW504 2PW511 - PW522 2PW524 - PW550 2PW556 - PW557 2PW561 - PW564 2PW571 - PW576 2PW591 - PW596 2PW611 - PW622 2PW631 - PW637 2PW661 - PW662 2PW681 - PW683 2PW701 - PW702 2PW711 - PW717 2PW741 - PW742 2PW761 2PW771 2PW831 2PW851 - PW856 2. Spares Affected None. B. Concurrent Requirements None. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 17 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 18 C. Reason This service bulletin gives instructions to inspect a wire penetration hole for cracking in the forward cargo compartment frames and frame reinforcements, between Stringer S-20 and S-21, on both left and right sides of the airplane. It also provides repair instructions for cracking at the wire penetration hole and instructions for a preventative modification. Undetected cracking in fuselage frames at the wire penetration hole intended for wire routing will reduce the frames structural capability below fail-safe load limits. Undetected cracking in the frames could lead to cracking in the skin and could result in rapid depressurization of the airplane. Boeing has received reports of cracking in the frame, or in the frame and frame reinforcement, common to the 1.04 inch nominal diameter wire penetration hole intended for wire routing, between S-20 and S-21, on both left and right sides of the airplane. The cracked frames are located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes. Cracking is occurring at the 1.04 inch nominal diameter wire penetration hole due to the effect of operating loads in combination with the stress concentration at the 1.04 inch nominal hole. Boeing received a report of frame cracking from an operator at the 1.04 inch nominal diameter wire penetration hole on a 737-400 airplane. The airplane had one cracked frame. Boeing has since received reports of more than fifty cracked frames at the 1.04 inch nominal diameter wire penetration hole on more than twenty airplanes, all either 737-300 or 737-500 airplanes. The airplanes had accumulated between 35,832 and 66,694 flight cycles. The cracking initiated at the 1.04 inch nominal diameter wire penetration hole and grew towards the inner chord. Boeing received a report of four cracked frames at BS 500B, BS 500C, BS 500D and BS 520 in the forward cargo compartment between S-20L and S-21L on a 737-300 airplane. The cracks at BS 500B and BS 500C were completely through the frame and fail-safe chord. The BS 500B frame was also cracked on the right hand side. The airplane had 44,535 flight cycles and 44,876 flight hours. Though the airplane was above the AD and service bulletin threshold of 32,000 flight cycles, the cracking was discovered before the airplane had reached the compliance time of the AD and of the original issue of this service bulletin. In total, Boeing has received more than 50 reports of frame cracking at the 1.04 inch nominal diameter wire penetration hole on 24 airplanes. Details of the cracking are as follows: — The cracking occurred at three frame stations on 737-300 airplanes, on four frame stations on 737-500 airplanes, and at one frame station on one 737-400 airplane. — Sixteen airplanes had cracking on multiple frames. — 10 frames had cracking at adjacent frames. — 43 frames had cracking only at the inboard side of the 1.04 inch nominal diameter wire penetration hole in the frame inner chord or in the frame and frame reinforcement inner chord. — 3 frames had cracking at the outboard side of the 1.04 inch nominal diameter wire penetration hole in the frame and the frame reinforcement. 2 of these frames were severed. — Some frames had additional cracking at either the standoff/tooling holes or at the 0.50 inch diameter hole positioned below the 1.04 inch nominal diameter wire penetration hole. This service bulletin gives instructions to inspect the 1.04 inch nominal diameter wire penetration hole for cracking in the frame and frame reinforcement, between S-20 and S-21, on both left and right sides of the airplane. It also provides repair instructions for cracking at the wire penetration hole and instructions for a preventative modification. An Inspection for cracking of the area and any necessary repair will assure the structural integrity of the fuselage. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 18 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 19 Boeing Service Related Problem (SRP) 737-SRP-53-0289 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0377 is related to this service bulletin. Revision 1 is sent to update Paragraph 1.E.Compliance with new inspection thresholds and separate compliance tables by airplane group. More background information is added and other references are updated throughout. D. Description Get access to the forward cargo bay. Remove the cargo handling system, if installed. Remove the wire shrouds, sidewall linings, aft bulkhead panels and insulation blankets, on both sides of the airplane to get access to frames STA 500B - STA 520 on 737-300 and -400 airplanes and STA 482 - STA 520 on 737-500 airplanes. Unscrew the power feeder cable guides as required, and move them away from the hole. Do a High Frequency Eddy Current (HFEC) inspection of the frame and frame reinforcement between S-20 and S-21 for cracking. If cracking is found at the 1.04 inch nominal diameter wire penetration hole, do additional HFEC inspections for cracking at the 0.50 inch diameter hole between S-20 and S-21 and all standoff/tooling hole locations between S-19 and S-22. If no additional cracking is found at the 0.50 inch or standoff/tooling holes, repair cracking at the wire penetration hole as given in this Service Bulletin. If additional cracking is found at the 0.50 inch or standoff/tooling holes, contact Boeing for repair instructions. Repair all cracking damage. WHEN CONTACTING BOEING FOR THE REPAIR PLAN, PLEASE INCLUDE THE FOLLOWING INFORMATION TO FACILITATE REPAIR PLAN DEVELOPMENT: 1. INSPECTION METHOD USED AND NOTCH CALIBRATION SIZE. 2. LOCATIONS OF ALL CRACKS FOUND. 3. WHETHER ANY CRACK FOUND IS IN THE FRAME, THE FRAME REINFORCEMENT, OR BOTH. 4. THE LENGTH OF ALL CRACKS FOUND. 5. IDENTIFY ALL LOCATIONS OF STANDOFF HOLES BETWEEN S-19 AND S-22 ON A DRAWING. INCLUDE SPACING BETWEEN THE STANDOFF HOLE AND IT'S NEAREST FASTENER. Send your report to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, AIRLINE SUPPORT Boeing would like to gather information on cracking found by the service bulletin inspections. Report crack inspection results to Boeing. In the report, identify the following: – Operator – Airplane ID (series and line number or variable number) – Flight cycles and flight hours when service bulletin inspection was accomplished – Results of inspections (crack findings or no crack findings) – Inspection method used and notch calibration size – If cracking is found, provide: frame location (BS LH or RH), parts cracked (frame web, reinforcement angle, and/or fail safe chord), location of crack (1.04 inch wire penetration hole, 1/2 inch hole, or other) and length of cracks. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 19 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 20 Retain all trimmed out frame sections (frame, frame reinforcement, and/or fail safe chord). Mark the frame station (BS and LH or RH) and the aircraft identification including the airplane cycles and hours, on each trimmed out section. Forward the samples to the following address: Spares Distribution Center Warranty and Overhaul Area, SSA 111 THE BOEING COMPANY Attention: Airline Support Manager / Cheri Tanner Mail Code 2L-78 2201 S 142nd ST PO BOX 3707 98124-2207 SEATAC WA 98168-3713 USA Forward to Post Production Fuselage Stress for engineering evaluation. Include a tag with the airplane information and Boeing Message Number (Service Request I.D.) along with a tracking number for the shipment. If no cracking is found at the 1.04 inch nominal diameter wire penetration hole, either accomplish the preventative modification as given in this service bulletin, or restore access, put the airplane back to a serviceable condition and do repeat inspections at the intervals given in Paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 208737-300 Group 2: Affected Maintenance Zones ZoneModel 208737-400 Group 3: Affected Maintenance Zones ZoneModel 208737-500 E. Compliance Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-02-06 R1 is related to this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 20 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 21 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. Boeing recommends that the inspections given in this service bulletin be done at the times specified in the tables below. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 21 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 22 Group 1: Table 1: Forward Cargo Bay - Inspection of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 30,000 total flight cy- cles (a) Do a HFEC Inspection for cracking at the 1.04 inch nominal diameter wire penetration hole in the forward cargo bay frames and frame reinforcements between S-20 and S-21 as given in Ac- complishment Instruction Paragraph 3.B.2. Part 2. Airplanes with less than 40,000 total flight cycles at the date on Revision 1 of this service bulletin OR Within 90 days from the date of revision 1 of this service bulletin (whichever occurs later) -For Group 1 (737-300) air- planes line number 1001- 2565, within 30 days from the date of revision 1 of this service bulletin (a) Do a HFEC Inspection for cracking at the 1.04 inch nominal diameter wire penetration hole in the forward cargo bay frames and frame reinforcements between S-20 and S-21 as given in Ac- complishment Instruction Paragraph 3.B.2. Part 2. Airplanes with 40,000 or more total flight cycles at the date of revision 1 of this ser- vice bulletin For Group 1 (737-300) air- planes line number 2567- 3130, within 90 days from the date of revision 1 of this service bulletin -Before Further FlightDo a HFEC Inspection for cracking at the 0.50 inch diameter hole between S- 20 and S-21 and all standoff/tooling holes between S-19 and S-22 as given in Accomplishment Instruction Para- graph 3.B.3. Part 3. Install repair as giv- en in Accomplishment Instruction Para- graph 3.B.3. Part 3. After accomplishment of the Paragraph 3.B.2. Part 2 Ini- tial Inspection, and cracking is found at 1.04 inch nominal diameter wire penetration hole in the frame or in the frame reinforcement. 4,500 flight cy- cles (b) Within 4,500 flight cycles or 90 days from the date of revi- sion 1 of this service bulletin, whichever occurs later (a) Do a HFEC Inspection for cracking at the 1.04 inch nominal diameter wire penetration hole in the forward cargo bay frames and frame reinforcements between S-20 and S-21 as given in Ac- complishment Instruction Paragraph 3.B.4. Part 4. After accomplishment of the Paragraph 3.B.2. Part 2 - Initial Inspection or Para- graph 3.B.4. Part 4 - Repeat Inspection and no cracking is found. -Before Further FlightDo a HFEC Inspection for cracking at the 0.50 inch diameter hole between S- 20 and S-21 and all standoff/tooling holes between S-19 and S-22 as given in Accomplishment Instruction Para- graph 3.B.3. Part 3. Install repair as giv- en in Accomplishment Instruction Para- graph 3.B.3. Part 3. After accomplishment of the Paragraph 3.B.4. Part 4 Re- peat Inspection, and crack- ing is found at 1.04 inch nominal diameter wire pene- tration hole in the frame or in the frame reinforcement. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 22 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 23 Group 1: Table 1: Forward Cargo Bay - Inspection of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition (a) Inspections are not necessary at locations that have been repaired as given by a Boeing Company autho- rized representative approved frame repair or repaired as given in Accomplishment Instruction Paragraph 3.B.3 Part 3. (b) Accomplishment of repair or preventative modification on a frame prior to further flight after the initial or any repeat inspection terminates the repeat inspections as given in this service bulletin for that frame only. Group 2-3: Table 2: Forward Cargo Bay - Inspection of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 30,000 total flight cy- cles (a) Do a HFEC Inspection for cracking at the 1.04 inch nominal diameter wire penetration hole in the forward cargo bay frames and frame reinforcements between S-20 and S-21 as given in Ac- complishment Instruction Paragraph 3.B.2. Part 2. All airplanes OR Within 90 days from the date of revision 1 of this service bulletin (whichever occurs later) -Before Further FlightDo a HFEC Inspection for cracking at the 0.50 inch diameter hole between S- 20 and S-21 and all standoff/tooling holes between S-19 and S-22 as given in Accomplishment Instruction Para- graph 3.B.3. Part 3. Install repair as giv- en in Accomplishment Instruction Para- graph 3.B.3. Part 3. After accomplishment of the Paragraph 3.B.2. Part 2 Ini- tial Inspection, and cracking is found at 1.04 inch nominal diameter wire penetration hole in the frame or in the frame reinforcement. 4,500 flight cy- cles (b) Within 4,500 flight cycles or 90 days from the date of revi- sion 1 of this service bulletin, whichever occurs later (a) Do a HFEC Inspection for cracking at the 1.04 inch nominal diameter wire penetration hole in the forward cargo bay frames and frame reinforcements between S-20 and S-21 as given in Ac- complishment Instruction Paragraph 3.B.4. Part 4. After accomplishment of the Paragraph 3.B.2. Part 2 - Initial Inspection or Para- graph 3.B.4. Part 4 - Repeat Inspection and no cracking is found. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 23 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 24 Group 2-3: Table 2: Forward Cargo Bay - Inspection of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before Further FlightDo a HFEC Inspection for cracking at the 0.50 inch diameter hole between S- 20 and S-21 and all standoff/tooling holes between S-19 and S-22 as given in Accomplishment Instruction Para- graph 3.B.3. Part 3. Install repair as giv- en in Accomplishment Instruction Para- graph 3.B.3. Part 3. After accomplishment of the Paragraph 3.B.4. Part 4 Re- peat Inspection, and crack- ing is found at 1.04 inch nominal diameter wire pene- tration hole in the frame or in the frame reinforcement. (a) Inspections are not necessary at locations that have been repaired as given by a Boeing Company autho- rized representative approved frame repair or repaired as given in Accomplishment Instruction Paragraph 3.B.3 Part 3. (b) Accomplishment of repair or preventative modification on a frame prior to further flight after the initial or any repeat inspection terminates the repeat inspections as given in this service bulletin for that frame only. NOTE: Damage Tolerance Post Repair Inspection: Damage tolerance post repair inspections for the SRM repairs referenced in this service bulletin are specified within each of the SRM repairs. 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. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the inspections, repairs and modifications defined in this service bulletin as an alternative method of compliance to the requirements of paragraphs (g) and (h) of AD 2009-02-06 or to the requirements of paragraphs (h) and (i) of AD 2009-02-06 R1. Where this service bulletin specifies contacting Boeing for instructions for removing damage and repairing cracking: before further flight, remove the damage or repair the cracking using a method approved in accordance with the procedures specified in paragraph (i) of AD 2009-02-06 or paragraph (j) of AD 2009-02-06 R1. All provisions of AD 2009-02-06 or AD 2009-02-06 R1 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 24 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 25 G. Manpower The table below shows an estimate of the task hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to inspect the work — Time to cure the materials — Time to make the parts — Time to find the tools. Group 1: Elapsed HoursTask HoursNumber of Persons Task 1.252.502Open Sidewalls and Blankets Open Access 0.750.751Figure 1 0.500.501Figure 3 0.300.301Figure 4 2.502.501Figure 7 (a)Inspect 2.002.001Figure 10 (b) 1.501.501Figure 13 (a) 0.300.301Figure 16Close Access 0.500.501Figure 19 0.750.751Figure 20 1.252.502Close Sidewalls and Blankets 8.1010.60TOTAL FOR EACH AIRPLANE (a) The FIGURE 13 inspection is optional to the FIGURE 7 inspection and is not included in the total. (b) This inspection is only necessary if cracking is found and is not included in the total. Group 2: Elapsed HoursTask HoursNumber of Persons Task 2.755.502Open Sidewalls and Blankets Open Access 0.500.501Figure 3 0.300.301Figure 5 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 25 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 26 Group 2: Elapsed HoursTask HoursNumber of Persons Task 3.503.501Figure 8 (a)Inspect 3.003.001Figure 11 (b) 1.501.501Figure 14 (a) 0.300.301Figure 17Close Access 0.500.501Figure 19 2.755.502Close Sidewalls and Blankets 13.3516.10TOTAL FOR EACH AIRPLANE (a) The FIGURE 14 inspection is optional to the FIGURE 8 inspection and is not included in the total. (b) This inspection is only necessary if cracking is found and is not included in the total. Group 3: Elapsed HoursTask HoursNumber of Persons Task 0.751.502Open Sidewalls and Blankets Open Access 0.750.751Figure 2 0.500.501Figure 3 0.300.301Figure 6 2.502.501Figure 9 (a)Inspect 2.002.001Figure 12 (b) 1.501.501Figure 15 (a) 0.300.301Figure 18Close Access 0.500.501Figure 19 0.750.751Figure 21 0.751.502Close Sidewalls and Blankets 7.108.60TOTAL FOR EACH AIRPLANE (a) The FIGURE 15 inspection is optional to the FIGURE 9 inspection and is not included in the total. (b) This inspection is only necessary if cracking is found and is not included in the total. H. Weight and Balance Changes None. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 26 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 27 I. Electrical Load Data Not changed. J. References 1. Existing Data: a. 737-300 Structural Repair Manual (SRM) 53-00-07 . b. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-52-73 , 25-52-91 . c. 737-400 Structural Repair Manual (SRM) 53-00-07 . d. 737-500 Structural Repair Manual (SRM) 53-00-07 . e. 737 Non-Destructive Testing (NDT) Manual, Part 6, 51-00-00 , Figure 4, Figure 16 and Figure 23. f. Boeing Drawing 65-88700. g. Boeing Parts Standards Document D-590. h. Service Related Problem (SRP) 737-SRP-53-289, 737-SRP-53-0377. i. FAA Airworthiness Directive AD 2009-02-06 R1 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number FRAME INSTALLATION - BODY STATION 52065-46534 FRAME INSTALLATION - BODY STATION 500B65C22908 FRAME INSTALLATION - BODY STATION 500C65C22909 FRAME INSTALLATION - BODY STATION 500D65C22910 SHROUD INSTALLATION - WIRE FORWARD CARGO AREA65C28198 FRAME INSTALLATION - BODY STATION 500E65C32351 FRAME INSTALLATION - BODY STATION 500F65C32352 FRAME INSTALLATION - BODY STATION 500G65C32353 FRAME INSTALLATION - BODY STA 48265C34355 FRAME INSTALLATION - BODY STA 482A65C34356 FRAME INSTALLATION - BODY STA 482B65C34357 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 27 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 28 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. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 28 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 29 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: NotesNameQTYPart Number / Specification (a)CARGO LINER JOINT SEALING TAPE36 YardsBMS 5-146 Optional P212HD (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. 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 Accomplishment of High Frequency Eddy Current edge inspections may be facilitated by using a probe which has a 90 degree zero drop. When ordering the probe, specify the type of connector, frequency range and the eddy current instrument model the probe will be used on. Part number of a probe with a 90 degree zero drop: PAB-90-60.03 FX The probe vendor contact is: — EC/NDT BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 29 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 30 1020 SOUTH 344th STREET SUITE 214 FEDERAL WAY, WA 98003 USA Phone Number (253) 815-0797 Fax (253) 815-0827 F. Special Tooling Necessary to do this Service Bulletin High Frequency Eddy Current inspection tools are necessary to do the change given in this service bulletin. To get the High Frequency Eddy Current inspection tools, refer to Paragraph 2.E., Special Tooling - Price and Availability . BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 30 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 31 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. 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 the 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. 6. These work instructions refer to procedures included on 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 "as given in" are included in the instruction, the procedure in the Boeing document must be used. B. WORK INSTRUCTIONS 1. PART 1 - ACCESS a. Get access to the forward cargo bay. b. Remove and keep the forward cargo bay handling system if installed. c. Group 1: Remove and keep the wire shroud. Refer to FIGURE 1 as an accepted procedure. d. Group 3: Remove and keep the wire shroud. Refer to FIGURE 2 as an accepted procedure. e. Remove and keep the aft bulkhead access panels. Refer to FIGURE 3 as an accepted procedure. NOTE: As an option, it is acceptable to remove air conditioning equipment at Station (STA) 520 if additional access is required to accomplish the inspection as given in this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 31 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 32 f. Group 1: Remove and keep sidewall panels 1314X and 1321X between STA 500 and STA 500D. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. g. Group 2: Remove and keep sidewall panels 1316Y, 1317Y, 1318Y, 1325Y, 1326Y and 1327Y between STA 500 and STA 500G. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. h. Group 3: Remove and keep sidewall panels 1309Z and 1315Z between STA 460 and STA 482B. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. i. Group 1-2: Remove and keep or move the insulation blankets as required between STA 500A to STA 540 and Stringer (S)-19 to S-22, left and right sides. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. j. Group 3: Remove and keep or move the insulation blankets as required between STA 460 to STA 540 and Stringer (S)-19 to S-22, left and right sides. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. k. Group 1: Move the guide assembly for the power feeder cable away from the frame as given in FIGURE 4. l. Group 2: Move the guide assembly for the power feeder cable away from the frame as given in FIGURE 5. m. Group 3: Move the guide assembly for the power feeder cable away from the frame as given in FIGURE 6. 2. PART 2 - INITIAL INSPECTION NOTE: Inspections are not necessary at locations that have been repaired as given by a Boeing Company authorized representative approved frame repair or repaired as given in PART 3 - REPAIR of this service bulletin. a. Group 1: STA 500B, STA 500C, STA 500D and STA 520 - Do one of the inspection options that follow: (1) Option 1: Do a High Frequency Eddy Current (HFEC) Surface Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 7. (a) At each Station, left or right, if any crack is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 32 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 33 1) Install the guide assemblies for the power feeder cable as given in FIGURE 16. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. (2) Option 2: Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 13. (a) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: 1) Install the guide assemblies for the power feeder cable as given in FIGURE 16. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. b. Group 2: STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520 - Do one of the inspection options that follow: (1) Option1: Do a High Frequency Eddy Current (HFEC) Surface Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 8. (a) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: 1) Install the guide assemblies for the power feeder cable as given in FIGURE 17. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. (2) Option 2: Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 14. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 33 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 34 (a) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: 1) Install the guide assemblies for the power feeder cable as given in FIGURE 17. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. c. Group 3: STA 482, STA 482A, STA 482B and STA 520 - Do one of the inspection options that follow: (1) Option 1: Do a High Frequency Eddy Current (HFEC) Surface Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 9. (a) At each Station, left or right, if any crack is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: 1) Install the guide assemblies for the power feeder cable as given in FIGURE 18. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. (2) Option 2: Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 15. (a) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (b) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or repeat inspections as given in the steps that follow: 1) Install the guide assemblies for the power feeder cable as given in FIGURE 18. 2) Do PART 6 - CLOSE ACCESS. 3) Do PART 4 - REPEAT INSPECTION at the interval given in Paragraph 1.E., Compliance. 3. PART 3 - REPAIR BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 34 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 35 a. Group 1: (1) At each Station, left or right, where cracking is found at the wire penetration hole: (a) Do a HFEC Inspection for cracking in the 0.50 inch diameter hole between S-20 and S-21 and all standoff/tooling holes in the frame and frame reinforcement, between S-19 and S-22 as given in FIGURE 10. 1) If the 0.50 inch hole and the standoff/tooling holes have no crack indications: a) Do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. b) Repair the frame as given in 737-300 SRM 53-00-07 Repair 13. 2) If cracking is found in the 0.50 inch hole and/or the standoff/tooling holes, repair all cracking in the frame. Contact Boeing for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of the repair as given in PART 3 terminates the Part 4 repeat inspections. b. Group 2: (1) At each Station, left or right, where cracking is found at the wire penetration hole: (a) Do a HFEC Inspection for cracking in the 0.50 inch diameter hole between S-20 and S-21 and all standoff/tooling holes in the frame and frame reinforcement, between S-19 and S-22 as given in FIGURE 11. 1) If the 0.50 inch hole and the standoff/tooling holes have no crack indications: a) Do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. b) Repair the frame as given in 737-400 SRM 53-00-07 Repair 13. 2) If cracking is found in the 0.50 inch hole and/or the standoff/tooling holes, repair all cracking in the frame. Contact Boeing for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of the repair as given in PART 3 terminates the Part 4 repeat inspections. c. Group 3: (1) At each Station, left or right, where cracking is found at the wire penetration hole: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 35 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 36 (a) Do a HFEC Inspection for cracking in the 0.50 inch diameter hole between S-20 and S-21 and all standoff/tooling holes in the frame and frame reinforcement, between S-19 and S-22 as given in FIGURE 12. 1) If the 0.50 inch hole and the standoff/tooling holes have no crack indications: a) Do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. b) Repair the frame as given in 737-500 SRM 53-00-07 Repair 13. 2) If cracking is found in the 0.50 inch hole and/or the standoff/tooling holes, repair all cracking in the frame. Contact Boeing for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of the repair as given in PART 3 terminates the Part 4 repeat inspections. 4. PART 4 - REPEAT INSPECTION NOTE: Inspections are not necessary at locations that have been repaired as given by a Boeing Company authorized representative approved frame repair or repaired as given in PART 3 - REPAIR of this service bulletin. a. Group 1: STA 500B, STA 500C, STA 500D and STA 520 - Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 13. (1) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (2) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or do the steps that follow: (a) Install the guide assemblies for the power feeder cable as given in FIGURE 16. (b) Do PART 6 - CLOSE ACCESS. (c) Repeat the Part 4 inspection at the interval given in Paragraph 1.E., Compliance. b. Group 2: STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520 - Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 14. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 36 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 37 (1) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (2) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or do the steps that follow: (a) Install the guide assemblies for the power feeder cable as given in FIGURE 17. (b) Do PART 6 - CLOSE ACCESS. (c) Repeat the Part 4 inspection at the interval given in Paragraph 1.E., Compliance. c. Group 3: STA 482, STA 482A, STA 482B and STA 520 - Do a HFEC Hole/Edge Inspection of the 1.04 inch nominal diameter wire penetration hole in the frame and frame reinforcement between S-20 and S-21 for cracking as given in FIGURE 15. (1) At each Station, left or right, if any cracking is found, do PART 3 - REPAIR at the section of frame where cracking is found. (2) If no cracking is found, do either PART 5 - PREVENTATIVE MODIFICATION, or do the steps that follow: (a) Install the guide assemblies for the power feeder cable as given in FIGURE 18. (b) Do PART 6 - CLOSE ACCESS. (c) Repeat the Part 4 inspection at the interval given in Paragraph 1.E., Compliance. 5. PART 5 - PREVENTATIVE MODIFICATION The preventative modification is applicable to frames for which either the PART 2 - INITIAL INSPECTION or the PART 4 - REPEAT INSPECTION has been accomplished, and the 1.04 inch nominal diameter wire penetration hole is crack free. a. Group 1: STA 500B, STA 500C, STA 500D and STA 520 (1) Inspect the 0.50 inch and standoff/tooling holes as given in FIGURE 10. (a) If no cracking is found at the 0.50 inch or the standoff/tooling holes, do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. (b) If cracking is found, contact Boeing for repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do an insurance cut at the wire penetration hole: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 37 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 38 (a) If the surface inspection was accomplished as given in FIGURE 7, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished as given in FIGURE 13, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. (3) Do the repair as given in 737-300 SRM 53-00-07 Repair 13, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 203 in Repair 13. NOTE: Accomplishment of the Preventative Modification as given in this section terminates the PART 4 - REPEAT INSPECTION. b. Group 2: STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520 (1) Inspect the 0.50 inch and standoff/tooling holes as given in FIGURE 11. (a) If no cracking is found at the 0.50 inch or the standoff/tooling holes, do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. (b) If cracking is found, contact Boeing for repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do an insurance cut at the wire penetration hole: (a) If the surface inspection was accomplished as given in FIGURE 8, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished as given in FIGURE 14, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. (3) Do the repair as given in 737-400 SRM 53-00-07 Repair 13, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 203 in Repair 13. NOTE: Accomplishment of the Preventative Modification as given in this section terminates the PART 4 - REPEAT INSPECTION. c. Group 3: STA 482, STA 482A, STA 482B and STA 520 (1) Inspect the 0.50 inch and standoff/tooling holes as given in FIGURE 12. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 38 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 39 (a) If no cracking is found at the 0.50 inch or the standoff/tooling holes, do a 0.03 inch insurance cut. Maintain a 63Ra or better surface finish. (b) If cracking is found, contact Boeing for repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) Do an insurance cut at the wire penetration hole: (a) If the surface inspection was accomplished as given in FIGURE 9, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished as given in FIGURE 15, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. (3) Do the repair as given in 737-500 SRM 53-00-07 Repair 13, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 203 in Repair 13. NOTE: Accomplishment of the Preventative Modification as given in this section terminates the PART 4 - REPEAT INSPECTION. 6. PART 6 - CLOSE ACCESS a. Group 1-2: Install removed insulation blankets between STA 500A to STA 540 and Stringer S-19 to S-22 left and right. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. b. Group 3: Install removed insulation blankets as between STA 460 to STA 540 and Stringer S-19 to S-22 left and right. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. c. Group 1: Install sidewall panels 1314X and 1321X between STA 500 and STA 500D. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. d. Group 2: Install sidewall panels 1316Y, 1317Y, 1318Y, 1325Y, 1326Y and 1327Y between STA 500 and STA 500G. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. e. Group 3: Install sidewall panels 1309Z and 1315Z between STA 460 and STA 482B. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. f. Install all air conditioning equipment that was removed for additional access and do the applicable function tests. g. Install the aft bulkhead access panels. Refer to FIGURE 19 as an accepted procedure. h. Group 1: Install the wire shroud. Refer to FIGURE 20 as an accepted procedure. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 39 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 40 i. Group 3: Install the wire shroud. Refer to FIGURE 21 as an accepted procedure. j. Install the forward cargo bay handling system, if removed. k. Put the airplane back to a serviceable condition. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1: September 02, 2011 40 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 41 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT This Figure applies only to: Group 1. FORWARD CARGO COMPARTMENT SEE A SEE SEE FWD FORWARD CARGO COMPARTMENT FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 1 OF 4) Original Issue: December 18, 2007 Revision 1 September 02, 2011 6LZIV£S-LEL BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. ### Page 42 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 2 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 42 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 43 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP To get access to the screws.--TapeRemove1 6BACS12FA3K12ScrewRemove/Keep2 6BACW10P106AWasher 6NAS43DD3-19Spacer FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 3 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 43 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 44 MORE DATAQTYIDENTIFICATIONNAMETASKSTEP 2BACS12FA( )K( )ScrewRemove/Keep3 2BACW10P43ALWasher 169-72995-3Wire ShroudRemove/Keep4 To get access to the screws.--TapeRemove5 6BACS12FA3K12ScrewRemove/Keep6 6BACW10P106AWasher 6NAS43DD3-19Spacer 2BACS12FA( )K( )ScrewRemove/Keep7 2BACW10P43ALWasher 169-72995-4Wire ShroudRemove/Keep8 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 4 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 44 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 45 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT This Figure applies only to: Group 3. FORWARD CARGO COMPARTMENT SEE A SEE SEE FWD FORWARD CARGO COMPARTMENT FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL (SHEET 1 OF 4) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 45 of 159 ### Page 46 FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL (SHEET 2 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 46 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 47 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP To get access to the screws.--TapeRemove1 6BACS12FA3K12ScrewRemove/Keep2 6BACW10P106AWasher 6NAS43DD3-19Spacer FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL (SHEET 3 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 47 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 48 MORE DATAQTYIDENTIFICATIONNAMETASKSTEP 2BACS12FA( )K( )ScrewRemove/Keep3 2BACW10P43ALWasher 169-72995-7Wire ShroudRemove/Keep4 To get access to the screws.--TapeRemove5 6BACS12FA3K12ScrewRemove/Keep6 6BACW10P106AWasher 6NAS43DD3-19Spacer 2BACS12FA( )K( )ScrewRemove/Keep7 2BACW10P43ALWasher 169-72995-8Wire ShroudRemove/Keep8 FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL (SHEET 4 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 48 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 49 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT FORWARD CARGO COMPARTMENT SEE FORWARD CARGO COMPARTMENT 1337041 FIGURE 3: FORWARD CARGO BAY - AFT BULKHEAD PANELS - REMOVAL (SHEET 1 OF 2) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 49 of 159 ### Page 50 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP Left Side11327Aft Bulkhead Ac- cess Panel Remove/Keep1 Center11330Aft Bulkhead Ac- cess Panel Remove/Keep2 Right Side11331Aft Bulkhead Ac- cess Panel Remove/Keep3 FIGURE 3: FORWARD CARGO BAY - AFT BULKHEAD PANELS - REMOVAL (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 50 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 51 This Figure applies only to: Group 1. FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 1 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 51 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 52 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT STA 500 STA 500A STA 500B STA 500C STA 500D STA 520 S-18R S-19R S-20R s-21R S-22R FWD < s-23R INBD K 5-24R S-25R 1338130 FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 2 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 52 of 159 ### Page 53 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT STA 500 STA 500A STA 500B STA 500C STA 500D STA 520 S-18L S-19L S-2OL S-21L S-22L S-23L @FWD S-241- D INBD S-25L B 1338135 FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 3 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 53 of 159 ### Page 54 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT GUIDE ASSEMBLY POWER CABLES S-20 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE 0.50 INCH DIAMETER HOLE (REFERENCE) UP INBD T S-21 A-A VIEW LOOKING FORWARD (TYPICAL FRAME SECTION) 1338144 STA 500B, STA 500C, STA 500D FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 4 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 Copyright © Unpublished Work - See page 1 for details. BOEING PROPRIETARY - 737-53A1279 54 of 159 ### Page 55 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP (a)669-73089-3Guide AssemblyTurn1 (b)669-73089-3Guide AssemblyMove2 (a) Turn the forward side of the guide assembly while holding the aft side until the assembly is in two pieces. (b) Move the two guide assembly pieces along the power feeder cable away from the frame to get access to the wire penetration hole. FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 5 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 55 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 56 This Figure applies only to: Group 2. FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 1 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 56 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 57 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT STA 500 STA 500A STA 500B STA 500C STA 500D STA 500E STA 500F STA 500G STA 520 5-18R S-19R s-20R S-21R S-22R 5-23R INBD 5-24R S-25R 1338186 FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 2 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 57 of 159 ### Page 58 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT STA 500 STA 500A STA 500B STA 500C STA 500D STA 500E STA 500F STA 500G STA 520 S-18L S-19L - S-20L- S-21L → FWD S-22L V INBD 5-231 5-24L S-25L ® 1338192 FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 3 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 58 of 159 ### Page 59 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT GUIDE ASSEMBLY POWER CABLES S-20 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE ХЯ B 0.50 INCH DIAMETER HOLE (REFERENCE) UP INBD C S-21 A-A VIEW LOOKING FORWARD STA 500E, STA 500F, STA 500G (TYPICAL FRAME SECTION) 1338152 FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 4 OF 5) Original Issue: December 18, 2007 Revision 1 September 02, 2011 BOEING PROPRIETARY - 737-53A1279 Copyright © Unpublished Work - See page 1 for details. 59 of 159 ### Page 60 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP (a)669-73089-3Guide AssemblyTurn1 (b)669-73089-3Guide AssemblyMove2 (a) Turn the forward side of the guide assembly while holding the aft side until the assembly is in two pieces. (b) Move the two guide assembly pieces along the power feeder cable away from the frame to get access to the wire penetration hole. FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE (SHEET 5 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 1 September 02, 2011 60 of 159 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/737-53a1279/file/33f8cce2fb29.md?from=61 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.