# Boeing Alert Service Bulletin 737-25A1544: Revision 4, part 1 of 2 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2023-1886; AD 2024-18-07 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-25A1544](https://openairdocs.org/service-documents/boeing/737-25a1544.md) - Title as filed: SB-737-25A1544-04--_Part1 - Pages: 124 - PDF: https://openairdocs.org/files/sha256/20/12/201272e70a1b06a7712caef3e29b015c32eec4aaa6dde6beda6909e93db384a7 - Page: https://openairdocs.org/service-documents/boeing/737-25a1544/file/201272e70a1b ## 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: 737-25A1544 Original Issue: October 04, 2006 Revision 4: February 15, 2022 ATA System: 2524 SUBJECT: EQUIPMENT/FURNISHING - Passenger Cabin Partitions and Compartments - Support Fitting Assembly Air Conditioning Extrusions Replacement EXPORT CONTROLLED - This technology or software is subject to the U.S. Export Administration Regulations (EAR), (15 C.F.R. Parts 730-774). No authorization from the U.S. Department of Commerce is required for export, re-export, in-country transfer, or access EXCEPT to country group E:1 or E:2 countries/persons per Supp.1 to Part 740 of the EAR. 9E991ECCN: Copyright © 2006 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. 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, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries 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. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 1 of 202 5.0 ### Page 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 2 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 S u m m a r y ...................................................... 9 1. PLANNING INFORMATION ........................................ 1 5 A . E f f e c t i v i t y ............................................... 1 5 1. Airplanes ............................................ 1 5 2 . S p a r e s A f f e c t e d ........................................ 1 8 B. Concurrent Requirements ...................................... 1 8 C. Reason ................................................ 1 8 D. Description .............................................. 2 0 E. Compliance .............................................. 2 2 F . A p p r o v a l ............................................... 2 4 G. Manpower .............................................. 2 5 H. Weight and Balance Changes .................................... 2 8 I. Electrical Load Data ......................................... 3 1 J . R e f e r e n c e s .............................................. 3 1 1. Existing Data: ......................................... 3 1 2. Data Supplied with this Service Bulletin: ........................... 3 2 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 2 K. Publications Affected ........................................ 3 3 L. Interchangeability and Intermixability of Parts ........................... 3 3 M. Software Accomplishment Summary ................................ 3 3 2. MATERIAL INFORMATION ........................................ 3 5 A. Material - Price and Availability ................................... 3 5 B. Industry Support Information .................................... 3 6 C. Parts Necessary for Each Airplane ................................. 3 6 1 . K i t s / P a r t s : ........................................... 3 6 2. Parts and Materials Supplied by the Operator: ........................ 4 0 3. Parts Modified and Reidentified: ............................... 4 7 4. Parts Removed and Not Replaced: .............................. 4 7 D. Parts Necessary to Change Spares ................................. 4 7 E. Special Tooling - Price and Availability ............................... 4 7 F. Special Tooling Necessary to do this Service Bulletin ....................... 4 8 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 4 9 A. GENERAL INFORMATION ..................................... 4 9 B. WORK INSTRUCTIONS ....................................... 5 0 FIGURE 1: INSPECTION OF FRAME ON LEFT SIDE OF THE AIRPLANE ............... 5 9 FIGURE 2: INSPECTION OF FRAME ON RIGHT SIDE OF THE AIRPLANE .............. 6 2 FIGURE 3: INSTALLATION OF REPAIR ANGLES WITH HI-LOKS ON LEFT SIDE OF THE AIRPLANE .................................................. 6 5 FIGURE 4: INSTALLATION OF REPAIR ANGLES WITH HI-LOKS ON RIGHT SIDE OF THE AIRPLANE .................................................. 7 3 FIGURE 5: INSTALLATION OF REPAIR ANGLES WITH RIVETS ON LEFT SIDE OF THE AIRPLANE . 81 FIGURE 6: INSTALLATION OF REPAIR ANGLES WITH RIVETS ON RIGHT SIDE OF THE AIRPLANE .................................................. 8 8 FIGURE 7: REMOVAL OF SUPPORT FITTING ASSEMBLY - AIR CONDITIONING EXTRUSIONS ON L E F T S I D E O F T H E A I R P L A N E ................................ 9 5 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 3 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 4 FIGURE 8: REMOVAL OF SUPPORT FITTING ASSEMBLY - AIR CONDITIONING EXTRUSIONS ON R I G H T S I D E O F T H E A I R P L A N E ............................... 9 7 FIGURE 9: INSTALLATION OF SUPPORT FITTING ASSEMBLY - AIR CONDITIONING EXTRUSIONS O N L E F T S I D E O F T H E A I R P L A N E ............................. 9 9 FIGURE 10: INSTALLATION OF SUPPORT FITTING ASSEMBLY - AIR CONDITIONING EXTRUSIONS O N R I G H T S I D E O F T H E A I R P L A N E ............................ 1 0 1 FIGURE 11: LEFT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION (OPTION 1 AND 2) - CUT OUT [Group 1-4, 6] ...... 1 0 3 FIGURE 12: RIGHT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION (OPTION 1 AND 2) - CUT OUT [Group 1-4, 6] ...... 1 1 1 FIGURE 13: LEFT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - MAKE REPAIR PARTS (OPTION 1) [Group 1-4, 6] . . . 119 FIGURE 14: RIGHT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - MAKE REPAIR PARTS (OPTION 1) [Group 1-4, 6] . . . 128 FIGURE 15: LEFT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - INSTALL REPAIR PARTS (OPTION 1) [Group 1-4, 6] . 137 FIGURE 16: RIGHT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - INSTALL REPAIR PARTS (OPTION 1) [Group 1-4, 6] . 145 FIGURE 17: LEFT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - MAKE REPAIR PARTS (OPTION 2) [Group 1-4, 6] . . . 152 FIGURE 18: RIGHT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - MAKE REPAIR PARTS (OPTION 2) [Group 1-4, 6] . . . 160 FIGURE 19: LEFT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - INSTALL REPAIR PARTS (OPTION 2) [Group 1-4, 6] . 168 FIGURE 20: RIGHT SIDE, STA 907 FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - INSTALL REPAIR PARTS (OPTION 2) [Group 1-4, 6] . 175 FIGURE 21: STA 360 THRU STA 887, Z-SECTION FRAME, SUPPORT BRACKET ATTACHMENT HOLES AT THE AIR CONDITIONING EXTRUSION - FULL FRAME SECTION REPAIR ..... 1 8 1 FIGURE 22: INSPECTION OF STA - 907 FRAME ON LEFT SIDE AND RIGHT SIDE OF THE AIRPLANE - PART 3 FRAME REPAIR OPTION 1 ............................ 1 8 6 FIGURE 23: INSPECTION OF STA - 907 FRAME ON LEFT SIDE AND RIGHT SIDE OF THE AIRPLANE - PART 3 FRAME REPAIR OPTION 2 ............................ 1 8 9 FIGURE 24: INSPECTION OF STA - 559 FRAME ON LEFT SIDE OF THE AIRPLANE ........ 1 9 2 FIGURE 25: INSPECTION OF STA - 559 FRAME ON RIGHT SIDE OF THE AIRPLANE ....... 1 9 4 APPENDIX A: 737 AIRPLANE FRAME STATUS AT AIR CONDITIONING SUPPORT BRACKET ATTACHMENT ................................................. 1 9 6 APPENDIX B: STRINGER 8L CLIP FABRICATION STA 907, AT S-8L [Group 1-4, 6] .......... 1 9 9 APPENDIX C: STRINGER 8R CLIP FABRICATION STA 907, AT S-8R [Group 1-4, 6] .......... 2 0 1 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 4 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-25A1544Original Issue: October 04, 2006 Revision 4: February 15, 2022 ATA System: 2524 SUBJECT: EQUIPMENT/FURNISHING - Passenger Cabin Partitions and Compartments - Support Fitting Assembly Air Conditioning Extrusions Replacement This revision includes all pages of the Service Bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-01-02 is related to this Service Bulletin. The effective date of AD 2009-01-02 is February 27, 2009. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this Service Bulletin. The Airworthiness Directive will make the compliance tasks and times given in this Service Bulletin mandatory. Airplane variable numbers YG044, YG067, YG069, YG074, YG081, YG084, YG088, YG201, and YG211 were moved from Group 2 to new Group 6. Effects of this Revision on airplanes on which Original Issue, Revision 1, Revision 2, or Revision 3 was previously done: 1. No More work is necessary on the airplane(s) changed in accordance with the Original Issue, Revision 1 or Revision 2. 2. More work is necessary on the airplane(s) that has done the repair at STA 907 in accordance with the Revision 3 of this Service Bulletin. The more work is to do the post repair inspections and on conditions corrective actions at STA 907. REASON FOR REVISION This revision is sent to change this Service Bulletin to an Alert Service Bulletin to add the required Damage Tolerance Inspections (DTI) for Station (STA) 907 repair, add new figures for the inspection at STA 559 and move 9 airplanes from Group 2 to new Group 6. These sections were changed: 1. Summary, Manpower, revised Manpower table to add Figure 22, Figure 23, Figure 24, Figure 25. 2. Summary, Material Information, revised the Material Table - STA 907 to add Stringer Clips Part number 147A3500-13 and 147A3500- () Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 5 of 202 ### Page 6 3. In Paragraph 1.A., Effectivity, added Service Bulletin index information and applicable line number information. Added new Group 6 to Group/Configuration table. 4. In Paragraph 1.C., Reason, updated reason statement. Added reason for revision statement. 5. In Paragraph 1.D., Description: Added instructions for new post repair inspections and new affected maintenance zones. 6. In Paragraph 1.E., Compliance, updated Federal Aviation Administration (FAA) Airworthiness Directive (AD) statement for possible release. Added the Boeing Business Jet (BBJ) lower cabin altitude statement, accomplish required action(s) statement, options and conditions statement, and new compliance tables. 7. In Paragraph 1.G., Manpower, updated manpower statement and updated and added new manpower tables. 8. In Paragraph 1.H., Weight and Balance Changes, added applicability to weight and balance tables. 9. In Paragraph 1.J.1., Existing Data, reference to PRR, Boeing SRP, Boeing Service Bulletin, Service Bulletin Index, Standard Overhaul Practices Manual (SOPM), Non-Destructive Testing (NDT) Manual, Aircraft Maintenance Manual (AMM), Structural Repair Manual (SRM) and Fleet Team Digest (FTD) are added. 10. In Paragraph 1.K.2., Publications Affected, Damage Tolerance Based Structural Inspections, new statements added. 11. In Paragraph 2.C., Parts Necessary for Each Airplane, added new operator supplied parts table. 12. In Paragraph 3.A., General Information, added new general notes. 13. In Paragraph 3.B., Work Instructions, update work instructions format and high level work instructions to add post repair inspections. 14. Revised Figure 11, Figure 12, Figure 13, Figure 14, Figure 15, Figure 16, Figure 17, Figure 18, Figure 19 and Figure 20 to give instructions for the frame repair at STA 907. 15. Added Figure 22 and Figure 23 to give instructions for Damage Tolerance Inspections (DTI) of the frame repair at STA 907. 16. Added Figure 24 and Figure 25 to give instructions for inspection for STA 559 frame, Group 3-6. 17. APPENDIX C, added Illustration for Stringer clip fabrication. The data given in Information Notice 737-25-1544 IN 06 is included in this revision. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity and format changes, to show the location of all content changes. Pages with no vertical lines have no changes. REVISION HISTORY October 04, 2006Original Issue: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 6 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 7 January 16, 2008Revision 1: March 23, 2011Revision 2: May 16, 2016Revision 3: February 15, 2022Revision 4: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 7 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 8 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 8 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT BLANK PAGE ### Page 9 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-25A1544Original Issue: October 04, 2006 Revision 4: February 15, 2022 ATA System: 2524 SUBJECT: EQUIPMENT/FURNISHING - Passenger Cabin Partitions and Compartments - Support Fitting Assembly Air Conditioning Extrusions Replacement THIS DOCUMENT 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 DOCUMENT TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE NEW OWNER. CONCURRENT REQUIREMENTS None. BACKGROUND This Service Bulletin gives instructions to do an inspection, and if necessary a repair of frames, at the air conditioning (A/C) rail bracket attachment fastener locations. Also, instructions are given to remove the support fitting assembly - A/C extrusions and replace them with new support fitting assembly - A/C extrusions that have better slip fitting. If this Service Bulletin is not accomplished, multiple frame failure could occur. Frame failure at the A/C rail attachment brackets could jeopardize the capability of the frame to support the overhead stowage bins under emergency landing loads. Multiple frame failure could exacerbate cracking of the chemically milled steps in the skin above Stringer 10 lap splice as addressed in Boeing Service Bulletin 737-53A1232, or precipitate cracking of the skin lap splice resulting in rapid decompression. Frame cracks have been found on 737-200/300/400/500 airplanes at the support bracket attachment holes of the air conditioning outlet extrusion. Frame cracks have also been found on 737-200/300/400/500 airplanes up to 0.6 inches long on the inboard flange of the Station (STA) 907 frame adjacent to the support bracket. The airplane structures on 737-200/300/400/500 and 737-600/700/700C/800/900 airplanes are almost the same in the areas where the frame cracks were discovered. Boeing has received reports of more than 345 frame cracks on 35 737-200/300/400/500 airplanes at the support bracket attachment holes of the air conditioning outlet extrusion. The cracks were reported by four different operators on 737-200/300/400/500 airplanes. The airplanes range from 12,000 to 62,000 flight cycles. The cracks are attributed to fatigue and are generally less than one inch in length, however one operator has reported a one inch long crack at the Station 907 frame. The cracks in the frame are fatigue cracks that radiate from multiple initiation sites around the hole. The cracks radiate from only one side of the hole, nearest the frame flanges. The cracks initiate from a combination of forward and aft loads from fuselage expansion, and down loads from fuselage deflection on the attached structure. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 9 of 202 ### Page 10 Accomplishment of this Service Bulletin on 737-600/700/700C/800/900 airplanes will retain the structural integrity of the airplane and eliminate the need for unscheduled downtime and extensive frame repairs. NOTE: Boeing has received reports of more than 43 frame cracks from multiple operators at the support bracket attachment holes of the air conditioning outlet extrusion. The airplanes range from 11,000 to 34,000 flight cycles. The cracks are attributed to fatigue and are generally less than one inch in length. This same condition is addressed on 737 Classic Service Bulletin 737-53-1216. The bracket configuration most susceptible to frame cracks is the support bracket with a two rivet hole attachment to the frame. The inspection threshold specified in this Service Bulletin is later than the total airplane flight cycles on some airplanes with reported cracks. This is acceptable based on the growth rate and cracking pattern of the cracks. In all known reported cases the frame cracks grow in a sun ray pattern from one side of the A/C attach bracket holes. The longest cracks grow in a circumferential direction to a total length from tip-to-tip of approximately 1 inch, at which time they appear to stop any significant growth. No significant growth has been reported in the inboard or outboard direction which is the critical direction affecting safety. If cracks longer than 0.5 inches are found growing in the inboard or outboard direction, please contact The Boeing Company with the details. Boeing Service Related Problem (SRP) 737NG-SRP-25-0229 and 737NG-SRP-53-0600 are related to this Service Bulletin. Boeing Structural Item Interim Advisory SIIA 737-258 is related to this Service Bulletin. Boeing Fleet Team Digest (FTD) 737NG-FTD-53-19002 is related to this Service Bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information. ReferenceAffectedPlanning Data Paragraph 1.A.2., Spares AffectedNoSpares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval YesAD Related Paragraph 1.H., Weight and Balance ChangesYesWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedYesPublications Affected Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew Operations Manual and/or FAA Approved Air- plane Flight Manual) Paragraph 2.C.1., Kits/PartsYesKits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator YesOperator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin YesSpecial Tooling Required Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 10 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 11 ACTION (PRR 38275-76S, PRR 39800-021RS) Get access to the support bracket of the air conditioning outlet extrusion by removal of the passenger service units. If more access room is needed, remove as necessary, the passenger seats, the overhead stowage bins, the sidewall lining, and the air conditioning outlet extrusion. Do a General Visual Inspection (GVI), a Medium Frequency Eddy Current (MFEC) inspection, a Low Frequency Eddy Current (LFEC) inspection and a High Frequency Eddy Current (HFEC) inspection of frames from STA 360 to STA 907 at Stringer 8L and Stringer 8R, for any crack at the air conditioning rail bracket attachment fastener locations, to make sure there are no cracks in the frame and if a frame repair is accomplished do the required Damage Tolerance Inspections (DTI) for Station (STA) 907 repair. Group 1-2: NOTE: The LFEC inspection is only required at STA 907 around the installed fastener at the outboard fastener location where the MFEC inspection is not applicable. Group 3-6: NOTE: The LFEC inspection is only required at STA 559 and STA 907 around the installed fastener at the outboard fastener location where the MFEC inspection is not applicable. NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all the frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified. An identification of the brackets at STA 540, STA 663.75, STA 685 and STA 727 is not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does not need to be inspected as this configuration is not susceptible to cracks. An identification of the brackets at STA 616, and STA 639 on 737-600/700/700C airplanes and STA 578, STA 601, STA 616 and STA 639 on 737-800/900 airplanes is also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. NOTE: An optional airplane frame status table for planning purposes is given in APPENDIX A. The table can be used for initial inspection, frame and bracket tabulation. The tables could benefit planning in subsequent inspections or modifications to reduce the access time for the next inspection or parts fabrication requirements. If any crack is found, repair the frame in accordance with this Service Bulletin. Remove the support fitting assembly - A/C extrusions, and install new support fitting assembly - A/C extrusions with better slip fitting on frames from STA 360 to STA 907 at Stringer 8L and Stringer 8R, in accordance with this Service Bulletin. Install as necessary if removed, the air conditioning outlet extrusion, the sidewall lining, the overhead stowage bins, and the passenger seats. Install the passenger service units. EFFECTIVITY 737-600/700/700C/800/900 Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s). COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-01-02 is related to this Service Bulletin. The effective date of AD 2009-01-02 is February 27, 2009. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 11 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 12 The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this Service Bulletin. The Airworthiness Directive will make the compliance tasks and times given in this Service Bulletin mandatory. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the configuration changes, inspection, and/or repair procedures given in this Service Bulletin. MANPOWER Refer to Paragraph 1.G., Manpower. MATERIAL INFORMATION Boeing Supplied Kits/Parts. Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 12 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 13 (OCR) BOEING SERVICE BULLETIN 737-25A1544 ALERT ALERT STRINGER 8 STA 360 STA 907 INSPECT: FRAMES FOR CRACKS AT THE AIR CONDITIONING SUPPORT BRACKET REPAIR: FRAME CRACKS AT THE AIR CONDITIONING SUPPORT BRACKET REMOVE: SUPPORT FITTING ASSEMBLY AIR CONDITIONING EXTRUSIONS INSTALL: SUPPORT FITTING ASSEMBLY AIR CONDITIONING EXTRUSIONS DO POST REPAIR INSPECTIONS AT STATION 907 D58611 Original Issue: October 04, 2006 Revision 4: February 15, 2022 Export Controlled ECCN: 9E991 737-25A1544 Copyright © Unpublished Work - See page 1 for details. 13 of 202 ### Page 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 14 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT BLANK PAGE ### Page 15 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-25A1544 Original Issue: October 04, 2006 Revision 4: February 15, 2022 ATA System: 2524 SUBJECT: EQUIPMENT/FURNISHING - Passenger Cabin Partitions and Compartments - Support Fitting Assembly Air Conditioning Extrusions Replacement THIS DOCUMENT 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 DOCUMENT TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes This bulletin is applicable to 737-600, 737-700, 737-700C, 737-800, 737-900 Airplane(s), line number(s) 1-1679 in 6 Group(s). Where the effectivity is presented with hyphens between line numbers, the airplane applicability means "through" and "inclusive", e.g. line numbers 1-9 means line numbers 1 through 9 inclusive. The Variable Numbers and Group Information for the applicable airplanes is given below. An equivalent change is on subsequent production airplanes. Refer to PRR 38275-76S and PRR 39800-021RS for data about this change. Refer to Service Bulletin Index D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. DESCRIPTIONCONFIGURATIONGROUP 737-600 Airplanes-1 737-700 Airplanes, except 737-700 Boeing Business Jet (BBJ) Airplanes and 737-700 Increased Gross Weight (IGW) Airplanes. -2 737-800 Airplanes and 737-800 Boeing Converted Freighter (BCF) Airplanes. -3 737-900 Airplanes-4 737-700C and 737-700 Boeing Business Jet (BBJ) Airplanes-5 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 15 of 202 ### Page 16 DESCRIPTIONCONFIGURATIONGROUP 737-700 Increased Gross Weight (IGW) Airplanes identified in the Variable Number Table below. -6 Airplane Models: 737-600, 737-700, 737-700C, 737-800, 737-900 GroupVariable Number 2YA001 - YA099 2YA101 - YA199 2YA201 - YA211 2YA221 2YA231 - YA242 2YA251 - YA256 2YA271 - YA272 2YA291 2YA301 - YA302 2YA311 - YA314 2YA321 - YA323 2YA336 - YA345 2YA351 2YA356 - YA357 2YA366 - YA367 2YA371 - YA377 2YA501 - YA536 2YA541 - YA552 2YA571 - YA578 2YA601 - YA615 2YA621 - YA622 2YA626 - YA631 2YA635 - YA636 2YA641 - YA642 2YA645 - YA650 2YA656 - YA659 GroupVariable Number 2YA666 - YA667 2YA671 - YA672 2YA681 - YA691 2YA701 - YA710 2YA721 - YA722 2YA731 - YA734 2YA751 - YA756 2YA801 - YA803 2YA809 2YA811 - YA814 2YA831 - YA835 2YA841 - YA862 2YA881 - YA882 2YA891 - YA892 2YA961 - YA976 2YB001 - YB006 2YB101 - YB132 2YB151 - YB153 2YB156 - YB157 2YB161 - YB164 2YB171 - YB172 2YB181 - YB184 2YB201 - YB208 2YB271 2YB276 2YB301 - YB310 GroupVariable Number 2YB371 - YB379 2YB501 - YB502 2YB521 - YB525 2YB541 - YB544 2YB551 2YB561 - YB572 2YB581 - YB586 2YB601 - YB629 2YB631 - YB632 2YB651 2YB656 2YB851 - YB859 2YB861 - YB863 2YB871 - YB873 2YB881 - YB888 2YB901 - YB903 2YB911 3YC001 - YC030 3YC051 - YC083 3YC091 - YC094 3YC101 - YC104 3YC111 - YC113 3YC121 3YC126 - YC127 3YC136 - YC141 3YC146 - YC147 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 16 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 17 GroupVariable Number 3YC151 - YC156 3YC166 - YC171 3YC176 - YC178 3YC186 - YC189 3YC201 - YC203 3YC206 3YC301 - YC305 3YC321 - YC384 3YC391 - YC394 3YC396 3YC401 - YC417 3YC421 - YC422 3YC426 - YC428 3YC436 - YC437 3YC441 - YC448 3YC451 - YC455 3YC459 3YC461 - YC467 3YC471 - YC499 3YC501 - YC526 3YC571 - YC583 3YC587 - YC589 3YC591 - YC593 3YC601 - YC655 3YC681 - YC696 3YC701 - YC715 3YC720 - YC725 3YC727 - YC741 3YC751 - YC752 3YC761 - YC770 3YC781 - YC793 3YC801 - YC892 3YC901 - YC907 GroupVariable Number 3YC921 - YC922 3YC931 - YC932 3YC941 - YC951 3YC971 - YC978 3YC981 - YC983 3YD001 - YD007 3YD021 - YD025 3YD041 - YD057 3YD081 - YD084 3YD101 - YD107 3YD121 - YD126 3YD151 - YD159 3YD171 - YD172 3YD201 - YD203 3YD206 - YD209 3YD216 - YD219 3YD251 - YD254 3YD256 - YD257 3YD261 3YD301 - YD334 3YD391 3YD401 - YD410 3YD412 3YD481 - YD485 4YD501 - YD512 4YD531 - YD535 4YD541 - YD547 4YD561 - YD564 4YD571 - YD572 4YD591 - YD594 4YD601 - YD612 1YE001 - YE020 1YE051 GroupVariable Number 1YE101 - YE109 1YE151 - YE157 1YE171 - YE172 1YE201 - YE206 1YE301 - YE305 1YE321 - YE326 5YG001 - YG043 6YG044 5YG061 - YG064 5YG066 6YG067 5YG068 6YG069 5YG070 - YG073 6YG074 5YG075 - YG080 6YG081 5YG082 - YG083 6YG084 5YG085 - YG087 6YG088 5YG089 6YG201 6YG211 5YG501 - YG508 5YG601 - YG602 3YJ001 - YJ004 3YJ011 - YJ012 3YJ021 3YJ471 - YJ480 3YJ501 - YJ517 3YJ531 - YJ545 3YJ591 - YJ593 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 17 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 18 GroupVariable Number 3YJ631 - YJ632 3YJ671 - YJ682 3YJ801 - YJ849 3YJ861 - YJ867 3YJ871 3YJ901 - YJ902 3YJ911 - YJ919 3YJ931 - YJ936 GroupVariable Number 3YJ941 3YK001 - YK007 3YK101 - YK104 3YK111 - YK112 3YK121 - YK122 3YK131 - YK132 3YK301 - YK304 3YK321 - YK329 GroupVariable Number 3YK361 - YK364 3YK401 - YK403 3YK431 3YK456 - YK457 2YM101 2YM201 - YM202 2YM251 - YM256 -- 2. Spares Affected None. B. Concurrent Requirements None. C. Reason This Service Bulletin gives instructions to do an inspection, and if necessary a repair of frames, at the air conditioning (A/C) rail bracket attachment fastener locations. Also, instructions are given to remove the support fitting assembly - A/C extrusions and replace them with new support fitting assembly - A/C extrusions that have better slip fitting. If this Service Bulletin is not accomplished, multiple frame failure could occur. Frame failure at the A/C rail attachment brackets could jeopardize the capability of the frame to support the overhead stowage bins under emergency landing loads. Multiple frame failure could exacerbate cracking of the chemically milled steps in the skin above Stringer 10 lap splice as addressed in Boeing Service Bulletin 737-53A1232, or precipitate cracking of the skin lap splice resulting in rapid decompression. Frame cracks have been found on 737-200/300/400/500 airplanes at the support bracket attachment holes of the air conditioning outlet extrusion. Frame cracks have also been found on 737-200/300/400/500 airplanes up to 0.6 inches long on the inboard flange of the Station (STA) 907 frame adjacent to the support bracket. The airplane structures on 737-200/300/400/500 and 737-600/700/700C/800/900 airplanes are almost the same in the areas where the frame cracks were discovered. Boeing has received reports of more than 345 frame cracks on 35 737-200/300/400/500 airplanes at the support bracket attachment holes of the air conditioning outlet extrusion. The cracks were reported by four different operators on 737-200/300/400/500 airplanes. The airplanes range from 12,000 to 62,000 flight cycles. The cracks are attributed to fatigue and are generally less than one inch in length, however one operator has reported a one inch long crack at the Station 907 frame. The cracks in the frame are fatigue cracks that radiate from multiple initiation sites around the hole. The cracks radiate from only one side of the hole, nearest the frame flanges. The cracks initiate from a combination of forward and aft loads from fuselage expansion, and down loads from fuselage deflection on the attached structure. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 18 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 19 Accomplishment of this Service Bulletin on 737-600/700/700C/800/900 airplanes will retain the structural integrity of the airplane and eliminate the need for unscheduled downtime and extensive frame repairs. NOTE: Boeing has received reports of more than 43 frame cracks from multiple operators at the support bracket attachment holes of the air conditioning outlet extrusion. The airplanes range from 11,000 to 34,000 flight cycles. The cracks are attributed to fatigue and are generally less than one inch in length. This same condition is addressed on 737 Classic Service Bulletin 737-53-1216. The bracket configuration most susceptible to frame cracks is the support bracket with a two rivet hole attachment to the frame. The inspection threshold specified in this Service Bulletin is later than the total airplane flight cycles on some airplanes with reported cracks. This is acceptable based on the growth rate and cracking pattern of the cracks. In all known reported cases the frame cracks grow in a sun ray pattern from one side of the A/C attach bracket holes. The longest cracks grow in a circumferential direction to a total length from tip-to-tip of approximately 1 inch, at which time they appear to stop any significant growth. No significant growth has been reported in the inboard or outboard direction which is the critical direction affecting safety. If cracks longer than 0.5 inches are found growing in the inboard or outboard direction, please contact The Boeing Company with the details. Boeing Service Related Problems (SRP) 737NG-SRP-25-0229 and 737NG-SRP-53-0600 are related to this Service Bulletin. Boeing Fleet Team Digest (FTD) 737NG-FTD-53-19002 is related to this Service Bulletin. Boeing Structural Item Interim Advisory SIIA 737-258 is related to this Service Bulletin. Revision 1 was sent to add airplane YB873 to the Service Bulletin effectivity and add reference to FAA Airworthiness Directive and FAA Notice of Proposed Rule Making in the compliance table. The data given in Information Notice 737-25-1544 IN 01 is included in this revision. This information notice was sent to remove all references to Boeing Service Bulletin 737-53-1232. In addition, this information notice was sent to change the totals shown in each manpower table to read Total For Each Airplane and not Total For Each Frame. Revision 2 was sent to clarify the material information for an aluminum filler and radius filler that are made and installed in this Service Bulletin. The data given in Information Notice 737-25-1544 IN 02 is included in this revision. This information notice was sent to make sure operators can clearly and accurately read fastener part numbers in Paragraph 3.B. Work Instructions, Part 3, Figure 3 and Figure 4 fastener code tables. The data given in Information Notice 737-25-1544 IN 03 is included in this revision. This information notice was sent to inform operators that Figures 3, 4, 5 and 6 view B-B should show angle A with a lip that extends around the existing frame when installed. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 19 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 20 The data given in Information Notice 737-25-1544 IN 04 is included in this revision. This information notice was sent to inform operators that the frame locations given in Appendix A, B, C and D may not be actual representations of the frame locations on the airplane. Appendix B, C and D have now been deleted from the Service Bulletin 737-25-1544 Revision 2 and Appendix A was changed to delete the frame STA number from the table. The operator can use this table to record the actual frame locations for their airplane. Additional information has also been added to the notes in steps 1 thru 14 of the Accomplishment Instructions 3.B Part 4 - Replacement of Support Fitting Assembly - Air Conditioning Extrusions. Note (b) in Service Bulletin 737-25-1544 revision 3. Figure 1 and 2 step tables has changed to clarify Appendix A. The data given in Information Notice 737-25-1544 IN 05 was included in Service Bulletin 737-25-1544 revision 2. This information notice was sent to inform operators that Summary/Background and Paragraph 1.C., Reason should include a note regarding reports of frame cracks found at the support bracket attachment holes of the air conditioning outlet extrusion. Revision 3 was sent to add work instructions for a frame repair at Station (STA) 907 for Group 1-4 airplanes, to add work instructions for a full frame section repair applicable to Z-section frames between STA 360 and STA 887, and to clarify the existing work instructions. Revision 4 is sent to change this Service Bulletin to an Alert Service Bulletin to add the required Damage Tolerance Inspections (DTI) for Station (STA) 907 repair, add new figures for the inspection at STA 559 and move 9 airplanes from Group 2 to new Group 6. Terminology has been changed in the Work Instructions to agree with the terminology defined in Paragraph 3.A., General Information - Notes. D. Description Get access to the support bracket of the air conditioning outlet extrusion by removal of the passenger service units. If more access room is needed, remove as necessary, the passenger seats, the overhead stowage bins, the sidewall lining, and the air conditioning outlet extrusion. Do a General Visual Inspection (GVI), a Medium Frequency Eddy Current (MFEC) inspection, a Low Frequency Eddy Current (LFEC) inspection and a High Frequency Eddy Current (HFEC) inspection of frames from STA 360 to STA 907 at Stringer 8L and Stringer 8R, for any crack at the air conditioning rail bracket attachment fastener locations, to make sure there are no cracks in the frame and if a frame repair is accomplished do the required Damage Tolerance Inspections (DTI) for Station (STA) 907 repair. Group 1-2: NOTE: The LFEC inspection is only required at STA 907 around the installed fastener at the outboard fastener location where the MFEC inspection is not applicable. Group 3-6: NOTE: The LFEC inspection is only required at STA 559 and STA 907 around the installed fastener at the outboard fastener location where the MFEC inspection is not applicable. NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all the frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified and inspect. An identification of the brackets at STA 540, STA 663.75, STA 685 and STA 727 is not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 20 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 21 not need to be inspected as this configuration is not susceptible to cracks. An identification of the brackets at STA 616, and STA 639 on 737-600/700/700C airplanes and STA 578, STA 601, STA 616 and STA 639 on 737-800/900 airplanes is also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. NOTE: An optional airplane frame status table for planning purposes is given in APPENDIX A. The table can be used for initial inspection, frame and bracket tabulation. The tables could benefit planning in subsequent inspections or modifications to reduce the access time for the next inspection or parts fabrication requirements. If any crack is found, repair the frame in accordance with this Service Bulletin. Remove the support fitting assembly - A/C extrusions, and install new support fitting assembly - A/C extrusions with better slip fitting on frames from STA 360 to STA 907 at Stringer 8L and Stringer 8R, in accordance with this Service Bulletin. Install as necessary if removed, the air conditioning outlet extrusion, the sidewall lining, the overhead stowage bins, and the passenger seats. Install the passenger service units. Revision 4 - Effects of this Revision on airplanes on which Original Issue, Revision 1, Revision 2, or Revision 3 was previously done: 1. No More work is necessary on the airplane(s) changed in accordance with the Original Issue, Revision 1 or Revision 2. 2. More work is necessary on the airplane(s) that has done the repair at STA 907 in accordance with the Revision 3 of this Service Bulletin. The more work is to do the post repair inspections and on conditions corrective actions at STA 907. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 221, 222, 231, 232, 241, 242737-600 Group 2, 6: Affected Maintenance Zones ZoneModel 221, 222, 231, 232, 241, 242737-700 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 21 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 22 Group 3: Affected Maintenance Zones ZoneModel 221, 222, 231, 232, 241, 242737-800 Group 4: Affected Maintenance Zones ZoneModel 221, 222, 231, 232, 241, 242737-900 Group 5: Affected Maintenance Zones ZoneModel 221, 222, 231, 232, 241, 242737-700, 737-700C E. Compliance Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-01-02 is related to this Service Bulletin. The effective date of AD 2009-01-02 is February 27, 2009. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this Service Bulletin. The Airworthiness Directive will make the compliance tasks and times given in this Service Bulletin mandatory. For airplanes which have incorporated Boeing Business Jet (BBJ) Lower Cabin Altitude Supplemental Type Certificate (STC) ST01697SE (6500 feet maximum cabin altitude in lieu of 8000 feet) as referenced in Boeing SB 737-21-1149, the flight cycle related compliance times are different from those specified in this Service Bulletin. All initial compliance times (thresholds) specified in flight cycles must be reduced to half of those specified in this Service Bulletin. All repeat interval compliance times specified in flight cycles must be reduced to one-quarter of those specified in this Service Bulletin. Accomplish the required action(s), based on the applicable condition(s) in Tables 1 and 2, in accordance with Paragraph 3. Accomplishment Instructions. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 22 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 23 Table 1: Inspection Type and Times for the Body Frame at the Air Conditioning Support Bracket Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 72 months after the effective date of AD 2009-01-02. Before 36,000 Total Flight Cy- cles. At Frames STA 360 to STA 907, do a One Time General Visual Inspection (GVI), a Medium Frequency Eddy Cur- rent (MFEC) Inspection, a Low Frequen- cy Eddy Current (LFEC) Inspection and a High Frequency Eddy Current (HFEC) Inspection for any crack in the frame in accordance with PART 2.(a) All Airplanes -Before further flight.Repair the frame in accordance with PART 3 and install new support fitting assembly in accordance with PART 4. Any crack is found -Before further flight.Install new support fitting assembly in accordance with PART 4. No crack is found (a) It is not required to do the inspection(s) for any crack in the frame at STA 360 to STA 907 in accordance with PART 2, in areas where a repair covers the affected inspection zone provided the installed repair was approved by the Boeing Company Organization Designation Authorization (ODA) via a FAA Form 8100- 9, with an AMOC to AD 2009-01-02. Group 1-4, 6: Table 2: Post Repair - Detailed and High Frequency Eddy Current (HFEC) Inspections of the Body Frame STA 907 at the Air Conditioning Support Bracket Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 7,000 flight cycles after the Revi- sion 4 date of this Service Bulletin. Before 36,000 Total Flight Cycles. Do a Detailed Inspec- tion and HFEC in- spection of the re- paired area at frame STA 907 for any crack in accordance with PART 6. Airplanes that have done the frame re- pair at STA 907 in accordance with Re- vision 3 of this Ser- vice Bulletin -Within 24,000 flight cycles after installa- tion of the repair. Before 36,000 Total Flight Cycles. Do a Detailed Inspec- tion and HFEC in- spection of the re- paired area at frame STA 907 for any crack in accordance with PART 6. Airplanes that have done the frame re- pair at STA 907 in accordance with PART 3 of Revision 4 of this Service Bul- letin and have in- stalled the support fitting assembly in accordance with PART 4 of Revision 4 of this Service Bul- letin. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 23 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 24 Group 1-4, 6: Table 2: Post Repair - Detailed and High Frequency Eddy Current (HFEC) Inspections of the Body Frame STA 907 at the Air Conditioning Support Bracket Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Before further flight.Contact The Boeing Company for repair instruction and do the repair. Any crack is found 24,000 Flight Cycle-Repeat the Detailed Inspection and HFEC inspection of the re- paired area at frame STA 907 for any crack in accordance with PART 6. No crack is found 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 Union 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. This Service Bulletin is also approved for airplanes having FAA Aviation Partners Boeing (APB) Supplemental Type Certificate (STC) number ST00830SE installed (not including any areas affected by the split scimitar winglet configuration). For 737-700C and BBJ models that have APB winglets installed by STC number ST00830SE, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this Service Bulletin if the bulletin is in the area affected by blended winglets. This Service Bulletin is also approved for airplanes converted into 737-800BCF under project number TS14-0042 that have incorporated Boeing drawing 800A0003 specified in the Type Certification Data Sheet A16WE. 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. In addition, the Manager of the FAA Seattle ACO approves accomplishment of the inspection, repair, and modification procedures of Service Bulletin 737-25A1544, Revision 4, as an alternative method of compliance (AMOC) to the inspection, repair, and modification procedures required by paragraphs (f) and (g) of AD 2009-01-02. Where SB 737-25A1544 Revision 4 specifies to Contact The Boeing Company for appropriate action, prior to further flight, repair using a method approved in accordance with paragraph (j) of AD 2009-01-02. All provisions of AD 2009-01-02 that are not specifically referenced above remain fully applicable and must be complied with accordingly. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 24 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 25 G. Manpower The tables below show an estimate of the task-hours necessary to do this inspection, repair, and preventive change. 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 examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. Group 1-2, 5-6: STA 360 thru STA 907 - Inspection and Support Fitting Extrusion Replacement Elapsed HoursTask-HoursNumber of PersonsTask 19.57137.007Open Access 53.95107.902FIGURE 1 53.95107.902FIGURE 2 33.6067.202FIGURE 7 33.6067.202FIGURE 8 56.00112.002FIGURE 9 56.00112.002FIGURE 10 21421FIGURE 22 21421FIGURE 23 1.51.51FIGURE 24 1.51.51FIGURE 25 32.57228.007Close Access 384.241026.20TOTAL FOR EACH AIRPLANE Group 3: STA 360 thru STA 907 - Inspection and Support Fitting Extrusion Replacement Elapsed HoursTask-HoursNumber of PersonsTask 19.57137.007Open Access 42.5585.102FIGURE 1 42.5585.102FIGURE 2 26.4052.802FIGURE 7 26.4052.802FIGURE 8 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 25 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 26 Group 3: STA 360 thru STA 907 - Inspection and Support Fitting Extrusion Replacement Elapsed HoursTask-HoursNumber of PersonsTask 44.0088.002FIGURE 9 44.0088.002FIGURE 10 21.0042.001FIGURE 22 21.0042.001FIGURE 23 1.501.501FIGURE 24 1.501.501FIGURE 25 32.57228.007Close Access 323.04903.80TOTAL FOR EACH AIRPLANE Group 4: STA 360 thru STA 907 - Inspection and Support Fitting Extrusion Replacement Elapsed HoursTask-HoursNumber of PersonsTask 19.57137.007Open Access 52.05104.102FIGURE 1 52.05104.102FIGURE 2 32.4064.802FIGURE 7 32.4064.802FIGURE 8 54.00108.002FIGURE 9 54.00108.002FIGURE 10 21.0042.001FIGURE 22 21.0042.001FIGURE 23 32.57228.007Close Access 371.041002.80TOTAL FOR EACH AIRPLANE STA 360 thru STA 887 - Frame Repair Elapsed HoursTask-HoursNumber of PersonsTask 5.0010.002FIGURE 3 5.0010.002FIGURE 4 4.559.102FIGURE 5 4.559.102FIGURE 6 (b)(b)-FIGURE 21 1.51.51FIGURE 24 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 26 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 27 STA 360 thru STA 887 - Frame Repair Elapsed HoursTask-HoursNumber of PersonsTask 1.51.51FIGURE 25 22.1032.10TOTAL FOR EACH AIRPLANE (a) (a) The estimates given are for one side of one frame. Multiply the estimated hours by the number of locations that require frame repair to get the total for each airplane. (b) The time necessary to do the frame repair depends on the damage found. Therefore no estimate is given. Group 1-4, 6: STA 907 - Frame Repair OPTION 1 Elapsed HoursTask-HoursNumber of PersonsTask (a)(a)-FIGURE 11 (a)(a)-FIGURE 12 (b)(b)-FIGURE 13 (b)(b)-FIGURE 14 (a)(a)-FIGURE 15 (a)(a)-FIGURE 16 (a)(a)-FIGURE 22 (a)(a)-FIGURE 23 (a)(a)TOTAL FOR EACH AIRPLANE (a) The time necessary to do the frame repair depends on the damage found. Therefore no estimate is given. (b) Time to make repair parts is lost time and is not included in this estimate. Group 1-4, 6: STA 907 - Frame Repair OPTION 2 Elapsed HoursTask-HoursNumber of PersonsTask (a)(a)-FIGURE 11 (a)(a)-FIGURE 12 (b)(b)-FIGURE 17 (b)(b)-FIGURE 18 (a)(a)-FIGURE 19 (a)(a)-FIGURE 20 (a)(a)-FIGURE 22 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 27 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 28 Group 1-4, 6: STA 907 - Frame Repair OPTION 2 Elapsed HoursTask-HoursNumber of PersonsTask (a)(a)-FIGURE 23 (a)(a)TOTAL FOR EACH AIRPLANE (a) The time necessary to do the frame repair depends on the damage found. Therefore no estimate is given. (b) Time to make repair parts is lost time and is not included in this estimate. H. Weight and Balance Changes Group 1: Support Fitting Extrusion Replacement Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane 1,300 (a)+2.0 (a)Each 737-600 Airplane (a) Weight and Balance change does not include changes made by structural repairs. Group 1: STA 360 thru STA 887 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane (b)+0.6 (a)Each 737-600 Airplane (a) The total Change in Weight is +0.6 Pounds per repair times the number of repairs. (b) The total Change in Moment for each model must be calculated. Measure the straight- line "X" distance in inches from the airplanes Station 360 frame to the center of the repair. The Station 360 frame is approximately 32 Inches aft of the center line of the left forward door. Add 334 inches to get Balance Arm (BA). Multiply BA times the weight of the repair (+0.6 Pounds typical). Record value. Repeat for each repair. To obtain the desired total Change in Moment, sum all individual moments. Group 1: STA 907 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane +1,248.1 (b)+1.3 (a)Each OPTION 1 Repair +782.6 (b)+0.8 (a)Each OPTION 2 Repair (a) The total Change in Weight for each model must be calculated. Multiply the Change in Weight for each repair by the number of repaired locations to get the total for each airplane. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 28 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 29 Group 1: STA 907 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane (b) The total Change in Moment for each model must be calculated. Multiply the Change in Moment for each repair by the number of repaired locations to get the total for each airplane. Group 2, 5-6: Support Fitting Extrusion Replacement Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane 1,480 (a)+2.3 (a)Each 737-700 and 700C Airplane (a) Weight and Balance change does not include changes made by structural repairs. Group 2, 5-6: STA 360 thru STA 887 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane (b)+0.6 (a)Each 737-700 and 700C Airplane (a) The total Change in Weight is +0.6 Pounds per repair times the number of repairs. (b) The total Change in Moment for each model must be calculated. Measure the straight- line "X" distance in inches from the airplanes Station 360 frame to the center of the repair. The Station 360 frame is approximately 32 Inches aft of the center line of the left forward door. Add 280 inches to get Balance Arm (BA). Multiply BA times the weight of the repair (+0.6 Pounds typical). Record value. Repeat for each repair. To obtain the desired total Change in Moment, sum all individual moments. Group 2, 6: STA 907 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane +1,299.7 (b)+1.3 (a)Each OPTION 1 Repair +815.0 (b)+0.8 (a)Each OPTION 2 Repair (a) The total Change in Weight for each model must be calculated. Multiply the Change in Weight for each repair by the number of repaired locations to get the total for each airplane. (b) The total Change in Moment for each model must be calculated. Multiply the Change in Moment for each repair by the number of repaired locations to get the total for each airplane. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 29 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 30 Group 3: Support Fitting Extrusion Replacement Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane 1,670 (a)+2.6 (a)Each 737-800 Airplane (a) Weight and Balance change does not include changes made by structural repairs. Group 3: STA 360 thru STA 887 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane (b)+0.6 (a)Each 737-800 Airplane (a) The total Change in Weight is +0.6 Pounds per repair times the number of repairs. (b) The total Change in Moment for each model must be calculated. Measure the straight- line "X" distance in inches from the airplanes Station 360 frame to the center of the repair. The Station 360 frame is approximately 32 Inches aft of the center line of the left forward door. Add 162 inches to get Balance Arm (BA). Multiply BA times the weight of the repair (+0.6 Pounds typical). Record value. Repeat for each repair. To obtain the desired total Change in Moment, sum all individual moments. Group 3: STA 907 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane +1,444.3 (b)+1.3 (a)Each OPTION 1 Repair +905.6 (b)+0.8 (a)Each OPTION 2 Repair (a) The total Change in Weight for each model must be calculated. Multiply the Change in Weight for each repair by the number of repaired locations to get the total for each airplane. (b) The total Change in Moment for each model must be calculated. Multiply the Change in Moment for each repair by the number of repaired locations to get the total for each airplane. Group 4: Support Fitting Extrusion Replacement Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane 1,830 (a)+2.9 (a)Each 737-900 Airplane (a) Weight and Balance change does not include changes made by structural repairs. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 30 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 31 Group 4: STA 360 thru STA 887 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane (b)+0.6 (a)Each 737-900 Airplane (a) The total Change in Weight is +0.6 Pounds per repair times the number of repairs. (b) The total Change in Moment for each model must be calculated. Measure the straight- line "X" distance in inches from the airplanes Station 360 frame to the center of the repair. The Station 360 frame is approximately 32 Inches aft of the center line of the left forward door. Add 100 inches to get Balance Arm (BA). Multiply BA times the weight of the repair (+0.6 Pounds typical). Record value. Repeat for each repair. To obtain the desired total Change in Moment, sum all individual moments. Group 4: STA 907 Frame Repairs Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane +1,498.5 (b)+1.3 (a)Each OPTION 1 Repair +939.6 (b)+0.8 (a)Each OPTION 2 Repair (a) The total Change in Weight for each model must be calculated. Multiply the Change in Weight for each repair by the number of repaired locations to get the total for each airplane. (b) The total Change in Moment for each model must be calculated. Multiply the Change in Moment for each repair by the number of repaired locations to get the total for each airplane. I. Electrical Load Data Not applicable. J. References 1. Existing Data: a. Engineering Change Memo PRR 38275-76S, PRR-39800-021RS b. Boeing Service Bulletin 737-21-1149, 737-25-1544,737-53-1216, 737-53A1232 c. Boeing Service Letter 737-SL-51-042 d. Boeing Service Related Problem (SRP) 737NG-SRP-25-0229, 737NG-SRP-53-0600 e. Boeing Structural Item Interim Advisory (SIIA) 737-258 f. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2009-01-02 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 31 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 32 g. 737NG-Fleet Team Digest (FTD) 737NG-FTD-53-19002 h. Service Bulletin Index D6-19567 i. Standard Overhaul Practices Manual (SOPM) 20-20-02, 20-41-02, 20-41-05, 20-43-03, 20-50-01, 20-50-10, 20-50-19, 20-50-20 j. 737 Non-Destructive Testing (NDT) Manual , Part 6, 51-00-00, Part 6, 51-00-26, Part 6, 53-30-00 k. 737-600/700/800/900 Aircraft Maintenance Manual (AMM) 25-21-25, 25-22-00, 25-23-61, 25-24-31 l. 737-600 Structural Repair Manual (SRM) 51-30-01, 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 m. 737-700 Structural Repair Manual (SRM) 51-30-01, 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 n. 737-700CONV Structural Repair Manual (SRM) 51-30-01 , 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 o. 737-700IGW Structural Repair Manual (SRM) 51-30-01, 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 p. 737-800 Structural Repair Manual (SRM) 51-30-01, 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 q. 737-900 Structural Repair Manual (SRM) 51-30-01 , 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 r. 737-800 BCF Structural Repair Manual (SRM) 51-30-01, 51-40-02, 51-40-05, 51-40-09, 53-00-00, 53-00-07 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number Extrusion Instl - Air Conditioning Outlet Sidewall412A3001 Support Structure Instl - Air Conditioning Extrusion 737-X Variable Section 41412A3241 Support Structure Instl - Air Conditioning Extrusion 737-X Variable Section 43412A3243 Support Structure Instl - Air Conditioning Extrusion 737-X Variable Section 47412A3247 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. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 32 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 33 K. Publications Affected 1. Publications: Chapter-SectionPublication 25-21737 Illustrated Parts Catalog 53-00737 Structural Repair Manual 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 Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information. M. Software Accomplishment Summary Not affected. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 33 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 34 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 34 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT BLANK PAGE ### Page 35 2. MATERIAL INFORMATION A. Material - Price and Availability Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the Service Bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this Service Bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 Group 1: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price as of December 31, 2008 (US Dol- lars) ROLT (Weeks) QTYDateNameTop Kit Number 19,854.0017119 Aug, 2005TOP KIT - A/C EXTRU- SION REVISION 012A8695-201 Group 2, 5-6: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price as of December 31, 2008 (US Dol- lars) ROLT (Weeks) QTYDateNameTop Kit Number 22,335.0017119 Aug, 2005TOP KIT - A/C EXTRU- SION REVISION 012A8695-202 Group 3: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price as of December 31, 2008 (US Dol- lars) ROLT (Weeks) QTYDateNameTop Kit Number 25,811.0017119 Aug, 2005TOP KIT - A/C EXTRU- SION REVISION 012A8695-203 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 35 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 36 Group 4: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price as of December 31, 2008 (US Dol- lars) ROLT (Weeks) QTYDateNameTop Kit Number 28,789.0017119 Aug, 2005TOP KIT - A/C EXTRU- SION REVISION 012A8695-204 B. Industry Support Information Boeing warranty remedies are not available for the configuration changes, inspection, and/or repair procedures given in this Service Bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts: To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. NOTE: One top kit is necessary for each airplane. If cracks are discovered in the airplane frames, the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, can also be required for each airplane. Group 1: Top Kit 012A8695-201 - TOP KIT - A/C EXTRUSION REVISION NotesExisting Part Number NameQTYNew Part Number -201 --TOP KIT - A/C EXTRUSION REVI- SION -012A8695-201 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL 1412A3002-15 Group 2, 5-6: Top Kit 012A8695-202 - TOP KIT - A/C EXTRUSION REVISION NotesExisting Part Number NameQTYNew Part Number -202 --TOP KIT - A/C EXTRUSION REVI- SION -012A8695-202 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL 1412A3002-16 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 36 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 37 Group 3: Top Kit 012A8695-203 - TOP KIT - A/C EXTRUSION REVISION NotesExisting Part Number NameQTYNew Part Number -203 --TOP KIT - A/C EXTRUSION REVI- SION -012A8695-203 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL 1412A3002-17 Group 4: Top Kit 012A8695-204 - TOP KIT - A/C EXTRUSION REVISION NotesExisting Part Number NameQTYNew Part Number -204 --TOP KIT - A/C EXTRUSION REVI- SION -012A8695-204 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL 1412A3002-18 Group 1: Sub Kit 412A3002-15 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -15 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL -412A3002-15 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 16412A3133-1 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 16412A3133-2 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-3 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-4 (a)(b)412N3133-25SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-5 (a)(b)412N3133-26SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-6 (a)(b)(c)BACB30NR4K4BOLT, HEX HEAD88BACB30NR4K4 (a)(b)(c)BACN10YR4CDNUT88BACN10YR4CD (a)(b)(c)BACS12ER3K9SCREW, 100 DEG HEAD88BACS12ER3K9 (a)(b)(c)BACS12FA3K8SCREW, WASHER HEAD88BACS12FA3K8 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 37 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 38 Group 1: Sub Kit 412A3002-15 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -15 (a)(b)(c)NAS1149E0463PWASHER, PLAIN176NAS1149E0463P (a) Discard the existing part. (b) You cannot use the existing part to replace the new or changed part. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Group 2, 5-6: Sub Kit 412A3002-16 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -16 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL -412A3002-16 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 18412A3133-1 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 18412A3133-2 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-3 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-4 (a)(b)412N3133-25SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-5 (a)(b)412N3133-26SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-6 (a)(b)(c)BACB30NR4K4BOLT, HEX HEAD99BACB30NR4K4 (a)(b)(c)BACN10YR4CDNUT99BACN10YR4CD (a)(b)(c)BACS12ER3K9SCREW, 100 DEG HEAD99BACS12ER3K9 (a)(b)(c)BACS12FA3K8SCREW, WASHER HEAD99BACS12FA3K8 (a)(b)(c)NAS1149E0463PWASHER, PLAIN198NAS1149E0463P (a) Discard the existing part. (b) You cannot use the existing part to replace the new or changed part. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 38 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 39 Group 3: Sub Kit 412A3002-17 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -17 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL -412A3002-17 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 22412A3133-1 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 22412A3133-2 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-3 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-4 (a)(b)412N3133-25SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-5 (a)(b)412N3133-26SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-6 (a)(b)(c)BACB30NR4K4BOLT, HEX HEAD115BACB30NR4K4 (a)(b)(c)BACN10YR4CDNUT115BACN10YR4CD (a)(b)(c)BACS12ER3K9SCREW, 100 DEG HEAD115BACS12ER3K9 (a)(b)(c)BACS12FA3K8SCREW, WASHER HEAD115BACS12FA3K8 (a)(b)(c)NAS1149E0463PWASHER, PLAIN230NAS1149E0463P (a) Discard the existing part. (b) You cannot use the existing part to replace the new or changed part. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Group 4: Sub Kit 412A3002-18 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -18 --KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL -412A3002-18 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 25412A3133-1 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 25412A3133-2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 39 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 40 Group 4: Sub Kit 412A3002-18 - KIT - AIR CONDITION EXTRUSION OUTLET, SIDEWALL NotesExisting Part Number NameQTYNew Part Number -18 (a)(b)412N3133-23SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-3 (a)(b)412N3133-24SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 4412A3133-4 (a)(b)412N3133-25SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-5 (a)(b)412N3133-26SUPPORT FITTING ASSEMBLY - A/C EXTRUSIONS 1412A3133-6 (a)(b)(c)BACB30NR4K4BOLT, HEX HEAD128BACB30NR4K4 (a)(b)(c)BACN10YR4CDNUT128BACN10YR4CD (a)(b)(c)BACS12ER3K9SCREW, 100 DEG HEAD128BACS12ER3K9 (a)(b)(c)BACS12FA3K8SCREW, WASHER HEAD128BACS12FA3K8 (a)(b)(c)NAS1149E0463PWASHER, PLAIN256NAS1149E0463P (a) Discard the existing part. (b) You cannot use the existing part to replace the new or changed part. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. 2. Parts and Materials Supplied by the Operator: The following parts or materials are necessary to do the change in this Service Bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available. a. MATERIAL TABLE - STA 360 THRU STA 887, FRAME REPAIR NotesNameQTYPart Number / Specification (a)(b)Sealant8 OuncesBMS 5-95, Class B-1/2, B-2 (a)(c)(l)Primer4 OuncesBMS 10-11, Type I (a)(d)Corrosion Inhibiting Compound4 OuncesBMS 3-29 (BMS 3-23 and BMS 3-35 optional) (e)(f)(m)Chemical Conversion Coating4 OuncesType 2, Class A Dimensions are approximate. (g)(h)(k) Repair Angle A3.07 x 12.50 Inches7075-0 Clad Sheet (QQ-A- 250/13) Repair Angle B3.07 x 9.30 Inches (i)(k)Radius Filler1.85 x 3.07 Inches7075 Aluminum Extrusion Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 40 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 41 NotesNameQTYPart Number / Specification (j)(k)Filler A27075-0 Aluminum Extrusion (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to SOPM 20-50-19. (c) Refer to SOPM 20-41-02. (d) Refer to SOPM 20-41-05. (e) Refer to SOPM 20-43-03. (f) The Boeing Company (81205), P.O. Box 3707 Seattle Washington USA 98124-2207. (g) Make the repair angles from sheet stock that is the same gage as the frame being retrofit. The possible gages needed are 0.050, 0.056, and 0.063 inch. On frames manufactured from 0.064 inch gage mate- rial, make the part from 0.063 inch gage material. On frames manufactured from 0.051 inch gage ma- terial, make the part from 0.050 inch gage material. Heat treat to T6 condition after repair angles are made. (h) An option for the operator is to order the repair angles from Boeing. Refer to the table that follows for part number information. (i) The radius filler can be made from any of the following three 7075 aluminum alloy material options: 7075-0 aluminum alloy, 7075-T6 aluminum alloy, or 7075-0 aluminum alloy and heat treat to T6 condition after the filler is made. (j) Filler for frame cutout. The operator should determine the required size after the cutout is made. On frames manufactured from 0.051 inch gage material make the filler from 0.050 inch gage material. On frames manufactured from 0.064 inch gage material make the filler from 0.063 inch gage material. Finish with Type 2, Class A chemical conversion coating and BMS 10-11, Type I primer. Optional to use 7075-T6 aluminum alloy or 7075-0 aluminum alloy and heat treat to the T6 condition after the filler is made. It is only necessary to make and install a filler if required to provide a flat surface for the support bracket attachment fasteners (hi-lok and collar). (k) Break sharp edges and maintain 125 microinches Ra finish or better. (l) Some primers contain Strontium Chromate and will not be available in the European Union after January 2019 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. (m) Some conversion coatings contain Chromium trioxide/Chromic acid and will not be available in the Eu- ropean Union after September 2017 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. b. REPAIR ANGLE - FORMED GageNameQTYPart Number 0.050 (a)Repair Angle A-69-78188-23 0.056 (a)Repair Angle A-69-78188-25 0.063 (a)Repair Angle A-69-78188-27 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 41 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 42 GageNameQTYPart Number 0.050 (a)Repair Angle B-69-78188-105 0.063 (a)Repair Angle B-69-78188-103 0.056 (a)Repair Angle B-69-78188-107 (a) The Boeing Company (81205), P.O. Box 3707 Seattle, Washington USA 98124-2207. c. MATERIAL TABLE - STA 360 THRU STA 887, Z-SECTION FRAME, FULL FRAME SECTION REPAIR NotesNameQTYPart Number / Specification (a)(b)Sealant8 OuncesBMS 5-95, Class B-1/2, B-2 (a)(c)(k)Primer4 OuncesBMS 10-11, Type I (a)(d)Corrosion Inhibiting Compound4 OuncesBMS 3-29 (BMS 3-23 and BMS 3-35 optional) (e)(f)(l)Chemical Conversion Coating4 OuncesType 2, Class A (g)(h)(j)Repair Angle D27075-0 Clad Sheet (QQ-A- 250/13) Repair Angle E2 (i)(j)Radius Filleras necessary7075 Aluminum Extrusion (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to SOPM 20-50-19. (c) Refer to SOPM 20-41-02. (d) Refer to SOPM 20-41-05. (e) Refer to SOPM 20-43-03. (f) The Boeing Company (81205), P.O. Box 3707 Seattle Washington USA 98124-2207. (g) Make the two repair angles from 7075-0 Clad Sheet, length as necessary. If the frame is manufactured from 0.051 inch gage material, make the Repair Angle D and Repair Angle E from 0.056 inch thick 7075-0 clad sheet. If the frame is manufactured from 0.064 inch gage material, make the Repair Angle D and Repair Angle E from 0.071 inch thick 7075-0 clad sheet. Heat treat to T6 condition after repair angles are made. (h) An option for the operator is to order the repair angles from Boeing. Refer to Boeing Drawing 69-78188 for part number information. (i) The radius filler can be made from any of the following three 7075 aluminum alloy material options: 7075-0 aluminum alloy, 7075-T6 aluminum alloy, or 7075-0 aluminum alloy and heat treated to the T6 condition after the filler is made. (j) Break sharp edges and maintain 125 microinches Ra finish or better. (k) Some primers contain Strontium Chromate and will not be available in the European Union after January 2019 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 42 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 43 NotesNameQTYPart Number / Specification (l) Some conversion coatings contain Chromium trioxide/Chromic acid and will not be available in the European Union after September 2017 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. d. Group 1-4, 6: MATERIAL TABLE - STA 907 FRAME REPAIR NotesNameQTYPart Number / Specification (a)(b)Sealant8 OuncesBMS 5-95, Class B-1/2, B-2 (a)(c)(q)Primer4 OuncesBMS 10-11, Type I (a)(d)Corrosion Inhibiting Compound4 OuncesBMS 3-29 (BMS 3-23 and BMS 3-35 optional) (e)(f)(r)Chemical Conversion Coating4 OuncesType 2, Class A (g)Radius Filleras necessary7075 Aluminum Extrusion (f)(j)Stringer Clip1147A3500-13 (k)(f)Stringer Clip1147A3500-( ) (f)(i)Frame Shear Tie2147A1007-( ) (h)(i)(l)(m)Repair Angle C27075-0 Clad Sheet (QQ-A- 250/13) (h)(n)Filler B27075-T6 Clad Sheet (QQ-A- 250/13) (h)(o)Filler C27075-T6 Clad Sheet (QQ-A- 250/13) (i)(p)Filler D27075-T6 Clad Sheet (QQ-A- 250/13) (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to SOPM 20-50-19. (c) Refer to SOPM 20-41-02. (d) Refer to SOPM 20-41-05. (e) Refer to SOPM 20-43-03. (f) The Boeing Company (81205), P.O. Box 3707 Seattle Washington USA 98124-2207. (g) The radius filler can be made from any of the following three 7075 aluminum alloy material options: 7075-0 aluminum alloy, 7075-T6 aluminum alloy, or 7075-0 aluminum alloy and heat treated to the T6 condition after the filler is made. (h) Necessary for STA 907 frame repair OPTION 1, left and right side. (i) Necessary for STA 907 frame repair OPTION 2, left and right side. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 43 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 44 NotesNameQTYPart Number / Specification (j) It is optional to make the stringer clip for Stringer 8L in accordance with APPENDIX B from 7075-0 clad sheet (QQ-A-250/13), 4.25 x 3.90 inches, 0.036 inch thick. Heat treat to T6 condition after repair the stringer clip is made. (k) Make the stringer clip for the Stringer 8R in accordance with APPENDIX C from AMS10136-2001, 7075-T73511 extrusion. (l) If the existing frame web is 0.056 inch thick, make Repair Angle C from 0.063 inch thick 7075-0 clad sheet. Heat treat to T6 condition after repair angle is made. (m) If the existing frame web is 0.071 inch thick, make Repair Angle C from 0.080 inch thick 7075-0 clad sheet. Heat treat to T6 condition after repair angle is made. (n) Filler B has the same thickness as the existing frame shear tie. (o) Filler C has the same thickness as the existing frame. (p) Filler D has the same thickness as the existing frame. (q) Some primers contain Strontium Chromate and will not be available in the European Union after January 2019 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. (r) Some conversion coatings contain Chromium trioxide/Chromic acid and will not be available in the European Union after September 2017 without an authorization. EU operators are encouraged to ensure their suppliers are authorized to provide the material after the sunset date and that downstream users comply with the risk mitigation measures and operational conditions. e. FASTENER TABLE - STA 360 THRU STA 887, FRAME REPAIR WITH HI-LOKS NotesNameQTYPart Number (a)(b)(c)(d)(f)(g)Hi-lok6BACB30FM6A2 (a)(b)(c)(d)(f)Hi-lok37BACB30FM6A3 (a)(b)(c)(d)(h)Hi-lok31BACB30FM6A4 (a)(b)(c)(d)(f)(g)Hi-lok6BACB30MC6A2 (a)(b)(c)(d)(h)Hi-lok6BACB30MC6A3 (a)(b)(c)(d)(f)(g)Hi-lok6BACB30MD6A2 (a)(b)(c)(d)(f)(g)(h)Hi-lok10BACB30MD6A3 (a)(b)(c)(d)(f)(g)(h)Hi-lok4BACB30MD6A4 (a)(b)(e)(f)Hi-lok2BACB30MB8A4 (a)(b)(e)(g)(h)Hi-lok2BACB30MB8A5 (a)(b)(e)(f)Hi-lok2BACB30NX8K4 (a)(b)(e)(g)(h)Hi-lok2BACB30NX8K5 (b)(c)Collar10BACC30AC6 (b)(c)Collar6BACC30BH6 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 44 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 45 NotesNameQTYPart Number (b)(c)Collar37BACC30M6 (b)(e)Collar2BACC30BH8 (a) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (b) Quantity shown is an approximate only for one side of one frame between STA 360 and STA 887. Multiply the quantity by the number of locations that require repair to get the total for each airplane. (c) BACB30MD6A with mating collar BACC30AC6 is optional to BACB30MC6A with mating collar BACC30BH6, or BACB30FM6A with mating collar BACC30M6. And BACB30MC6A with mating collar BACC30BH6 is optional to BACB30FM6A with mating collar BACC30M6. (d) If radius filler is required to install fastener, measure build-up to determine fastener grip length. (e) BACB30MB8A with mating collar BACC30BH8 is an optional to BACB30NX8K with mating collar BACC30BH8. BACB30NX8K with mating collar BACC30BH8 is preferred. (f) Use when frame gage is 0.051 inch. (g) Use when frame gage is 0.056 inch. (h) Use when frame gage is 0.064 inch. f. FASTENER TABLE - STA 360 THRU STA 887, FRAME REPAIR WITH RIVETS NotesNameQTYPart Number (a)(b)(d)(e)Hi-lok2BACB30NX8K4 (a)(b)(d)(f)(g)Hi-lok2BACB30NX8K5 (a)(b)(d)(e)Hi-lok2BACB30MB8A4 (a)(b)(d)(f)(g)Hi-lok2BACB30MB8A5 (b)(d)Collar2BACC30BH8 (a)(b)(c)(e)(f)Rivet37BACR15BB6AD7C (a)(b)(c)(g)Rivet37BACR15BB6AD8C (a)(b)(e)(f)(g)Rivet4BACR15BB6D7C (a)(b)(e)(f)(g)Rivet4BACR15BB6D8C (a) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (b) Quantity shown is an approximate only for one side of one frame between STA 360 and STA 887. Multiply the quantity by the number of locations that require repair to get the total for each airplane. (c) If radius filler is required to install fastener, measure build-up to determine fastener grip length. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 45 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 46 NotesNameQTYPart Number (d) BACB30MB8A with mating collar BACC30BH8 is an optional to BACB30NX8K with mating collar BACC30BH8. BACB30NX8K with mating collar BACC30BH8 is preferred. (e) Use when frame gage is 0.051 inch. (f) Use when frame gage is 0.056 inch. (g) Use when frame gage is 0.064 inch. g. FASTENER TABLE - STA 360 THRU STA 887, Z-SECTION FRAME, FULL FRAME SECTION REPAIR NotesNameQTYPart Number (a)(b)(c)Hi-lok26BACB30FM6A2 (a)(b)Hi-lok23BACB30FM6A3 (a)(b)Hi-lok4BACB30MD6A4 (a)(b)Hi-lok2BACB30NX8K4 (b)Collar4BACC30AC6 (b)Collar49BACC30M6 (b)Collar2BACC30BH8 (a) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (b) Quantity shown is an approximate only for one side of one frame between STA 360 and STA 887. Multiply the quantity by the number of locations that require repair to get the total for each airplane. (c) If radius filler is required to install fastener, measure build-up to determine fastener grip length. h. Group 1-4, 6: FASTENER TABLE - STA 907 FRAME REPAIR NotesNameQTYPart Number (a)(b)Hi-lok4BACB30FM6A2 (a)(b)(c)(d)Hi-lok38BACB30FM6A3 (a)(b)(c)(d)Hi-lok38BACB30FM6A4 (a)(b)(d)(e)Hi-lok18BACB30MC6A3 (a)(b)(d)(e)Hi-lok20BACB30MC6A4 (a)(b)(d)(e)Hi-lok2BACB30MC6A5 (a)(b)(d)(f)Hi-lok18BACB30MD6A3 (a)(b)(d)(f)Hi-lok20BACB30MD6A4 (a)(b)(d)(f)Hi-lok2BACB30MD6A4 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 46 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 47 NotesNameQTYPart Number (a)(d)Hi-lok2BACB30NX8K4 (a)(d)Hi-lok2BACB30NX8K5 (b)Collar20BACC30AC6 (b)Collar2BACC30BH8 (b)Collar42BACC30M6 (b)Collar20BACC30X6 (a)Rivet14BACR15GF6D6 (a) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (b) Quantity shown is an approximate only for one side of the frame at STA 907. Multiply the quantity by the number of locations that require repair to get the total for each airplane. (c) If radius filler is required to install fastener, measure build-up to determine fastener grip length. (d) Fastener grip length to be determined on installation. (e) This fastener has a 1/64 (first) nominal oversize shank. (f) This fastener has a 1/32 (second) nominal oversize shank. 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 The 737-600 SRM 51-40-09, 737-700 SRM 51-40-09, 737-700IGW (BBJ) SRM 51-40-09, 737-700CONV SRM 51-40-09, 737-800 SRM 51-40-09, 737-800 BCF SRM 51-40-09 and 737-900 SRM 51-40-09 gives data about cold working tools and sleeves necessary to do the work given in this Service Bulletin. These tools are available from industry sources. Engineering, service, and a kit of cold working tools made for this change are available from Fatigue Technology, Inc. or West Coast Industries, Inc. • Refer To: FTI Kit Number: FTI-737-25-1544-1 Fatigue Technology, Inc. P.O. Box C-88388 Seattle, WA 98188 USA Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 47 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 48 Phone Number (206) 246-2010 Fax (206) 244-9886 • Refer To: WCI Kit Number: WCI-737-25-1544 West Coast Industries, Inc. 14900 Whitman Avenue North Seattle, WA 98133-6532 USA Phone Number (206) 365-7513 Fax (206) 365-7483 F. Special Tooling Necessary to do this Service Bulletin Cold working tools are necessary to do the change given in this Service Bulletin. To get the cold working tools, refer to Paragraph 2.E., Special Tooling - Price and Availability. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 48 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 49 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION 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. CAUTION 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 Values: — Values for structural fasteners are given in 737 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 737 Aircraft Maintenance Manual (AMM). — Non-standard torque values for maintenance tasks are included in the applicable installation step. 4. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 5. If the length of any fasteners specified in this Service Bulletin does not meet the installation standards given in Structural Repair Manual (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. This could include tactile assessment in which a component or assembly can be checked for tightness/security. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors and magnifying lenses may be necessary. Surface cleaning and elaborate access procedures may be required. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 49 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 50 7. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 8. 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. 9. 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. 10. Refer to APPENDIX A, 737 Airplane Frame Status at Air Conditioning Support Bracket Attachment, for planning purposes (optional). 11. Refer to APPENDIX B , APPENDIX C for stringer clip fabrication (optional). 12. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 13. 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. 14. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 15. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. B. WORK INSTRUCTIONS PART 1 - ACCESS 1. Get access to the left and right side support brackets of the air conditioning (A/C) outlet extrusion between Station (STA) 360 and STA 907. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 50 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 51 Group 1-2, 5-6: NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified. Inspections of the frames at STA 540, STA 663.75, STA 685, and STA 727 are not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does not need to be inspected as this configuration is not susceptible to cracks. Inspections of the frames at STA 616, and STA 639 on 737-600 and 737-700/700C airplanes are also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. Access to these brackets is necessary for the replacement of support fitting assemblies in accordance with PART 4. Group 3-4: NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified. Inspections of the frames at STA 540, STA 663.75, STA 685, and STA 727 are not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does not need to be inspected as this configuration is not susceptible to cracks. Inspections of the frames at STA 578, STA 601, STA 616, and STA 639 on 737-800 and 737-900 airplanes are also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. Access to these brackets is necessary for the replacement of support fitting assemblies in accordance with PART 4. a. Remove the equipment that follows to get access: (1) The passenger seats. Refer to 737-600/700/800/900 AMM 25-22-00 as an accepted procedure. (2) The passenger service units. Refer to 737-600/700/800/900 AMM 25-23-61 as an accepted procedure. (3) The overhead stowage bins. Refer to 737-600/700/800/900 AMM 25-24-31 as an accepted procedure. (4) The sidewall lining. Refer to 737-600/700/800/900 AMM 25-21-25 as an accepted procedure. PART 2 - INSPECTION 1. Do a General Visual Inspection (GVI), a Medium Frequency Eddy Current (MFEC) inspection, a Low Frequency Eddy Current (LFEC) inspection and a High Frequency Eddy Current (HFEC) inspection of frames from STA 360 to STA 907 at Stringer 8L and Stringer 8R, for any crack at the A/C rail bracket attachment fastener locations, to identify the locations on the airplane where to do a repair. The suspect bracket is attached to the frame with a two rivet attachment configuration. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 51 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 52 Group 1-2, 5-6: NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified. Inspections of the frames at STA 540, STA 663.75, STA 685, and STA 727 are not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does not need to be inspected as this configuration is not susceptible to cracks. Inspections of the frames at STA 616, and STA 639 on 737-600 and 737-700/-700C airplanes are also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. Group 1-2: NOTE: The LFEC inspection is only required at STA 907 around the installed fastener at the outboard fastener location where the MFEC inspection is not applicable. Group 3-4: NOTE: The location of the support brackets vary due to different air conditioning configurations. As a result, all frames from STA 360 to STA 907 that have a support bracket with a two rivet attachment configuration need to be identified. Inspections of the frames at STA 540, STA 663.75, STA 685, and STA 727 are not necessary. The frames at STA 540, STA 663.75, and STA 727 are machined frames and are not susceptible to the subject frame cracks. The frame at STA 685 has a support bracket with a four rivet attachment and does not need to be inspected as this configuration is not susceptible to cracks. Inspections of the frames at STA 578, STA 601, STA 616, and STA 639 on 737-800 and 737-900 airplanes are also not necessary because the frames are manufactured from a thicker material and they are not susceptible to the subject frame cracks. Group 3-6: NOTE: The Low Frequency Eddy Current (LFEC) inspection is only required at STA 559 and STA 907 around the installed fastener at the outboard fastener location where the Medium Frequency Eddy Current (MFEC) inspection is not applicable. NOTE: For planning purposes an optional airplane frame status table is given in APPENDIX A. The table can be used for initial inspection, frame and bracket tabulation. The table could benefit planning in subsequent inspections or modifications to reduce the access time for inspections or parts fabrication requirements. NOTE: If the support bracket is installed then the inside radius must be inspected. NOTE: If a frame has previously been repaired in accordance with 737 SRM 53-00-07, Repair 1, contact The Boeing Company for an alternative method of inspection and do the inspection. a. For frames on the left side of the airplane, do the General Visual Inspection (GVI), the Medium Frequency Eddy Current (MFEC) inspection, the Low Frequency Eddy Current (LFEC) inspection and the High Frequency Eddy Current (HFEC) inspection for any crack in accordance with FIGURE 1, FIGURE 24. b. For frames on the right side of the airplane, do the General Visual Inspection (GVI), the Medium Frequency Eddy Current (MFEC) inspection, the Low Frequency Eddy Current (LFEC) inspection and the High Frequency Eddy Current (HFEC) inspection for any crack in accordance with FIGURE 2, FIGURE 25. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 52 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 53 2. If any crack is found, more work is necessary, do PART 3, then do PART 4. 3. If no crack is found, more work is necessary, do PART 4. PART 3 - REPAIR OF DAMAGED FRAMES 1. Repair damaged frames as follows: a. To repair the frames between STA 360 and STA 887, except for STA 706 and STA 559 (Group 3-6), go to Step 2 of PART 3. If any frame cannot be repaired in accordance with Step 2, go to Step 4 of PART 3. b. Group 1-4, 6: To repair the frame at STA 907, go to Step 3 of PART 3. c. Group 5: To repair the frame at STA 907, contact The Boeing Company for repair instructions and do the repair. d. To repair the frame at STA 706, contact The Boeing Company for repair instructions and do the repair. e. Group 3-6: To repair the frame at STA 559, contact The Boeing Company for repair instructions and do the repair. 2. To repair the frames between STA 360 and STA 887, except for STA 706 and STA 559 (Group 3-6), install two repair angles, Angle A and Angle B, at each location where cracks were found. NOTE: It is possible to install Angle A and Angle B with hi-loks or rivets. The operator must determine if they use hi-loks or rivets. a. If hi-loks are used to install Angle A and Angle B, it is necessary to cold work the six end holes common to Angle A. (1) For frames on the left side of the airplane, install the repair angles in accordance with FIGURE 3. (2) For frames on the right side of the airplane, install the repair angles in accordance with FIGURE 4. b. If rivets are used to install Angle A and Angle B, it is not necessary to cold work the six end holes common to Angle A. (1) For frames on the left side of the airplane, install the repair angles in accordance with FIGURE 5. (2) For frames on the right side of the airplane, install the repair angles in accordance with FIGURE 6. 3. Group 1-4, 6: To repair the frame at STA 907, do OPTION 1 or OPTION 2 as follows: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 53 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 54 NOTE: OPTION 1 will remove the existing frame shear ties and install the same frame shear ties again. 1. 2. OPTION 2 will remove the existing frame shear ties and install new frame shear ties. 3. OPTION 1 and OPTION 2 are applicable for a formed J-section frame thickness of 0.056 inch or 0.071 inch between Stringer 8L and Stringer 9L or between Stringer 8R and Stringer 9R at STA 907. a. OPTION 1: (1) Cut out all cracks in the frame in accordance with the figures below: Right SideLeft Side FIGURE 12FIGURE 11 (a) If any crack is found in an open fastener hole, contact The Boeing Company for repair instructions and do the repair. (b) If any crack is found in the adjacent structure between Stringer 6L and Stringer 10L or between Stringer 6R and Stringer 10R at STA 907, contact The Boeing Company for repair instructions and do the repair. (2) Make the repair parts in accordance with the figures below: Right SideLeft Side FIGURE 14FIGURE 13 (3) Install the repair parts in accordance with the figures below: Right SideLeft Side FIGURE 16FIGURE 15 b. OPTION 2: (1) Cut out all cracks in the frame in accordance with the figures below: Right SideLeft Side FIGURE 12FIGURE 11 (a) If any crack is found in an open fastener hole, contact The Boeing Company for repair instructions and do the repair. (b) If any crack is found in the adjacent structure between Stringer 6L and Stringer 10L or between Stringer 6R and Stringer 10R at STA 907, contact The Boeing Company for repair instructions and do the repair. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 54 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 55 (2) Make the repair parts in accordance with the figures below: Right SideLeft Side FIGURE 18FIGURE 17 (3) Install the repair parts in accordance with the figures below: Right SideLeft Side FIGURE 20FIGURE 19 4. If any formed Z-section frame between STA 360 and STA 887, except for STA 706 and STA 559 (Group 3-6) cannot be repaired in accordance with Step 2, do a repair of the frame in accordance with FIGURE 21. NOTE: This repair is not applicable at the locations that follow: 1. Edge frames or auxiliary frames 2. Frame sections that include doublers or other repair parts. a. If any crack is found in an open fastener hole, contact The Boeing Company for repair instructions and do the repair. b. If any crack is found in the adjacent structure between Stringer 6L and Stringer 10L or between Stringer 6R and Stringer 10R, contact The Boeing Company for repair instructions and do the repair. PART 4 - REPLACEMENT OF SUPPORT FITTING ASSEMBLY - AIR CONDITIONING EXTRUSIONS 1. The following notes provide general information on the replacement of support fitting assemblies. NOTE: If the airplane has 412N3133-( ) support fittings on the frame at STA 360, replace a left side support fitting with 412A3133-5 and a right side support fitting with 412A3133-6. NOTE: If any frames forward of STA 480 (except at STA 360) have 412N3133-( ) support fittings, replace left side support fittings with 412A3133-3 and right side support fittings with 412A3133-4. NOTE: If any frames at and aft of STA 480 have 412N3133-( ) support fittings, replace left side support fittings with 412A3133-1 and right side support fittings with 412A3133-2. NOTE: As a guide to identify 412N3133-( ) support fittings that need to be replaced, they are located inboard of the frames, (on the A/C rails) between stringers S-8 and S-9, at approximately WL 272, BL 55.5. They can be visually identified as in the Figure 1 and Figure 2 illustrations. NOTE: There are no support fitting assemblies installed at STA 458.27 (460). 2. At the left side frames forward of STA 458.27, except at STA 360, on the air conditioning outlet assembly, do as follows: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 55 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 56 a. Remove the support fitting assembly - A/C extrusions part number 412N3133-23 in accordance with FIGURE 7. b. Install new support fitting assembly - A/C extrusions part number 412A3133-3 in accordance with FIGURE 9. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800 SRM 53-00-00, 737-800BCF SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. 3. At the right side frames forward of STA 458.27, except at STA 360, on the air conditioning outlet assembly, do as follows: a. Remove the support fitting assembly - A/C extrusions part number 412N3133-24 in accordance with FIGURE 8. b. Install new support fitting assembly - A/C extrusions part number 412A3133-4 in accordance with FIGURE 10. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800BCF SRM 53-00-00, 737-800 SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. 4. At the left side frame STA 360.00, on the air conditioning outlet assembly, do as follows: NOTE: If the airplane does not have a 412N3133-25 fitting at STA 360 it is not necessary to do the following Steps 4.a and 4.b. a. Remove the support fitting assembly - A/C extrusions part number 412N3133-25 in accordance with FIGURE 7. b. Install new support fitting assembly - A/C extrusions part number 412A3133-5 in accordance with FIGURE 9. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800 SRM 53-00-00, 737-800BCF SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. 5. At the right side frame STA 360.00, on the air conditioning outlet assembly, do as follows: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 56 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 57 NOTE: If the airplane does not have a 412N3133-26 fitting at STA 360 it is not necessary to do the following Steps 5.a and 5.b. a. Remove the support fitting assembly - A/C extrusions part number 412N3133-26 in accordance with FIGURE 8. b. Install new support fitting assembly - A/C extrusions part number 412A3133-6 in accordance with FIGURE 10. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800 SRM 53-00-00, 737-800BCF SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. 6. At the left side frames aft of STA 458.27, on the air conditioning outlet assembly, do as follows: a. Remove the support fitting assembly - A/C extrusions part number 412N3133-23 in accordance with FIGURE 7. b. Install new support fitting assembly - A/C extrusions part number 412A3133-1 in accordance with FIGURE 9. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800 SRM 53-00-00, 737-800BCF SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. 7. At the right side frames aft of STA 458.27, on the air conditioning outlet assembly, do as follows: a. Remove the support fitting assembly - A/C extrusions part number 412N3133-24 in accordance with FIGURE 8. b. Install new support fitting assembly - A/C extrusions part number 412A3133-2 in accordance with FIGURE 10. NOTE: The optional table given in APPENDIX A can be used for frame and bracket tabulation. The operator can use this table to record the STA locations of the applicable frames and brackets. The table could benefit planning in subsequent modifications to reduce the access time for inspections or parts fabrication requirements. Refer to 737-600 SRM 53-00-00, 737-700 SRM 53-00-00, 737-700CONV SRM 53-00-00, 737-700IGW (BBJ) SRM 53-00-00, 737-800 SRM 53-00-00, 737-800BCF SRM 53-00-00, or 737-900 SRM 53-00-00, for specific frame locations. PART 5 - CLOSE ACCESS 1. Install the equipment that follows: Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 57 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 58 a. The sidewall lining. Refer to 737-600/700/800/900 AMM 25-21-25 as an accepted procedure. b. The overhead stowage bins. Refer to 737-600/700/800/900 AMM 25-24-31 as an accepted procedure. c. The passenger service units. Refer to 737-600/700/800/900 AMM 25-23-61 as an accepted procedure. d. The passenger seats. Refer to 737-600/700/800/900 AMM 25-22-00 as an accepted procedure. e. Put the airplane back to a serviceable condition. Group 1-4, 6: PART 6 - POST REPAIR - BODY FRAME STA 907 BETWEEN S-7 AND S-9 AT THE AIR CONDITIONING SUPPORT BRACKET - INSPECTION 1. Do a Detailed Inspection of the repaired area at frame STA 907 for any crack, do a High Frequency Eddy Current (HFEC) inspection around the critical end fasteners at frame STA 907 for any crack and do a HFEC inspection along the edge of the fail safe chord at frame STA 907 for any crack in accordance with figure below based on the repair option accomplished: a. For airplanes that have accomplished Part 3 frame repair option 1 in accordance with FIGURE 22. b. For airplanes that have accomplished Part 3 frame repair option 2 in accordance with FIGURE 23. 2. If any crack is found, contact The Boeing Company for repair instructions and do the repair. 3. If no crack is found. a. Repeat the Detailed Inspection of the repaired area at frame STA 907 for any crack, do a HFEC inspection around the critical end fasteners at frame STA 907 for any crack and do a HFEC inspection along the edge of the fail safe chord at frame STA 907 for any crack in accordance with figure below based on the repair option accomplished: (1) For airplanes that have accomplished Part 3 frame repair option 1 in accordance with FIGURE 22. (2) For airplanes that have accomplished Part 3 frame repair option 2 in accordance with FIGURE 23. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: October 04, 2006 737-25A1544Revision 4: February 15, 2022 58 of 202 BOEING SERVICE BULLETIN 737-25A1544 ALERTALERT ### Page 59 (OCR) BOEING SERVICE BULLETIN 737-25A1544 ALERT ALERT STA 360 STA 887 STA 907 TYPICAL CRACKS IN RADIUS S-8L SUPPORT BRACKET TYPICAL CRACKS S-9L AIR CONDITIONING OUTLET ASSEMBLY FIGURE 1: INSPECTION OF FRAME ON LEFT SIDE OF THE AIRPLANE (SHEET 1 OF 3) Original Issue: October 04, 2006 Revision 4 February 15, 2022 Export Controlled ECCN: 9E991 737-25A1544 Copyright © Unpublished Work - See page 1 for details. 59 of 202 ### Page 60 (OCR) BOEING SERVICE BULLETIN 737-25A1544 ALERT ALERT TYPICAL CRACKS IN RADIUS STA 907 S-8L FRAME SHEAR TIE TYPICAL CRACKS | SUPPORT BRACKET S-9L FAIL SAFE CHORD AIR CONDITIONING OUTLET ASSEMBLY 2291287 FIGURE 1: INSPECTION OF FRAME ON LEFT SIDE OF THE AIRPLANE (SHEET 2 OF 3) Original Issue: October 04, 2006 Revision 4 February 15, 2022 737-25A1544 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 60 of 202 The text continues at https://openairdocs.org/service-documents/boeing/737-25a1544/file/201272e70a1b.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.