# Boeing Alert Service Bulletin 737-53A1279: Revision 2 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2015-5812; AD 2016-11-04 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-53A1279](https://openairdocs.org/service-documents/boeing/737-53a1279.md) - Title as filed: U.S. DOT/FAA - SB-737-53A1279-02 - Pages: 199 - PDF: https://openairdocs.org/files/sha256/45/18/4518dbc4ed9bf4a8dbaa13bc2c18e0437d8a1d18f6cc6080fda0fd34bd369739 - Page: https://openairdocs.org/service-documents/boeing/737-53a1279/file/4518dbc4ed9b ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1279 Original Issue: December 18, 2007 Revision 2: April 21, 2015 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 22 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole, 0.50 Inch Diameter Hole, Standoff/Tooling Holes and Production Fastener Holes Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2007 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 Unpublished Work.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: December 18, 2007 737-53A1279Revision 2: April 21, 2015 1 of 199 4.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 2 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 40 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 43 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 44 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL [Group 1, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 FIGURE 2: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - REMOVAL [Group 3, 6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 FIGURE 3: FORWARD CARGO BAY - AFT BULKHEAD PANELS - REMOVAL . . . . . . . . . . . . 66 FIGURE 4: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 1, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 FIGURE 5: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 2, 5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 FIGURE 6: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - MOVE [Group 3, 6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 3 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 4 FIGURE 7: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 1, 4] . . . . . . . . . . . . . . . . . 83 FIGURE 8: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 2, 5] . . . . . . . . . . . . . . . . . 90 FIGURE 9: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) SURFACE INSPECTION [Group 3, 6] . . . . . . . . . . . . . . . . . 97 FIGURE 10: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 1, 4] . . . . . . . . . . . . . . . 104 FIGURE 11: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 2, 5] . . . . . . . . . . . . . . . 112 FIGURE 12: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 3, 6] . . . . . . . . . . . . . . . 120 FIGURE 13: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 1, 4] . . . . . . . . . . . . . . . 128 FIGURE 14: FORWARD CARGO BAY - STATION 500B TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 2, 5] . . . . . . . . . . . . . . . 136 FIGURE 15: FORWARD CARGO BAY - STATION 482 TO 520 FRAMES - HIGH FREQUENCY EDDY CURRENT (HFEC) HOLE/EDGE INSPECTION [Group 3, 6] . . . . . . . . . . . . . . . 144 FIGURE 16: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 1, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 FIGURE 17: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 2, 5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 FIGURE 18: FORWARD CARGO BAY - POWER FEEDER CABLE GUIDE ASSEMBLY - INSTALL [Group 3, 6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 FIGURE 19: FORWARD CARGO BAY - AFT BULKHEAD PANELS - INSTALL . . . . . . . . . . . . 167 FIGURE 20: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - INSTALL [Group 1, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 FIGURE 21: FORWARD CARGO BAY - STATION 460 TO STATION 482B - WIRE SHROUD - INSTALL [Group 3, 6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 FIGURE 22: FORWARD CARGO BAY - STA 500B TO 520 FRAMES - DETAILED INSPECTION [Group 1, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 FIGURE 23: FORWARD CARGO BAY - STA 500B TO 520 FRAMES - DETAILED INSPECTION [Group 2, 5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 FIGURE 24: FORWARD CARGO BAY - STA 482 TO 520 FRAMES - DETAILED INSPECTION [Group 3, 6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 FIGURE 25: FORWARD CARGO BAY - PREVENTATIVE MODIFICATION INSPECTION [Group 1-3, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 FIGURE 26: FORWARD CARGO BAY - PREVENTATIVE MODIFICATION INSPECTION [Group 4-6, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 4 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-53A1279Original Issue: December 18, 2007 Revision 2: April 21, 2015 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 22 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole, 0.50 Inch Diameter Hole, Standoff/Tooling Holes and Production Fastener Holes This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directive AD 2011-23-05 is related to this service bulletin. AD 2011-23-05 supersedes AD 2009-02-06 R1. 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. More work is necessary on airplanes changed or inspected in accordance with the Revision 1 or the original issue of this service bulletin: ActionConditionGroup Accomplish post modification/repair inspection at compliance times in accordance with Paragraph 1.E., Compliance. Previously accomplished the repair or preventative modification in accor- dance with Revision 1 or the original issue of this bulletin. All Configurations 1 and 2. Accomplish preventative modifica- tion before the threshold in accor- dance with Paragraph 1.E. Compli- ance. Locations without a preventative modification or repair installed. All Configurations 3. NOTE: Part 26 DTI requirements provided in Revision 2 of this service bulletin supersede the DTI requirements for the previous revisions of this service bulletin contained in 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, 737-500 SRM 53-00-07, Repair 13. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 5 of 199 ### Page 6 REASON FOR REVISION This revision is sent to add new inspection areas and to make sure of the accomplishment of inspections before the installation of preventative modifications installed between the dates March 12, 2012 and February 1, 2014. This revision is also sent to add post preventative modification and repair inspections, and to add a compliance threshold for the accomplishment of the preventative modification. This revision also moves 737-300/-400 and -500 airplanes, line numbers 2566 thru 3132 into three new groups to separate bonded skin airplanes from solid skin airplanes. These sections were changed: 1. Revised title to include new inspection, repair and preventative modification locations. 2. Summary – Background - Revised to include new inspection areas and Summary Evaluation Table is added. – Action - New inspection areas are added. – Compliance - Existing AD replaced by superseding AD and new more work table added. – Graphic revised to show new inspection areas. 3. Paragraph 1.A1. Airplanes – Airplanes 737-300, line numbers 2566 thru 3132 are moved from group 1 to new group 4. – Airplanes 737-400, line numbers 2566 thru 3132 are moved from group 2 to new group 5. – Airplanes 737-500, line numbers 2566 thru 3132 are moved from group 3 to new group 6. – Configurations are added to all groups. 4. Paragraph 1.C. Reason - New inspection areas added and 'Revision 2 is sent to' statement added. 5. Paragraph 1.D. Description - New inspection areas are added. 6. Paragraph 1.E. Compliance - Existing AD replaced by latest AD, compliance tables revised for new inspection areas and compliance tables added for installation of the preventative modification and for airplanes that previously installed a repair or preventative modification per Revision 1 or Revision 0 of this service bulletin. 7. Paragraph 1.F. Approval - Paragraph three revised for latest AD. 8. Paragraph 1.G. Manpower - Existing tables revised to show new inspection areas, and new table added for post modification inspection. 9. Paragraph 1.M. Software Accomplishment Summary added. 10. Paragraph 3.A. General Information - Added new notes. 11. Paragraph 3.B. Work Instructions - Existing steps revised to show added inspection, repair and preventative modification areas, and new steps added for post modification inspection instruction. 12. Figures 1, 2, 7 through 9, 10 through 18, 20, and 21 have updated group applicability. 13. Revised footnotes in Figures 7 through 9, and 13 through 15. 14. Revised footnotes and step tables in Figures 10 through 12. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 6 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 7 15. New figures 22 thru 26 added to show new inspection and preventative modification areas. 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 December 18, 2007Original Issue: September 02, 2011Revision 1: April 21, 2015Revision 2: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 7 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 8 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 8 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT BLANK PAGE ### Page 9 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-53A1279Original Issue: December 18, 2007 Revision 2: April 21, 2015 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 22 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole, 0.50 Inch Diameter Hole, Standoff/Tooling Holes and Production Fastener Holes THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None. BACKGROUND This service bulletin gives instructions to inspect a 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes for cracking in the forward cargo compartment frames and frame reinforcements, between Stringer (S) S-19 and S-22, on both left and right sides of the airplane. It also provides repair instructions for cracking at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes and instructions for a preventative modification. Undetected cracking in fuselage frames at the 1.04 inch nominal diameter wire penetration hole intended for wire routing, the 0.50 inch diameter hole, the standoff/tooling holes or the production fastener holes will reduce the frames structural capability below fail-safe load limits. Undetected cracking in the frames could lead to cracking in the skin and could result in rapid depressurization of the airplane. Boeing has received reports of cracking in the frame, or in the frame and frame reinforcement, common to the 1.04 inch nominal diameter wire penetration hole intended for wire routing, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes, between S-19 and S-22, on both left and right sides of the airplane. The cracked frames are located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes. Cracking is occurring at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes due to the effect of operating loads in combination with the stress concentration at the 1.04 inch nominal hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 9 of 199 ### Page 10 Boeing received a report of frame cracking from an operator at the 1.04 inch nominal diameter wire penetration hole on a 737-400 airplane. The airplane had one cracked frame. Boeing has since received reports of more than fifty cracked frames at the 1.04 inch nominal diameter wire penetration hole on more than twenty airplanes, all either 737-300 or 737-500 airplanes. The airplanes had accumulated between 35,832 and 66,694 flight cycles. The cracking initiated at the 1.04 inch nominal diameter wire penetration hole and grew towards the inner chord. Boeing received a report of four cracked frames at BS 500B, BS 500C, BS 500D and BS 520 in the forward cargo compartment between S-20L and S-21L on a 737-300 airplane. The cracks at BS 500B and BS 500C were completely through the frame and fail-safe chord. The BS 500B frame was also cracked on the right hand side. The airplane had 44,535 flight cycles and 44,876 flight hours. Though the airplane was above the AD and service bulletin threshold of 32,000 flight cycles, the cracking was discovered before the airplane had reached the compliance time of the AD and of the original issue of this service bulletin. In total, Boeing has received more than 50 reports of frame cracking at the 1.04 inch nominal diameter wire penetration hole on 24 airplanes. Details of the cracking are as follows: — The cracking occurred at three frame stations on 737-300 airplanes, on four frame stations on 737-500 airplanes, and at one frame station on one 737-400 airplane. — Sixteen airplanes had cracking on multiple frames. — 10 frames had cracking at adjacent frames. — 43 frames had cracking only at the inboard side of the 1.04 inch nominal diameter wire penetration hole in the frame inner chord or in the frame and frame reinforcement inner chord. — 3 frames had cracking at the outboard side of the 1.04 inch nominal diameter wire penetration hole in the frame and the frame reinforcement. 2 of these frames were severed. — Some frames had additional cracking at either the standoff/tooling holes or at the 0.50 inch diameter hole positioned below the 1.04 inch nominal diameter wire penetration hole. Boeing received a report of cracking common to the 0.50 inch diameter hole with no reported cracking common to the 1.04 inch nominal diameter wire penetration hole. Boeing has also received a report of cracking common to the standoff/tooling hole with no reported cracking common to the 1.04 inch nominal diameter wire penetration hole or the 0.50 inch diameter hole. Inspections of the 0.50 inch diameter hole and standoff/tooling holes were only required in accordance with previous revisions of this service bulletin if any crack was found at the 1.04 inch nominal diameter wire penetration hole. Boeing has received multiple reports of cracking common to the production fastener holes during installation of a repair in accordance with 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 13. An Inspection for cracking of the area and any necessary repair will assure the structural integrity of the fuselage. This service bulletin provides additional inspections for airplanes that didn't inspect production fastener holes before the installation of preventative modifications on frames located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes between March 12, 2012 and February 1, 2014. Inspections in PART 7 are required at frames that accomplished PART 5 - PREVENTATIVE MODIFICATION in accordance with Revision 1 of this bulletin because PART 5 states: "Do the repair as given in 737 SRM 53-00-07 Repair 13 except omit the steps in the Damage Removal Procedure". Between the dates of March 12, 2012 and February 1, 2014, the HFEC open hole inspections for the production fastener holes in the frame using 737 NDT Manual Part 6, 51-00-00 Procedure 16 was moved within 737 SRM 53-00-07 Repair 13 into Section 4.B. Damage Removal from Section 4.C. Installation of Repair Parts. Boeing Service Related Problem (SRP) 737-SRP-53-0289 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0377 is related to this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 10 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 11 The fuselage frames addressed in this service bulletin from STA 500B to STA 520 on 737-300/-400 airplanes, and from STA 482 to STA 520 on 737-500 airplanes between S-19 and S-22 have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). 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 ChangesNoWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedNoPublications 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/PartsNoKits/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 ACTION Get access to the forward cargo bay. Remove the cargo handling system, if installed. Remove the wire shrouds, sidewall linings, aft bulkhead panels and insulation blankets, on both sides of the airplane to get access to frames STA 500B - STA 520 on 737-300 and -400 airplanes and STA 482 - STA 520 on 737-500 airplanes. Unscrew the power feeder cable guides as required and move them away from the hole. Do a High Frequency Eddy Current (HFEC) inspection and a Detailed inspection of the frame and frame reinforcement between Stringers S-19 and S-22 for cracking. If any crack is found at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes or the production fastener holes between Stringers S-19 and S-22 do a repair in accordance with this Service Bulletin. If no crack is found at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes, either accomplish the preventative modification in accordance with this service bulletin, or restore access, put the airplane back to a serviceable condition and do repeat inspections at the intervals given in Paragraph 1.E., Compliance. Group 1-3: If a preventative modification was accomplished in accordance with Revision 1 of this service bulletin between March 12, 2012 and February 1, 2014, make sure the production fastener holes in the frame and frame reinforcement common to the modification angles were inspected using the inspection procedure in accordance with 737-Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 16. If the pre-modification inspections of the production fastener holes were not performed, then do a HFEC inspection of the frame re-inforcement, the 1.04 inch nominal diameter hole, the 0.50 inch diameter hole, a detailed inspection of the frame where visible, and a Low Frequency Eddy Current (LFEC) inspection of the frame in accordance with Revision 2 of this service Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 11 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 12 bulletin in accordance with compliance times listed in Paragraph 1.E., Compliance. If the pre-modification inspections of the production fastener holes or the preventative modification were accomplished before 12 March 2012, or after 1 February 2014, then do a post-modification inspection in accordance with 737 Structural Repair Manual 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 20 at the compliance times listed in Paragraph 1.E., Compliance. Group 4-6: If a preventative modification was accomplished in accordance with Revision 1 of this service bulletin between March 12, 2012 and February 1, 2014, make sure the production fastener holes in the frame and frame reinforcement common to the modification angles were inspected using the inspection procedure in accordance with 737-Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 16. If the pre-modification inspections of the production fastener holes were not performed, then do a HFEC inspection of the frame re-inforcement, the 1.04 inch nominal diameter hole, the 0.50 inch diameter hole, the fail safe chord, and a detailed inspection of the frame where visible in accordance with Revision 2 of this service bulletin in accordance with compliance times listed in Paragraph 1.E., Compliance. If the pre-modification inspections of the production fastener holes or the preventative modification were accomplished before 12 March 2012, or after 1 February 2014, then do a post-modification inspection in accordance with 737 Structural Repair Manual737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 20 at the compliance times listed in Paragraph 1.E., Compliance. EFFECTIVITY All 737-300/400/500 Series Airplanes. Refer to Paragraph 1.A.1 Airplanes, for the list of affected airplanes. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2011-23-05 is related to this service bulletin. 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. See Service Bulletin Paragraph 1.E., for compliance information. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. MANPOWER See Service Bulletin Paragraph 1.G., for manpower information. MATERIAL INFORMATION Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability . Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 12 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 13 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT INSPECT ALL PRODUCTION FASTENER HOLE LOCATIONS IN SHADED AREA BETWEEN S-19 AND S-22 FOR CRACKING. IF NO CRACKING IS FOUND DO REPEAT INSPECTIONS, OR ACCOMPLISH THE PREVENTATIVE MODIFICATION. IF CRACKING IS FOUND, CONTACT THE BOEING COMPANY FOR REPAIR INSTRUCTIONS AND DO THE REPAIR. SEE - S-19R TYPICAL CRACKING AT OUTBOARD AND INBOARD SIDE OF 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE. INSPECT THE 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE FOR CRACKING. IF NO CRACKING IS FOUND AT THE 1.04 INCH NOMINAL DIAMETER WIRE PENETRATION HOLE, DO REPEAT INSPECTIONS, OR ACCOMPLISH THE PREVENTATIVE MODIFICATION. IF CRACKING IS FOUND, REPAIR THE CRACKING IN ACCORDANCE WITH THIS SERVICE BULLETIN. -S-20R INSPECT THE 0.50 INCH DIAMETER HOLE AND ALL STANDOFF/TOOLING HOLES BETWEEN STRINGER 19 AND STRINGER 22. IF NO CRACKING IS FOUND AT THE 0.50 INCH DIAMETER OR STANDOFF/TOOLING HOLES, DO REPEAT INSPECTIONS OR ACCOMPLISH THE PREVENTATIVE MODIFICATION. S-21R IF CRACKING IS FOUND AT THE 0.50 INCH DIAMETER HOLE, REPAIR THE CRACKING IN ACCORDANCE WITH THIS SERVICE BULLETIN, IF CRACKING IS FOUND AT THE STANDOFF/TOOLING HOLES, CONTACT THE BOEING COMPANY FOR REPAIR INSTRUCTIONS AND DO THE REPAIR. *S-22R UP VIEW LOOKING FORWARD INBD (TYPICAL FRAME SECTION) 1339121 RIGHT SIDE SHOWN LEFT SIDE OPPOSITE Original Issue: December 18, 2007 Revision 2: April 21, 2015 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-53A1279 Work - See page 1 for details. 13 of 199 ### Page 14 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 14 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT BLANK PAGE ### Page 15 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1279 Original Issue: December 18, 2007 Revision 2: April 21, 2015 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Forward Cargo Bay Stringer 19 to Stringer 22 - Frames and Frame Reinforcements - Inspection, Repair and Preventative Modification at Wire Penetration Hole, 0.50 Inch Diameter Hole, Standoff/Tooling Holes and Production Fastener Holes THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 15 of 199 ### Page 16 DESCRIPTIONCONFIGURATIONGROUP 737-300 Series Airplanes line numbers 1001-2565.-1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 737-400 Series Airplanes line numbers 1487-2564.-2 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 16 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 17 DESCRIPTIONCONFIGURATIONGROUP 737-500 Series Airplanes line numbers 1718-2553.-3 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 737-300 Series Airplanes line numbers 2567-3130-4 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 17 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 18 DESCRIPTIONCONFIGURATIONGROUP 737-400 Series Airplanes line numbers 2568-3132-5 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 737-500 Series Airplanes line numbers 2566-3116-6 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which did not inspect the production fastener holes common to the modified area during the installation in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16. 1 Airplanes with a preventative modification installed in accordance with Revision 1, Part 5, between March 12, 2012 and February 1, 2014, which inspected the production fastener holes common to the modified area in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 16, OR with a preventative modification installed in accordance with the original issue or Revision 1, Part 5 before March 12, 2012 or after February 1, 2014, OR a repair installed in accordance with Part 3 of the Original issue or Revision 1 of this Service Bulletin. 2 Airplanes without a preventative modification or repair installed3 Airplane Models: 737-300, 737-400, 737-500 GroupVariable Number 2PJ301 - PJ302 2PJ551 - PJ552 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 18 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 19 GroupVariable Number 5PJ553 - PJ561 5PJ601 - PJ615 5PJ811 5PJ816 - PJ817 1PM381 - PM399 1PM401 - PM417 1PM541 - PM547 4PM548 - PM550 2PM551 - PM564 1PP001 - PP054 1PP101 - PP169 1PP181 - PP199 1PP201 - PP205 1PP221 1PP231 - PP243 1PP281 - PP286 1PP301 - PP305 1PP351 - PP353 1PP376 - PP384 1PP391 - PP393 1PP401 - PP440 1PP471 - PP475 1PP501 - PP517 4PP518 - PP520 1PP521 - PP522 1PP631 - PP634 1PP651 - PP652 1PP671 - PP699 1PP701 - PP733 1PP771 - PP779 1PP801 - PP808 1PP821 - PP827 1PP831 - PP848 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 19 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 20 GroupVariable Number 1PP851 - PP852 1PP861 - PP875 4PP876 - PP877 1PP891 - PP899 1PP901 - PP936 1PP946 - PP948 1PP951 - PP952 1PP961 - PP967 1PP981 - PP991 1PP993 1PQ001 - PQ016 1PQ026 - PQ041 1PQ051 - PQ092 1PQ101 - PQ199 1PQ201 - PQ202 1PQ221 - PQ237 1PQ241 - PQ243 1PQ251 - PQ267 1PQ281 - PQ296 4PQ297 - PQ299 1PQ301 - PQ307 1PQ331 - PQ332 1PQ341 - PQ344 4PQ345 - PQ348 1PQ361 - PQ369 4PQ370 - PQ373 4PQ391 - PQ395 1PQ401 - PQ408 4PQ409 - PQ410 1PQ411 - PQ413 4PQ414 - PQ418 1PQ421 4PQ431 - PQ438 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 20 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 21 GroupVariable Number 4PQ447 - PQ448 4PQ451 4PQ454 1PQ471 - PQ473 4PQ474 - PQ475 1PQ479 - PQ481 1PQ486 - PQ487 1PQ491 - PQ493 1PQ771 4PQ772 1PQ791 - PQ793 1PQ801 - PQ805 1PQ931 - PQ932 4PQ933 - PQ935 4PQ951 4PQ971 - PQ997 4PR001 - PR017 4PR021 - PR034 4PR041 - PR045 4PR061 - PR072 4PR077 - PR082 4PR091 - PR092 4PR096 4PR101 4PR121 - PR122 4PR131 - PR132 4PR141 - PR143 4PR161 - PR172 4PR181 1PS601 - PS616 4PS617 - PS630 1PS631 1PS636 - PS638 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 21 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 22 GroupVariable Number 1PS641 - PS644 1PS651 - PS657 1PS666 - PS669 1PS691 - PS692 1PS701 - PS703 4PS704 - PS706 1PS751 - PS762 4PS763 - PS799 4PS811 4PS836 - PS837 4PS841 - PS846 4PS851 - PS852 4PS856 4PS861 - PS863 4PS866 - PS868 4PS871 - PS874 4PS896 - PS897 4PS901 - PS941 4PS956 - PS957 4PS961 - PS963 4PS971 - PS978 3PT001 - PT011 6PT012 - PT015 3PT021 - PT028 6PT029 - PT031 3PT041 - PT064 3PT101 - PT105 3PT121 - PT125 6PT126 - PT138 3PT146 - PT148 3PT161 - PT170 3PT181 - PT187 6PT188 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 22 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 23 GroupVariable Number 3PT211 - PT220 3PT295 3PT301 - PT306 6PT307 - PT309 3PT331 - PT360 3PT381 - PT399 3PT401 - PT438 3PT501 - PT512 6PT513 - PT517 3PT561 - PT565 3PT581 - PT584 6PT585 - PT586 3PT611 - PT621 3PT641 - PT642 6PT643 - PT644 3PT651 - PT655 6PT656 3PT671 - PT672 6PT681 - PT685 3PT701 - PT703 6PT716 - PT717 6PT721 - PT725 6PT801 - PT834 6PT851 - PT854 6PT871 - PT886 6PT901 - PT930 6PT971 - PT973 6PT981 - PT985 6PT996 3PU001 - PU025 6PU301 6PU311 - PU313 2PV001 - PV055 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 23 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 24 GroupVariable Number 2PV201 - PV203 5PV204 - PV209 5PV226 - PV229 2PV231 - PV237 2PV271 - PV272 2PV281 - PV283 5PV284 - PV287 5PV296 5PV301 - PV302 5PV351 5PV356 - PV357 2PW001 - PW054 2PW061 - PW068 2PW072 5PW086 - PW088 2PW091 - PW094 2PW101 - PW102 2PW106 2PW111 - PW120 2PW156 - PW157 2PW161 - PW167 5PW168 - PW171 2PW201 - PW245 5PW246 - PW252 2PW261 5PW262 - PW264 2PW265 - PW268 5PW271 - PW276 2PW278 2PW281 - PW284 5PW285 - PW292 2PW293 2PW296 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 24 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 25 GroupVariable Number 2PW301 - PW327 5PW401 - PW408 5PW411 - PW418 5PW421 - PW424 5PW431 - PW435 5PW441 - PW450 2PW461 - PW467 2PW501 - PW504 2PW511 - PW520 5PW521 - PW522 5PW524 - PW525 2PW526 5PW527 - PW530 2PW531 - PW546 5PW547 - PW550 2PW556 - PW557 2PW561 - PW564 2PW571 - PW576 2PW591 - PW596 2PW611 - PW620 5PW621 - PW622 2PW631 - PW634 5PW635 - PW637 2PW661 - PW662 2PW681 - PW683 2PW701 - PW702 2PW711 - PW717 2PW741 - PW742 2PW761 2PW771 5PW831 5PW851 - PW856 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 25 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 26 2. Spares Affected None. B. Concurrent Requirements None. C. Reason This service bulletin gives instructions to inspect a 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes for cracking in the forward cargo compartment frames and frame reinforcements, between Stringer (S) S-19 and S-22, on both left and right sides of the airplane. It also provides repair instructions for cracking at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes and instructions for a preventative modification. Undetected cracking in fuselage frames at the 1.04 inch nominal diameter wire penetration hole intended for wire routing, the 0.50 inch diameter hole, the standoff/tooling holes or the production fastener holes will reduce the frames structural capability below fail-safe load limits. Undetected cracking in the frames could lead to cracking in the skin and could result in rapid depressurization of the airplane. Boeing has received reports of cracking in the frame, or in the frame and frame reinforcement, common to the 1.04 inch nominal diameter wire penetration hole intended for wire routing, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes, between S-19 and S-22, on both left and right sides of the airplane. The cracked frames are located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes. Cracking is occurring at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes due to the effect of operating loads in combination with the stress concentration at the 1.04 inch nominal hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes. Boeing received a report of frame cracking from an operator at the 1.04 inch nominal diameter wire penetration hole on a 737-400 airplane. The airplane had one cracked frame. Boeing has since received reports of more than fifty cracked frames at the 1.04 inch nominal diameter wire penetration hole on more than twenty airplanes, all either 737-300 or 737-500 airplanes. The airplanes had accumulated between 35,832 and 66,694 flight cycles. The cracking initiated at the 1.04 inch nominal diameter wire penetration hole and grew towards the inner chord. Boeing received a report of four cracked frames at BS 500B, BS 500C, BS 500D and BS 520 in the forward cargo compartment between S-20L and S-21L on a 737-300 airplane. The cracks at BS 500B and BS 500C were completely through the frame and fail-safe chord. The BS 500B frame was also cracked on the right hand side. The airplane had 44,535 flight cycles and 44,876 flight hours. Though the airplane was above the AD and service bulletin threshold of 32,000 flight cycles, the cracking was discovered before the airplane had reached the compliance time of the AD and of the original issue of this service bulletin. In total, Boeing has received more than 50 reports of frame cracking at the 1.04 inch nominal diameter wire penetration hole on 24 airplanes. Details of the cracking are as follows: — The cracking occurred at three frame stations on 737-300 airplanes, on four frame stations on 737-500 airplanes, and at one frame station on one 737-400 airplane. — Sixteen airplanes had cracking on multiple frames. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 26 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 27 — 10 frames had cracking at adjacent frames. — 43 frames had cracking only at the inboard side of the 1.04 inch nominal diameter wire penetration hole in the frame inner chord or in the frame and frame reinforcement inner chord. — 3 frames had cracking at the outboard side of the 1.04 inch nominal diameter wire penetration hole in the frame and the frame reinforcement. 2 of these frames were severed. — Some frames had additional cracking at either the standoff/tooling holes or at the 0.50 inch diameter hole positioned below the 1.04 inch nominal diameter wire penetration hole. Boeing received a report of cracking common to the 0.50 inch diameter hole with no reported cracking common to the 1.04 inch nominal diameter wire penetration hole. Boeing has also received a report of cracking common to the standoff/tooling hole with no reported cracking common to the 1.04 inch nominal diameter wire penetration hole or the 0.50 inch diameter hole. Inspections of the 0.50 inch diameter hole and standoff/tooling holes were only required in accordance with previous revisions of this service bulletin if any crack was found at the 1.04 inch nominal diameter wire penetration hole. Boeing has received multiple reports of cracking common to the production fastener holes during installation of a repair in accordance with 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 13 . An Inspection for cracking of the area and any necessary repair will assure the structural integrity of the fuselage. This service bulletin provides additional inspections for airplanes that didn't inspect production fastener holes before the installation of preventative modifications on frames located between Station (STA) 500B and STA 520 on 737-300/400 airplanes and STA 482 and STA 520 on 737-500 airplanes between March 12, 2012 and February 1, 2014. Inspections in PART 7 are required at frames that accomplished PART 5 - PREVENTATIVE MODIFICATION in accordance with Revision 1 of this bulletin because PART 5 states: "Do the repair as given in 737 SRM 53-00-07 Repair 13 except omit the steps in the Damage Removal Procedure". Between the dates of March 12, 2012 and February 1, 2014, the HFEC open hole inspections for the production fastener holes in the frame using 737 NDT Manual Part 6, 51-00-00 Procedure 16 was moved within 737 SRM 53-00-07 Repair 13 into Section 4.B. Damage Removal from Section 4.C. Installation of Repair Parts. Boeing Service Related Problem (SRP) 737-SRP-53-0289 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0377 is related to this service bulletin. The fuselage frames addressed in this service bulletin from STA 500B to STA 520 on 737-300/-400 airplanes, and from STA 482 to STA 520 on 737-500 airplanes between S-19 and S-22 have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). Revision 1 was sent to update Paragraph 1.E.Compliance with new inspection thresholds and separate compliance tables by airplane group. More background information is added and other references are updated throughout. Revision 2 is sent to add new inspection areas and to make sure of the accomplishment of inspections before the installation of preventative modifications installed between the dates March 12, 2012 and February 1, 2014. This revision is also sent to add post preventative modification and repair inspections, and to add a compliance threshold for the accomplishment of the preventative modification. This revision also moves 737-300/-400 and -500 airplanes, line numbers 2566 thru 3132 into three new groups to separate bonded skin airplanes from solid skin airplanes. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 27 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 28 D. Description Get access to the forward cargo bay. Remove the cargo handling system, if installed. Remove the wire shrouds, sidewall linings, aft bulkhead panels and insulation blankets, on both sides of the airplane to get access to frames STA 500B - STA 520 on 737-300 and -400 airplanes and STA 482 - STA 520 on 737-500 airplanes. Unscrew the power feeder cable guides as required and move them away from the hole. Do a High Frequency Eddy Current (HFEC) inspection and a Detailed inspection of the frame and frame reinforcement between Stringers S-19 and S-22 for cracking. If any crack is found at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes or the production fastener holes between Stringers S-19 and S-22 do a repair in accordance with this Service Bulletin. If no crack is found at the 1.04 inch nominal diameter wire penetration hole, the 0.50 inch diameter hole, the standoff/tooling holes and the production fastener holes, either accomplish the preventative modification in accordance with this service bulletin, or restore access, put the airplane back to a serviceable condition and do repeat inspections at the intervals given in Paragraph 1.E., Compliance. Group 1-3: If a preventative modification was accomplished in accordance with Revision 1 of this service bulletin between March 12, 2012 and February 1, 2014, make sure the production fastener holes in the frame and frame reinforcement common to the modification angles were inspected using the inspection procedure in accordance with 737-Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 16. If the pre-modification inspections of the production fastener holes were not performed, then do a HFEC inspection of the frame re-inforcement, the 1.04 inch nominal diameter hole, the 0.50 inch diameter hole, a detailed inspection of the frame where visible, and a Low Frequency Eddy Current (LFEC) inspection of the frame in accordance with Revision 2 of this service bulletin in accordance with compliance times listed in Paragraph 1.E., Compliance. If the pre-modification inspections of the production fastener holes or the preventative modification were accomplished before 12 March 2012, or after 1 February 2014, then do a post-modification inspection in accordance with 737 Structural Repair Manual 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 20 at the compliance times listed in Paragraph 1.E., Compliance. Group 4-6: If a preventative modification was accomplished in accordance with Revision 1 of this service bulletin between March 12, 2012 and February 1, 2014, make sure the production fastener holes in the frame and frame reinforcement common to the modification angles were inspected using the inspection procedure in accordance with 737-Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 16. If the pre-modification inspections of the production fastener holes were not performed, then do a HFEC inspection of the frame re-inforcement, the 1.04 inch nominal diameter hole, the 0.50 inch diameter hole, the fail safe chord, and a detailed inspection of the frame where visible in accordance with Revision 2 of this service bulletin in accordance with compliance times listed in Paragraph 1.E., Compliance. If the pre-modification inspections of the production fastener holes or the preventative modification were accomplished before 12 March 2012, or after 1 February 2014, then do a post-modification inspection in accordance with 737 Structural Repair Manual 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07 Repair 20 at the compliance times listed in Paragraph 1.E., Compliance. WHEN CONTACTING BOEING FOR THE REPAIR PLAN, PLEASE INCLUDE THE FOLLOWING INFORMATION TO FACILITATE REPAIR PLAN DEVELOPMENT: 1. INSPECTION METHOD USED AND NOTCH CALIBRATION SIZE. 2. LOCATIONS OF ALL CRACKS FOUND. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 28 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 29 3. WHETHER ANY CRACK FOUND IS IN THE FRAME, THE FRAME REINFORCEMENT, OR BOTH. 4. THE LENGTH OF ALL CRACKS FOUND. 5. IDENTIFY ALL LOCATIONS OF STANDOFF/TOOLING HOLES BETWEEN S-19 AND S-22 ON A DRAWING. INCLUDE SPACING BETWEEN THE STANDOFF HOLE AND IT'S NEAREST FASTENER. Send your report to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, AIRLINE SUPPORT Boeing would like to gather information on cracking found by the service bulletin inspections. Report crack inspection results to Boeing. In the report, identify the following: – Operator – Airplane ID (series and line number or variable number) – Flight cycles and flight hours when service bulletin inspection was accomplished – Results of inspections (crack findings or no crack findings) – Inspection method used and notch calibration size – If any crack is found, provide: frame location (BS LH or RH), parts cracked (frame web, reinforcement angle, and/or fail safe chord), location of crack (1.04 inch nominal diameter wire penetration hole, 0.50 inch diameter hole, or other) and length of cracks. Retain all trimmed out frame sections (frame, frame reinforcement, and/or fail safe chord). Mark the frame station (BS and LH or RH) and the aircraft identification including the airplane cycles and hours, on each trimmed out section. Forward the samples to the following address: The Boeing Company 12200 Monarch St Dock "A" Garden Grove, CA 92841 ATTN: Mary Lovett 714-934-0366 Forward to Post Production Fuselage Stress for engineering evaluation. Include a tag with the airplane information and Boeing Message Number (Service Request I.D.) along with a tracking number for the shipment. More work is necessary on airplanes changed or inspected in accordance with Revision 1 or the original issue of this service bulletin: ActionConditionGroup Accomplish post modification/repair inspection at compliance times in accordance with Paragraph 1.E., Compliance. Previously accomplished the repair or preventative modification as shown in Revision 1 or the original issue of this bulletin. All Configuration 1 and 2. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 29 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 30 ActionConditionGroup Accomplish preventative modifica- tion before the threshold in accor- dance with Paragraph 1.E. Compli- ance. Locations without a preventative modification or repair installed All Configurations 3. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1, 4: Affected Maintenance Zones ZoneModel 208737-300 Group 2, 5: Affected Maintenance Zones ZoneModel 208737-400 Group 3, 6: Affected Maintenance Zones ZoneModel 208737-500 E. Compliance Federal Aviation Administration (FAA) Airworthiness Directive AD 2011-23-05 is related to this service bulletin. The effective date of AD 2011-23-05 is November 16, 2011. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Do the required actions in accordance with Paragraph 3. Accomplishment Instructions. Boeing recommends that the inspections in this service bulletin are accomplished at the times specified in the tables below. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 30 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 31 Group 1-6, Configuration 3: Table 1: Forward Cargo Bay - Inspections of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 30,000 total flight cycles. Do PART 2 - INITIAL DETAIL AND HFEC IN- SPECTION for cracking. Airplanes with 30,000 total flight cycles or less at the Revision 2 date of this ser- vice bulletin. AND Have not accomplished any inspections in accor- dance with Revision 1 of this service bulletin. -Within 4,500 flight cycles after the ini- tial or repeat in- spection accom- plished in accor- dance with Revi- sion 1 of this ser- vice bulletin. Do PART 4 - REPEAT DETAIL AND HFEC IN- SPECTIONS for cracking. (a) Airplanes with more than 30,000 total flight cycles at the Revision 2 date of this service bulletin. OR Airplanes that have accom- plished the initial inspection and/or repeat inspections in accordance with Revi- sion 1 of this bulletin. Before further flight. Do the repair in accor- dance with PART 3 - RE- PAIR. (b) Any crack found after the accomplishment of PART 2 - INITIAL DETAIL AND HFEC INSPECTION or PART 4 - REPEAT DETAIL AND HFEC INSPECTION. -Before further flight. Option 1: Do the preven- tative modification in ac- cordance with PART 5 - PREVENTATIVE MODIFI- CATION. (c) No crack found after the accomplishment of PART 2 - INITIAL DETAIL AND HFEC INSPECTION or PART 4 - REPEAT DETAIL AND HFEC INSPEC- TIONS. OR 4,500 flight cycles. (b) -Option 2: Repeat PART 4 - REPEAT DETAIL AND HFEC INSPEC- TIONS for cracking. (a) (a) If any PART 3 - REPAIR, or PART 5 - PREVENTATIVE MODIFICATION was installed at the 1.04 inch nominal diameter wire penetration hole and 0.5 inch diameter hole, the PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS and PART 5 - PREVENTATIVE MODI- FICATION are not required at the repair or modified location only. (b) Accomplishment of repair in accordance with PART 3 - REPAIR terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS and PART 5 - PREVENTATIVE MODIFICATION in accordance with this service bulletin for the repaired location only. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 31 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 32 Group 1-6, Configuration 3: Table 1: Forward Cargo Bay - Inspections of Frames and Frame Reinforcements between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance TimeActionCondition (c) Accomplishment of preventative modification in accordance with PART 5 - PREVENTATIVE MODIFICATION terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTION in accordance with this service bulletin for the modified location only. Group 1-6, Configuration 3: Table 2: Installation of Preventative Modification of Frames between S-19 and S-22 Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before 50,000 total flight cycles.Do the preventative mod- ification in accordance with PART 5 - PREVEN- TATIVE MODIFICATION. (a) Airplanes with 45,499 total flight cycles or less at the Revision 2 date of this ser- vice bulletin, that have not accomplished the repair or preventative modification in accordance with this service bulletin. -Within 4,500 flight cycles after the Revision 2 date of this service bulletin. Do the preventative mod- ification in accordance with PART 5 - PREVEN- TATIVE MODIFICATION. (a) Airplanes with 45,500 to 50,000 total flight cycles at the Revision 2 date of this service bulletin, that have not accomplished the re- pair or preventative modifi- cation in accordance with this service bulletin. -Within 24 months after the Revision 2 date of this service bulletin. Within 4,500 flight cycles af- ter the Revision 2 date of this service bulletin. Do the preventative mod- ification in accordance with PART 5 - PREVEN- TATIVE MODIFICATION. (a) Airplanes with 50,001 total flight cycles or more at the Revision 2 date of this ser- vice bulletin, that have not accomplished the repair or preventative modification in accordance with this service bulletin. (a) If any PART 3 - REPAIR or PART 5 - PREVENTATIVE MODIFICATION was installed to repair or prevent cracking at the 1.04 inch nominal diameter wire penetration hole and 0.5 inch diameter hole, the PART 5 - PREVENTATIVE MODIFICATION is not required at the repaired or modified location only. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 32 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 33 Group 1-3, Configuration 1: Table 3: Inspections of Frames and Frame Reinforcements. Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 4,500 flight cycles after the Revision 2 date of this service bul- letin. Do a HFEC, LFEC and Detailed inspection for cracking in accordance with PART 7 - INSPEC- TION OF PREVENTA- TIVE MODIFICATION. All Airplanes. -Before further flight. Contact The Boeing Company for repair in- structions and do the re- pair. Any crack found after the accomplishment of PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. 5,000 flight cycles.-Do a HFEC, LFEC and Detailed inspection for cracking in accordance with PART 7 - INSPEC- TION OF PREVENTA- TIVE MODIFICATION. No crack found after the accomplishment of PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. (a) Accomplishment of these inspections at the compliance times shown in this table terminates the inspection requirements in accordance with Repair 13 of 737-300 SRM 53-00-07, 737- 400 SRM 53-00-07, and 737-500 SRM 53-00-07. Group 1-3, Configuration 2: Table 4: Inspections of Frames and Frame Reinforcements. Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Within 4,500 flight cycles af- ter the Revision 2 date of this service bulletin. Within 5,500 flight cycles af- ter the installa- tion of the pre- ventative modifi- cation or repair. Before 60,000 total flight cy- cles. Do the inspections in accor- dance with PART 8 - IN- SPECTION OF PREVEN- TATIVE MODIFICATION. (a) All Airplanes. -Before further flight.Contact The Boeing Com- pany for repair instructions and do the repair. Any crack found after the accom- plishment of in- spections in ac- cordance with PART 8 - IN- SPECTION OF PREVENTATIVE MODIFICATION. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 33 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 34 Group 1-3, Configuration 2: Table 4: Inspections of Frames and Frame Reinforcements. Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 5,500 flight cy- cles. -Repeat the inspections in accordance with PART 8 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. No crack found after the accom- plishment of in- spections in ac- cordance with PART 8 - IN- SPECTION OF PREVENTATIVE MODIFICATION (a) Accomplishment of these inspections at the compliance times shown in this table terminates the inspection requirements in accordance with Repair 13 of 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, and 737- 500 SRM 53-00-07. Group 4-6, Configuration 1: Table 5: Inspections of Frames and Frame Reinforcements. Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 4,500 flight cycles after the Revision 2 date of this service bul- letin. Do a HFEC and Detailed inspection for cracking in accordance with PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. (a) All Airplanes. -Before further flight. Contact The Boeing Company for repair in- structions and do the re- pair. Any crack found after the accomplishment of PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. 22,000 flight cy- cles. -Do a HFEC and Detailed inspection for cracking in accordance with PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. (a) No crack found after the accomplishment of PART 7 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. (a) Accomplishment of these inspections at the compliance times shown in this table terminates the inspection requirements in accordance with Repair 13 of 737-300 SRM 53-00-07, 737- 400 SRM 53-00-07, and 737-500 SRM 53-00-07. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 34 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 35 Group 4-6, Configuration 2: Table 6: Inspections of Frames and Frame Reinforcements. Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Within 24,000 flight cycles af- ter the last in- spection in ac- cordance with Figure 205 of Repair 13 as given in 737- 300 SRM 53- 00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07. Within 24,000 flight cycles af- ter the installa- tion of the pre- ventative modifi- cation or repair. Before 66,000 total flight cy- cles. Do the inspections in accor- dance with PART 8 - IN- SPECTION OF PREVEN- TATIVE MODIFICATION. (a) All Airplanes. -Before further flight.Contact The Boeing Com- pany for repair instructions and do the repair. Any crack found after the accom- plishment of in- spections in ac- cordance with PART 8 - IN- SPECTION OF PREVENTATIVE MODIFICATION. 24,000 flight cy- cles. -Repeat the inspections in accordance with PART 8 - INSPECTION OF PRE- VENTATIVE MODIFICA- TION. No crack found after the accom- plishment of in- spections in ac- cordance with PART 8 - IN- SPECTION OF PREVENTATIVE MODIFICATION. (a) Accomplishment of these inspections at the compliance times shown in this table terminates the inspection requirements in accordance with Repair 13 of 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, and 737-500 SRM 53-00-07. NOTE: Damage Tolerance Post Repair and Modification Inspection: The damage tolerance inspections specified in Figure 206 of 737-300 SRM 53-00-07 Repair 20, 737-400 SRM 53-00-07 Repair 20, and 737-500 SRM 53-00-07 Repair 20 may be used in support of compliance with 14 Code of federal Regulations (CFR), Section 121.1109 or 129.109 for the preventative modifications or repairs accomplished in accordance with Revision 2 of this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 35 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 36 F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the inspections, repairs, modifications and compliance times defined in this service bulletin as an alternative method of compliance (AMOC) to the requirements of paragraphs (g), (h), (i) and (j) of Airworthiness Directive (AD) AD 2011-23-05. Where this service bulletin specifies contacting Boeing for instructions for removing damage and repairing cracking: before further flight, remove the damage or repair the cracking using a method approved in accordance with the procedures specified in paragraph (m) of AD 2011-23-05. All provisions of AD 2011-23-05 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. The Manager of the FAA Seattle ACO approves the inspection methods, thresholds and repeat intervals defined in Paragraph 1.E., Compliance, Table 3, Table 4, Table 5, and Table 6 as an AMOC to the inspections of SSI F-33A of SSID D6-82669 required by paragraphs (g) and (h) of AD 2008-09-13. This approval applies only to this SSI and only for the areas covered by these repairs or modifications. All provisions of AD 2008-09-13 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. If operators choose this AMOC then they must revise their FAA approved maintenance or inspection program to incorporate these alternative inspections. G. Manpower The table below shows an estimate of the task hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to inspect the work — Time to cure the materials — Time to make the parts — Time to find the tools. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 36 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 37 Group 1, 4: Inspections of Frames and Frame Reinforcements between S-19 and S-22 Elapsed HoursTask HoursNumber of PersonsTask 1.252.502Open Sidewalls and Blankets Open Access 0.750.751FIGURE 1 0.500.501FIGURE 3 0.300.301FIGURE 4 2.502.501FIGURE 7 (a)Inspect 2.002.001FIGURE 10 1.501.501FIGURE 13 (a) 3.507.002FIGURE 22 0.300.301FIGURE 16Close Access 0.500.501FIGURE 19 0.750.751FIGURE 20 1.252.502Close Sidewalls and Blankets 13.6019.60TOTAL FOR EACH AIRPLANE (a) The FIGURE 13 inspection is optional to the FIGURE 7 inspection and is not included in the total. Group 2, 5: Inspections of Frames and Frame Reinforcements between S-19 and S-22 Elapsed HoursTask HoursNumber of PersonsTask 2.755.502Open Sidewalls and Blankets Open Access 0.500.501FIGURE 3 0.300.301FIGURE 5 3.503.501FIGURE 8 (a)Inspect 3.003.001FIGURE 11 1.501.501FIGURE 14 (a) 6.0012.002FIGURE 23 0.300.301FIGURE 17Close Access 0.500.501FIGURE 19 2.755.502Close Sidewalls and Blankets 19.6031.10TOTAL FOR EACH AIRPLANE Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 37 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 38 Group 2, 5: Inspections of Frames and Frame Reinforcements between S-19 and S-22 Elapsed HoursTask HoursNumber of PersonsTask (a) The FIGURE 14 inspection is optional to the FIGURE 8 inspection and is not included in the total. Group 3, 6: Inspections of Frames and Frame Reinforcements between S-19 and S-22 Elapsed HoursTask HoursNumber of PersonsTask 0.751.502Open Sidewalls and Blankets Open Access 0.750.751FIGURE 2 0.500.501FIGURE 3 0.300.301FIGURE 6 2.502.501FIGURE 9 (a)Inspect 2.002.001FIGURE 12 1.501.501FIGURE 15 (a) 3.507.002FIGURE 24 0.300.301FIGURE 18Close Access 0.500.501FIGURE 19 0.750.751FIGURE 21 0.751.502Close Sidewalls and Blankets 12.6017.60TOTAL FOR EACH AIRPLANE (a) The FIGURE 15 inspection is optional to the FIGURE 9 inspection and is not included in the total. Group 1-6, Configuration 1: Inspection of Preventative Modification Elapsed HoursTask HoursNumber of PersonsTask 2.755.502Open Sidewalls and Blankets Open Access 0.750.751FIGURE 1 or FIG- URE 2 0.500.501FIGURE 3 2.8011.204FIGURE 25 or FIG- URE 26 Inspect Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 38 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 39 Group 1-6, Configuration 1: Inspection of Preventative Modification Elapsed HoursTask HoursNumber of PersonsTask 0.500.501FIGURE 19Close Access 0.750.751FIGURE 20 or FIG- URE 21 2.755.502Close Sidewalls and Blankets 10.8024.70TOTAL FOR EACH AIRPLANE Group 1-6, Configuration 3: Installation of Preventative Modification of Frames between S-19 and S-22 Elapsed HoursTask HoursNumber of PersonsTask 2.755.502Open Sidewalls and Blankets Open Access 0.750.751FIGURE 1 or FIG- URE 2 0.500.501FIGURE 3 9.0018.002Installation (a) 0.500.501FIGURE 19Close Access 0.750.751FIGURE 20 or FIG- URE 21 2.755.502Close Sidewalls and Blankets 8.0013.50TOTAL FOR EACH AIRPLANE (a) Estimate given is for 1 side of 1 frame location and is not included in the total shown. Multiply the number of locations requiring modification by the estimate given and add this to the total to get a revised total for each airplane. H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Boeing Service Letter 737-SL-51-042 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 39 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 40 b. Boeing Service Related Problem (SRP) 737-SRP-53-0289, 737-SRP-53-0377 c. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2011-23-05, AD 2008-09-13 d. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 4, Procedure 16 and Procedure 23. e. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-52-73, 25-52-91 f. 737-300 Structural Repair Manual (SRM) 53-00-07 g. 737-400 Structural Repair Manual (SRM) 53-00-07 h. 737-500 Structural Repair Manual (SRM) 53-00-07 i. 737-300/400/500 Supplemental Structural Inspection Document (SSID) D6-82669 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number FRAME INSTALLATION - BODY STATION 52065-46534 FRAME INSTALLATION - BODY STATION 500B65C22908 FRAME INSTALLATION - BODY STATION 500C65C22909 FRAME INSTALLATION - BODY STATION 500D65C22910 SHROUD INSTALLATION - WIRE FORWARD CARGO AREA65C28198 FRAME INSTALLATION - BODY STATION 500E65C32351 FRAME INSTALLATION - BODY STATION 500F65C32352 FRAME INSTALLATION - BODY STATION 500G65C32353 FRAME INSTALLATION - BODY STA 48265C34355 FRAME INSTALLATION - BODY STA 482A65C34356 FRAME INSTALLATION - BODY STA 482B65C34357 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. K. Publications Affected 1. Publications: None. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 40 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 41 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. M. Software Accomplishment Summary Not affected. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 41 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 42 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 42 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT BLANK PAGE ### Page 43 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are not available for the inspection, and/or repair procedures in accordance with this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: NotesNameQTYPart Number / Specification (a)CARGO LINER JOINT SEALING TAPE36 YardsBMS 5-146 Optional P212HD (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability Accomplishment of High Frequency Eddy Current edge inspections may be facilitated by using a probe which has a 90 degree zero drop. When ordering the probe, specify the type of connector, frequency range and the eddy current instrument model the probe will be used on. Part number of a probe with a 90 degree zero drop: PAB-90-60.03 FX The probe vendor contact is: — EC/NDT 1020 SOUTH 344th STREET SUITE 214 FEDERAL WAY, WA 98003 USA Phone Number (253) 815-0797 Fax (253) 815-0827 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 43 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 44 F. Special Tooling Necessary to do this Service Bulletin High Frequency Eddy Current inspection tools are necessary to do the change in accordance with this service bulletin. To get the High Frequency Eddy Current inspection tools, refer to Paragraph 2.E., Special Tooling - Price and Availability . Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 44 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 45 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque Values: — Values for structural fasteners are given in 737-300/-400/-500 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 737-300/-400/-500 Aircraft Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). — Values for engine maintenance tasks are included in Chapter 70 of 737-300/-400/-500 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 fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate full threaded fasteners (screws) needed for installation in this service bulletin. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 45 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 46 7. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 8. Boeing Service Letter 737-SL-51-042 , Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 9. 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. 10. 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. 11. Where the work instructions include installation of a kept part, a new part with the same part number can be installed as an alternative to the kept part. 12. If shading is used, shaded areas in Figures are to separate the non-critical and non-authoritative information from the critical and authoritative information. 13. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. B. WORK INSTRUCTIONS 1. PART 1 - ACCESS a. Get access to the forward cargo bay. b. Remove and keep the forward cargo bay handling system if installed. c. Group 1, 4: Remove and keep the wire shroud. Refer to FIGURE 1 as an accepted procedure. d. Group 3, 6: Remove and keep the wire shroud. Refer to FIGURE 2 as an accepted procedure. e. Remove and keep the aft bulkhead access panels. Refer to FIGURE 3 as an accepted procedure. NOTE: As an option, it is acceptable to remove air conditioning equipment at Station (STA) 520 if additional access is required to accomplish the inspection in accordance with this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 46 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 47 f. Group 1, 4: Remove and keep sidewall panels 1314X and 1321X between STA 500 and STA 500D. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. g. Group 2, 5: Remove and keep sidewall panels 1316Y, 1317Y, 1318Y, 1325Y, 1326Y and 1327Y between STA 500 and STA 500G. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. h. Group 3, 6: Remove and keep sidewall panels 1309Z and 1315Z between STA 460 and STA 482B. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. i. Group 1-2, 4-5: Remove and keep or move the insulation blankets as required between STA 500A to STA 540 and Stringer (S)-19 to S-22, left and right sides. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. j. Group 3, 6: Remove and keep or move the insulation blankets as required between STA 460 to STA 540 and Stringer (S)-19 to S-22, left and right sides. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. k. Group 1, 4: Move the guide assembly for the power feeder cable away from the frame in accordance with FIGURE 4. l. Group 2, 5: Move the guide assembly for the power feeder cable away from the frame in accordance with FIGURE 5. m. Group 3, 6: Move the guide assembly for the power feeder cable away from the frame in accordance with FIGURE 6. 2. Group 1-6, Configuration 3: PART 2 - INITIAL DETAIL AND HFEC INSPECTION a. Group 1, 4, Configuration 3: At STA 500B, STA 500C, STA 500D and STA 520, left and right, do the following: (1) Do PART 1 - ACCESS. (2) Do a detailed inspection of the production fastener holes for cracking in accordance with FIGURE 22 and do one of the inspection options that follow: (a) Option 1: Do a High Frequency Eddy Current (HFEC) surface inspection for cracking in accordance with FIGURE 7. Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 10. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 47 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 48 b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 16. {2} Do PART 6 - CLOSE ACCESS. {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. (b) Option 2: Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 10 and FIGURE 13. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 16. {2} Do PART 6 - CLOSE ACCESS {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. b. Group 2, 5, Configuration 3: At STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520, left and right, do the following: (1) Do PART 1 - ACCESS. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 48 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 49 (2) Do a detailed inspection of the production fastener holes for cracking in accordance with FIGURE 23 and do one of the inspection options that follow: (a) Option 1: Do a High Frequency Eddy Current (HFEC) surface inspection for cracking in accordance with FIGURE 8. Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 11. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 17. {2} Do Part 6 - CLOSE ACCESS. {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. (b) Option 2: Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 11 and FIGURE 14. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 49 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 50 {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 17. {2} Do PART 6 - CLOSE ACCESS {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. c. Group 3, 6, Configuration 3: At STA 482, STA 482A, STA 482B and STA 520, left and right, do the following: (1) Do PART 1 - ACCESS. (2) Do a detailed inspection of the production fastener holes for cracking in accordance with FIGURE 24 and do one of the inspection options that follow: (a) Option 1: Do a High Frequency Eddy Current (HFEC) surface inspection for cracking in accordance with FIGURE 9. Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 12. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 18. {2} Do Part 6 - CLOSE ACCESS. {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. (b) Option 2: Do a HFEC Hole/Edge inspection for cracking in accordance with FIGURE 12 and FIGURE 15. 1) If any crack is found, do the following: a) At each station, left or right, Do PART 3 - REPAIR at the section of the frame where any crack is found. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 50 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 51 b) Do PART 6 - CLOSE ACCESS. 2) If no crack is found, do one of the following options: a) Option 1: Do the following: {1} Do PART 5 - PREVENTATIVE MODIFICATION. {2} Do PART 6 - CLOSE ACCESS. b) Option 2: Do the following: {1} Install the guide line assemblies for the power feeder cable in accordance with FIGURE 18. {2} Do PART 6 - CLOSE ACCESS {3} Do PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. 3. Group 1-6, Configuration 3: PART 3 - REPAIR a. Group 1, 4, Configuration 3: At STA 500B, STA 500C, STA 500D and STA 520, left and right, do the following: (1) If any crack is found at the 1.04 inch nominal diameter wire penetration hole and/or the 0.50 inch diameter hole, repair the frame in accordance with 737-300 SRM 53-00-07 Repair 20. (a) If any crack is found outside the limits of the SRM, contact The Boeing Company for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) If any crack is found at the standoff/tooling holes, and/or the production fastener holes, contact The Boeing Company for damage removal and repair instructions and do the repair. (3) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of repair in accordance with PART 3 - REPAIR terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS and PART 5 - PREVENTATIVE MODIFICATION in accordance with this service bulletin for the repaired location only. b. Group 2, 5, Configuration 3: At STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520, left and right, do the following: (1) If any crack is found at the 1.04 inch nominal diameter wire penetration hole and/or the 0.50 inch diameter hole, repair the frame in accordance with 737-400 SRM 53-00-07 Repair 20. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 51 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 52 (a) If any crack is found outside the limits of the SRM, contact The Boeing Company for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) If any crack is found at the standoff/tooling holes, and/or the production fastener holes, contact The Boeing Company for damage removal and repair instructions and do the repair. (3) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of repair in accordance with PART 3 - REPAIR terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS and PART 5 - PREVENTATIVE MODIFICATION in accordance with this service bulletin for the repaired location only. c. Group 3, 6, Configuration 3: At STA 482, STA 482A, STA 482B and STA 520, left and right, do the following: (1) If any crack is found at the 1.04 inch nominal diameter wire penetration hole and/or the 0.50 inch diameter hole, repair the frame in accordance with 737-500 SRM 53-00-07 Repair 20. (a) If any crack is found outside the limits of the SRM, contact The Boeing Company for damage removal and repair instructions and do the repair. When requesting repair instructions, include a description of the location and extent of damage. Refer to Paragraph 1.D., Description for information about reporting the damage to Boeing. (2) If any crack is found at the standoff/tooling holes, and/or the production fastener holes, contact The Boeing Company for repair instructions and do the repair. (3) Do PART 6 - CLOSE ACCESS. NOTE: Accomplishment of repair in accordance with PART 3 - REPAIR terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS and PART 5 - PREVENTATIVE MODIFICATION in accordance with this service bulletin for the repaired location only. 4. Group 1-6, Configuration 3: PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS NOTE: If any PART 3 - REPAIR or PART 5 - PREVENTATIVE MODIFICATION was installed to repair or prevent cracking at the 1.04 inch nominal diameter wire penetration hole and 0.5 inch diameter hole, the PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS are not required at the repaired or modified location only. a. Group 1, 4, Configuration 3: At STA 500B, STA 500C, STA 500D and STA 520, left and right, do the following: (1) Do PART 1 - ACCESS. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 52 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 53 (2) Do a detailed inspection of the production fastener holes in accordance with FIGURE 22 and do a HFEC Hole/Edge Inspection for cracking in accordance with FIGURE 10 and FIGURE 13. (a) If any crack is found, do the following: 1) At each station, left or right, do PART 3 - REPAIR at the section of frame where any crack is found. 2) Do PART 6 - CLOSE ACCESS. (b) If no crack is found, do one of the following options: 1) Option1: do the following: a) Do PART 5 - PREVENTATIVE MODIFICATION. b) Do PART 6 - CLOSE ACCESS. 2) Option 2: Do the following: a) Install the guide assemblies for the power feed cable in accordance with FIGURE 16. b) Do PART 6 - CLOSE ACCESS. c) Repeat PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. b. Group 2, 5, Configuration 3: At STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520, left and right, do the following: (1) Do PART 1 - ACCESS. (2) Do a detailed inspection of the production fastener holes for cracking in accordance with FIGURE 23, and do a HFEC Hole/Edge Inspection for cracking in accordance with FIGURE 11 and FIGURE 14. (a) If any crack is found, do the following: 1) At each Station, left or right, if any crack is found, do PART 3 - REPAIR at the section of frame where any crack is found. 2) Do PART 6 - CLOSE ACCESS. (b) If no crack is found, do one of the following options: 1) Option 1: Do the following: a) Do PART 5 - PREVENTATIVE MODIFICATION. b) Do PART 6 - CLOSE ACCESS. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 53 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 54 2) Option 2: Do the following: a) Install the guide assemblies for the power feed cable in accordance with FIGURE 17. b) Do PART 6 - CLOSE ACCESS. c) Repeat PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. c. Group 3, 6, Configuration 3: At STA 482, STA 482A, STA 482B and STA 520 do the following: (1) Do PART 1 - ACCESS. (2) Do a detailed inspection of the production fastener holes for cracking in accordance with FIGURE 24 , and do a HFEC Hole/Edge Inspection for cracking in accordance with FIGURE 12 and FIGURE 15. (a) If any crack is found, do the following: 1) At each Station, left or right, if any crack is found, do PART 3 - REPAIR at the section of frame where any crack is found. 2) Do PART 6 - CLOSE ACCESS. (b) If no crack is found, do one of the following options: 1) Option 1: Do the following: a) Do PART 5 - PREVENTATIVE MODIFICATION. b) Do PART 6 - CLOSE ACCESS. 2) Option 2: Do the following: a) Install the guide assemblies for the power feed cable in accordance with FIGURE 18. b) Do PART 6 - CLOSE ACCESS. c) Repeat PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS at the interval given in Paragraph 1.E., Compliance. 5. Group 1-6, Configuration 3: PART 5 - PREVENTATIVE MODIFICATION The preventative modification is applicable to frames for which either the PART 2 - INITIAL DETAIL AND HFEC INSPECTION or the PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS has been accomplished, and the 1.04 inch nominal diameter wire penetration hole,the 0.50 inch diameter hole, the standoff/tooling holes, and the production fastener holes are crack free. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 54 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 55 a. Group 1, 4, Configuration 3: At STA 500B, STA 500C, STA 500D and STA 520 do the following: (1) Do an insurance cut at the wire penetration hole: (a) If the surface inspection was accomplished in accordance with FIGURE 7, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished in accordance with FIGURE 13, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. (2) Do the repair in accordance with 737-300 SRM 53-00-07 Repair 20, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 204 in Repair 20. NOTE: Accomplishment of preventative modification in accordance with PART 5 - PREVENTATIVE MODIFICATION terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS in accordance with this service bulletin for the modified location only. b. Group 2, 5, Configuration 3: At STA 500B, STA 500C, STA 500D, STA 500E, STA 500F, STA 500G and STA 520 do the following: (1) Do an insurance cut at the wire penetration hole: (a) If the surface inspection was accomplished in accordance with FIGURE 8, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished in accordance with FIGURE 14, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. (2) Do the repair in accordance with 737-400 SRM 53-00-07 Repair 20, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 204 in Repair 20. NOTE: Accomplishment of preventative modification in accordance with PART 5 - PREVENTATIVE MODIFICATION terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS in accordance with this service bulletin for the modified location only. c. Group 3, 6, Configuration 3: At STA 482, STA 482A, STA 482B and STA 520 do the following: (1) Do an insurance cut at the wire penetration hole: (a) If the surface inspection was accomplished in accordance with FIGURE 9, do a 0.10 inch insurance cut. Maintain a 32Ra or better surface finish. (b) If the hole/edge inspection was accomplished in accordance with FIGURE 15, do a 0.04 inch insurance cut. Maintain a 32Ra or better surface finish. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 55 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 56 (2) Do the repair in accordance with 737-500 SRM 53-00-07 Repair 20, except omit the steps in the Damage Removal Procedure. Layout the repair angles using Detail I of Figure 204 in Repair 20. NOTE: Accomplishment of preventative modification in accordance with PART 5 - PREVENTATIVE MODIFICATION terminates the requirements for PART 4 - REPEAT DETAIL AND HFEC INSPECTIONS in accordance with this service bulletin for the modified location only. 6. PART 6 - CLOSE ACCESS a. Group 1, 4: Install the guide assembly for the power feeder cable into the frame in accordance with FIGURE 16. b. Group 2, 5: Install the guide assembly for the power feeder cable into the frame in accordance with FIGURE 17. c. Group 3, 6: Install the guide assembly for the power feeder cable into the frame in accordance with FIGURE 18. d. Group 1-2, 4-5: Install removed insulation blankets between STA 500A to STA 540 and Stringer S-19 to S-22 left and right. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. e. Group 3, 6: Install removed insulation blankets as between STA 460 to STA 540 and Stringer S-19 to S-22 left and right. Refer to 737-300/400/500 AMM 25-52-91 as an accepted procedure. f. Group 1, 4: Install sidewall panels 1314X and 1321X between STA 500 and STA 500D. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. g. Group 2, 5: Install sidewall panels 1316Y, 1317Y, 1318Y, 1325Y, 1326Y and 1327Y between STA 500 and STA 500G. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. h. Group 3, 6: Install sidewall panels 1309Z and 1315Z between STA 460 and STA 482B. Refer to 737-300/400/500 AMM 25-52-73 as an accepted procedure. i. Install all air conditioning equipment that was removed for additional access and do the applicable function tests. j. Install the aft bulkhead access panels. Refer to FIGURE 19 as an accepted procedure. k. Group 1, 4: Install the wire shroud. Refer to FIGURE 20 as an accepted procedure. l. Group 3, 6: Install the wire shroud. Refer to FIGURE 21 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 56 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 57 m. Install the forward cargo bay handling system, if removed. n. Put the airplane back to a serviceable condition. 7. Group 1-6, Configuration 1: PART 7 - INSPECTION OF PREVENTATIVE MODIFICATION a. Do PART 1 - ACCESS. b. Group 1-3, Configuration 1: Do a HFEC, LFEC and Detailed inspection for cracking in accordance with FIGURE 25. (1) If any crack is found, contact The Boeing Company for repair instructions and do the repair as instructed by Boeing. (2) If no crack is found, do PART 6 - CLOSE ACCESS. c. Group 4-6, Configuration 1: Do a HFEC and Detailed inspection for cracking in accordance with FIGURE 26. (1) If any crack is found, contact The Boeing Company for repair instructions and do the repair as instructed by Boeing. (2) If no crack is found, do PART 6 - CLOSE ACCESS. d. Repeat PART 7 - INSPECTION OF PREVENTATIVE MODIFICATION at the interval given in Paragraph 1.E., Compliance. NOTE: PART 7 - INSPECTION OF PREVENTATIVE MODIFICATION inspections are only required on frames that accomplished PART 5 - PREVENTATIVE MODIFICATION in accordance with Revision 1 of this bulletin between March 12, 2012 and February 1, 2014 and did not accomplish HFEC open hole inspections of the production fastener holes in the frame using 737 NDT Manual Part 6, 51-00-00 Procedure 16. 8. Group 1-6, Configuration 2: PART 8 - INSPECTION OF PREVENTATIVE MODIFICATION a. Do the inspections in accordance with Figure 206 of Repair 20 as given in 737-300 SRM 53-00-07, 737-400 SRM 53-00-07, or 737-500 SRM 53-00-07. (1) If any crack is found, contact The Boeing Company for repair instructions and do the repair as instructed by Boeing. (2) If no crack is found, do PART 6 - CLOSE ACCESS. b. Repeat PART 8 - INSPECTION OF PREVENTATIVE MODIFICATION at the interval given in Paragraph 1.E., Compliance. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2: April 21, 2015 57 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 58 (OCR) BOEING SERVICE BULLETIN 737-53A1279 ALERT ALERT This Figure applies only to: Group 1, 4. FORWARD CARGO COMPARTMENT SEE A SEE SEE (B FWD FORWARD CARGO COMPARTMENT 1335155 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 1 OF 4) Original Issue: December 18, 2007 Revision 2 April 21, 2015 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 661089 ### Page 59 FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 2 OF 4) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2 April 21, 2015 59 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT ### Page 60 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP To get access to the screws.--TapeRemove1 6BACS12FA3K12ScrewRemove/Keep2 6BACW10P106AWasher 6NAS43DD3-19Spacer FIGURE 1: FORWARD CARGO BAY - STATION 500A TO STATION 500D - WIRE SHROUD - REMOVAL (SHEET 3 OF 4) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 18, 2007 737-53A1279Revision 2 April 21, 2015 60 of 199 BOEING SERVICE BULLETIN 737-53A1279 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/737-53a1279/file/4518dbc4ed9b.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.