# Boeing Alert Service Bulletin 737-53A1116: Revision 4 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2014-0057; AD 2014-25-03 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-53A1116](https://openairdocs.org/service-documents/boeing/737-53a1116.md) - Title as filed: U.S. DOT/FAA - SB-737-53A1116-04 - Pages: 64 - PDF: https://openairdocs.org/files/sha256/da/5c/da5c475fefb0344dea622bc400fcef6f8f9a29ed94d5456cdccebd1df40cf2e6 - Page: https://openairdocs.org/service-documents/boeing/737-53a1116/file/da5c475fefb0 ## 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: 737-53A1116 Original Issue: July 21, 1988 Revision 4: September 30, 2013 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Forward Galley Service Doorway Upper and Lower Corners - Inspection, Repair and Preventive Modification 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 © 1989 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 Unpublished Work.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: July 21, 1988 737-53A1116Revision 4: September 30, 2013 1 of 64 7.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 2 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 Summary ...................................................... 7 1. PLANNING INFORMATION ........................................ 1 3 A. Effectivity ............................................... 1 3 1. Airplanes ............................................ 1 3 2. Spares Affected ........................................ 2 6 B. Concurrent Requirements ...................................... 2 6 C. Reason ................................................ 2 6 D. Description .............................................. 2 8 E. Compliance .............................................. 2 9 F. Approval ............................................... 4 2 G. Manpower .............................................. 4 3 H. Weight and Balance Changes .................................... 4 3 I. Electrical Load Data ......................................... 4 3 J. References .............................................. 4 3 1. Existing Data: ......................................... 4 3 2. Data Supplied with this Service Bulletin: ........................... 4 4 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 4 4 K. Publications Affected ........................................ 4 4 L. Interchangeability and Intermixability of Parts ........................... 4 4 M. Software Accomplishment Summary ................................ 4 4 2. MATERIAL INFORMATION ........................................ 4 5 A. Material - Price and Availability ................................... 4 5 B. Industry Support Information .................................... 4 5 C. Parts Necessary for Each Airplane ................................. 4 5 1. Kits/Parts ............................................ 4 5 2. Parts and Materials Supplied by the Operator ........................ 4 5 3. Parts Modified and Reidentified ................................ 4 5 4. Parts Removed and Not Replaced .............................. 4 5 D. Parts Necessary to Change Spares ................................. 4 5 E. Special Tooling - Price and Availability ............................... 4 5 F. Special Tooling Necessary to do this Service Bulletin ....................... 4 5 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 4 7 A. GENERAL INFORMATION ..................................... 4 7 B. WORK INSTRUCTIONS ....................................... 4 8 FIGURE 1: THIS FIGURE IS DELETED .................................. 5 4 FIGURE 2: THIS FIGURE IS DELETED .................................. 5 5 FIGURE 3: THIS FIGURE IS DELETED .................................. 5 6 FIGURE 4: FORWARD GALLEY SERVICE DOORWAY - UPPER AFT CORNER INSPECTION . . . 57 FIGURE 5: FORWARD GALLEY SERVICE DOORWAY - UPPER FORWARD CORNER INSPECTION .................................................. 5 9 FIGURE 6: FORWARD GALLEY SERVICE DOORWAY - LOWER AFT CORNER INSPECTION . . . 61 FIGURE 7: FORWARD GALLEY SERVICE DOORWAY - LOWER FORWARD CORNER INSPECTION .................................................. 6 3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 3 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 4 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 4 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT BLANK PAGE ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-53A1116Original Issue: July 21, 1988 Revision 4: September 30, 2013 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Forward Galley Service Doorway Upper and Lower Corners - Inspection, Repair and Preventive Modification This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directives AD 2008-08-23, AD 2008-09-13, AD 90-06-02 and AD 98-11-04 R1 are related to this service bulletin. More work is necessary on airplane(s) inspected or changed in accordance with the original issue, Revision 1, 2 or 3 of this service bulletin. Airplanes that have installed the preventive modification in accordance with original issue, Revision 1, 2 or 3 of this service bulletin, require follow-on inspection. Airplanes that have installed a repair at the upper forward corner in accordance with original issue, Revision 1, 2, or 3 require follow-on inspection. All airplanes require new inspections at the forward galley service doorway lower corners. Airplane line numbers 1561 thru 3132 were added to this service bulletin effectivity. REASON FOR REVISION This revision is sent to add airplane line numbers 1561 thru 3132 to the effectivity of this service bulletin and to revise the compliance information and the inspection instructions. The repairs and kits provided in the previous revisions are deleted and replaced with Structural Repair Manual (SRM) repairs. Terminology has been changed in the Work Instructions to agree with the terminology defined in Paragraph 3.A., General Information - Notes. The following sections are changed: 1. The service bulletin subject is updated. 2. The Summary Background is updated and a Summary Evaluation Table is added. 3. The Summary Action, Summary Effectivity, Summary Compliance, Summary Manpower, Summary Material Information and Summary Illustration are updated. 4. Paragraph 1.A.1., Airplanes - 737-300/-400 airplanes line numbers 1001 through 1560 are moved from Group 1 to Group 2. Airplane line numbers 1-291 are moved from group 1 to new Group 5. 737-300/-400/-500 airplanes line numbers 1561 through 3132 are added to new Group 3. 737-200 airplanes line numbers 1565 through 1585 are added to new Group 4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 5 of 64 ### Page 6 5. Paragraph 1.D., Description is updated and affected maintenance zones are added. 6. Paragraph 1.E., Compliance - Reference to FAA Airworthiness Directives AD 2008-08-23, AD 2008-09-13, AD 90-06-02 and AD 98-11-04 R1 is added and compliance information is updated. 7. Paragraph 1.F., Approval - Alternative Method of Compliance (AMOC) statements are added. 8. Paragraph 1.G., Manpower - Manpower information is updated. 9. Paragraph 1.H., Weight and Balance Changes - The Weight and Balance table is deleted. 10. Paragraph 1.J.1., Existing Data - References are updated. 11. Paragraph 1.J.2., Data Supplied with this Service Bulletin - The Drawings table is deleted. 12. Paragraph 1.K., Publications Affected - Reference to 737-500 SRM is added, reference 737-100/200 SRM is deleted and a Damage Tolerance Inspection (DTI) statement is added. 13. Paragraph 2.A., Material - Price and Availability - This information is deleted. 14. Paragraph 2.C.1., Kits/Parts - The kits are deleted. 15. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - The parts and materials table is deleted. 16. Paragraph 2.E., Special Tooling - Price and Availability - The cold working tools information is deleted. 17. Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin - The cold working tools information is deleted. 18. Paragraph 1.M., Software Accomplishment Summary - Section is added. 19. Paragraph 3.A., General Information - Notes are added. 20. Paragraph 3.B., Work Instructions - Inspections instructions are added. 21. Figures 1, 2 and 3 are deleted and Figures 4 thru 7 are added. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY July 21, 1988Original Issue: September 07, 1989Revision 1: September 30, 1993Revision 2: July 20, 1995Revision 3: September 30, 2013Revision 4: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 6 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 7 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-53A1116Original Issue: July 21, 1988 Revision 4: September 30, 2013 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Forward Galley Service Doorway Upper and Lower Corners - Inspection, Repair and Preventive Modification 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 Based on a structural review of the 737 airplane, incorporation of the modification per this service bulletin is recommended on aging airplanes. This service bulletin gives instructions to inspect the skin and bearstrap in the forward galley service doorway upper and lower corners for cracking. If the work in this service bulletin is not done, undetected cracking in the forward galley service doorway corners could extend and result in rapid loss of cabin pressure and cause unscheduled maintenance. Six operators have found seventeen cracks in the skin and doublers at the upper corners of the forward galley service doorway on eight airplanes. There were eight cracks reported at the upper aft corner on three airplanes and nine cracks in the skin at the forward corner on five airplanes. The airplanes had accumulated from 29,000 to 47,300 flight hours and from 40,500 to 60,800 flight cycles. Cause of the cracking is attributed to fatigue from pressurization cycles. There have been nine reports of cracking at the upper forward and aft corner fastener locations of the forward galley service doorway in airplanes beyond the effectivity of Revision 3 of this service bulletin. A 0.5 inch long crack was reported on an airplane with 23,426 total flight cycles. Two cracks were reported common to the upper forward and aft corner radius fastener locations of the forward galley service doorway on airplanes that had incorporated the preventive modification in accordance with the original issue, Revision 1, 2 and 3 of this service bulletin. Multiple cracks were reported outside the inspection area of Revision 3 of this service bulletin common to the upper forward and aft door corners of the forward galley service doorway. A 6.5 inch long bearstrap crack was reported just below the upper forward corner inspection zone. The airplane had accumulated 59,804 total flight cycles. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 7 of 64 ### Page 8 Service bulletin 737-53-1074 provides inspection, preventive modification and repair instructions for the forward galley service doorway lower forward and aft corner areas for 737 airplane line numbers 1 thru 1014. Multiple cracks have been reported common to the skin and bearstrap at the lower forward and aft doorway corners in 737 airplane line numbers 1015 thru 3132 that are beyond the effectivity of service bulletin 737-53-1074. Several cracks ranging from 0.5 inch to 2 inches were reported in the skin and bearstrap at the lower forward doorway corner on airplanes that had accumulated between 44,796 and 73,109 total flight cycles. Multiple cracks ranging from 0.03 inch to 2.5 inches were reported in the skin and bearstrap at the lower aft doorway corner on airplanes that had accumulated between 28,040 and 70,456 total flight cycles. New inspections have been added to service bulletin 737-53A1116 for cracking of the forward galley service doorway lower forward and aft corners for all airplanes within this service bulletin's effectivity. After accomplishing the inspections in accordance with service bulletin 737-53A1116 Revision 4, operators do not need to accomplish service bulletin 737-53-1074 inspections for the forward service doorway lower corners. Boeing Service Related Problem (SRP) 737-SRP-53-0380 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 737 FTD 53-11003 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information. ReferenceAffectedPlanning Data Paragraph 1.A.2., Spares AffectedNoSpares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval YesAD Related Paragraph 1.H., Weight and Balance ChangesNoWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedYesPublications Affected Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew Operations Manual and/or FAA Approved Air- plane Flight Manual) Paragraph 2.C.1., Kits/PartsNoKits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator NoOperator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin NoSpecial Tooling Required ACTION Get access to the interior surface of the forward galley service doorway. Group 1: At the upper and lower forward and aft corners of the forward galley service doorway, where no repair is installed that covers the corner radius fasteners, do an external Low Frequency Eddy Current (LFEC) inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found in the skin or bearstrap at the upper aft corner, install a repair in accordance with this service bulletin or contact Boeing for repair instructions and do the work instructed by Boeing. If any crack is found in the skin or bearstrap Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 8 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 9 at the upper forward corner, lower aft corner or lower forward corner, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections install the preventive modification in accordance with this service bulletin or contact Boeing for preventive modification instructions and do the work instructed by Boeing, as applicable. Group 2-3: At the upper and lower forward and aft corners of the forward galley service doorway where no Boeing approved repair is installed that covers the corner radius fasteners, do an external LFEC inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found in the skin or bearstrap at the upper aft corner, lower aft corner or lower forward corner, install a Structural Repair Manual (SRM) repair or contact Boeing for repair instructions and do the work instructed by Boeing. If any crack is found in the skin or bearstrap at the upper forward corner, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections install the preventive modification in accordance with this service bulletin or contact Boeing for preventive modification instructions and do the work instructed by Boeing, as applicable. Group 4: At the upper and lower forward and aft corners of the forward galley service doorway where no Boeing approved repair is installed that covers the corner radius fasteners, do an external LFEC inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections contact Boeing for preventive modification instructions and do the work instructed by Boeing. Group 5: Contact Boeing to get instructions for the inspections and repairs for this service bulletin 737-53A1116, Revision 4, and do the work instructed by Boeing. EFFECTIVITY 737-100, -200, -200C, -300, -400 and -500 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directives AD 2008-08-23, AD 2008-09-13, AD 90-06-02 and AD 98-11-04 R1 are related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 9 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 10 MANPOWER Refer to Paragraph 1.G., Manpower. Elapsed HoursTotal Task HoursAirplanes 13.8518.30Group 1-4 MATERIAL INFORMATION None. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 10 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 11 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT DO AN EXTERNAL DETAILED SEE INSPECTION OF THE SKIN AND INTERNAL DETAILED INSPECTION OF THE BEARSTRAP AND SKIN FOR CRACKING. SKIN SEE BEARSTRAP S-6R • CRACKS (TYPICAL) DO AN EXTERNAL LFEC INSPECTION FOR CRACKING AROUND THE CORNER RADIUS FASTENERS. S-9R →→FWD FORWARD GALLEY DOORWAY UPPER CORNERS S-15R DO AN EXTERNAL LFEC INSPECTION FOR CRACKING CRACKS AROUND THE CORNER RADIUS (TYPICAL) FASTENERS. BEARSTRAP S-19R - → FWD DO AN EXTERNAL EXTERNAL AND INTERNAL •DETAILED INSPECTION OF DETAILED SKIN THE SKIN AND INTERNAL INSPECTION AREA DETAILED INSPECTION OF LFEC FORWARD GALLEY THE BEARSTRAP AND SKIN A71701 INSPECTION AREA DOORWAY LOWER CORNERS FOR CRACKING. Original Issue: July 21, 1988 Revision 4: September 30, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1116 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 64 ### Page 12 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 12 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT BLANK PAGE ### Page 13 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1116 Original Issue: July 21, 1988 Revision 4: September 30, 2013 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Forward Galley Service Doorway Upper and Lower Corners - Inspection, Repair and Preventive Modification THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes Refer to Service Bulletin Index D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. DESCRIPTIONCONFIGURATIONGROUP 737-200/-200C airplanes line numbers 292 through 1560, excluding variable numbers PJ201 through PJ219. -1 737-300/-400 airplanes line numbers 1001 through 1560. A repair exists in the Structural Repair Manual for these airplanes. -2 737-300/-400/-500 airplanes line numbers 1561 through 3132. These airplanes have cold worked fastener holes at the forward galley service doorway upper corners and are added at Revision 4 of this service bulletin. A repair exists in the Structural Repair Manual for these airplanes. -3 737-200 airplanes line numbers 1565 through 1585. These airplanes have cold worked fastener holes at the forward galley service doorway upper corners and are added at Revision 4 of this service bulletin. -4 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 13 of 64 ### Page 14 DESCRIPTIONCONFIGURATIONGROUP 737-100/-200/-200C airplanes line numbers 1 through 291. These airplanes have cold bonded skins. -5 Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 GroupVariable Number 5PA001 - PA022 5PA099 5PA231 - PA232 5PC001 - PC005 5PG001 - PG075 5PG199 5PG201 - PG230 5PG251 - PG255 5PG271 - PG279 5PG301 - PG314 5PG331 - PG332 5PG351 - PG356 5PG375 5PG401 - PG403 5PG431 - PG442 5PG471 - PG475 5PG501 - PG505 5PG571 - PG583 1PG584 - PG586 5PG621 - PG630 5PG651 - PG652 5PG701 - PG705 1PH001 1PH011 - PH013 1PH021 - PH024 5PH701 - PH715 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 14 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 15 GroupVariable Number 5PH731 - PH732 5PH741 - PH742 1PH743 5PJ001 - PJ002 1PJ003 - PJ009 5PJ031 - PJ032 5PJ071 - PJ072 5PJ101 - PJ104 1PJ105 - PJ119 3PJ301 - PJ302 3PJ551 - PJ561 3PJ601 - PJ615 3PJ811 3PJ816 - PJ817 1PK026 - PK029 1PK041 - PK053 1PK061 - PK070 1PK081 - PK082 1PK091 - PK099 1PK101 - PK103 1PK111 - PK120 1PK141 - PK146 1PK201 - PK204 1PK211 - PK223 1PK231 - PK241 1PK251 - PK258 1PK271 - PK274 1PK281 - PK289 1PK291 1PK301 - PK318 1PK341 1PK351 - PK361 1PK391 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 15 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 16 GroupVariable Number 1PK431 - PK433 1PK451 - PK452 1PK461 - PK469 1PK495 1PK501 - PK504 1PK511 - PK515 1PK519 1PK521 - PK527 4PK528 1PK541 - PK565 1PK581 1PK591 - PK599 1PK601 - PK617 1PK621 - PK637 1PK641 - PK642 1PK661 - PK666 1PK671 - PK681 1PK691 - PK697 1PK711 - PK716 1PK731 - PK765 1PK771 - PK779 1PK801 - PK804 1PK819 - PK827 1PK830 1PK861 - PK863 1PK871 - PK874 1PK881 - PK884 1PK901 - PK938 1PK971 - PK974 1PL001 - PL028 1PL061 1PL081 1PL101 - PL113 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 16 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 17 GroupVariable Number 1PL151 1PL171 - PL172 1PL201 - PL203 1PL221 1PL401 - PL417 1PL421 1PL441 1PL451 - PL456 1PL471 1PL491 1PL501 - PL506 1PL551 - PL562 1PL581 1PL601 - PL603 1PL611 1PL621 - PL626 1PL631 - PL632 5PL711 - PL712 5PL716 1PL717 - PL747 1PL756 1PL758 1PL761 - PL770 1PL781 - PL788 1PL793 5PL801 - PL803 1PM001 - PM006 1PM016 - PM017 1PM021 - PM023 1PM051 - PM066 1PM101 - PM119 1PM141 - PM142 1PM171 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 17 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 18 GroupVariable Number 1PM181 1PM251 - PM255 1PM281 - PM283 3PM381 - PM399 3PM401 - PM417 3PM541 - PM564 1PN001 - PN002 1PN021 - PN043 1PN081 - PN086 1PN101 - PN117 1PN131 - PN163 1PN401 - PN420 1PN431 - PN433 1PN451 - PN456 1PN471 - PN472 4PN473 - PN474 1PN481 1PN491 - PN493 1PN501 - PN502 1PN511 4PN512 4PN521 2PP001 - PP045 3PP046 - PP054 2PP101 - PP135 3PP136 - PP160 2PP161 - PP169 2PP181 - PP192 3PP193 - PP199 2PP201 - PP205 2PP221 2PP231 - PP243 2PP281 - PP286 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 18 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 19 GroupVariable Number 2PP301 - PP305 2PP351 - PP353 2PP376 - PP384 2PP391 - PP392 3PP393 2PP401 - PP436 3PP437 - PP440 2PP471 - PP475 2PP501 - PP504 3PP505 - PP520 2PP521 - PP522 2PP631 - PP634 2PP651 - PP652 2PP671 - PP699 2PP701 - PP733 2PP771 - PP779 2PP801 - PP804 3PP805 - PP808 2PP821 - PP827 2PP831 - PP842 3PP843 - PP845 2PP846 - PP848 2PP851 - PP852 2PP861 - PP870 3PP871 - PP877 2PP891 - PP899 2PP901 - PP910 3PP911 - PP930 2PP931 - PP936 2PP946 - PP948 2PP951 - PP952 2PP961 - PP965 3PP966 - PP967 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 19 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 20 GroupVariable Number 2PP981 - PP982 3PP983 - PP990 2PP991 3PP993 2PQ001 - PQ012 3PQ013 - PQ016 2PQ026 - PQ037 3PQ038 - PQ041 2PQ051 - PQ065 3PQ066 - PQ085 2PQ086 - PQ090 3PQ091 - PQ092 2PQ101 - PQ123 3PQ124 - PQ199 3PQ201 - PQ202 3PQ221 - PQ230 2PQ231 - PQ233 3PQ234 - PQ237 2PQ241 - PQ242 3PQ243 3PQ251 - PQ267 3PQ281 - PQ299 3PQ301 - PQ307 3PQ331 - PQ332 3PQ341 - PQ348 3PQ361 - PQ373 3PQ391 - PQ395 3PQ401 - PQ418 3PQ421 3PQ431 - PQ438 3PQ447 - PQ448 3PQ451 3PQ454 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 20 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 21 GroupVariable Number 3PQ471 - PQ475 3PQ479 - PQ481 3PQ486 - PQ487 3PQ491 - PQ493 3PQ771 - PQ772 3PQ791 - PQ793 3PQ801 - PQ805 3PQ931 - PQ935 3PQ951 3PQ971 - PQ997 3PR001 - PR017 3PR021 - PR034 3PR041 - PR045 3PR061 - PR072 3PR077 - PR082 3PR091 - PR092 3PR096 3PR101 3PR121 - PR122 3PR131 - PR132 3PR141 - PR143 3PR161 - PR172 3PR181 3PS601 - PS631 3PS636 - PS638 3PS641 - PS644 3PS651 - PS657 3PS666 - PS669 3PS691 - PS692 3PS701 - PS706 3PS751 - PS799 3PS811 3PS836 - PS837 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 21 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 22 GroupVariable Number 3PS841 - PS846 3PS851 - PS852 3PS856 3PS861 - PS863 3PS866 - PS868 3PS871 - PS874 3PS896 - PS897 3PS901 - PS941 3PS956 - PS957 3PS961 - PS963 3PS971 - PS978 3PT001 - PT015 3PT021 - PT031 3PT041 - PT064 3PT101 - PT105 3PT121 - PT138 3PT146 - PT148 3PT161 - PT170 3PT181 - PT188 3PT211 - PT220 3PT295 3PT301 - PT309 3PT331 - PT360 3PT381 - PT399 3PT401 - PT438 3PT501 - PT517 3PT561 - PT565 3PT581 - PT586 3PT611 - PT621 3PT641 - PT644 3PT651 - PT656 3PT671 - PT672 3PT681 - PT685 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 22 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 23 GroupVariable Number 3PT701 - PT703 3PT716 - PT717 3PT721 - PT725 3PT801 - PT834 3PT851 - PT854 3PT871 - PT886 3PT901 - PT930 3PT971 - PT973 3PT981 - PT985 3PT996 3PU001 - PU025 3PU301 3PU311 - PU313 2PV001 - PV004 3PV005 - PV055 3PV201 - PV209 3PV226 - PV229 3PV231 - PV237 3PV271 - PV272 3PV281 - PV287 3PV296 3PV301 - PV302 3PV351 3PV356 - PV357 3PW001 - PW054 3PW061 - PW068 3PW072 3PW086 - PW088 3PW091 - PW094 3PW101 - PW102 3PW106 3PW111 - PW120 3PW156 - PW157 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 23 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 24 GroupVariable Number 3PW161 - PW171 3PW201 - PW252 3PW261 - PW268 3PW271 - PW276 3PW278 3PW281 - PW293 3PW296 3PW301 - PW327 3PW401 - PW408 3PW411 - PW418 3PW421 - PW424 3PW431 - PW435 3PW441 - PW450 3PW461 - PW467 3PW501 - PW504 3PW511 - PW522 3PW524 - PW550 3PW556 - PW557 3PW561 - PW564 3PW571 - PW576 3PW591 - PW596 3PW611 - PW622 3PW631 - PW637 3PW661 - PW662 3PW681 - PW683 3PW701 - PW702 3PW711 - PW717 3PW741 - PW742 3PW761 3PW771 3PW831 3PW851 - PW856 5PX071 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 24 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 25 GroupVariable Number 5PX701 5PY001 - PY008 5PY021 1PY022 5PY031 1PY036 - PY037 1PY046 - PY048 1PY051 - PY053 1PY056 - PY057 1PY101 - PY103 1PY111 - PY113 1PY131 - PY135 1PY141 - PY143 1PY151 - PY154 1PY156 - PY157 1PY161 - PY162 1PY166 1PY191 1PY201 1PY221 - PY222 1PY231 1PY241 - PY244 1PY270 - PY275 1PY281 1PY286 5PY301 - PY304 5PY321 - PY323 5PY341 - PY346 5PY361 - PY362 5PY381 1PY401 1PY409 - PY411 1PY421 - PY422 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 25 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 26 GroupVariable Number 1PY441 1PY451 1PY461 - PY463 1PY591 - PY595 1PY611 - PY612 1PY621 1PY631 1PY651 1PY671 - PY672 1PY721 1PY741 2. Spares Affected None. B. Concurrent Requirements None. C. Reason As a result of the FAA-sponsored Aging Fleet Conference, a 737 Structures Task Group with Airline and Boeing members and FAA observers was formed to review structural service bulletin modifications and recommend selected bulletins for incorporation on aging airplanes. This service bulletin modification has been recommended for incorporation on aging 737 airplanes. This service bulletin gives instructions to inspect the skin and bearstrap in the forward galley service doorway upper and lower corners for cracking. If the work in this service bulletin is not done, undetected cracking in the forward galley service doorway corners could extend and result in rapid loss of cabin pressure and cause unscheduled maintenance. Inspection of the upper corners of the forward galley service doorway will detect cracking that could result in pressurization difficulties. Repair of cracks or accomplishment of preventive modification on uncracked structure is terminating action for inspection per this service bulletin. Cause of the cracking is attributed to fatigue from pressurization cycles. Six operators have reported cracks in the upper corner of the forward galley service doorways on a total of eight airplanes. Three airplanes had a total of eight cracks in the upper aft corner, with crack lengths of up to 2 inches in the skin, and a 2 inch long crack in the bearstrap doubler on one airplane. Five airplanes had a total of nine cracks from 0.1 inch to 1.5 inches in length in the upper forward corner skin. The airplanes had accumulated from 29,000 to 47,300 flight hours, and from 40,500 to 60,800 flight cycles. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 26 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 27 There have been nine reports of cracking at the upper forward and aft corner fastener locations of the forward galley service doorway in airplanes beyond the effectivity of Revision 3 of this service bulletin. A 0.5 inch long crack was reported on an airplane with 23,426 total flight cycles. Two cracks were reported common to the upper forward and aft corner radius fastener locations of the forward galley service doorway on airplanes that had incorporated the preventive modification in accordance with the original issue, Revision 1, 2 and 3 of this service bulletin. Multiple cracks were reported outside the inspection area of Revision 3 of this service bulletin common to the upper forward and aft door corners of the forward galley service doorway. A 6.5 inch long bearstrap crack was reported just below the upper forward corner inspection zone. The airplane had accumulated 59,804 total flight cycles. Service bulletin 737-53-1074 provides inspection, preventive modification and repair instructions for the forward galley service doorway lower forward and aft corner areas for 737 airplane line numbers 1 thru 1014. Multiple cracks have been reported common to the skin and bearstrap at the lower forward and aft doorway corners in 737 airplane line numbers 1015 thru 3132 that are beyond the effectivity of service bulletin 737-53-1074. Several cracks ranging from 0.5 inch to 2 inches were reported in the skin and bearstrap at the lower forward doorway corner on airplanes that had accumulated between 44,796 and 73,109 total flight cycles. Multiple cracks ranging from 0.03 inch to 2.5 inches were reported in the skin and bearstrap at the lower aft doorway corner on airplanes that had accumulated between 28,040 and 70,456 total flight cycles. New inspections have been added to service bulletin 737-53A1116 for cracking of the forward galley service doorway lower forward and aft corners for all airplanes within this service bulletin's effectivity. After accomplishing the inspections in accordance with service bulletin 737-53A1116 Revision 4, operators do not need to accomplish service bulletin 737-53-1074 inspections for the forward service doorway lower corners. Boeing Service Related Problem (SRP) 737-SRP-53-0380 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 737 FTD 53-11003 is related to this service bulletin. Revision 1 of this service bulletin was issued to provide the recommendations of the Aging Fleet 737 Structures Working Group and to change the forward galley service doorway upper forward corner repair doubler installation. The installation change eliminates one fastener and moves one fastener to make the repair compatible with the service bulletin 737-53-1074 modification. Revision 2 was sent to provide a list of reference service bulletins applicable to 737 door corners and hinge cutouts. Also, the crack location and limits that can be repaired with instructions in this bulletin were defined in this revision. Revision 3 was sent to: – Add the contents of the preventive modification and repair kits to Paragraph 2.C., Parts Necessary for Each Airplane. This data was inadvertently omitted in Revision 2. – Add structural repair manual subject numbers to stop drill 737-300 and 737-400 airplanes in accordance with Figure 2. – Add structural repair manual subject numbers to coldwork 737-300 and 737-400 airplanes in accordance with Figure 3. – Add reference to the Maintenance Planning Document item number that is related to the inspections in this service bulletin. – Add reference to the structural repair manual subject numbers changed by the repairs and modifications shown in this service bulletin. Revision 4 is sent to add airplane line numbers 1561 thru 3132 to the effectivity of this service bulletin and to revise the compliance information and the inspection instructions. The repairs and kits provided in the previous revisions are deleted and replaced with Structural Repair Manual (SRM) repairs. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 27 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 28 The forward galley door upper forward corner repair installed in accordance with this service bulletin overlaps the preventive modification for the upper hinge cutout installed in accordance with service bulletin 737-53-1074. Service bulletin 737-53-1074 has similar access requirements as this service bulletin. D. Description Get access to the interior surface of the forward galley service doorway. Group 1: At the upper and lower forward and aft corners of the forward galley service doorway, where no repair is installed that covers the corner radius fasteners, do an external Low Frequency Eddy Current (LFEC) inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found in the skin or bearstrap at the upper aft corner, install a repair in accordance with this service bulletin or contact Boeing for repair instructions and do the work instructed by Boeing. If any crack is found in the skin or bearstrap at the upper forward corner, lower aft corner or lower forward corner, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections install the preventive modification in accordance with this service bulletin or contact Boeing for preventive modification instructions and do the work instructed by Boeing, as applicable. Group 2-3: At the upper and lower forward and aft corners of the forward galley service doorway where no Boeing approved repair is installed that covers the corner radius fasteners, do an external LFEC inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found in the skin or bearstrap at the upper aft corner, lower aft corner or lower forward corner, install a Structural Repair Manual (SRM) repair or contact Boeing for repair instructions and do the work instructed by Boeing. If any crack is found in the skin or bearstrap at the upper forward corner, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections install the preventive modification in accordance with this service bulletin or contact Boeing for preventive modification instructions and do the work instructed by Boeing, as applicable. Group 4: At the upper and lower forward and aft corners of the forward galley service doorway where no Boeing approved repair is installed that covers the corner radius fasteners, do an external LFEC inspection for cracking in the skin and bearstrap at the corner radius fasteners. Do an external detailed inspection for cracking in the skin and do an internal detailed inspection for cracking in the skin and bearstrap. If any crack is found contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the intervals given in Paragraph 1.E., Compliance, or to terminate repeat inspections contact Boeing for preventive modification instructions and do the work instructed by Boeing. Group 5: Contact Boeing to get instructions for the inspections and repairs for this service bulletin 737-53A1116, Revision 4, and do the work instructed by Boeing. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 28 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 29 Revision 4 - More work is necessary on airplane(s) inspected or changed in accordance with the original issue, Revision 1, 2 or 3 of this service bulletin. Airplanes that have installed the preventive modification in accordance with original issue, Revision 1, 2 or 3 of this service bulletin, require follow-on inspection. Airplanes that have installed a repair at the upper forward corner in accordance with original issue, Revision 1, 2, or 3 require follow-on inspection. All airplanes require new inspections at the forward galley service doorway lower corners. NOTE: This service bulletin is listed in Boeing Document D6-38505. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 1-6737-200, 737-200C Group 2: Affected Maintenance Zones ZoneModel 106737-300, 737-400 Group 3: Affected Maintenance Zones ZoneModel 106737-300, 737-400, 737-500 Group 4: Affected Maintenance Zones ZoneModel 1-6737-200 Group 5: Affected Maintenance Zones ZoneModel 1-6737-100, 737-200, 737-200C E. Compliance Federal Aviation Administration (FAA) Airworthiness Directives AD 2008-08-23, AD 2008-09-13, AD 90-06-02 and AD 98-11-04 R1 are related to this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 29 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 30 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. Group 5: Contact Boeing to get instructions for the inspections and repairs for this service bulletin 737-53A1116, Revision 4, and do the work instructed by Boeing within 120 days of the issue date of this service bulletin. Group 1: Table 1: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (a) 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external Low Fre- quency Eddy Current (LFEC) inspection of the skin and bearstrap for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.a.(1). Airplanes that have not ac- complished the preventive modification or the repair in accordance with the original issue, Revision 1, 2 or 3 of this service bul- letin. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.a.(1). 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.a.(1). Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 30 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 31 Group 1: Table 1: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (a) 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Within 35,000 flight cycles af- ter the installa- tion of the pre- ventive modifica- tion. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.a.(1). Airplanes that have accom- plished the preventive modification in accordance with the original issue, Re- vision 1, 2 or 3 of this ser- vice bulletin. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.a.(1) 18,000 flight cy- cles. Within 9,000 flight cycles af- ter the Revision 4 date of this service bulletin. Within 35,000 flight cycles af- ter the installa- tion of the pre- ventive modifica- tion. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.a.(1). -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. (a) Accomplishment of a repair in accordance with the original issue or Revision 1, 2 or 3 of this service bulletin terminates the requirement for repeat inspections as given in Table 1 for the repaired doorway corner. Post repair inspections are provided in Table 11. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 31 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 32 Group 2: Table 2: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (b) 4,500 flight cycles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.b.(1). Airplanes that have not ac- complished the preventive modification or the repair in accordance with the original issue, Revision 1, 2 or 3 of this service bul- letin. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.b.(1). 18,000 flight cy- cles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.b.(1). -Before further flight.Do the repair in accor- dance with Paragraph 3.B., Work Instructions, step 2.b.(1)(a). If any crack is found in the skin or bearstrap. (a) 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Within 35,000 flight cycles af- ter the installa- tion of the pre- ventive modifica- tion. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.b.(2). Airplanes that have accom- plished the preventive modification in accordance with the original issue, Re- vision 1, 2 or 3 of this ser- vice bulletin. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.b.(2). 18,000 flight cy- cles. Within 9,000 flight cycles af- ter the Revision 4 date of this service bulletin. Within 35,000 flight cycles af- ter the installa- tion of the pre- ventive modifica- tion. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.b.(2). Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 32 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 33 Group 2: Table 2: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (b) -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. (a) Accomplishment of a repair or preventive modification in accordance with Revision 4 of this service bulletin terminates the requirement for repeat inspections as given in Table 2 for the repaired or preventive modified doorway corner. Post repair and post preventive modification inspections are provided in the applicable SRM. (b) Accomplishment of a repair in accordance with the original issue or Revision 1, 2 or 3 of this service bulletin terminates the requirement for repeat inspections as given in Table 2 for the repaired doorway corner. Post repair inspections are provided in Table 11. Group 3: Table 3: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.c.(1). All airplanes Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.c.(1). 18,000 flight cy- cles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.c.(1). -Before further flight.Do the repair in accor- dance with Paragraph 3.B., Work Instructions, step 2.c.(1)(a). If any crack is found in the skin or bearstrap. (a) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 33 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 34 Group 3: Table 3: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (a) Accomplishment of a repair or preventive modification in accordance with Revision 4 of this service bulletin terminates the requirement for repeat inspections as given in Table 3 for the repaired or preventive modified doorway corner. Post repair and post preventive modification inspections are provided in the applicable SRM. Group 4: Table 4: Forward Galley Service Doorway Upper Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.d.(1). All airplanes Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 2.d.(1). 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 2.d.(1). -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 34 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 35 Group 1-2: Table 5: Forward Galley Service Doorway Upper Forward Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.a. Airplanes that have not ac- complished the preventive modification or installed a repair at the upper forward corner in accordance with original issue, Revision 1, 2 or 3 of this service bul- letin. Do an external detailedinspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 3.a. 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.b. 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Within 35,000 flight cycles af- ter the installa- tion of the pre- ventive modifica- tion. Do an external LFEC in- spection of the skin and bearstrap in accordance with Paragraph 3.B., Work Instructions, step 3.a. Airplanes that have accom- plished the preventive modification in accordance with original issue, Revi- sion 1, 2 or 3 of this service bulletin. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 3.a. 18,000 flight cy- cles. Within 9,000 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.b. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 35 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 36 Group 1-2: Table 5: Forward Galley Service Doorway Upper Forward Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition No further action is re- quired per this service bulletin in the repaired area. Airplanes with a repair in- stalled that meets the re- quirements of the Accom- plishment Instructions, Paragraph 3.A.14. of this service bulletin. 18,000 flight cy- cles. Within 9,000 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.b. Airplanes with a Boeing re- pair approved by FAA 8100-9 form installed at the upper forward corner that does not meet the require- ments as given in the Ac- complishment Instructions Paragraph 3.A.14. (a) -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. (a) In addition, post repair inspections are provided in the D6-38669 Repair Assessment Guidelines document. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 36 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 37 Group 3-4: Table 6: Forward Galley Service Doorway Upper Forward Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap in accordance with Paragraph 3.B., Work Instructions, step 3.a. Airplanes that have not in- stalled a repair at the upper forward corner. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 3.a. 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.b. No further action is re- quired per this service bulletin in the repaired area. Airplanes with a repair in- stalled that meets the re- quirements of the Accom- plishment Instructions, Paragraph 3.A.14. of this service bulletin. 18,000 flight cy- cles. Within 9,000 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 3.b. Airplanes with a Boeing re- pair approved by FAA 8100-9 form installed at the upper forward corner that does not meet the require- ments as given in the Ac- complishment Instructions Paragraph 3.A.14. (a) -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. (a) In addition, post repair inspections are provided in the D6-38669 Repair Assessment Guidelines document. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 37 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 38 Group 1, 4: Table 7: Forward Galley Service Doorway Lower Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection for cracking in the skin and bearstrap in accordance with Para- graph 3.B., Work Instruc- tions, step 4.a.(1). All airplanes Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 4.a.(1). 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 4.a.(1). -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 38 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 39 Group 2-3: Table 8: Forward Galley Service Doorway Lower Aft Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 4.b.(1). All airplanes Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 4.b.(1). 18,000 flight cy- cles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 4.b.(1). -Before further flight.Do the repair in accor- dance with Paragraph 3.B., Work Instructions, step .4.b.(1)(a) If any crack is found in the skin or bearstrap. (a) (a) Accomplishment of a repair or preventive modification in accordance with Revision 4 of this service bulletin terminates the requirement for repeat inspections as given in Table 8 for the repaired or preventive modified doorway corner. Post repair and post preventive modification inspections are provided in the applicable SRM. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 39 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 40 Group 1, 4: Table 9: Forward Galley Service Doorway Lower Forward Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles.Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 5.a.(1). All airplanes. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 5.a.(1). 18,000 flight cy- cles. Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 5.a.(1). -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boe- ing. If any crack is found in the skin or bearstrap. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 40 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 41 Group 2-3: Table 10: Forward Galley Service Doorway Lower Forward Corner Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 4,500 flight cycles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an external LFEC in- spection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 5.b.(1). All airplanes. Do an external detailed inspection of the skin for any crack in accordance with Paragraph 3.B., Work Instructions, step 5.b.(1). 18,000 flight cy- cles. (a) Within 4,500 flight cycles af- ter the Revision 4 date of this service bulletin. Before 35,000 total flight cy- cles. Do an internal detailed inspection of the skin and bearstrap for any crack in accordance with Para- graph 3.B., Work Instruc- tions, step 5.b.(1). -Before further flight.Do the repair in accor- dance with Paragraph 3.B., Work Instructions, step 5.b.(1)(a). If any crack is found in the skin or bearstrap. (a) (a) Accomplishment of a repair or preventive modification in accordance with Revision 4 of this service bulletin terminates the requirement for repeat inspections as given in Table 10 for the repaired or preventive modified doorway corner. Post repair and post preventive modification inspections are provided in the applicable SRM. Group 1-2: Table 11: Inspection of Fuselage Skin Assembly and Bearstrap for Airplanes With a Boeing Drawing 65C33800 Repair Installed in Accordance With the Original Issue or Revision 1, 2 or 3 of This Service Bulletin. Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition Repeat the inspec- tion at interval in accordance with the RAG. Within 12,000 flight cycles af- ter the repair was installed. Before 60,000 total flight cy- cles. Do the inspection in accor- dance with the Repair Assessment Guidelines (RAG) D6-38669. Airplanes that have in- stalled a Boeing drawing 65C33800 repair in accor- dance with the Original Is- sue or Revision 1, 2 or 3 of this Service Bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 41 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 42 F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves accomplishment of the applicable inspections, repairs, and modifications, with the corresponding compliance times, provided in Section 1.E, Compliance, of this service bulletin, Revision 4, as an alternative method of compliance (AMOC) to the requirements of paragraph A of Airworthiness Directive (AD) 90-06-02. The modification in accordance with SB 737-53A1116, Figure 3 is no longer required. This AMOC applies only to the modification specified in Boeing document D6-38505 for SB 737-53A1116. All provisions of AD 90-06-02 that are not specifically referenced above remain fully applicable and must be complied with accordingly. For Boeing Model 737-100/200 series airplanes, the Manager of the FAA Seattle ACO approves the supplemental inspection methods, thresholds and repeat intervals as given in the Repair Assessment Guidelines D6-38669 for the repair defined in the applicable tables of Paragraph 1.E., Compliance, of this Service Bulletin, Revision 4 as an method of compliance (MOC) to the inspections of Structurally Significant Item (SSI) F-15A required by paragraph (g), of AD 98-11-04 R1. This approval applies to this SSI and only for the portions of the bear strap and skin that have been repaired in accordance with this SB. If operators choose this MOC, then they must revise their FAA-approved maintenance or inspection program to incorporate these alternative inspections. All provisions of AD 98-11-04 R1 that are not specifically referenced above remain fully applicable and must be complied with accordingly. In addition, for Boeing Model 737-200C series airplanes, the Manager of the FAA Seattle ACO approves the inspection methods, thresholds, repeat intervals, as given in the Repair Assessment Guidelines D6-38669 for the repairs defined in the applicable tables of Paragraph 1.E., Compliance, of Boeing Alert Service Bulletin 737-53A1116, Revision 4 as an AMOC to the inspections of SSI F-15A required by paragraphs (g) and (h) of AD 2008-08-23. This approval applies to this SSI and only for the portions of the bearstrap and skin that have been repaired in accordance with this service bulletin. If operators choose this AMOC, then they must revise their FAA-approved maintenance or inspection program to incorporate these alternative inspections. All provisions of AD 2008-08-23 that are not specifically referenced above remain fully applicable and must be complied with accordingly. In addition, for Boeing Model 737-300/-400/-500 series airplanes, the Manager of the FAA Seattle ACO approves the inspection methods, thresholds, repeat intervals as given in the Repair Assessment Guidelines D6-38669 for the repairs defined in the applicable tables of Paragraph 1.E., Compliance, of Boeing Alert Service Bulletin 737-53A11116, Revision 4 as an AMOC to the inspections of SSI F-15A as required by paragraphs (g) and (h) of AD 2008-09-13. This approval applies to this SSI and only for the portions of the bearstrap and frame chord that have been repaired in accordance with this service bulletin. If operators choose this AMOC, then they must revise their FAA-approved maintenance or inspection program to incorporate these alternative inspections. All provisions of AD 2008-09-13 that are not specifically referenced above remain fully applicable and must be complied with accordingly. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 42 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 43 G. Manpower The table below shows an estimate of the task hours necessary to do this service bulletin 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. Elapsed HoursTask HoursNumber of PersonsTask 1.001.001Open Access 2.204.402FIGURE 4 2.254.502FIGURE 5 3.703.701FIGURE 6 3.703.701FIGURE 7 1.001.001Close Access 13.8518.30TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Boeing Service Bulletin 737-53-1074 b. Boeing Service Letter 737-SL-51-042 c. Boeing Service Related Problem (SRP) 737-SRP-53-0380 d. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2008-08-23, 2008-09-13, 2008-11-04, 90-06-02, 98-11-04 R1 e. Service Bulletin Index D6-19567 f. 737 Fleet Team Digest (FTD) 53-11003 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 43 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 44 g. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-26 h. 737-300 Structural Repair Manual (SRM) 53-10-01 i. 737-400 Structural Repair Manual (SRM) 53-10-01 j. 737-500 Structural Repair Manual (SRM) 53-10-01 k. Boeing Document D6-38505, "Aging Airplane Service Bulletin Structural Modification and Inspection Program - Model 737-100/-200/-200C" 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. K. Publications Affected 1. Publications: Chapter-SectionPublication 53-10737-300 Structural Repair Manual 53-10737-400 Structural Repair Manual 53-10737-500 Structural Repair Manual 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts 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: July 21, 1988 737-53A1116Revision 4: September 30, 2013 44 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 45 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator None. 3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 45 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 46 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 46 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT BLANK PAGE ### Page 47 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 47 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 48 8. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 9. Boeing Service Letter 737-SL-51-042, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 10. 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. 11. 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. 12. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 13. If a Boeing external doubler corner repair approved by FAA 8100-9 form is installed common to the door corner radius fasteners of the upper aft corner, lower aft corner or lower forward corner, then the inspections given in this service bulletin are not required for the repaired area. Post repair inspections are provided in the FAA 8100-9 form approving the repair. 14. If a Boeing repair approved by FAA 8100-9 form is installed at the upper forward doorway corner, inspections as given in this service bulletin for the upper forward corner are not required in the repair area if the repair meets the following requirements: – The repair doubler covers the doorway upper forward corner and the upper hinge cutout. – The repair has been approved as an Alternative Method of Compliance (AMOC) to AD 2008-11-04. Post repair inspections are provided in the FAA 8100-9 form approving the repair. 15. If the external detailed inspection area is hidden by an existing non-corner Boeing repair approved by FAA 8100-9 form, the external detailed inspection of the skin is not required common to the hidden area. External detailed inspection is still required in the area not hidden by the repair. B. WORK INSTRUCTIONS Group 5: Contact Boeing to get instructions for the inspections and repairs for this service bulletin 737-53A1116, Revision 4, and do the work instructed by Boeing. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 48 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 49 1. Part 1: Access a. Open the forward galley door for access to interior surface of door cutout to accomplish inspection and rework of doorway upper and lower corners. 2. Group 1-4: Part 2: Forward Galley Service Doorway Upper Aft Corner Inspection a. Group 1: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper aft corner of the forward galley service doorway in accordance with FIGURE 4. (a) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. b. Group 2: (1) Airplanes that have not accomplished the preventive modification or the repair in accordance with the original issue, Revision 1, 2 or 3 of this service bulletin, do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper aft corner of the forward galley service doorway in accordance with FIGURE 4. (a) If any crack is found in the skin or bearstrap, do the repair in accordance with applicable 737-300 SRM 53-10-01 Repair 16 or 737-400 SRM 53-10-01 Repair 16. NOTE: 1. Installation of 737-300 SRM 53-10-01 Repair 16 or 737-400 SRM 53-10-01 Repair 16 terminates repeat inspection requirements of this service bulletin for the upper aft corner. 2. Post repair inspections are provided in the applicable SRM. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance or do the preventive modification in accordance with applicable 737-300 SRM 53-10-01 Repair 16 or 737-400 SRM 53-10-01 Repair 16. NOTE: 1. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 16 or 737-400 SRM 53-10-01 Repair 16 terminates repeat inspection requirements of this service bulletin for the upper aft corner. 2. Post preventive modification inspections are provided in the applicable SRM. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 49 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 50 (2) Airplanes that have accomplished the preventive modification in accordance with the original issue, Revision 1, 2 or 3 of this service bulletin, do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper aft corner of the forward galley service doorway in accordance with FIGURE 4. (a) If any crack is found contact Boeing for repair instructions and do the work instructed by Boeing. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. c. Group 3: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper aft corner of the forward galley service doorway in accordance with FIGURE 4. (a) If any crack is found in the skin or bearstrap, do the repair in accordance with applicable 737-300 SRM 53-10-01 Repair 16, 737-400 SRM 53-10-01 Repair 16 or 737-500 SRM 53-10-01 Repair 16. NOTE: 1. Installation of 737-300 SRM 53-10-01 Repair 16, 737-400 SRM 53-10-01 Repair 16 or 737-500 SRM 53-10-01 Repair 16 terminates repeat inspection requirements of this service bulletin for the upper aft corner. 2. Post repair inspections are provided in the applicable SRM. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance or do the preventive modification in accordance with applicable 737-300 SRM 53-10-01 Repair 16, 737-400 SRM 53-10-01 Repair 16 or 737-500 SRM 53-10-01 Repair 16. NOTE: 1. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 16, 737-400 SRM 53-10-01 Repair 16 or 737-500 SRM 53-10-01 Repair 16 terminates repeat inspection requirements of this service bulletin for the upper aft corner. 2. Post preventive modification inspections are provided in the applicable SRM. d. Group 4: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper aft corner of the forward galley service doorway in accordance with FIGURE 4. (a) If any crack is found in the skin or bearstrap, contact Boeing for repair instructions and do the work instructed by Boeing. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 50 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 51 (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. 3. Group 1-4: Part 3: Forward Galley Service Doorway Upper Forward Corner Inspection a. Do an external LFEC inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the upper forward corner of the forward galley service doorway in accordance with FIGURE 5. (1) If any crack is found in the skin or bearstrap, contact Boeing for repair instructions and do the work instructed by Boeing. (2) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. b. Do an internal detailed inspection of all visible surfaces of the skin and bearstrap for any crack at the upper forward corner of the forward galley service doorway in accordance with FIGURE 5. (1) If any crack is found in the skin or bearstrap, contact Boeing for repair instructions and do the work instructed by Boeing. (2) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. 4. Group 1-4: Part 4: Forward Galley Service Doorway Lower Aft Corner Inspection a. Group 1, 4: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the lower aft corner of the forward galley service doorway in accordance with FIGURE 6. (a) If any crack is found in the skin or bearstrap, contact Boeing for repair instructions and do the work instructed by Boeing. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance. b. Group 2-3: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the lower aft corner of the forward galley service doorway in accordance with FIGURE 6. (a) If any crack is found in the skin or bearstrap, do the repair in accordance with applicable 737-300 SRM 53-10-01 Repair 19, Repair 20, 737-400 SRM 53-10-01 Repair 19, Repair 20, 737-500 SRM 53-10-01 Repair 19, Repair 20. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 51 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 52 NOTE: 1. For aircraft line numbers 1001 thru 1922, Boeing recommends installing applicable 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 if existing repairs do not prevent the installation of this SRM repair. 2. Installation of the 737-300 SRM 53-10-01 Repair 19, 737-400 SRM 53-10-01 Repair 19, or 737-500 SRM 53-10-01 Repair 19 terminates repeat inspection requirements of this service bulletin for the lower aft corner. 3. Installation of the 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 terminates repeat inspection requirements of this service bulletin for the lower aft and forward corner. 4. Post repair inspections are provided in the applicable SRM. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance or do the preventive modification in accordance with applicable 737-300 SRM 53-10-01 Repair 19, Repair 20, 737-400 SRM 53-10-01 Repair 19, Repair 20, or 737-500 SRM 53-10-01 Repair 19, Repair 20. NOTE: 1. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 19, 737-400 SRM 53-10-01 Repair 19, or 737-500 SRM 53-10-01 Repair 19 terminates repeat inspection requirements of this service bulletin for the lower aft corner. 2. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 terminates repeat inspection requirements of this service bulletin for the lower aft and forward corner. 3. Post preventive modification inspections are provided in the applicable SRM. 5. Group 1-4: Part 5: Forward Galley Service Doorway Lower Forward Corner Inspection a. Group 1, 4: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the lower forward corner of the forward galley service doorway in accordance with FIGURE 7. (a) If any crack is found in the skin or bearstrap, contact Boeing for repair instructions and do the work instructed by Boeing. (b) If no cracking is found, do the repeat inspections 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: July 21, 1988 737-53A1116Revision 4: September 30, 2013 52 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 53 b. Group 2-3: (1) Do an external LFEC inspection, an internal detailed inspection of the skin and bearstrap and an external detailed inspection of the skin for any crack at the lower forward corner of the forward galley service doorway in accordance with FIGURE 7. (a) If any crack is found in the skin or bearstrap, do the repair in accordance with applicable 737-300 SRM 53-10-01 Repair 18, Repair 20, 737-400 SRM 53-10-01 Repair 18, Repair 20, 737-500 SRM 53-10-01 Repair 18, Repair 20. NOTE: 1. For aircraft line numbers 1001 thru 1922, Boeing recommends installing applicable 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 if existing repairs do not prevent the installation of this SRM repair. 2. Installation of the 737-300 SRM 53-10-01 Repair 18, 737-400 SRM 53-10-01 Repair 18, or 737-500 SRM 53-10-01 Repair 18 terminates repeat inspection requirements of this service bulletin for the lower forward corner. 3. Installation of the 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 terminates repeat inspection requirements of this service bulletin for the lower aft and forward corner. 4. Post repair inspections are provided in the applicable SRM. (b) If no cracking is found, do the repeat inspections at the interval given in Paragraph 1.E., Compliance or do the preventive modification in accordance with applicable 737-300 SRM 53-10-01 Repair 18, Repair 20, 737-400 SRM 53-10-01 Repair 18, Repair 20, or 737-500 SRM 53-10-01 Repair 18, Repair 20. NOTE: 1. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 18, 737-400 SRM 53-10-01 Repair 18, or 737-500 SRM 53-10-01 Repair 18 terminates repeat inspection requirements of this service bulletin for the lower forward corner. 2. Installation of the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 20, 737-400 SRM 53-10-01 Repair 20 or 737-500 SRM 53-10-01 Repair 20 terminates repeat inspection requirements of this service bulletin for the lower aft and forward corner. 3. Post preventive modification inspections are provided in the applicable SRM. 6. Part 6: Close Access a. Refinish the rework area around doorway as required, and put the airplane back to a serviceable condition. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4: September 30, 2013 53 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 54 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT THIS FIGURE IS DELETED. IGURE 1: THIS FIGURE IS DELETE SHEET 1 OF 1 original issue: July 21, 1900 Revision 4 September 30, 2013 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-53A1116 Work - See page 1 for details. 54 of 64 ### Page 55 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT THIS FIGURE IS DELETED. D38438 FIGURE 2: THE 1 021)S DELETED riginal Issue: July 21, 1988 evision 4 September 30, 201: Export Controlled ECCN: 9E991 - BOEING 737-53A1116 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 64 ### Page 56 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT THIS FIGURE IS DELETED. IGURE 3: THIS FIGURE IS DELETE SHEET 1 OF 1 original issue: July 21, 1900 Revision 4 September 30, 2013 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-53A1116 Work - See page 1 for details. 56 of 64 ### Page 57 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT SEE STA STA STA 312 332 328 S-6R S-7R - 2446211 BEARSTRAP S-8R (1) 9 LOCATIONS SKIN S-9R - →→WD EXTERNAL AND INTERNAL DETAILED 2185101 INSPECTION AREA UPPER AFT CORNER FIGURE 4: FORWARD GALLEY SERVICE DOORWAY - UPPER AFT CORNER INSPECTION (SHEET 1 OF 2) Original Issue: July 21, 1988 Revision 4 September 30, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1116 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 64 ### Page 58 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. More DataQtyIdentificationNameTaskStep (a)--Skin and BearstrapInspect1 (b)--SkinInspect2 (c)--Skin and BearstrapInspect3 (a) Do an external Low Frequency Eddy Current (LFEC) inspection for any crack in the skin and bearstrap around the corner fasteners in accordance with 737 NDT Manual Part 6, 51-00-26. (b) Do an external detailed inspection for any crack in the skin. (c) Do an internal detailed inspection for any crack in the skin and bearstrap. FIGURE 4: FORWARD GALLEY SERVICE DOORWAY - UPPER AFT CORNER INSPECTION (SHEET 2 OF 2) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4 September 30, 2013 58 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT ### Page 59 (OCR) BOEING SERVICE BULLETIN 737-53A1116 ALERT ALERT SEE STA 312 STA STA STA 303 294 291 - S-6R - S-7R • BEARSTRAP - S-8R 10 LOCATIONS - SKIN - S-9R EXTERNAL AND → FWD INTERNAL DETAILED 2185102 INSPECTION AREA UPPER FORWARD CORNER FIGURE 5: FORWARD GALLEY SERVICE DOORWAY - UPPER FORWARD CORNER INSPECTION (SHEET 1 OF 2) Original Issue: July 21, 1988 Revision 4 September 30, 2013 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1116 Work - See page 1 for details. 59 of 64 ### Page 60 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. More DataQtyIdentificationNameTaskStep (a)--Skin and BearstrapInspect1 (b)--SkinInspect2 (c)--Skin and BearstrapInspect3 (a) Do an external Low Frequency Eddy Current (LFEC) inspection for any crack in the skin and bearstrap around the corner fasteners in accordance with 737 NDT Manual Part 6, 51-00-26. (b) Do an external detailed inspection for any crack in the skin. (c) Do an internal detailed inspection for any crack in the skin and bearstrap. FIGURE 5: FORWARD GALLEY SERVICE DOORWAY - UPPER FORWARD CORNER INSPECTION (SHEET 2 OF 2) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 21, 1988 737-53A1116Revision 4 September 30, 2013 60 of 64 BOEING SERVICE BULLETIN 737-53A1116 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/737-53a1116/file/da5c475fefb0.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.