### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-53A1163**  Original Issue: December 21, 1993 Revision 1: January 08, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Forward Entry Doorway Skin Cutout - Upper Forward and Upper Aft Corners - Inspection, Modification, and Repair 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.9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 1993 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 1 of 67 6.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 2 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 9 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 34 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 35 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 42 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 43 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 1. . . . . . . . . . . . . . . . . . . . . . . 51 FIGURE 2: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION [Group 1, Configuration 2; Group 3]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 FIGURE 3: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION [Group 2, Configuration 2]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 FIGURE 4: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL [Group 1, Configuration 2]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 FIGURE 5: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL [Group 2, Configuration 2]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 3 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 4 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Revision Transmittal Sheet**  **Number: 737-53A1163** Original Issue: December 21, 1993 Revision 1: January 08, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Forward Entry Doorway Skin Cutout - Upper Forward and Upper Aft Corners - Inspection, Modification, and Repair This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** More work is necessary on airplanes that have not installed the repair or preventive modification in accordance with the original issue of this service bulletin. Inspection areas are increased and inspections methods are changed. No more work is necessary on the airplanes that have installed the repair or preventive modification in accordance with the original issue of this service bulletin. 737-300/-400/-500 airplanes line numbers 1923 to 3132 are added to new Group 3 of this service bulletin effectivity. Federal Aviation Administration (FAA) Airworthiness Directives AD 98-11-04 R1, AD 2008-08-23 and AD 2008-09-13 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. **REASON FOR REVISION** This revision is sent to add new airplanes to the service bulletin effectivity. This revision is also sent to increase the inspection area, to remove internal inspection and to change external inspection methods for group 1 and 2 airplanes. Airplane line numbers 1 through 291 are moved from Group 1 and 2 to new Group 4. 737-300/-400/-500 airplanes line numbers 1923 to 3132 are added to new Group 3 of this service bulletin effectivity. Terminology has been changed in the Work Instructions to agree with the terminology defined in Paragraph 3.A., General Information - Notes. These sections were changed: 1. Title changed to add primary section affected by this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 5 of 672. Summary Section: Updated Background and added new service history, summary planning table, fleet team digest reference and service related problem reference. 3. Summary Section - Updated Action with increased inspection areas, changed inspection methods and instructions for new airplanes. 4. Summary Section - Updated Effectivity, Industry Support Information, Manpower and Material Information sections. 5. Summary Section - Compliance: Added related FAA Airworthiness Directives. 6. Paragraph 1.C., Reason - added new service history, fleet team digest reference, service related problem reference, reason for revision and Notice of Status Change 1 reference. 7. Paragraph 1.D., Description - Added increased inspection areas, changed inspection methods and instructions for new airplanes. Added maintenance zone tables. 8. Paragraph 1.E., Compliance - Added related FAA Airworthiness Directives. Added new compliance tables 1, 2 and 3. 9. Paragraph 1.F., Approval - Added new approval paragraph and alternative methods of compliance for related FAA Airworthiness Directives. 10. Paragraph 1.G., Manpower - Updated manpower tables for Group 1 and 2. 11. Paragraph 1.J., References - Existing Data list is updated and new drawing is added to Data Supplied with this Service Bulletin. 12. Paragraph 1.K.2., Damage Tolerance Based Structural Inspections - Added new section. 13. Paragraph 1.L., Interchangeability and Intermixability of Parts - Added new section. 14. Paragraph 1.M., Software Accomplishment Summary - Added new section. 15. Paragraph 2.A., Material - Price and Availability - Updated prices for all kits. 16. Paragraph 2.B., Industry Support Information - Updated warranty information. 17. Paragraph 2.C., Parts Necessary for Each Airplane - Added kit tables. 18. Paragraph 3.A., General Information - Added new notes. 19. Paragraph 3.B., Work Instructions - Updated instructions for Group 1 and 2. Added new instructions for Group 3. 20. Figure 1 has been deleted. 21. Figures 2 and 3 have been added to show increased inspection areas and changed inspection methods. 22. Figures 4 and 5 have been added to show crack removal. The data given in Notice of Status Change 737-53-1163 NSC 1 related to inspections is not included in revision 1 of this service bulletin as the inspections have been replaced.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 6 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**The data given in Notice of Status Change 737-53-1163 NSC 1 related to kit prices is included in revision 1 of this service bulletin. 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** December 21, 1993 Original Issue: January 08, 2014 Revision 1:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 7 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 8 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **Number: 737-53A1163** Original Issue: December 21, 1993 Revision 1: January 08, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Forward Entry Doorway Skin Cutout - Upper Forward and Upper Aft Corners - Inspection, Modification, and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Seventeen operators have found cracks in the upper corners of the forward entry door skin cutout. The airplanes had collected from 33,150 to 76,242 flight cycles. The cause of the cracks is fatigue from cabin pressure. Continued operation with cracks in the doorway upper corners can result in cabin depressurization and unscheduled downtime for repairs. Installation of doublers as given in this service bulletin can prevent cracks at the doorway upper corners. Since the release of the original issue of this service bulletin there have been 3 reports of cracking at the forward entry doorway upper corners on airplanes that were outside the effectivity of the original issue of this service bulletin. The reports are listed below. **Service History Report**  **Cycles/Hours** 1 inch crack common to the bearstrap only found at the upper forward corner. 59804 / 69512 Crack in the skin only at the upper aft corner. 31238 / 37443 Crack in skin only at the upper forward corner. 38126 / 46173 Boeing Fleet Team Digest (FTD) 737 FTD 53-11003 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0381 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 9 of 67**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval Yes AD Related Paragraph 1.H., Weight and Balance Changes Yes Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts Yes Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator Yes Operator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

**ACTION Group 1-2, Configuration 1:**  Airplanes with the repair/preventive modification installed in accordance with the original issue of this SB are not required to be inspected in accordance with the SB. Post repair/preventive modification inspections are provided in the D6-38669 Repair Assessment Guidelines document. **Group 1-2, Configuration 2; Group 3:** Get access to the upper corners of the forward entry doorway. Do an external detailed inspection and a Low Frequency Eddy Current (LFEC) inspection of the skin assembly and bearstrap for any crack at the upper corners of the forward entry doorway. **Group 1-2, Configuration 2:** If any crack is found in the skin assembly and/or bearstrap, install a repair in accordance with this service bulletin. If no cracks are found, install the preventive modification or do repeat inspections at the times given in Paragraph 1.E., Compliance. **Group 3:** If any crack is found in the skin assembly and/or bearstrap, install a repair in accordance with this service bulletin and do repeat inspections of the area not covered by the repair at the times given in Paragraph 1.E., Compliance. If no cracks are found, install the preventive modification or do repeat inspections of the entire inspection area at the times given in Paragraph 1.E., Compliance. **Group 4:** On Group 4 airplanes, contact Boeing to get instructions for the inspection and/or repair for this service bulletin, 737-53A1163 Revision 1, and do the work instructed by Boeing. **EFFECTIVITY** All 737-100/-200/-200C/-300/-400/-500 Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s).

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 10 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT COMPLIANCE**  Federal Aviation Administration (FAA) Airworthiness Directives AD 98-11-04 R1, AD 2008-08-23 and AD 2008-09-13 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/preventive modification procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION Group 1-2, Configuration 1; Group 3-4:**  None. **Group 1-2, Configuration 2:** Boeing Supplied Kits/Parts. **Group 1-2, Configuration 2:** Refer to Paragraph 2.A., Material - Price and Availability.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 11 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 12 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-53A1163**  Original Issue: December 21, 1993 Revision 1: January 08, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Forward Entry Doorway Skin Cutout - Upper Forward and Upper Aft Corners - Inspection, Modification, and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes This service bulletin is for the airplane(s) shown below. Refer to Service Bulletin Index D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.
**DESCRIPTION CONFIGURATION**  **GROUP** 737-200/-300/-400/-500 series airplanes, line numbers 292-1922.

- 1 Airplanes that have accomplished the repair or preventive modification in accordance with the original issue of this service bulletin. 1
Airplanes that have not accomplished the repair or preventive modification in accordance with the original issue of this service bulletin. 2

737-200C series airplanes, line numbers 292-1113.

- 2 Airplanes that have accomplished the repair or preventive modification in accordance with the original issue of this service bulletin. 1
Airplanes that have not accomplished the repair or preventive modification in accordance with the original issue of this service bulletin. 2

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 13 of 67**DESCRIPTION CONFIGURATION**  **GROUP** 737-300/-400/-500 series airplanes, line numbers 1923-3132.

- 3 737-100/-200/-200C series airplanes, line numbers 1-291.

- 4

Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 **Group Variable Number** 4 PA001 - PA022 4 PA099 4 PA231 - PA232 4 PC001 - PC005 4 PG001 - PG075 4 PG199 4 PG201 - PG230 4 PG251 - PG255 4 PG271 - PG279 4 PG301 - PG314 4 PG331 - PG332 4 PG351 - PG356 4 PG375 4 PG401 - PG403 4 PG431 - PG442 4 PG471 - PG475 4 PG501 - PG505 4 PG571 - PG583 1 PG584 - PG586 4 PG621 - PG630 4 PG651 - PG652 4 PG701 - PG705 1 PH001 1 PH011 - PH013 1 PH021 - PH024

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 14 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**4 PH701 - PH715 4 PH731 - PH732 4 PH741 - PH742 1 PH743 4 PJ001 - PJ002 1 PJ003 - PJ009 4 PJ031 - PJ032 4 PJ071 - PJ072 4 PJ101 - PJ104 1 PJ105 - PJ119 1 PJ201 - PJ219 3 PJ301 - PJ302 3 PJ551 - PJ561 3 PJ601 - PJ615 3 PJ811 3 PJ816 - PJ817 1 PK026 - PK029 1 PK041 - PK053 1 PK061 - PK070 1 PK081 - PK082 1 PK091 - PK099 1 PK101 - PK103 1 PK111 - PK120 1 PK141 - PK146 1 PK201 - PK204 1 PK211 - PK223 1 PK231 - PK241 1 PK251 - PK258 1 PK271 - PK274 1 PK281 - PK289 1 PK291 1 PK301 - PK318 1 PK341

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 15 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PK351 - PK361 1 PK391 1 PK431 - PK433 1 PK451 - PK452 1 PK461 - PK469 1 PK495 1 PK501 - PK504 1 PK511 - PK515 1 PK519 1 PK521 - PK528 1 PK541 - PK565 1 PK581 1 PK591 - PK599 1 PK601 - PK617 1 PK621 - PK637 1 PK641 - PK642 1 PK661 - PK666 1 PK671 - PK681 1 PK691 - PK697 1 PK711 - PK716 1 PK731 - PK765 1 PK771 - PK779 1 PK801 - PK804 1 PK819 - PK827 1 PK830 1 PK861 - PK863 1 PK871 - PK874 1 PK881 - PK884 1 PK901 - PK938 1 PK971 - PK974 1 PL001 - PL028 1 PL061 1 PL081

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 16 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PL101 - PL113 1 PL151 1 PL171 - PL172 1 PL201 - PL203 1 PL221 1 PL401 - PL417 1 PL421 1 PL441 1 PL451 - PL456 1 PL471 1 PL491 1 PL501 - PL506 1 PL551 - PL562 1 PL581 1 PL601 - PL603 1 PL611 1 PL621 - PL626 1 PL631 - PL632 4 PL711 - PL712 4 PL716 1 PL717 - PL747 1 PL756 1 PL758 1 PL761 - PL770 1 PL781 - PL788 1 PL793 4 PL801 - PL803 1 PM001 - PM006 1 PM016 - PM017 1 PM021 - PM023 1 PM051 - PM066 1 PM101 - PM119 1 PM141 - PM142

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 17 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PM171 1 PM181 1 PM251 - PM255 1 PM281 - PM283 1 PM381 - PM392 3 PM393 - PM399 3 PM401 - PM417 3 PM541 - PM564 1 PN001 - PN002 1 PN021 - PN043 1 PN081 - PN086 1 PN101 - PN117 1 PN131 - PN163 1 PN401 - PN420 1 PN431 - PN433 1 PN451 - PN456 1 PN471 - PN474 1 PN481 1 PN491 - PN493 1 PN501 - PN502 1 PN511 - PN512 1 PN521 1 PP001 - PP054 1 PP101 - PP148 3 PP149 - PP160 1 PP161 - PP169 1 PP181 - PP199 1 PP201 - PP205 1 PP221 1 PP231 - PP243 1 PP281 - PP286 1 PP301 - PP305 1 PP351 - PP353

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 18 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PP376 - PP384 1 PP391 - PP393 1 PP401 - PP440 1 PP471 - PP475 1 PP501 - PP510 3 PP511 - PP520 1 PP521 - PP522 1 PP631 - PP634 1 PP651 - PP652 1 PP671 - PP699 1 PP701 - PP733 1 PP771 - PP779 1 PP801 - PP808 1 PP821 - PP827 1 PP831 - PP848 1 PP851 - PP852 1 PP861 - PP873 3 PP874 - PP877 1 PP891 - PP899 1 PP901 - PP924 3 PP925 - PP930 1 PP931 - PP936 1 PP946 - PP948 1 PP951 - PP952 1 PP961 - PP967 1 PP981 - PP987 3 PP988 - PP990 1 PP991 1 PP993 1 PQ001 - PQ016 1 PQ026 - PQ041 1 PQ051 - PQ073 3 PQ074 - PQ085

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 19 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PQ086 - PQ092 1 PQ101 - PQ198 3 PQ199 3 PQ201 - PQ202 1 PQ221 - PQ229 3 PQ230 1 PQ231 - PQ236 3 PQ237 1 PQ241 - PQ243 1 PQ251 - PQ255 3 PQ256 - PQ267 1 PQ281 - PQ286 3 PQ287 - PQ299 1 PQ301 - PQ305 3 PQ306 - PQ307 1 PQ331 - PQ332 3 PQ341 - PQ348 3 PQ361 - PQ373 3 PQ391 - PQ395 3 PQ401 - PQ418 3 PQ421 3 PQ431 - PQ438 3 PQ447 - PQ448 3 PQ451 3 PQ454 3 PQ471 - PQ475 3 PQ479 - PQ481 3 PQ486 - PQ487 3 PQ491 - PQ493 3 PQ771 - PQ772 3 PQ791 - PQ793 3 PQ801 - PQ805 3 PQ931 - PQ935

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 20 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**3 PQ951 3 PQ971 - PQ997 3 PR001 - PR017 3 PR021 - PR034 3 PR041 - PR045 3 PR061 - PR072 3 PR077 - PR082 3 PR091 - PR092 3 PR096 3 PR101 3 PR121 - PR122 3 PR131 - PR132 3 PR141 - PR143 3 PR161 - PR172 3 PR181 3 PS601 - PS631 3 PS636 - PS638 1 PS641 - PS642 3 PS643 - PS644 3 PS651 - PS657 1 PS666 - PS668 3 PS669 3 PS691 - PS692 3 PS701 - PS706 3 PS751 - PS799 3 PS811 3 PS836 - PS837 3 PS841 - PS846 3 PS851 - PS852 3 PS856 3 PS861 - PS863 3 PS866 - PS868 3 PS871 - PS874

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 21 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**3 PS896 - PS897 3 PS901 - PS941 3 PS956 - PS957 3 PS961 - PS963 3 PS971 - PS978 3 PT001 - PT015 1 PT021 - PT023 3 PT024 - PT031 3 PT041 - PT064 1 PT101 3 PT102 - PT105 1 PT121 - PT123 3 PT124 - PT138 1 PT146 3 PT147 - PT148 3 PT161 - PT170 1 PT181 - PT182 3 PT183 - PT188 1 PT211 - PT214 3 PT215 - PT220 1 PT295 3 PT301 - PT309 3 PT331 - PT360 3 PT381 - PT399 3 PT401 - PT438 3 PT501 - PT517 3 PT561 - PT565 3 PT581 - PT586 3 PT611 - PT621 3 PT641 - PT644 3 PT651 - PT656 3 PT671 - PT672 3 PT681 - PT685

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 22 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**3 PT701 - PT703 3 PT716 - PT717 3 PT721 - PT725 3 PT801 - PT834 3 PT851 - PT854 3 PT871 - PT886 3 PT901 - PT930 3 PT971 - PT973 3 PT981 - PT985 3 PT996 1 PU001 - PU007 3 PU008 - PU025 3 PU301 3 PU311 - PU313 1 PV001 - PV040 3 PV041 - PV055 3 PV201 - PV209 3 PV226 - PV229 3 PV231 - PV237 3 PV271 - PV272 3 PV281 - PV287 3 PV296 3 PV301 - PV302 3 PV351 3 PV356 - PV357 1 PW001 - PW036 3 PW037 - PW050 1 PW051 3 PW052 - PW054 1 PW061 - PW063 3 PW064 - PW068 3 PW072 3 PW086 - PW088

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 23 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**1 PW091 - PW093 3 PW094 3 PW101 - PW102 3 PW106 1 PW111 - PW117 3 PW118 - PW120 3 PW156 - PW157 1 PW161 - PW162 3 PW163 - PW171 3 PW201 - PW252 3 PW261 - PW268 3 PW271 - PW276 3 PW278 3 PW281 - PW293 3 PW296 3 PW301 - PW327 3 PW401 - PW408 3 PW411 - PW418 3 PW421 - PW424 3 PW431 - PW435 3 PW441 - PW450 3 PW461 - PW467 1 PW501 - PW503 3 PW504 1 PW511 - PW518 3 PW519 - PW522 3 PW524 - PW530 1 PW531 - PW535 3 PW536 - PW550 3 PW556 - PW557 1 PW561 - PW563 3 PW564 1 PW571 - PW573

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 24 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**3 PW574 - PW576 1 PW591 - PW594 3 PW595 - PW596 1 PW611 - PW615 3 PW616 - PW622 1 PW631 - PW632 3 PW633 - PW637 1 PW661 3 PW662 3 PW681 - PW683 3 PW701 - PW702 3 PW711 - PW717 3 PW741 - PW742 3 PW761 3 PW771 3 PW831 3 PW851 - PW856 4 PX071 4 PX701 4 PY001 - PY008 4 PY021 2 PY022 4 PY031 2 PY036 - PY037 2 PY046 - PY048 2 PY051 - PY053 2 PY056 - PY057 2 PY101 - PY103 2 PY111 - PY113 2 PY131 - PY135 2 PY141 - PY143 2 PY151 - PY154 2 PY156 - PY157

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 25 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group**  **Variable Number**2 PY161 - PY162 2 PY166 2 PY191 2 PY201 2 PY221 - PY222 2 PY231 2 PY241 - PY244 2 PY270 - PY275 2 PY281 2 PY286 4 PY301 - PY304 4 PY321 - PY323 4 PY341 - PY346 4 PY361 - PY362 4 PY381 2 PY401 2 PY409 - PY411 2 PY421 - PY422 2 PY441 2 PY451 2 PY461 - PY463 2 PY591 - PY595 2 PY611 - PY612 2 PY621 2 PY631 2 PY651 2 PY671 - PY672 2 PY721 2 PY741 2. Spares Affected None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 26 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT B. Concurrent Requirements**  None. **C. Reason** Seventeen operators have found cracks in the upper corners of the skin at the forward entry doorway. The airplanes had collected from 33,150 to 76,242 flight cycles. The cause of the cracks is fatigue from cabin pressure loads. Continued operation with cracks in the doorway upper corners can result in cabin depressurization and unscheduled downtime for repairs. Installation of doublers as given in this service bulletin can prevent cracks at the doorway corners. Since the release of the original issue of this service bulletin there have been 3 reports of cracking at the forward entry doorway upper corners on airplanes that were outside the effectivity of the original issue of this service bulletin. The reports are listed below. **Service History Report**  **Cycles/Hours** 1 inch crack common to the bearstrap only found at the upper forward corner. 59804 / 69512 Crack in the skin only at the upper aft corner. 31238 / 37443 Crack in skin only at the upper forward corner. 38126 / 46173 Boeing Fleet Team Digest (FTD) 737 FTD 53-11003 is related to this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0381 is related to this service bulletin. Terminology has been changed in the Work Instructions to agree with the terminology defined in Paragraph 3.A., General Information - Notes. Revision 1 is sent to add new airplanes to the service bulletin effectivity. Revision 1 is also sent to increase the inspection area, to remove internal inspection and to change external inspection methods for group 1 and 2. The data given in Notice of Status Change 737-53-1163 NSC 1 related to inspections is not included in revision 1 of this service bulletin as the inspections have been replaced. The data given in Notice of Status Change 737-53-1163 NSC 1 related to kit prices is included in revision 1 of this service bulletin. **D. Description Group 1-2, Configuration 1:**  Airplanes with the repair/preventive modification installed in accordance with the original issue of this SB are not required to be inspected in accordance with the SB. Post repair/preventive modification 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: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 27 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1-2, Configuration 2; Group 3:**  Get access to the upper corners of the forward entry doorway. Do an external detailed inspection and a Low Frequency Eddy Current (LFEC) inspection of the skin assembly and bearstrap for any crack at the upper corners of the forward entry doorway. **Group 1-2, Configuration 2:** If any crack is found in the skin assembly and/or bearstrap, install a repair in accordance with this service bulletin. If no cracks are found, install the preventive modification or do repeat inspections at the times given in Paragraph 1.E., Compliance. **Group 3:** If any crack is found in the skin assembly and/or bearstrap, install a repair in accordance with this service bulletin and do repeat inspections of the area not covered by the repair at the times given in Paragraph 1.E., Compliance. If no cracks are found, install the preventive modification or do repeat inspections of the entire inspection area at the times given in Paragraph 1.E., Compliance. **Group 4:** On Group 4 airplanes, contact Boeing to get instructions for the inspection and/or repair for this service bulletin, 737-53A1163 Revision 1, and do the work instructed by Boeing. Revision 1 - More work is necessary on airplanes that have not installed the repair or preventive modification in accordance with the original issue of this service bulletin. Inspection areas are increased and inspections methods are changed. No more work is necessary on the airplanes that have installed the repair or preventive modification in accordance with the original issue of this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 1-3, 1-5, 1-7 737-200 **Group 1, 3:**
**Affected Maintenance Zones Zone**  **Model** 103, 105, 107 737-300, 737-400, 737-500 **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 1-3, 1-5, 1-7 737-200C

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 28 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 4:** 
**Affected Maintenance Zones Zone**  **Model** 1-3, 1-5, 1-7 737-100, 737-200, 737-200C **E. Compliance** Federal Aviation Administration (FAA) Airworthiness Directives AD 98-11-04 R1, AD 2008-08-23 and AD 2008-09-13 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. **Group 4:** On Group 4 airplanes, contact Boeing to get instructions for the inspection and/or repair for this service bulletin, 737-53A1163 Revision 1, and do the work instructed by Boeing, within 120 days of the issue date of Revision 1 to this service bulletin. **Group 1-2, Configuration 1:** Airplanes with the repair/preventive modification installed in accordance with the original issue of this SB are not required to be inspected in accordance with the SB. Post repair/preventive modification inspections are provided in Table 3 of Paragraph 1.E., Compliance. **Group 1-2, Configuration 2: Table 1: Inspection of Fuselage Skin Assembly and Bearstrap at the Forward Entry Doorway Upper**  **Corners Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition** 4,500 Flight Cycles (a) (b) Within 4,500Flight Cycles after the Revision 1 date of this service bulletin Before 27,000Total Flight Cycles Do an external detailedinspection of the skin assembly and a Low Frequency Eddy Current (LFEC) inspection of the skin assembly and bearstrap for any crack inaccordance with Paragraph 3.B., Work Instructions, PART 1 - Inspection. All airplanes

- Before further flight. Install the repair in accor- dance with Paragraph 3.B., Work Instructions, PART 3 - Repair. If any crack is found in the skin assembly or bearstrap.
(b)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 29 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1-2, Configuration 2:**  **Table 1: Inspection of Fuselage Skin Assembly and Bearstrap at the Forward Entry Doorway Upper Corners**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  (a) Accomplishment of the preventive modification in accordance with Original issue or Revision 1 of this service bulletin terminates the inspection of Table 1. Post preventive modification inspection are provided in Table 3 of Paragraph 1.E., Compliance. (b) Accomplishment of the repair in accordance with the Original issue or Revision 1 of this service bulletin terminates the inspection of Table 1. Post repair inspection are provided in Table 3 of Paragraph 1.E., Compliance. **Group 3: Table 2: Inspection of Fuselage Skin Assembly and Bearstrap at the Forward Entry Doorway Upper**  **Corners Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition** 4,500 Flight Cycles (a) (b) Within 4,500Flight Cycles after the Revision 1 date of this service bulletin. Before 27,000Total Flight Cycles Do an external detailedinspection of the skin assembly and a LFEC inspection of the skin assembly and bearstrap for any crack in accordance with Paragraph 3.B., Work Instructions, PART 1 - Inspection. All Airplanes

- Before further flight. Install a repair in accor- dance with Paragraph 3.B., Work Instructions, PART 3 - Repair. (b) If any crack is found in the skin assembly or bearstrap.

(a) Accomplishment of the preventive modification in accordance with Revision 1 of this Service Bulletinterminates the inspection of Table 2. Post preventive modification inspections are provided in the applicable SRM.(b) Accomplishment of the repair in accordance with Revision 1 of this Service Bulletin terminates the inspection of Table 2 in the repaired area. If a repair is only installed on one corner, inspections in the area not repaired are still required in accordance with Table 2. Post repair inspections are provided in the applicable SRM.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 30 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1-2:**  **Table 3: Inspection of Fuselage Skin Assembly and Bearstrap For Airplanes With a Repair or Preventive Modification Installed**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  Repeat the inspection at interval in accordance with RAG. Within 12,000flight cycles after repair has been installed Before 60,000 total flight cyclesDo the inspection in accordance with D6-38669, Repair Assessment Guidelines-Model 737- 100 to -500.Airplanes that have installed the repair or preventive modification in accordance with the Original Issue or Revision 1 of this Service Bulletin. **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. For Boeing 737-200 series airplanes, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the supplemental inspection methods, thresholds and repeat intervals as given in Table 3 of Paragraph 1.E., Compliance for the repair or preventive modification defined in Table 1 of Paragraph 1.E., Compliance, of Revision 1 of this service bulletin as a method of compliance (MOC) to paragraph (g) of AD 98-11-04 R1 for the inspections of Structurally Significant Items (SSI) F-13A and F-14A. This approval applies to these SSIs and only for the portions of the skin and bear strap 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. For Boeing 737-200C series airplanes, the Manager of the FAA Seattle ACO approves the inspection methods, thresholds and repeat intervals as given in Table 3 of Paragraph 1.E., Compliance for the repair or preventive modification defined in Table 1 of Paragraph 1.E., Compliance, of Revision 1 of this service bulletin as an alternative method of compliance (AMOC) to the inspections of SSIs F-13A and F-14A, required by paragraphs (g) and (h) of AD 2008-08-23. This approval applies to these SSIs and only for the portions of the skin and bear strap that have been repaired in accordance with this SB. 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 31 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**For Boeing 737-300/-400/-500 series airplanes identified as Group 1 airplanes, the Manager of the FAA Seattle ACO approves the inspection methods, thresholds and repeat intervals as given in Table 3 of Paragraph 1.E., Compliance for the repair or preventive modification defined in Table 1 of Paragraph 1.E., Compliance, of Revision 1 of this service bulletin as an AMOC to the inspections of SSIs F-13A and F-14A, required by paragraphs (g) and (h) of AD 2008-09-13. This approval applies to these SSIs and only for the portions of the skin and bear strap that have been repaired or modified in accordance with this SB. 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. **G. Manpower** The table below shows an estimate of the task hours necessary to do this change for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Group 1, Configuration 2: Elapsed Hours**  **Task Hours Number of Persons**  **Task** 3.00 3.00 1 FIGURE 2 2.75 5.50 2 FIGURE 4 1.00 1.00 (a) 1 Open Access 30.00 (a) 60.00 (a) 2 Repair (a) 22.00 (a) 44.00 (a) 2 Preventive Modification (a) 1.00 1.00 (a) 1 Close Access 5.75 8.50 TOTAL FOR EACH AIRPLANE (a) The Repair and Preventive Modification estimates are not included in the total estimates. **Group 2, Configuration 2: Elapsed Hours**  **Task Hours Number of Persons**  **Task** 3.00 3.00 1 FIGURE 3 2.75 5.50 2 FIGURE 5 1.00 1.00 (a) 1 Open Access 30.00 (a) 60.00 (a) 2 Repair (a) 22.00 (a) 44.00 (a) 2 Preventive Modification (a)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 32 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 2, Configuration 2:**  **Elapsed Hours Task Hours**  **Number of Persons Task**  1.00 (a) 1.00 (a) 1 Close Access 5.75 8.50 TOTAL FOR EACH AIRPLANE (a) The Repair and Preventive Modification estimates are not included in the total estimates. **Group 3: Elapsed Hours**  **Task Hours Number of Persons**  **Task** 3.00 3.00 1 FIGURE 2 **H. Weight and Balance Changes Group 1, Configuration 2:**  **Change in Moment (Pound-Inches) Change in**  **Weight (Pounds)**  **Kit 737-500**  **737-400 737-300**  **737-200 737-100**  + 1177.8 + 686.4 + 967.2 + 1138.8 + 1279.2 + 3.9 65C36941-1 + 1751.6 + 1020.8 + 1438.4 + 1693.6 + 1902.4 + 5.8 65C36941-5 + 3050.2 + 1777.6 + 2504.8 + 2949.2 + 3312.8 + 10.1 65C36941-7 **Group 2, Configuration 2: 737-200C Model Series Airplanes**  **Change in Moment (Pound-Inches)**  **Change in Weight (Pounds)**  **Kit** + 1635.2 + 5.6 65C36941-13 + 2219.2 + 7.6 65C36941-15 + 3095.2 + 10.6 65C36941-17 **Group 1-2, Configuration 1; Group 3-4:** None. **I. Electrical Load Data** Not applicable. **J. References** 1. Existing Data: a. Boeing Service Letter 737-SL-51-042.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 33 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**b. Boeing Service Related Problem (SRP) 737-SRP-53-0381. c. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2008-08-23, 2008-09-13, 98-11-04 R1. d. Service Bulletin Index D6-19567. e. D6-38669 Repair Assessment Guidelines (RAG) -Model 737-100 to -500. f. Standard Overhaul Practices Manual (SOPM) 20-41-02, 20-43-03, 20-50-19. g. 737 Fleet Team Digest (FTD) 53-11003. h. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Part 6, 51-00-26, Part 6, 53-30-00. i. 737-100/200 Aircraft Maintenance Manual (AMM) 25-21-31, 25-21-41. j. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-21-31. k. 737-100/200 Structural Repair Manual (SRM) 51-30-08 l. 737-300 Structural Repair Manual (SRM) 51-40-08, 53-10-01. m. 737-400 Structural Repair Manual (SRM) 51-40-08, 53-10-01. n. 737-500 Structural Repair Manual (SRM) 51-40-08, 53-10-01. 2. Data Supplied with this Service Bulletin: a. Drawings:
**ADCN DCN/REV**  **Sheet Title**  **Drawing No**

- - 1 Repair and Preventive Modification, Upper Forward Entry Doorway - Kit 65C36941

- - 2 1, 2

- PL

- A PSDL 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. Boeing Process Specifications referred to on drawings are not given in this service bulletin since these procedures are frequently used as standard shop practices. **K. Publications Affected** 1. Publications: None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 34 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 35 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 36 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  **Group 1-2, Configuration 1; Group 3-4:** None. **Group 1-2, Configuration 2:** Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. **Group 1-2, Configuration 2:** Reference this service bulletin and submit your purchase order by one of these methods: **Group 1-2, Configuration 2:** 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **Group 1-2, Configuration 2: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER**  **AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION**
**Unit Price as of the Revision 1** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** 

**vice Bulletin (Weeks)**  **Name Kit Number** 

$2222.00 25 Kit - Preventive Modification 65C36941-1 $2527.00 25 Kit - Repair 65C36941-5 $4573.00 25 Kit - Repair 65C36941-7 $3912.00 25 Kit - Preventive Modification 65C36941-13 $4103.00 25 Kit - Repair 65C36941-15 $4964.00 25 Kit - Repair 65C36941-17 **B. Industry Support Information** Boeing warranty remedies are not available for the inspection, and/or repair/preventive modification procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts **Group 1-2, Configuration 1; Group 3-4:** None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 37 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1-2, Configuration 2:**  To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **Group 1-2, Configuration 2: NOTE:** One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. **Group 1, Configuration 2: Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification** **Notes Name**  **QTY Part Number**  **-7 -5**  **-1** PREVENTIVE MODIFICATION REPAIR INSTL

. . - 65C36941-1 (a) REPAIR INSTL

. - . 65C36941-5 (b) REPAIR INSTL

- . . 65C36941-7 (c) STOCK DOUBLER

. 1 1 65C36941-2 (c) DOUBLER

. 1 1 65C36941-3 (d) STOCK TRIPLER

. 1

. 65C36941-4 (d) TRIPLER

. 1

. 65C36941-6 (e) STOCK DOUBLER 1

. . 65C36941-8 (e) DOUBLER 1

. . 65C36941-9 (f) STOCK TRIPLER 1

. . 65C36941-10 (f) TRIPLER 1

. . 65C36941-11 (g) WASHER, REPAIR 250 250 250 66-2955-40 (g) WASHER, REPAIR 5 5 5 66-2955-41 (g) WASHER, REPAIR 50 50 50 66-2955-47 (g) (h) HI-LOK, 3/16 DIA 14 3 6 BACB30NW6K10X (g) (h) HI-LOK, 3/16 DIA

. 4

. BACB30NW6K11X (g) (h) HI-LOK, 3/16 DIA 3

. . BACB30NW6K13X (g) (h) HI-LOK, 3/16 DIA 3 3 3 BACB30NW6K3X (g) (h) HI-LOK, 3/16 DIA 3 42 76 BACB30NW6K4X (g) (h) HI-LOK, 3/16 DIA 50 57 50 BACB30NW6K5X (g) (h) HI-LOK, 3/16 DIA 12 35 40 BACB30NW6K6X (g) (h) HI-LOK, 3/16 DIA 34 60 34 BACB30NW6K7X (g) (h) HI-LOK, 3/16 DIA 54 14 3 BACB30NW6K8X (g) (h) HI-LOK, 3/16 DIA 40

. . BACB30NW6K9X (g) (h) HI-LOK, 1/4 DIA 5 5 5 BACB30NW8K8X

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 38 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1, Configuration 2:**  **Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification Notes**  **Name QTY**  **Part Number -7**  **-5 -1**  (g) (h) HI-LOK, 3/16 DIA

. 5 6 BACB30VU6K2 (g) (h) HI-LOK, 3/16 DIA 62 58 58 BACB30VU6K3 (g) (h) HI-LOK, 3/16 DIA

. 28 54 BACB30VU6K4 (g) (h) HI-LOK, 3/16 DIA 28 20 3 BACB30VU6K5 (g) (h) HI-LOK, 3/16 DIA 2 2

. BACB30VU6K6 (g) (h) HI-LOK, 3/16 DIA 20

. . BACB30VU6K7 (g) COLLAR 114 114 114 BACC30BL6 (g) COLLAR 220 220 220 BACC30M6 (g) COLLAR 5 5 5 BACC30M8 FILLER 1 1 1 BACF3F010J175NN FILLER 1 1

. BACF3F010J225NN (g) (h) RIVET 2

. . BACR15BB4D10 (g) (h) RIVET

. . 3 BACR15BB4D5 (g) (h) RIVET

. 3 2 BACR15BB4D6 (g) (h) RIVET

. 2

. BACR15BB4D8 (g) (h) RIVET 3

. . BACR15BB4D9 (g) (h) RIVET 4

. . BACR15BB5D11 (g) (h) RIVET

. . 2 BACR15BB5D5 (g) (h) RIVET

. 2 4 BACR15BB5D7 (g) (h) RIVET 2 4

. BACR15CE5D9 (g) (h) RIVET

. 3

. BACR15CE6D10 (g) (h) RIVET 34

. . BACR15CE6D11 (g) (h) RIVET 3

. . BACR15CE6D12 (g) (h) RIVET

. 4 33 BACR15CE6D7 (g) (h) RIVET 10 36 9 BACR15CE6D8 (g) (h) RIVET

. 4 3 BACR15CE6D9 (i) WASHER 50 50 50 BACW10BN3AP (i) WASHER 100 100 100 BACW10BN31AP (i) WASHER 10 10 10 BACW10BN41AP (a) For repair use if crack is in skin assembly but there are no cracks in the bearstrap.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 39 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1, Configuration 2:**  **Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification Notes**  **Name QTY**  **Part Number -7**  **-5 -1**  (b) For repair use if crack is in skin assembly and bearstrap. (c) 65C36941-2 is used to make 65C36941-3. (d) 65C36941-4 is used to make 65C36941-6. (e) 65C36941-8 is used to make 65C36941-9. (f) 65C36941-10 is used to make 65C36941-11. (g) There are more parts than are necessary. (h) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. (i) Use if required to bring material thickness within bolt grip range. Maximum of (2) washers allowed. **Group 2, Configuration 2: Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification** **Notes Name**  **QTY Part Number**  **-17 -15**  **-13** PREVENTIVE MODIFICATION REPAIR INSTL

. . - 65C36941-13 (a) REPAIR INSTL

. - . 65C36941-15 (b) REPAIR INSTL

- . . 65C36941-17 (c) STOCK DOUBLER 1 1 1 65C36941-8 (c) DOUBLER 1 1 1 65C36941-14 (d) STOCK TRIPLER

. 1

. 65C36941-4 (d) TRIPLER

. 1

. 65C36941-16 (e) TRIPLER 1

. . 65C36941-18 (e) STOCK TRIPLER 1

. . 65C36941-10 (f) WASHER, REPAIR 10 10 10 66-2955-11 (f) WASHER, REPAIR 250 250 250 66-2955-40 (f) WASHER, REPAIR 20 20 20 66-2955-41 (f) WASHER, REPAIR 50 50 50 66-2955-47 (f) (g) HI-LOK, 3/16 DIA 12 8 16 BACB30NW6K10X (f) (g) HI-LOK, 3/16 DIA 14 12 4 BACB30NW6K11X

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 40 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 2, Configuration 2:**  **Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification Notes**  **Name QTY**  **Part Number -17**  **-15 -13**  (f) (g) HI-LOK, 3/16 DIA 8

. . BACB30NW6K12X (f) (g) HI-LOK, 3/16 DIA 3 3 3 BACB30NW6K4X (f) (g) HI-LOK, 3/16 DIA 22 22 50 BACB30NW6K5X (f) (g) HI-LOK, 3/16 DIA 20 48 66 BACB30NW6K6X (f) (g) HI-LOK, 3/16 DIA 62 108 90 BACB30NW6K7X (f) (g) HI-LOK, 3/16 DIA 63 34 17 BACB30NW6K8X (f) (g) HI-LOK, 3/16 DIA 47 14 4 BACB30NW6K9X (f) (g) HI-LOK, 1/4 DIA 9 9 9 BACB30NW8K7X (f) (g) HI-LOK, 1/4 DIA 4 4 4 BACB30NW8K8X (f) (g) HI-LOK, 1/4 DIA 3 3 3 BACB30NW8K9X (f) (g) HI-LOK, 3/16 DIA 21 22 24 BACB30VU6K3 (f) (g) HI-LOK, 3/16 DIA 16 18 16 BACB30VU6K4 (f) (g) HI-LOK, 3/16 DIA 30 29 38 BACB30VU6K5 (f) (g) HI-LOK, 3/16 DIA 4 12 3 BACB30VU6K6 (f) (g) HI-LOK, 3/16 DIA 2 2 2 BACB30VU6K7 (f) (g) HI-LOK, 3/16 DIA 10

. . BACB30VU6K8 (f) COLLAR 84 84 84 BACC30BL6 (f) COLLAR 250 250 250 BACC30M6 (f) COLLAR 16 16 16 BACC30M8 FILLER 1 1 1 BACF3F010M175NN FILLER

. 1

. BACF3F010J225NN FILLER 1

. . BACF3F010V225NN (f) (g) RIVET 2

. . BACR15BB4D11 (f) (g) RIVET

. . 3 BACR15BB4D6 (f) (g) RIVET 3

. BACR15BB4D7 (f) (g) RIVET

. . 2 BACR15BB4D8 (f) (g) RIVET 3 2

. BACR15BB4D9 (f) (g) RIVET 5

. . BACR15BB5D11 (f) (g) RIVET 5 BACR15BB5D8 (f) (g) RIVET 5

. BACR15BB5D9

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 41 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 2, Configuration 2:**  **Kit 65C36941 Upper Forward Entry Doorway - Repair and Preventive Modification Notes**  **Name QTY**  **Part Number -17**  **-15 -13**  (f) (g) RIVET

. 3

. BACR15CE6D10 (f) (g) RIVET 32

. . BACR15CE6D11 (f) (g) RIVET 7 7 36 BACR15CE6D8 (f) (g) RIVET

. 29 3 BACR15CE6D9 (f) (g) RIVET 6 7 9 BACR15DS7D10 (f) (g) RIVET 2 4

. BACR15DS7D11 (f) (g) RIVET 4

. . BACR15DS7D13 (f) (g) RIVET

. . 2 BACR15DS7D9 (h) WASHER 50 50 50 BACW10BN3AP (h) WASHER 100 100 100 BACW10BN31AP (h) WASHER 10 10 10 BACW10BN41AP (a) For repair use if crack is in skin assembly but there are no cracks in the bearstrap. (b) For repair use if crack is in skin assembly and bearstrap. (c) 65C36941-8 is used to make 65C36941-14. (d) 65C36941-4 is used to make 65C36941-16. (e) 65C36941-10 is used to make 65C36941-18. (f) There are more parts than are necessary. (g) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. (h) Use if required to bring material thickness within bolt grip range. Maximum of (2) washers allowed. 2. Parts and Materials Supplied by the Operator **Group 1-2, Configuration 1; Group 4:** None. **Group 1-2, Configuration 2:** The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 42 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT Group 1-2, Configuration 2:** 
**Notes Name**  **QTY Part Number /**  **Specification** (a) Sealant 8 Oz BMS 5-95, Class B-1/2, -2 or -4 (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. **Group 3:** No special parts or materials are necessary to do the change in this service bulletin. But, parts and materials in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available. 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: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 43 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 44 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:**KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. Refer to 737-100/200 SRM 51-30-08, or 737-300 SRM 51-40-08, or 737-400 SRM 51-40-08, or 737-500 SRM 51-40-08 for countersink instructions and instructions on how to install countersink repair washers. 6. Refer to the SOPM 20-50-11 for application of aerodynamic smoother. 7. 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. 8. 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. 9. 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 45 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**10. 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. 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. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-' (dash) part number. Boeing Drawing 005W0900 contains more data. 14. Shaded areas in Figures are reference only. Shaded areas in Figures may look different than your airplane. **B. WORK INSTRUCTIONS**
1.**Group 4:** Contact Boeing to get instructions for the inspection and/or repair for this service bulletin, 737-53A1163 Revision 1, and do the work instructed by Boeing. 2.**Group 1-2, Configuration 1:** Airplanes with the repair or preventive modification installed in accordance with the original issue of this SB are not required to be inspected in accordance with the SB. Post repair/preventive modification inspections are provided in Table 3 of Paragraph 1.E., Compliance. 3.**Group 1-2, Configuration 2; Group 3:** Do Parts 1, 2 and 3 as applicable. Refer to Paragraph 1.E., Compliance.
4.**Group 1-3:** For door corners that have a repair provided by Boeing and approved via FAA Form 8100-9 installed, the inspection in this SB is not required for the repaired door corner(s). Refer to the repair approval for any supplemental inspection of the repair area. **Group 1-2, Configuration 2; Group 3: PART 1 - INSPECTION**  1. Get external access to the upper corners of the forward entry doorway.
2.**Group 1, Configuration 2; Group 3:** Do an external detailed inspection of the skin assembly and a Low Frequency Eddy Current (LFEC) inspection of the skin assembly and bearstrap for any crack in accordance with FIGURE 2. a. If any crack is found, do Part 3 - Repair. b. If no cracks are found, do Part 2 - Preventive Modification or do repeat inspections at the times given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 46 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**3.**Group 2, Configuration 2:** Do an external detailed inspection of the skin assembly and a LFEC inspection of the skin assembly and bearstrap for any crack in accordance with FIGURE 3. a. If any crack is found, do Part 3 - Repair. b. If no cracks are found, do Part 2 - Preventive Modification or do repeat inspections at the times given in Paragraph 1.E., Compliance. 4. Put the airplane back to a serviceable condition. **Group 1-2, Configuration 2; Group 3: PART 2 - PREVENTIVE MODIFICATION**  1. Get access to the passenger cabin side of the forward entry doorway upper corners by removing the sidewall lining panels. Refer to 737-100/200 AMM 25-21-41 and 737-100/200 AMM 25-21-31 or 737-300/400/500 AMM 25-21-31 as an accepted procedure.
2.**Group 1, Configuration 2:** Install the preventive modification (Kit 65C36941-1) in accordance with 65C36941 Sheet 1 and Sheet PSDL and general repair notes given below. – Remove all fasteners common to the preventive modification area. At all open holes common to the preventive modification area, do fastener hole probe inspection in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 16. – Make sure that all repair parts and machine surfaces have a minimum of 63 RMS finish or better. This requirement supersedes the 125 RMS for all machine surfaces of 65C36941 PSDL, General Note 1. – Maintain a minimum 2D edge margin on all repair parts except for repair filler. Maintain a minimum 1.5D edge margin on fillers. – Install all rivets dry and over-driven to a minimum of 1.4D driven head. Install all hex-drive bolts wet with BMS 5-95 sealant in transition fit holes. – Prior to clamp up, shim all gaps greater than 0.01 inches up to a maximum of 0.04 inches. Contact Boeing for any gap greater than 0.04 inches. – Install all parts wet with faying surface seal BMS 5-95 sealant. Refer to SOPM 20-50-19 as an acceptable procedure. **NOTE:**Accomplishment of the preventive modification in accordance with the above noted repair terminates the inspection requirements in Table 1 of Paragraph 1.E., Compliance. Post preventive modification inspections are provided in Table 3 of Paragraph 1.E., Compliance. 3.**Group 2, Configuration 2:** Install the preventive modification (Kit 65C36941-13) in accordance with 65C36941 Sheet 2 and Sheet PSDL and general repair notes given below. – Remove all fasteners common to the preventive modification area. At all open holes common to the preventive modification area, do fastener hole probe inspection in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 16. – Make sure that all repair parts and machine surfaces have a minimum of 63 RMS finish or better. This requirement supersedes the 125 RMS for all machine surfaces of 65C36941 PSDL, General Note 1. – Maintain a minimum 2D edge margin on all repair parts except for repair filler. Maintain a minimum 1.5D edge margin on fillers.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 47 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**– Install all rivets dry and over-driven to a minimum of 1.4D driven head. Install all hex-drive bolts wet with BMS 5-95 sealant in transition fit holes. – Prior to clamp up, shim all gaps greater than 0.01 inches up to a maximum of 0.04 inches. Contact Boeing for any gap greater than 0.04 inches. – Install all parts wet with faying surface seal BMS 5-95 sealant. Refer to SOPM 20-50-19 as an acceptable procedure. **NOTE:**Accomplishment of the preventive modification in accordance with the above noted repair terminates the inspection requirements in Table 3 of Paragraph 1.E., Compliance. Post preventive modification inspections are provided in Table 3 of Paragraph 1.E., Compliance.
4.**Group 3:** Install the preventive modification in accordance with 737-300 SRM 53-10-01 Repair 22, or 737-400 SRM 53-10-01 Repair 22, or 737-500 SRM 53-10-01 Repair 22. **NOTE:**Accomplishment of the preventive modification in accordance with the above noted repair terminates the inspection requirements of this service bulletin. Post preventive modification inspections are provided in the applicable SRM. 5. Install the forward entry doorway sidewall lining panels that were removed. Refer to 737-100/200 AMM 25-21-41 and 737-100/200 AMM 25-21-31 or 737-300/400/500 AMM 25-21-31 as an accepted procedure. 6. Put the airplane back to a serviceable condition. **Group 1-2, Configuration 2; Group 3: PART 3 - REPAIR**  1. Get access to the passenger cabin side of the forward entry doorway upper corners by removing the sidewall lining panels. Refer to 737-100/200 AMM 25-21-41 and 737-100/200 AMM 25-21-31 or 737-300/400/500 AMM 25-21-31 as an accepted procedure.
2.**Group 1, Configuration 2:** Do as follows: a. Cut out all cracks found in accordance with FIGURE 4. **NOTE:**Stop drill to terminate a crack is no longer an accepted procedure. b. Remove all the fasteners common to the repair area. At all open fastener holes common to the repair area, do an HFEC hole probe inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 16. If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. c. If any crack is found outside the maximum cutout area or if the cutout area is larger than then maximum cutout area allowed, contact Boeing for instructions and do the work instructed by Boeing. d. If cutout in only in the skin assembly but not in the bearstrap, install the repair (Kit 65C36941-5) in accordance with 65C36941 Sheet 1 and Sheet PSDL and general notes below. e. If cutout is in the skin assembly and the bearstrap, install the repair (Kit 65C36941-7) in accordance with 65C36941 Sheet 1 and Sheet PSDL and general notes below.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 48 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**f. General repair notes: – Make sure that all repair parts and machine surfaces have a minimum of 63 RMS finish or better. This requirement supersedes the 125 RMS for all machine surfaces of 65C36941 PSDL, General Note 1. – Maintain a minimum 2D edge margin on all repair parts except for repair filler. Maintain a minimum 1.5D edge margin on fillers. – Install all rivets dry and over-driven to a minimum of 1.4D driven head. Install all hex-drive bolts wet with BMS 5-95 sealant in transition fit holes. – Prior to clamp up, shim all gaps greater than 0.01 inches up to a maximum of 0.04 inches. Contact Boeing for any gap greater than 0.04 inches. – Install all parts wet with faying surface seal BMS 5-95 sealant. Refer to SOPM 20-50-19 as an acceptable procedure. g. Accomplishment of the repairs in accordance with the procedure above terminates the inspection requirements of Table 1 of Paragraph 1.E., Compliance. Post repair inspections are provided in Table 3 of Paragraph 1.E., Compliance. 3.**Group 2, Configuration 2:** Do as follows: a. Cut out all cracks found in accordance with FIGURE 5. **NOTE:**Stop drill to terminate a crack is no longer an accepted procedure. b. Remove all the fasteners common to the repair area. At all open fastener holes common to the repair, do an HFEC hole probe inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 16. c. If any crack is found outside the maximum cutout area or if the cutout area is larger than then maximum cutout area allowed, contact Boeing for instructions and do the work instructed by Boeing. d. If cutout in only in the skin assembly but not in the bearstrap, install the repair (Kit 65C36941-15) in accordance with 65C36941 Sheet 1 and Sheet PSDL and general notes below. e. If cutout is in the skin assembly and the bearstrap, install the repair (Kit 65C36941-17) in accordance with 65C36941 Sheet 1 and Sheet PSDL and general notes below. f. General repair notes: – Make sure that all repair parts and machine surfaces have a minimum of 63 RMS finish or better. This requirement supersedes the 125 RMS for all machine surfaces of 65C36941 PSDL, General Note 1. – Maintain a minimum 2D edge margin on all repair parts except for repair filler. Maintain a minimum 1.5D edge margin on fillers. – Install all rivets dry and over-driven to a minimum of 1.4D driven head. Install all hex-drive bolts wet with BMS 5-95 sealant in transition fit holes. – Prior to clamp up, shim all gaps greater than 0.01 inches up to a maximum of 0.04 inches. Contact Boeing for any gap greater than 0.04 inches. – Install all parts wet with faying surface seal BMS 5-95 sealant. Refer to SOPM 20-50-19 as an acceptable procedure.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 49 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**g. Accomplishment of the repairs in accordance with the procedure above terminates the inspection requirements of Table 1 of Paragraph 1.E., Compliance. Post repair inspections are provided in Table 3 of Paragraph 1.E., Compliance.
4.**Group 3:** Do as follows: a. If any crack is found in the forward upper corner of the doorway but there are no cracks at the aft upper corner, install the repair in accordance with the applicable 737-300 SRM 53-10-01 Repair 17, or 737-400 SRM 53-10-01 Repair 17, or 737-500 SRM 53-10-01 Repair 17. **NOTE:**As an option, in addition to the repair, install the preventive portion for the aft upper corner in accordance with the applicable 737-300 SRM 53-10-01 Repair 17, or 737-400 SRM 53-10-01 Repair 17, or 737-500 SRM 53-10-01 Repair 17. b. If any crack is found in the aft upper corner of the doorway but there are no cracks at the forward upper corner, install the repair in accordance with the applicable 737-300 SRM 53-10-01 Repair 21, or 737-400 SRM 53-10-01 Repair 21, or 737-500 SRM 53-10-01 Repair 21. **NOTE:**As an option, in addition to the repair, install the preventive portion for the forward upper corner in accordance with the applicable 737-300 SRM 53-10-01 Repair 21, or 737-400 SRM 53-10-01 Repair 21, or 737-500 SRM 53-10-01 Repair 21. c. If any crack is found in the forward and aft upper corner of the doorway, install the repair in accordance with the applicable 737-300 SRM 53-10-01 Repair 22, or 737-400 SRM 53-10-01 Repair 22, or 737-500 SRM 53-10-01 Repair 22. d. Accomplishment of the repairs or preventive modification in accordance with the applicable SRM terminates the inspection requirements of this service bulletin in the modified area. Post repair inspections are provided in the applicable SRM. 5. Install the forward entry doorway sidewall lining panels that were removed. Refer to 737-100/200 AMM 25-21-41 and 737-100/200 AMM 25-21-31 or 737-300/400/500 AMM 25-21-31 as an accepted procedure. 6. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1: January 08, 2014 50 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 1**  **(SHEET 1 OF 1)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 51 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT This Figure applies only to: Group 1, Configuration 2; Group 3.** 

**FIGURE 2: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION (SHEET 1 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 52 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 2: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 53 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 2: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION**  **(SHEET 3 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 54 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Skin Assembly Inspect 1 (b)

- - Skin Assembly and Bearstrap Inspect 2 (a) Do an external detailed inspection for any crack in the Skin Assembly in the area shown. (b) Do an external Low Frequency Eddy Current (LFEC) inspection around the fastener head for any crack in the skin assembly and bear strap in accordance with 737 NDT Manual Part 6, 51-00-26.

**FIGURE 2: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 55 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT This Figure applies only to: Group 2, Configuration 2.** 

**FIGURE 3: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION (SHEET 1 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 56 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 3: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 57 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 3: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION**  **(SHEET 3 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 58 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Skin Assembly Inspect 1 (b)

- - Skin Assembly and Bearstrap Inspect 2 (a) Do an external detailed inspection for any crack in the Skin Assembly in the area shown. (b) Do an external Low Frequency Eddy Current (LFEC) inspection around the fastener head for any crack in the skin assembly and bearstrap in accordance with 737 NDT Manual Part 6, 51-00-26.

**FIGURE 3: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - INSPECTION (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 59 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT This Figure applies only to: Group 1, Configuration 2.** 

**FIGURE 4: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL (SHEET 1 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 60 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 4: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 61 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 4: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL**  **(SHEET 3 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 62 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Skin Assembly Cut 1 (a)

- - Bearstrap Cut (b)

- - Cutout Inspect 2 (c)

- - Skin Assembly (As Re- quired) Cut 3 (c)

- - Bearstrap (As Re- quired) Cut (d) (e)

- 2024-T3 Filler Make 4 (e)

- TYPE 2, CLASS A Chemical Conversion Coating Apply 5 (f)

- BMS10-11, TYPE 1 Primer Apply (a) Cut out the skin assembly and/or bearstrap as required to remove all damages. Maintain a minimum 0.5 inch radius. If the cut out exceeds the maximum dimension shown, contact Boeing for repair and do the repair. Maintain 2D edge margin to adjacent fasteners. For skin and bonded doubler assemblies, cut both skin and doubler together. (b) Do a High Frequency Eddy Current (HFEC) inspection of the cutout for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 4 or Figure 23. (c) If any crack is found, re-accomplish Step 1. If there are no crack indications, oversize the cutout by 0.04 inches minimum. Maintain a minimum of 63 RMS finish on the cutout and a 2D minimum edge margin for adjacent fasteners. If the cut out exceeds the maximum dimension shown, contact Boeing for repair and do the repair. (d) Size of filler to be determined by size of cutout and thickness of filler to be determined by build up of repair thickness at the crack location. (e) Apply chemical conversion coating to the edge of the cutout and the filler. Refer to SOPM 20-43-03 as an accepted procedure. (f) Apply two coats of primer BMS 10-11, Type 1 to the edge of the cutout and the filler. Refer to SOPM 20- 41-02 as an accepted procedure.

**FIGURE 4: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 63 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT This Figure applies only to: Group 2, Configuration 2.** 

**FIGURE 5: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL (SHEET 1 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 64 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 5: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 65 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT FIGURE 5: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL**  **(SHEET 3 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 66 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Skin Assembly Cut 1 (a)

- - Bearstrap Cut (b)

- - Cutout Inspect 2 (c)

- - Skin Assembly (As Re- quired) Cut 3 (c)

- - Bearstrap (As Re- quired) Cut (d) (e)

- 2024-T3 Filler Make 4 (e)

- TYPE 2, CLASS A Chemical Conversion Coating Apply 5 (f)

- BMS10-11, TYPE 1 Primer Apply (a) Cut out the skin assembly and/or bearstrap as required to remove all damages. Maintain a minimum 0.5 inch radius. If the cut out exceeds the maximum dimension shown, contact Boeing for repair and do the repair. Maintain 2D edge margin to adjacent fasteners. For skin and bonded doubler assemblies, cut both skin and doubler together. (b) Do a High Frequency Eddy Current (HFEC) inspection of the cutout for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Figure 4 or Figure 23. (c) If any crack is found, re-accomplish Step 1. If there are no crack indications, oversize the cutout by 0.04 inches minimum. Maintain a minimum of 63 RMS finish on the cutout and a 2D minimum edge margin for adjacent fasteners. If the cut out exceeds the maximum dimension shown, contact Boeing for repair and do the repair. (d) Size of filler to be determined by size of cutout and thickness of filler to be determined by build up of repair thickness at the crack location. (e) Apply chemical conversion coating to the edge of the cutout and the filler. Refer to SOPM 20-43-03 as an accepted procedure. (f) Apply two coats of primer BMS 10-11, Type 1 to the edge of the cutout and the filler. Refer to SOPM 20- 41-02 as an accepted procedure.

**FIGURE 5: FORWARD ENTRY DOORWAY - BEARSTRAP AND SKIN ASSEMBLY - CRACK REMOVAL (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 21, 1993 737-53A1163 Revision 1 January 08, 2014 67 of 67 **BOEING SERVICE BULLETIN 737-53A1163 ALERT**  **ALERT**