### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-53A2088**  Original Issue: March 08, 1974 Revision 4: January 11, 2013 ATA System: 5300 **SUBJECT:** FUSELAGE - Body Station 760 or 780 - Frame to Tension Tie Joint - Inspection / 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. 9E991 ECCN: 

## 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 Unpublished Work.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, DreamlinerTM, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and 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. BOEING is a trademark of Boeing Management Company.

Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 1 of 62 5.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 2 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 23 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 23 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 26 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 27 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 FIGURE 1: UNMODIFIED TENSION TIE INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . 33 FIGURE 2: MODIFIED TENSION TIE INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . 36 FIGURE 3: FRAME TENSION TIE MODIFICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 38 FIGURE 4: THIS FIGURE IS DELETED (REVISION 4) . . . . . . . . . . . . . . . . . . . . . . . . . 43 FIGURE 5: THIS FIGURE IS DELETED (REVISION 4) . . . . . . . . . . . . . . . . . . . . . . . . . 44 FIGURE 6: THIS FIGURE IS DELETED (REVISION 4) . . . . . . . . . . . . . . . . . . . . . . . . . 45 FIGURE 7: ALTERNATIVE MODIFICATION [Group 1]. . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 8: ALTERNATIVE MODIFICATION [Group 2]. . . . . . . . . . . . . . . . . . . . . . . . . . 51 FIGURE 9: ALTERNATIVE MODIFICATION [Group 3]. . . . . . . . . . . . . . . . . . . . . . . . . . 56 APPENDIX A: ADDENDUM - FLIGHT SAFETY SECTION. . . . . . . . . . . . . . . . . . . . . . . . . . 61

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 3 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 4 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Revision Transmittal Sheet**  **Number: 747-53A2088** Original Issue: March 08, 1974 Revision 4: January 11, 2013 ATA System: 5300 **SUBJECT:** FUSELAGE - Body Station 760 or 780 - Frame to Tension Tie Joint - Inspection / Modification This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** More work is necessary on all airplanes that have not been modified in accordance with the original issue, Revision 1, Revision 2 or Revision 3 of this service bulletin. Do a surface High Frequency Eddy Current (HFEC) inspection of the radius common to the aft channel of the tension tie at the next inspection that is scheduled to be done in accordance with Paragraph 1.E., Compliance and accomplish the tension tie modification at the time given in Paragraph 1.E., Compliance. Federal Aviation Administration (FAA) Airworthiness Directive AD 84-19-01 is related to this service bulletin. **REASON FOR REVISION** This revision is sent to add a surface High Frequency Eddy Current (HFEC) inspection of the upper and lower radius common to the aft channel of the tension tie and to add a compliance time for the accomplishment of the tension tie modification. These sections were changed: 1. Summary Section: Added new Background information related to the revision. Updated Action section to reflect new requirements. Added Federal Aviation Administration (FAA) Airworthiness Directive information to the compliance section. Added new industry support information. Revised Summary illustration text to reflect changed actions. 2. In Paragraph 1.C., Reason: Added new background information related to the revision. 3. In Paragraph 1.D., Description: Updated the action descriptions to reflect new requirements, added "More work" statement and added maintenance zone tables. 4. In Paragraph 1.E., Compliance: Updated compliance times and added new compliance tables. 5. In Paragraph 1.F., Approval: Is updated and a new approval statement added. 6. In Paragraph 1.G., Manpower: Updated manpower estimate.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 5 of 627. In Paragraph 1.H., Weight and Balance Changes: Updated weight and balance and added new weight and balance tables. 8. In Paragraph 1.J., References: Added new references related to this revision. 9. In Paragraph 1.K., Publications Affected: Added statement for damage tolerance inspections. 10. In Paragraph 2.B., Industry Support Information: Added new industry support information. 11. In Paragraph 3.A., General Information: Updated general notes to current requirements. 12. In Paragraph 3.B., Work Instructions, PART I - Flight Safety Inspection Program: Added a new surface High Frequency Eddy Current (HFEC) inspection of tension ties. Removed compliance times and removed the reference to report any discrepancies in the Flight Safety Addendum. 13. Figure 1: Added a new detailed inspection and surface High Frequency Eddy Current (HFEC) inspection of tension ties. 14. Figure 2: Updated the AMM reference for ceiling panel removal. Removed the word optional from the view A-A illustration. Changed close visual inspection to a detailed inspection. 15. Figure 3: Added a new section view to the illustration. 16. Figure 4, Figure 5 and Figure 6 logic diagrams have been deleted. The flight safety and economic based inspection program information can be found in Paragraph 1.E., Compliance. 17. Figure 7, Figure 8 and Figure 9: Added and removed typical measurements from the illustrations. 18. APPENDIX A: In table 1 the inspection method and repeat inspection threshold times have been updated. 19. ADDENDUM: Removed the evaluation form from the addendum section. 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** March 08, 1974 Original Issue: May 01, 1974 Revision 1: August 26, 1983 Revision 2: September 08, 1994 Revision 3: January 11, 2013 Revision 4:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 6 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **Number: 747-53A2088** Original Issue: March 08, 1974 Revision 4: January 11, 2013 ATA System: 5300 **SUBJECT:** FUSELAGE - Body Station 760 or 780 - Frame to Tension Tie Joint - Inspection / 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** Accomplishment of the inspection program detailed in this bulletin will make sure the structural integrity of the Body Station 760 or 780 (as applicable) tension tie throughout the operational life of the airplane. Undetected tension tie cracking could eventually result in in-flight depressurization of the airplane and the inability to withstand current regulatory failsafe loads. Inspection of the fatigue test airplane after the equivalent of 12,000 flight-cycles revealed a crack in the BS 760 tension tie as a result of bending due to cabin pressurization. Structural reassessment of the 747 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure the safe operation of 747 airplanes throughout their operational life. As a result of this reassessment, the BS 760 or 780 (as applicable) tension tie has been determined to be structurally significant in that it is critical to the structural integrity of the airplane. Tension tie cracking not detected prior to it reaching critical crack length may result in in-flight depressurization of the airplane and the inability to withstand current regulatory failsafe loads. Therefore, a flight-safety inspection program which will continue throughout the operational life of the airplane is defined in this service bulletin. The upper deck tension ties have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). For more information about WFD, refer to Boeing Service Letter 747-SL-53-088. Boeing Fleet Team Digest (FTD) 747 FTD 53-03005 is related to this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 7 of 62Boeing Service Related Problem (SRP) 747-SRP-53-0403 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance 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 Yes 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 (PRR 85901-120RS)** This bulletin contains a flight safety inspection, an economics based inspection, and a modification. The flight safety inspection is the minimum inspection program to maintain the structural integrity of the affected area of the airplane. The economics based inspection, applicable to airplanes on which the modification described herein has not been incorporated, may be used in lieu of the flight safety inspection, at operator's option, until the modification is incorporated. The modification described herein will improve the resistance to cracking of the tension tie but does not alter the structural environment of the tension tie such that a flight safety inspection is not required. It does enable the initiation of the flight safety inspection to be deferred and increases the reinspection interval. Flight Safety Inspection Program - Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection for cracking in the outboard ends of each affected tension tie. If any cracking is found within specified limits, do the modification. If any cracking is found out of specified limits, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections until the tension tie is repaired or modified. Do the tension tie modification at the time in accordance with Paragraph 1.E., Compliance. The modification consists of replacing the existing tension tie doubler with a longer doubler. At tension tie locations that have been repaired or modified, do a detailed inspection for any cracking. If any cracking is found in a repaired or modified tension tie, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the times in accordance with Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 8 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Economic Inspection Program - The economics based inspections (detailed and surface HFEC inspections at operator's option) are used to detect cracking at an earlier stage. If any cracking is found within specified limits do the modification. If cracking is found out of specified limits, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections until the tension tie is repaired or modified. **EFFECTIVITY** 747-100, 747-200B, 747-200F Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s). **COMPLIANCE** Refer to Paragraph 1.E., Compliance. Federal Aviation Administration (FAA) Airworthiness Directive AD 84-19-01 is related to this service bulletin. **INDUSTRY SUPPORT INFORMATION** This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether the operator previously filed a warranty claim with Boeing on this service bulletin. **MANPOWER Elapsed Hours**  **Total Task Hours Airplanes**  2.50 5.00 Inspection 16.00 32.00 Modification
**MATERIAL INFORMATION** Boeing Supplied Kits/Parts. 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: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 9 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 10 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 11 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 12 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-53A2088**  Original Issue: March 08, 1974 Revision 4: January 11, 2013 ATA System: 5300 **SUBJECT:** FUSELAGE - Body Station 760 or 780 - Frame to Tension Tie Joint - Inspection / 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 This service bulletin is for the airplane(s) shown below. Refer to PRR85901-120RS for data about this change. Refer to Service Bulletin Index D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. **NOTE:** Airplanes that follow that have been modified by Boeing to the Special Freighter configuration are not affected by this service bulletin. 1.
2. Airplanes that follow that have been modified by Boeing to the Extended Upper Deck configuration are not affected by this service bulletin. 3. Airplanes that follow that have been modified as shown in Boeing Service Bulletin 747-25-2692, "Equipment/Furnishings - Upper Deck Passenger Compartment Conversion - Upper Deck Extension Station 710 - Station 780 Modification," are not affected by this service bulletin.
**DESCRIPTION CONFIGURATION**  **GROUP** 747-100 and 747-200B Passenger airplanes with a different Tension tie lay out to Group 2 and Group 3 airplanes. - 1

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 13 of 62**DESCRIPTION CONFIGURATION**  **GROUP** 747-100 and 747-200B Passenger airplanes with a different Tension tie lay out to Group 1 and Group 3 airplanes. - 2
747-200F airplanes with a different Tension tie lay out to Group 1 and Group 2 airplanes. - 3

Airplane Models: 747-100, 747-200B, 747-200F **Group Variable Number**  1 RA001 - RA025 1 RA027 - RA028 1 RA030 - RA032 1 RA034 1 RA104 - RA110 1 RA113 - RA115 2 RA164 1 RA201 - RA203 1 RA216 2 RA217 1 RA251 - RA255 2 RA256 - RA261 2 RA309 2 RA311 1 RA351 - RA360 1 RA369 - RA371 2 RA372 - RA373 1 RA404 2 RA413 1 RA501 - RA502 1 RA521 - RA523 2 RA525 - RA527 1 RA532 - RA534 2 RA535 - RA540

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 14 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Group**  **Variable Number** 1 RA551 - RA552 1 RA559 - RA560 2 RA561 1 RA581 - RA582 2 RA585 1 RA601 - RA602 1 RA631 1 RA633 1 RA651 - RA652 2 RA676 1 RA701 2 RA702 1 RA721 1 RA741 1 RA761 1 RA781 1 RA903 - RA909 1 RA914 2 RB071 - RB075 1 RB101 - RB102 3 RR201 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of the inspection program detailed in this bulletin will make sure the structural integrity of the Body Station 760 or 780 (as applicable) tension tie throughout the operational life of the airplane. Undetected tension tie cracking could eventually result in in-flight depressurization of the airplane and the inability to withstand current regulatory failsafe loads.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 15 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Body tension ties are located in the upper body just aft of the upper deck floor structure to reduce body flexure caused by pressurization cycles. On the fatigue test airplane, the tension tie at BS 760 was found cracked after the equivalent of 12,000 flights. Cracking occurred near the inboard end of the splice doubler at the juncture of the tension tie and the BS 760 frame. Cracking is attributed to bending loads induced by frame flexure during cabin pressurization. Structural reassessment of the 747 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure the safe operation of 747 airplanes throughout their operational life. As a result of this reassessment, the affected tension tie has been determined to be structurally significant in that it is critical to the structural integrity of the airplane. Tension tie cracking not detected prior to it reaching critical crack length may result in in-flight depressurization of the airplane. Therefore, a flight-safety inspection program which will continue throughout the operational life of the airplane is defined in this service bulletin. Revision 1 added previously omitted airplanes to Group 1 of the effectivity and incorporated Notice of Status Change dated 5 April, 1974 which corrected a typographical error in the note under Paragraph I .A.1. Revision 2 added the flight safety and economics based inspection program definitions, where applicable, throughout the service bulletin. In addition, a flight safety addendum is added to the bulletin as a summary of the inspections required to ensure the structural integrity of the applicable area and to provide the format for reporting inspection results to Boeing. Notices of Status Change dated 16 October, 1975 and 4 April, 1980 are incorporated to revise subkit nomenclature and to note that airplanes converted to the Special Freighter configuration are not affected by this bulletin. Also, the effectivity is updated to reflect current airplane ownership. Revision 3 is sent to add an alternative tension tie modification. This is shown in new Figures 7, 8, and 9. Revision 3 is also sent to add reference to Boeing Service Bulletin 747-25-2692, "Equipment/Furnishings - Upper Deck Passenger Compartment Conversion - Upper Deck Extension Station 710 - Station 780 Modification." As part of the change in Service Bulletin 747-25-2692, the tension tie at STA 760 is removed and replaced with a floor beam. The work shown in this service bulletin is not necessary after the change in Service Bulletin 747-25-2692 has been installed. The airplanes that follow have been removed from Paragraph I.A.1, Effectivity. These airplanes were changed by Boeing to the Special Freighter or Extended Upper Deck configuration: RA029, RA033, RA101-RA103, RA111-RA112, RA161-RA163, RA245-RA246, RA301-RA306, RA307-RA308, RA310, RA312, RA524, RA632, RA634-RA635, RA671-RA675, RA677, RA722-RA724, RA742-RA743, RA901-RA902, RA910-RA913, RA915-RA916, RB041, RB043. As part of the change to the Special Freighter or Extended Upper Deck configuration, the tension tie at STA 760 was removed and replaced with a floor beam. Airplane RB013 has also been removed from Paragraph I.A.1, Effectivity. On this airplane, a floor beam was installed at BS 760 in production. All affected airplanes, unmodified or modified per previous issues of this bulletin require flight safety inspection as noted herein. The upper deck tension ties have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). For more information about WFD, refer to Boeing Service Letter 747-SL-53-088.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 16 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Boeing Fleet Team Digest (FTD) 747 FTD 53-03005 is related to this service bulletin. Boeing Service Related Problem (SRP) 747-SRP-53-0403 is related to this service bulletin. Revision 4 is sent to add a surface High Frequency Eddy Current (HFEC) inspection of the upper and lower radius common to the aft channel of the tension tie and to add a compliance time for the accomplishment of the tension tie modification. **D. Description** This bulletin contains a flight safety inspection, an economics based inspection, and a modification. The flight safety inspection is the minimum inspection program to maintain the structural integrity of the affected area of the airplane. The economics based inspection, applicable to airplanes on which the modification described herein has not been incorporated, may be used in lieu of the flight safety inspection, at operator's option, until the modification is incorporated. The modification described herein will improve the resistance to cracking of the tension tie but does not alter the structural environment of the tension tie such that a flight safety inspection is not required. It does enable the initiation of the flight safety inspection to be deferred and increases the reinspection interval. Flight Safety Inspection Program - Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection for cracking in the outboard ends of each affected tension tie. If any cracking is found within specified limits, do the modification. If any cracking is found out of specified limits, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections until the tension tie is repaired or modified. Do the tension tie modification at the time in accordance with Paragraph 1.E., Compliance. The modification consists of replacing the existing tension tie doubler with a longer doubler. At tension tie locations that have been repaired or modified, do a detailed inspection for any cracking. If any cracking is found in a repaired or modified tension tie, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections at the times in accordance with Paragraph 1.E., Compliance. Economic Inspection Program - The economics based inspections (detailed and surface HFEC inspections at operator's option) are used to detect cracking at an earlier stage. If any cracking is found within specified limits do the modification. If cracking is found out of specified limits, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found, repeat the inspections until the tension tie is repaired or modified. Revision 3 - No more work is necessary on airplanes changed by the initial release, Revision 1, or Revision 2 of this service bulletin as a result of Revision 3. The effectivity is divided into three groups because of differences in inspection and modification area. PLEASE REPORT ADVERSE INSPECTION RESULTS TO BOEING USING THE REPORT SYSTEM DESCRIBED IN APPENDIX A OF THIS SERVICE BULLETIN. **NOTE:** Contact Boeing for instructions if any damaged areas exceed the specified limits. To expedite Boeing response, be specific when defining and locating the damage. Circumstances leading up to the damage and any secondary effects, when known, should be included in the communication and followed up by sketches and photographs when appropriate.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 17 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**SEND TO: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT Revision 4 - More work is necessary on all airplanes that have not been modified in accordance with the original issue, Revision 1, Revision 2 or Revision 3 of this service bulletin. Do a surface High Frequency Eddy Current (HFEC) inspection of the radius common to the aft channel of the tension tie at the next inspection that is scheduled to be done in accordance with Paragraph 1.E., Compliance and accomplish the tension tie modification at the time given in Paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1-2:**
**Affected Maintenance Zones Zone**  **Model** 233, 234 747-100, 747-200B **Group 3:**
**Affected Maintenance Zones Zone**  **Model** 233, 234 747-200F **E. Compliance** Federal Aviation Administration (FAA) Airworthiness Directive AD 84-19-01 is related to this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 18 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Table 1: Tension Tie Inspection and Modification (Flight Safety Inspection Program)**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  3,700 flight cycles.(a) Within 500 flight cycles after the effective date of AD 84-19-01.Before 8,000 total flight cycles. Do a detailed inspection of the tension tie at BS760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) for any cracking in accordance with Paragraph 3.B., Work Instructions Part I.Airplanes that have not accomplished the modification to the tension tie at BS 760 (Group 1 and 2) or BS780 (Group 3) in accordance with this service bulletin.
Within 3,700flight cycles after the Revision 4 date of this service bulletin.Before 8,000 total flight cycles. Do a detailed inspectionand a surface High Frequency Eddy Current (HFEC) inspection of the tension tie at BS 760 (Group 1 and 2 airplanes)or BS 780 (Group 3 airplanes) for any crackingin accordance with Paragraph 3.B., Work Instructions Part I.

- Before further flight. Do the modification in ac- cordance with Paragraph 3.B., Work Instructions Part III. If cracking is found within limits.
(a)

- Before further flight. Contact Boeing for repair instructions and do thework instructed by Boeing. If cracking is found in the tension tie out of limits.

- Within 2,000flight cycles after the Revision 4 date of this service bulletin. Before 16,000total flight cycles.Do the modification in accordance with Paragraph 3.B., Work Instructions Part III. (a) If no cracking is found.

(a) Accomplishment of the modification terminates the repeat inspection requirement. Refer to Table 2 for post modification inspections.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 19 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Table 2: Post Modification Inspection (Flight Safety Inspection Program)**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  8,000 flight cycles. (a) Within 1,000flight cycles after the effective date of AD 84- 19-01. (a) Within 10,000flight cycles after the accomplishment of the modification. (a) Do a detailed inspection of the tension tie at BS760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) for any cracking in accordance with Paragraph 3.B., Work Instructions Part I.Airplanes that have accomplished the Modification to the tension tie at BS 760 (Group 1 and 2 airplanes)or BS 780 (Group 3 airplanes) in accordance with this service bulletin.

- Before further flight. Contact Boeing for repair instructions and do thework instructed by Boeing. If any crack is found in a modified tension tie.

(a) Additional post modification inspections are given in Boeing service bulletin 747-53A2502. **Table 3: Tension Tie Inspection and Modification (Economic Based Inspection Program) Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition** 1,000 flight cycles.(a) Before 7,000 total flight cycles. Do a detailed inspectionand a surface High Frequency Eddy Current (HFEC) inspection of the tension tie at BS 760 (Group 1 and 2 airplanes)or BS 780 (Group 3 airplanes) for any crackingin accordance with Paragraph 3.B., Work Instructions Part II.Airplanes that have not accomplished the modification to the tension tie at BS 760 (Group 1 and 2) or BS780 (Group 3) in accordance with this service bulletin.

- Before further flight. Do the modification in ac- cordance with Paragraph 3.B., Work Instructions Part III. If cracking is found within limits.
(a)

- Before further flight. Contact Boeing for repair instructions and do thework instructed by Boeing. If cracking is found in the tension tie out of limits.

- Within 2,000flight cycles after the Revision 4 date of this service bulletin. Before 16,000total flight cycles.Do the modification in accordance with Paragraph 3.B., Work Instructions Part III. (a) If no cracking is found.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 20 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Table 3: Tension Tie Inspection and Modification (Economic Based Inspection Program)**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  (a) Accomplishment of the modification terminates the repeat inspection requirement. Refer to Table 2 for post modification inspections. **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. In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of the inspection, modification and post modification inspections with the corresponding compliance times given in Service Bulletin 747-53A2088, Revision 4, as an alternative method of compliance to the inspection, optional modification, and post modification inspection requirements with corresponding compliance times required by paragraphs (A) and (B) of AD 84-19-01. Where this SB states to contact Boeing for repair instructions, these instructions must be approved as an AMOC per the instructions in paragraph (C) of AD 84-19-01. All provisions of AD 84-19-01 that are not specifically referenced in this paragraph 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 inspection and modification 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 Hours Task Hours**  **Number of Persons Task**  0.50 1.00 2 Open Access 1.50 3.00 2 Inspection (a) (a) (a) Repair 15.00 30.00 2 Modification

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 21 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Elapsed Hours**  **Task Hours Number of Persons**  **Task** 0.50 1.00 2 Restoration TOTAL FOR EACH AIRPLANE 1.50 3.00 Inspection (a) (a) Repair 16 32 Modification (a) For some tension tie cracks, the modification can be used as a repair. For unmodified airplanes with cracks other than as described in Paragraph 3.B., Work Instructions, repair time will depend on extent of cracking. **H. Weight and Balance Changes Group 1-2:**  **Change in Moment (Pound-Inches)**  **Change in Weight (Pounds)**  **Airplane** + 585.2 + 0.8 Tension Tie Modification + 390.7 + 0.5 Alternative Modification **Group 3: Change in Moment**  **(Pound-Inches) Change in Weight**  **(Pounds) Airplane**  + 627.8 + 0.8 Tension Tie Modification + 401.0 + 0.5 Alternative Modification
**I. Electrical Load Data** Not applicable. **J. References** 1. Existing Data: a. Engineering Change Memo PRR 85901-120RS b. Boeing Service Bulletin 747-25-2692, 747-53A2502 c. Boeing Service Letter 747-SL-51-048, 747-SL-53-088 d. Boeing Service Related Problem (SRP) 747-SRP-53-0403 e. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 84-19-01 f. Service Bulletin Index D6-30300

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 22 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**g. 747 Fleet Team Digest (FTD) 53-03005 h. 747 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00 Procedure 1, Procedure 4, Procedure 11, Procedure 16, Procedure 23 i. 747-100/200/300 Aircraft Maintenance Manual (AMM) 25-22-01 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  Tension Tie Installation - STA 760 to STA 940 65B09631 The table above lists applicable drawings used to prepare this service bulletin. The drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. The drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  53-10 747 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: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 23 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 24 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **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 03** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **Revision 03 date**

**of this Service Bulletin (Calendar**  **Days) Name**  **Kit Number**

$672.00 280 KIT, FRAME TO TENSION TIE JOINT MODIFICATION - BODY STATION 760 63B12132-1
**B. Industry Support Information** This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether the operator previously filed a warranty claim with Boeing on this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **NOTE:** Top kit assembly is divided into subkits for convenience of installation. One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. **63B12132 - FRAME TO TENSION TIE JOINT MODIFICATION - BODY STATION 760**
**Kit 63B12132-1 Name**  **QTY New Part Number**  **-1 -2**  **-3** Top Kit Assembly

- . . 63B12132-1 Kit Assembly, Left Side 1

- . 63B12132-2

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 25 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT 63B12132 - FRAME TO TENSION TIE JOINT MODIFICATION - BODY STATION 760** 
**Kit 63B12132-1 Name**  **QTY New Part Number**  **-1 -2**  **-3** Kit Assembly, Right Side 1

. - 63B12132-3 Doubler

. 1

. 65B42544-1 Doubler

. . 1 65B42544-2 Bolt

. 6 6 BACB30KK6-3 Bolt

. 12 12 BACB30KK6-4 Bolt

. 15 15 BACB30KK6-5 Bolt

. 3 3 BACB30KK8-6 Bolt

. 5 5 BACB30KK8-7 Bolt

. 5 5 BACB30KK8-8 Collar

. 33 33 BACC30R6 Collar

. 13 13 BACC30R8 Rivet

. 2 2 BACR15BA6D10 2. Parts and Materials Supplied by the Operator **NOTE:** The parts and materials shown in the table that follows are necessary to install the alternative modification shown in Figures 7, 8, or 9.
**Notes Name**  **Group 1 QTY**  **Group 2 QTY**  **Group 3 QTY**  **Part Number / Specification**  (a) Strap 2

. . A (b) Strap

. 2

. B (c) Strap

. . 2 C (e) Bolt 1 1 4 BACB30MY6K4X (e) Bolt 6 6 3 BACB30MY6K5X (e) Bolt 1 1

. BACB30MY6K6X (e) Bolt 3 2

. BACB30MY6K7X (e) Bolt

. . 5 BACB30MY6K8X (e) Bolt

. . 5 BACB30MY6K9X (e) Bolt 6 6 8 BACB30MY6K4Y (e) Bolt 2 2 2 BACB30MY8K4 (e) Bolt 1

. . BACB30MY8K7X

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 26 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT Notes**  **Name Group 1**  **QTY Group 2**  **QTY Group 3**  **QTY Part Number /**  **Specification** (e) Bolt 5 3

. BACB30MY8K8X (e) Bolt

. 3

. BACB30MY8K9X

- Collar 10 9 15 BACC30M6

- Collar 8 8 2 BACC30M8

- Collar 6 6 8 BACC30R6 (d) Sealant 4 Ounces 4 Ounces 4 Ounces BMS 5-95

- Paint 4 Ounces 4 Ounces 4 Ounces BMS 10-11, Type I (a) Make as shown in FIGURE 7. (b) Make as shown in FIGURE 8. (c) Make as shown in FIGURE 9. (d) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (e) Refer to 747 Structural Repair Manual Chapter 51 for alternate fasteners.
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: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 27 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 28 of 62 **BOEING SERVICE BULLETIN 747-53A2088 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 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. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 8. Boeing Service Letter 747-SL-51-048 Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 9. Refer to Appendix A for Addendum on flight safety.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 29 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**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. **B. WORK INSTRUCTIONS PART I - FLIGHT SAFETY INSPECTION PROGRAM**  1. On airplanes on which Part III - Modification has not been incorporated accomplish the following: a. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of the tension tie at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) for any cracking in accordance with FIGURE 1. b. If no cracking is found, repeat the tension tie inspections in accordance with FIGURE 1 at the time given in Paragraph 1.E., Compliance or alternatively, accomplish Part III - Modification and do the tension tie inspection in accordance with Part I, Step 2. c. If any cracking is found in one channel of the tension tie at the most inboard row of fasteners common to the tension tie channels and the existing steel joint doubler or in the aft channel in the area of the channel trim out, do the Part III - Modification as a repair and do the inspections in accordance with Part I, Step 2. If any cracking is found other than as described above, contact Boeing for repair instructions and do the work instructed by Boeing. d. Restore access and return the airplane to a serviceable condition. 2. On airplanes on which Part III - Modification has been incorporated accomplish the following: a. Do a detailed inspection of the tension tie at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) for any cracking in accordance with FIGURE 2 at the time given in Paragraph 1.E., Compliance. b. If no cracking is found, repeat the inspections in accordance with FIGURE 2 at the time given in Paragraph 1.E., Compliance. c. If any cracking is found, contact Boeing for repair instructions and do the work instructed by Boeing. d. Restore access and return the airplane to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 30 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT PART II - ECONOMICS BASED INSPECTION PROGRAM - OPERATOR'S OPTION**  1. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of the tension tie at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) for any cracking in accordance with FIGURE 1. **NOTE:** 1. This inspection may be used in lieu of Part I - Flight Safety Inspection Program, at operator's option, until Part III - Modification is accomplished. 2. This inspection applies only to airplanes on which Part III - Modification has not been accomplished. 2. If no cracking is found, repeat the tension tie inspection in accordance with FIGURE 1 at the time given in Paragraph 1.E., Compliance or alternatively, do the modification in accordance with Part III - Modification and do tension tie modification inspections in accordance with Part I, Step 2. 3. If any cracking is found in one channel of the tension tie at the most inboard row of fasteners common to the tension tie channels and the existing steel joint doubler or in the aft channel in the area of the channel trim out, do the Part III - Modification as a repair and initiate re-inspections in accordance with Part I, Step 2. If any cracking is found other than as described above, contact Boeing for repair instructions and do the work instructed by Boeing. 4. Restore access and return the airplane to a serviceable condition. **PART III - MODIFICATION** 1. Get access to the tension tie ends at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) by removing ceiling panels 231HL and 231HR (if installed). Refer to 747-100/200/300 AMM 25-22-01 or operator's comparable procedure. **NOTE:** This modification may be used as an alternative to repeat inspections in accordance with Part II, as a means of deferring initial or repeat inspections in accordance with Part I, or as a repair for cracks as shown in the notes that follow. The modification does not terminate Part I inspection requirements. 2. Replace existing tension tie end doublers with longer doublers in accordance with FIGURE 3. As an alternative, modify the tension tie in accordance with FIGURE 7, FIGURE 8 or FIGURE 9. **NOTE:** 1. The modification in accordance with FIGURE 3 may be used as a repair for a crack in one channel of the tension tie at the most inboard row of fasteners common to the tension tie channels and the existing steel joint doubler on unmodified airplanes. 2. The modification in accordance with FIGURE 7, FIGURE 8 or FIGURE 9 can also be used as a repair for cracks in the aft channel of the tension tie. This repair can only be used if the trim in accordance with FIGURE 7, FIGURE 8 or FIGURE 9 completely removes all cracks in the aft channel. If the trim does not completely remove all cracks from the aft channel, or if other cracks are found, contact Boeing for repair instructions and do the work instructed by Boeing. 3. Reinstall access panels and return the airplane to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 31 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**4. Do inspections of the modified tension ties in accordance with Part I. Step 2, 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: March 08, 1974 747-53A2088 Revision 4: January 11, 2013 32 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 1: UNMODIFIED TENSION TIE INSPECTION**  **(SHEET 1 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 33 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 1: UNMODIFIED TENSION TIE INSPECTION**  **(SHEET 2 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 34 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Ceiling Panels Remove / Keep 1 (b)

- - Tension Tie Inspect 2 (c) (d)

- - Tension Tie Inspect 3 (c) (d)

- - Tension Tie Inspect 4 (a) Get access to the tension tie ends at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) by removing ceiling panels 231HL and 231HR (if installed). Refer to 747-100/200/300 AMM 25-22-01 or operator's comparable procedure. (b) Do a detailed inspection of the indicated tension tie area on the left and right side for any cracking. (c) Do a detailed inspection of the edge of the radius of the tension tie aft channel on the left and right side for any cracking. (d) Do a surface High Frequency Eddy Current (HFEC) inspection on the edge of the radius of the tension tie aft channel on the left and right side for any cracking. Do the inspection in accordance with 747 NDT Part 6, 51-00-00, Procedure 4 or Procedure 23.

**FIGURE 1: UNMODIFIED TENSION TIE INSPECTION (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 35 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 2: MODIFIED TENSION TIE INSPECTION**  **(SHEET 1 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 36 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Ceiling Panels Remove / Keep 1 (b)

- - Tension Tie Inspect 2 (a) Get access to the tension tie ends at BS 760 (Group 1 and 2 airplanes) or BS 780 (Group 3 airplanes) by removing ceiling panels 231HL and 231HR (if installed). Refer to 747-100/200/300 AMM 25-22-01 or operator's comparable procedure. (b) Do a detailed inspection of the indicated tension tie area on the left and right side for any cracking.

**FIGURE 2: MODIFIED TENSION TIE INSPECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 37 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 3: FRAME TENSION TIE MODIFICATION**  **(SHEET 1 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 38 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 3: FRAME TENSION TIE MODIFICATION**  **(SHEET 2 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 39 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 3: FRAME TENSION TIE MODIFICATION**  **(SHEET 3 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 40 of 62 **BOEING SERVICE BULLETIN 747-53A2088 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**  Group 1. 40

- Fasteners Remove 1 Group 2 and 3. 39

- Fasteners Remove

- - 65B09614-27 (65B09614-19 or 65B09614-21 optional) Doubler Remove 2

Group 2 only. 2

- Hole Countersink 3 Left side. 1 65B42544-1 Doubler Install (New) 4 Right side. 1 65B42544-2 Doubler Install (New)

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  Install with BMS 5-95 sealant. 0.216 - 0.219

- BACB30KK6-( ) Bolt A

- - - BACC30R6 Collar Install with BMS 5-95 sealant 0.278 - 0.281

- BACB30KK8-( ) Bolt B

- - - BACC30R8 Collar

**FIGURE 3: FRAME TENSION TIE MODIFICATION (SHEET 4 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 41 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT More Data**  **Hole Dia Qty**  **Identification Name**  **Code** 100 degree countersink0.33 inch diameter forward side only. - - BACR15BA6D10 Rivet C

**FIGURE 3: FRAME TENSION TIE MODIFICATION (SHEET 5 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 42 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 4: THIS FIGURE IS DELETED (REVISION 4)**  **(SHEET 1 OF 1)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 43 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 5: THIS FIGURE IS DELETED (REVISION 4)**  **(SHEET 1 OF 1)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 44 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 6: THIS FIGURE IS DELETED (REVISION 4)**  **(SHEET 1 OF 1)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 45 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT This Figure applies only to: Group 1.** 

**FIGURE 7: ALTERNATIVE MODIFICATION (SHEET 1 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 46 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 7: ALTERNATIVE MODIFICATION**  **(SHEET 2 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 47 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 7: ALTERNATIVE MODIFICATION**  **(SHEET 3 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 48 of 62 **BOEING SERVICE BULLETIN 747-53A2088 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 one side of the airplane. **NOTE:** The figure shows two alternate aft channel trims. Any trim line that is between those shown in the figure is acceptable. At least five fasteners in each row are necessary common to the aft channel, forward channel and repair strap inboard of the trim line. 1.

2. Install all parts with BMS 5-95 sealant. 3. All trimmed edges and repair parts should be finished to 125 microinches or better.
**More Data Qty**  **Identification Name**  **Task Step** 

- - - Fasteners Remove 1

- 1

- Plate Remove / Keep 2

- 1

- Aft Channel Cut 3

- 1

- Trimmed Section Remove 4 To aft channel to match adjacent structure. - - Paint Apply 5

0.071 thick 2024-T3. 1 A Repair Strap Make 6 One coat BMS 10- 11, Type I. - - Paint Apply Trim as necessary. 1 A Repair Strap Install (New)

- 1

- Plate Install (Kept) 7

**FIGURE 7: ALTERNATIVE MODIFICATION (SHEET 4 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 49 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  Install with BMS 5-95 sealant. 0.2026 - 0.2036 - BACB30MY6K( )X Bolt D

- - - BACC30M6 Collar Install with BMS 5-95 sealant. 0.2651 - 0.2661 - BACB30MY8K( )X Bolt E

- - - BACC30M8 Collar Install with BMS 5-95 sealant. 0.216 - 0.219

- BACB30MY6K4Y Bolt F

- - - BACC30R6 Collar Install with BMS 5-95 sealant. 0.2495 - 0.2505 (a) - BACB30MY8K4 Bolt G

- - - BACC30M8 Collar (a) Before the hole is made larger, do an open hole HFEC inspection at these locations in accordance with 747 NDT Part 6, 51-00-00, Procedure 1 or Procedure 11 or Procedure 16. If no cracking is found, make the fastener holes the size shown.

**FIGURE 7: ALTERNATIVE MODIFICATION (SHEET 5 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 50 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT This Figure applies only to: Group 2.** 

**FIGURE 8: ALTERNATIVE MODIFICATION (SHEET 1 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 51 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 8: ALTERNATIVE MODIFICATION**  **(SHEET 2 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 52 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 8: ALTERNATIVE MODIFICATION**  **(SHEET 3 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 53 of 62 **BOEING SERVICE BULLETIN 747-53A2088 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 one side of the airplane. **NOTE:** The figure shows two alternate aft channel trims. Any trim line that is between those shown in the figure is acceptable. At least five fasteners in each row are necessary common to the aft channel, forward channel and repair strap inboard of the trim line. 1.

2. Install all parts with BMS 5-95 sealant. 3. All trimmed edges and repair parts should be finished to 125 microinches or better.
**More Data Qty**  **Identification Name**  **Task Step** 

- - - Fasteners Remove 1

- 1

- Plate Remove / Keep 2

- 1

- Aft Channel Cut 3

- 1

- Trimmed Section Remove 4 To aft channel to match adjacent structure. 1

- Paint Apply 5

0.071 thick 2024-T3. 1 B Repair Strap Make 6 One coat BMS 10- 11, Type I. - - Paint Apply Trim as necessary

- B Repair Strap Install (New)

- 1

- Plate Install (Kept) 7

**FIGURE 8: ALTERNATIVE MODIFICATION (SHEET 4 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 54 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  Install with BMS 5-95 sealant. 0.2026 - 0.2036 - BACB30MY6K( )X Bolt D

- - - BACC30M6 Collar Install with BMS 5-95 sealant. 0.2651 - 0.2661 - BACB30MY8K( )X Bolt E

- - - BACC30M8 Collar Install with BMS 5-95 sealant. 0.216 - 0.219

- BACB30MY6K4Y Bolt F

- - - BACC30R6 Collar Install with BMS 5-95 sealant. 0.2495 - 0.2505 (a) - BACB30MY8K4 Bolt G

- - - BACC30M8 Collar (a) Before the hole is made larger, do an open hole HFEC inspection at these locations in accordance with 747 NDT Part 6, 51-00-00, Procedure 1 or Procedure 11 or Procedure 16. If no cracking is found, make the fastener holes the size shown.

**FIGURE 8: ALTERNATIVE MODIFICATION (SHEET 5 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 55 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT This Figure applies only to: Group 3.** 

**FIGURE 9: ALTERNATIVE MODIFICATION (SHEET 1 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 56 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 9: ALTERNATIVE MODIFICATION**  **(SHEET 2 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 57 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT FIGURE 9: ALTERNATIVE MODIFICATION**  **(SHEET 3 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 58 of 62 **BOEING SERVICE BULLETIN 747-53A2088 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 one side of the airplane.
**More Data Qty**  **Identification Name**  **Task Step** 

- - - Fasteners Remove 1

- 1

- Plate Remove / Keep 2

- 1

- Aft Channel Cut 3

- 1

- Trimmed Section Remove 4 To aft channel to match adjacent structure. 1

- Paint Apply 5

0.071 thick 2024-T3. 1 C Repair Strap Make 6 One coat BMS 10- 11, Type I. 1

- Paint Apply Trim as necessary.

- C Repair Strap Install (New)

- 1

- Plate Install (Kept) 7

**FIGURE 9: ALTERNATIVE MODIFICATION (SHEET 4 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 59 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  Install with BMS 5-95 sealant. 0.2026 - 0.2036 - BACB30MY6K( )X Bolt D

- - - BACC30M6 Collar Install with BMS 5-95 sealant. 0.2651 - 0.2661 - BACB30MY8K( )X Bolt E

- - - BACC30M8 Collar Install with BMS 5-95 sealant. 0.216 - 0.219

- BACB30MY6K4Y Bolt F

- - - BACC30R6 Collar Install with BMS 5-95 sealant. 0.2495 - 0.2505 (a) - BACB30MY8K4 Bolt G

- - - BACC30M8 Collar (a) Before the hole is made larger, do an open hole HFEC inspection at these locations in accordance with 747 NDT Part 6, 51-00-00, Procedure 1 or Procedure 11 or Procedure 16. If no cracking is found, make the fastener holes the size shown.

**FIGURE 9: ALTERNATIVE MODIFICATION (SHEET 5 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 60 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**APPENDIX A: INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME A structural reassessment of the 747 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure safe operation of 747 airplanes throughout their operational life. Table I is a summary of the inspections specified in the Accomplishment Instructions, Part 1 - Flight Safety Inspection Program that are recommended for the detection of cracks in the Body Station (BS) 760 or 780 (as applicable) tension tie prior to their reaching critical length. Failure to detect cracks prior to their reaching critical length may result in in-flight depressurization of the airplane and the inability to withstand current regulatory failsafe loads. Any cracked tension ties should be repaired prior to further flight unless specifically approved by your cognizant regulatory agency. Please report any discrepancies using the reporting system described in this addendum. **TABLE I Repeat Inspection Inter**  **val (Flights) Repeat Inspection**  **Threshold (Flights) Inspection Method**  **Airplane Condition**
3,700 8,000 or within 500 after the effective date of AD84-19-01, whichever occurs later. Detailed Inspection Service Bulletin Modifica- tion Not Accomplished

3,700 8,000 Detailed Inspection and a surface High FrequencyEddy Current (HFEC) Inspection (a)

8,000 10,000 after Modification Detailed Inspection Service Bulletin Modifica- tion Accomplished (b) (a) For airplanes over the threshold at receipt of addendum, inspect within 3,700 flights after the Revision 4 date of this service bulletin. (b) For airplanes over the threshold at receipt of addendum, inspect within 1000 flights after the effective date of AD 84-19-01. Boeing requests that operators use the following Structural Significant Item (SSI) Reporting System to report any discrepancies that are found during accomplishment of a Flight Safety Inspection. 1. Upon recognition of a discrepancy, the following information should be telegraphed to Boeing: Heading: ATTENTION - SSI DISCREPANCY - SERVICE BULLETIN RELATED – Service Bulletin Number – Airplane serial number upon which discrepancy was found – Identification of structural item found damaged – Flight-cycles and hours on damaged item

**APPENDIX A: ADDENDUM - FLIGHT SAFETY SECTION (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 61 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**– Location and description of damage including direction and size – When discovered and inspection method used. Send telegram through Boeing Field Service Representative or directly to: 747 Customer Support Engineering 2. An Operator's Follow-up Report containing all available pertinent data relative to the structural discrepancy shall be sent to Boeing. A summary of the information that should be reported is shown in the SSI DISCREPANCY REPORT form in the Supplemental Structural Inspection Document (SSID), Boeing Document D6-35022. Operators may use this form or any suitable alternative which contains the same information. 3. All data and reports dealing with the Flight Safety Inspection Program shall be submitted either through a Boeing Field Service Representative or directly to: Boeing Commercial Airplane Group P.O. Box 3707 Seattle, Washington 98124 Attn: Director, 747/767 Customer Support Engineering Org. M-7201, Mail Stop 04-CR 4. All reports will be reviewed immediately. 5. The Boeing Company will summarize the results of all reported significant data for distribution semiannually to operators and appropriate Airworthiness Authorities.

**APPENDIX A: ADDENDUM - FLIGHT SAFETY SECTION (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 08, 1974 747-53A2088 Revision 4 January 11, 2013 62 of 62 **BOEING SERVICE BULLETIN 747-53A2088 ALERT**  **ALERT**