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ALERT ALERT

Commercial

Airplanes 747

ALERT ALERT

Service Bulletin

Number: 747-53A2502

Original Issue: April 21, 2005

Revision 1: June 17, 2010

ATA System: 5300

SUBJECT: FUSELAGE - Non Stretched Upper Deck Tension Ties and Frames - Inspection and 

Repair.

BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET

Copyright © 2005 The Boeing Company

Unpublished Work - All Rights Reserved

Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable 

subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.

This document includes proprietary information owned by The Boeing Company and/or one or more third 

parties. Treatment of the document and the information it contains is governed by contract with Boeing. For 

more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.

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, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing 

livery 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.
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 Table of Contents

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Table of Contents

Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 38

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 39

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 40

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 42

3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 42

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

FIGURE 1: INSPECTION - Group 1, Configuration 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 64

FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1 . . . . . . . . . . . . . . . . . . 73

FIGURE 3: INSPECTION - Group 1, Configuration 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 80

FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2 . . . . . . . . . . . . . . . . . . 90

FIGURE 5: INSPECTION - Group 1, Configuration 3 . . . . . . . . . . . . . . . . . . . . . . . . . . 99

FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3 . . . . . . . . . . . . . . . . . . 107

FIGURE 7: INSPECTION - Group 1, Configuration 4 . . . . . . . . . . . . . . . . . . . . . . . . . . 114

FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4 . . . . . . . . . . . . . . . . . . . 122

FIGURE 9: ACCESS - Group 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

FIGURE 10: INSPECTION - Group 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

FIGURE 11: OVERSIZED HOLE REPAIR - Group 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 136
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FIGURE 12: CLOSE ACCESS - Group 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

FIGURE 13: INSPECTION - Group 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

FIGURE 14: OVERSIZED HOLE REPAIR - Group 3. . . . . . . . . . . . . . . . . . . . . . . . . . 149

FIGURE 15: INSPECTION - Group 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

FIGURE 16: OVERSIZED HOLE REPAIR - Group 4. . . . . . . . . . . . . . . . . . . . . . . . . . 163

FIGURE 17: INSPECTION - Group 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

FIGURE 18: OVERSIZE HOLE REPAIR - Group 5 . . . . . . . . . . . . . . . . . . . . . . . . . . 179

FIGURE 19: INSPECTION - Group 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

FIGURE 20: OVERSIZE HOLE REPAIR - Group 6 . . . . . . . . . . . . . . . . . . . . . . . . . . 194

FIGURE 21: HFEC INSPECTION OF HOLES FOR INSULATION BLANKET STUDS . . . . . . . . 201

FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2 . . . . . . . . 204

FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2 . . . . . . 218

APPENDIX A: DELETED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

APPENDIX B: TENSION TIE DISCONNECTION METHODS . . . . . . . . . . . . . . . . . . . . . 224

APPENDIX C: GENERAL ILLUSTRATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
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ALERT ALERT

Commercial

Airplanes 747

ALERT ALERT

Service Bulletin

Number: 747-53A2502 Revision Transmittal Sheet

Original Issue: April 21, 2005

Revision 1: June 17, 2010

ATA System: 5300

SUBJECT: FUSELAGE - Non Stretched Upper Deck Tension Ties and Frames - Inspection and 

Repair.

This Revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

Group 2: More work is necessary on airplanes changed as shown in the original issue of this service bulletin. 

After additional analysis of the tension tie structure, Boeing has determined that the initial inspection of tension 

ties at STA 720, STA 740, and STA 760 should be done at an earlier time. The new compliance time for the 

initial inspection is given in paragraph 1.E., Compliance. In addition, a new one-time inspection (and corrective 

action, as necessary) has been added to ensure the configuration of all tension ties on Group 2 airplanes is in 

accordance with production engineering configuration.

Group 1, 3-6: No more work is necessary on airplanes changed as shown in the original issue of this service 

bulletin. However, all previously released actions given in this service bulletin have been upgraded from 

"Special Attention" status to "Alert" status based on the current criteria for determination of airplane safety 

related issues.

Federal Aviation Administration (FAA) Airworthiness Directive 84-19-01, is related to this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive 94-13-06, is related to this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive 2004-07-22 R1, is related to this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive 2006-01-07, is related to this service bulletin.

REASON FOR REVISION

This revision is sent to reduce the initial inspection compliance time for Group 2 airplanes at STA 720, STA 740, 

and STA 760 and to add an inspection to ensure the correct tension tie configurations on Group 2 airplanes. 

Other changes have also been made in Revision 1.

Terminology has been changed in the Work Instruction to agree with the terminology defined in Paragraph 3.A., 

General Information - Notes.

These sections were changed:

— In Summary: Updated to reflect current information and requirements.
 

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— In paragraph 1.C., Reason: Updated to reflect current information and requirements.

— In paragraph 1.D., Description: Clarified description of existing work, and added description of new 

requirements for Group 2 airplanes.

— In paragraph 1.E., Compliance: Revised compliance information for existing inspection requirements for 

Group 2 airplanes. Added Table 4 for compliance information related to new inspections. Updated 

Airworthiness Directive references.

— In paragraph 1.F., Approval: Updated approval paragraph and existing AMOC statements. Added AMOC 

statement for AD 2006-01-07.

— In paragraph 1.G., Manpower: Revised notes in some tables. Added table for new inspection 

requirements.

— In paragraph 1.J., References: Has been updated.

— In paragraph 1.K., Publications Affected: Added Damage Tolerance Inspection statement.

— In paragraph 2.A., Material - Price and Availability: Added tension tie segment and tension tie splice 

channel.

— In paragraph 2.B., Industry Support Information: Added warranty statement for the new one-time 

inspection and corrective actions for 747-400F airplanes.

— In paragraph 2.C., Parts Necessary For Each Airplane: Added tension tie segment and tension tie splice 

channel.

— In paragraph 3.A., General Information: Updated, clarified, and corrected existing notes. Added notes 22, 

23, and 24.

— In paragraph 3.B., Work Instructions: Added one-time inspection for correct configuration (Revision 1 - 

more work). Updated AMM references in ACCESS and RESTORATION section. Added SRM references 

for tension tie repairs and frame repairs. Also, clarified and/or removed redundant steps throughout this 

section. Changes to this section have resulted in re-sequencing and/or re-numbering of some steps.

— In Figures 1, 3, 5, 7, 10, 13, 15, 17, and 19: Clarified notes (e) and (g), corrected note (d) step number 

reference in some inspection figures, and corrected and/or revised some view section arrows and view 

callouts. Also, added inspection requirement for aluminum channel at STA 940, which was previously in 

the Work Instructions.

— In Figures 10, 11, 13, and 14: Corrected SRM references.

— Figure 22: This new figure has been added for one-time inspection for correct tension tie configuration on 

747-400F airplanes (Group 2 only).

— Figure 23: This new figure has been added to give additional inspection requirements if an incorrect 

tension tie configuration is found (Group 2 only).

— Appendix A: The Appendix has been deleted. In the original issue of this service bulletin, Appendix A was 

a logic diagram of inspection requirements. Logic diagrams are no longer maintained to match current 

compliance information.

— Appendix B: Deleted Method 2 and 4 for disconnecting tension ties. Method 2 and 4, that were specified 

in the original issue, are no longer recommended.

The data given in Information Notice 747-53-2502 IN 01 is included in this revision

Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity 

paragraph for changes.

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.
 

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REVISION HISTORY

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Revision 1:
 

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ALERT ALERT

Commercial

Airplanes 747

ALERT ALERT

Service Bulletin

Number: 747-53A2502 Summary

Original Issue: April 21, 2005

Revision 1: June 17, 2010

ATA System: 5300

SUBJECT: FUSELAGE - Non Stretched Upper Deck Tension Ties and Frames - Inspection 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

Accomplishment of the work given in this service bulletin will make sure the tension ties and frames aft of the 

upper deck floor are not cracked. Cracks in tension ties and/or frames could cause the tension ties to become 

severed or disconnected from the frames. Severed or disconnected tension ties and/or frames at multiple 

locations could result in rapid in-flight decompression.

Tension ties are installed to connect the left and right hand sides of the body structure aft of the upper deck floor.

During routine maintenance of a 747-200F airplane one operator reported a crack in the tension tie, at the body 

station (STA) 820 frame connection. The crack was found to be 1/8 inch at a fastener hole. Inspection of the 

747SR fatigue test airplane showed similar cracks in both the tension ties and frames at the tension tie to frame 

connections. The cracks were found at STA 800, 820, and 840 at 40,000 flight cycles (20,000 operating cycles, 

20,000 test cycles). Cracks in the frames were up to 1.25 inches long, and cracks in the tension ties were up to 

0.20 inches long.

Revision 1: Subsequent to the release of the original issue of this service bulletin, an operator reported finding 

a total of twelve cracks on forward and aft tension tie channels at STA 740 and STA 760 on a 747-400F airplane. 

After comparing the structure to the Boeing design configuration, it was determined that only seven fasteners 

were installed common to the frame at each end of the STA 760 tension tie. A quantity of nine fasteners should 

have been installed common to the frame at each end of the tension tie. 

Revision 1: After investigation, it has been determined that the airplane on which the discrepancy was found 

was manufactured and delivered by Boeing with the incorrect tension tie configuration at STA 760. Reduced 

load carrying capability of the STA 760 tension tie, due to cracks, subsequently lead to increased loads and 

premature fatigue cracks in the adjacent tension tie at STA 740.
 

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Revision 1: 747-200F airplanes and Boeing modified 747 Special Freighter airplanes have a unique tension tie 

configuration at STA 760, and only 747-400F airplanes have tension ties at STA 720 and STA 740. Therefore, 

only 747-400F airplanes are affected by the new inspection for correct configuration which was added in 

Revision 1.

Revision 1: In addition, due to new analysis of the tension tie structure, Boeing has determined that stresses are 

higher in the STA 720, STA 740, and STA 760 tension ties on 747-400F airplanes. Therefore, even if the tension 

tie configurations are correct, the detailed and high frequency eddy current (HFEC) inspections given in this 

service bulletin should begin at an earlier time. This has resulted in a reduced flight cycle compliance time for 

the initial inspection threshold at STA 720, STA 740, and STA 760 tension ties on 747-400F airplanes.

This service bulletin provides instructions for inspections and repair of the tension ties and frames aft of the 

upper deck floor. 

The tension ties and frames have been found to be structually significant in that it is critical to the structual 

integrity of the airplane. tension tie and frame cracks not found before they reach critical crack lengths can cause 

in-flight depressurization. If the work given in this service bulletin is not done the airplane structure may not be 

able to withstand current regulatory fail-safe loads.

Boeing Service Related Problem (SRP) 747OP-SRP-53-0200 is related to this service bulletin.

Boeing Service Related Problem (SRP) 747-SRP-53-0349 is related to this service bulletin.

Boeing Fleet Team Digest (FTD) article 747-FTD-53-09008 is related to this service bulletin.

Modification Service Bulletin 747-53A2605 has been released to address Widespread Fatigue Damage (WFD) 

in the tension ties and adjacent frame structure. Accomplishment of the modification in accordance with Service 

Bulletin 747-53A2605 will terminate the repeat inspection requirements of this service bulletin.

ACTION (PRR 85901-46RS)

Group 1, 3-6: Get access to all tension ties. Do detailed and HFEC inspections for cracks in all tension ties, 

adjacent frame structure, and adjacent structure that attaches to the tension ties. If any crack is found, repair 

as specified in this service bulletin, before further flight. Repeat inspections at the specified intervals.

Group 2: Do detailed and HFEC inspections for cracks in the tension ties and adjacent structure. If cracks are 

found, do the repair given in this service bulletin before further flight. Repeat inspections at the specified 

intervals. In addition, do a one-time general visual inspection at each tension tie location to determine if the 

correct design configuration is installed. At any tension tie where the correct configuration is not installed, do 

detailed and open hole HFEC inspections for cracks in the tension tie channels where they attach to the side of 

body frames. If no crack is found, install the correct tension tie configuration. If any crack is found, repair the 

tension tie in accordance with this service bulletin, or contact Boeing for repair instructions. 

All actions specified in this section should be done at the times given in paragraph 1.E., Compliance.

This service bulletin contains only a flight safety inspection program. The flight safety inspection program is the 

minimum inspection program to maintain the structural integrity of the affected area of the airplane. An optional 

economics based inspection, to be done earlier than the flight safety inspection, would usually be included in 

this type of bulletin. However, for this area there is no economics based inspection program. The repair 

necessary when a crack is found in the flight safety inspection is the same as the repair necessary if a crack is 

found earlier.
 

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EFFECTIVITY

747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SP, and 747SR airplanes. Refer to 

paragraph 1.A.1., Airplanes, for the list of affected airplanes.

COMPLIANCE

Refer to paragraph 1.E., Compliance.

Federal Aviation Administration (FAA) Airworthiness Directive AD 84-19-01 is related to this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 94-13-06 is related to this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 2004-07-22 R1 is related to this service 

bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 2006-01-07 is 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.

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the inspection or repair procedures given in this service bulletin, 

except for the one-time inspection and corrective actions related to inspection for incorrect configurations on 

747-400F airplanes. Please refer to Paragraph 2.B., Industry Support Information section of this service bulletin 

for more information.

MANPOWER

Refer to Paragraph 1.G., Manpower.

MATERIAL INFORMATION

Operator Supplied Parts/Materials.

Refer to Paragraph 2.A., Material - Price and Availability.
 

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FRAME (TYPICAL)

TENSION TIE (TYPICAL)

HORIZONTAL SHEAR WEB

(TYPICAL BOTH SIDES)

SLOPING SHEAR WEB

(TYPICAL BOTH SIDES)

INSPECT TENSION

TIES, FRAMES, AND

ADJACENT STRUCTURE

FOR FATIGUE CRACKS.

ON 747-400F

AIRPLANES, ALSO DO

A ONETIME

INSPECTION TO

ENSURE CORRECT

TENSION TIE

CONFIGURATIONS. DO

REPAIRS AND/OR

INSTALL THE CORRECT

CONFIGURATIONS, AS

NECESSARY.

FWD

359685
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ALERT ALERT

Commercial

Airplanes 747

ALERT ALERT

Service Bulletin

Number: 747-53A2502

Original Issue: April 21, 2005

Revision 1: June 17, 2010

ATA System: 5300

SUBJECT: FUSELAGE - Non Stretched Upper Deck Tension Ties and Frames - Inspection 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 airplanes shown below. Refer to PRR 85901-46RS for data about 

this change.
 

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Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line 

Number, and Serial Number data.

Airplane models:

747-100 747-100B 747-200B 747-200C

747-200F 747-400F 747SP 747SR

IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER

3P AIR FREIGHTERS (PFL)

5 RR307

GROUP CONFIGURATION DESCRIPTION

1 - All 747-100, -100B, -200B, and 747SR 

airplanes, except airplanes that have been 

modified by Boeing to Special Freighter 

configuration.

1 Group 1 airplanes, line numbers 1 through 203, 

that have not had a long steel plate installed at 

STA 760 in accordance with Service Bulletin 

747-53-2088.

2 Group 1 airplanes, line numbers 1 through 203 

that have had a long steel plate installed at STA 

760 in accordance with Service Bulletin 747-53-

2088.

3 Group 1 airplanes with Extended Upper Deck 

(EUD) modifications, or other modifications not 

listed elsewhere, that replaced the tension tie at 

STA 760 and/or STA 780 with a floor beam.

4 Group 1 airplanes, line numbers 203 and on, 

that had a long steel plate installed at STA 760 

during production.

2 - All 747-400F airplanes. These airplanes have 

tension ties from STA 720 to STA 940.

3 - All 747-SP airplanes. These airplanes have 

tension ties from STA 1040 to STA 1140.

4 - 747-100, -200B, and 747SR airplanes that have 

been modified by Boeing to Special Freighter 

configuration.

5 - All 747-200F airplanes. These airplanes have 

tension ties from STA 760 to STA 940 and a 

long steel plate installed at STA 780.

6 - All 747-200C (convertible) airplanes. These 

airplanes have tension ties from STA 800 to 

STA 940, and have a long steel plate installed at 

STA 920.
 

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ALERT ALERT

AAR AIRCRAFT SALES & LEASING (AFD)

1 RB681–RB682 RB691

AERO CONTROLS (AEO)

1 RA722–RA723

AEROLINEAS ARGENTINAS (ARG)

1 RD122–RD127

AFRICA UNITED HOLDING CO. (UHD)

1 RB010 RD513

AFX (AXL)

1 RD201

AGES AIRCRAFT SALES & LEASING (AGJ)

1 RB004

AIR ATLANTA ICELANDIC (AID)

1 RD414 RD647–RD648 RD755 RD771

2 RM861

5 RR204

AIR CHINA (BEJ)

1 RD783

5 RR451

AIR CHINA CARGO (CGC)

2 RL501–RL502 RR853

AIR CONTRACTORS LIMITED (HCA)

5 RR561

AIR FRANCE (AFA)

2 RL671 RL673–RL675

5 RR308–RR309

AIR INDIA (AIN)

1 RA729 RA731

AIR UNIVERSAL (UVL)

1 RD291 RD649

AIRBRIDGE CARGO (ABM)

2 RL576–RL577 RL579 RL672

5 RR555–RR556

ARKIA ISRAELI AIRLINES (ARK)

1 RA253

ASIANA AIRLINES (AAR)

2 RM862–RM863 RR746–RR747
 

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ALERT ALERT

ATLAS AIR (TLS)

1 RD692 RD753–RD754

2 RM892–RM893 RM895 RM897–RM899 RM901–RM904

RM906 RR748

4 RD361–RD364 RD366 RD641 RD646

RD691

5 RR301

6 RJ333

AVIATION EXPOSURE MANAGEMENT (EXU)

1 RD131–RD132 RD143

BAHRAIN ROYAL FLIGHT (BHR)

3 RH102

BALTIA AIR LINES (BLT)

1 RD004

BANC OF AMERICA LEASING (SBC)

1 RD001–RD002

BIMAN BANGLADESH AIRLINES (BNG)

1 RD260

BOEING (TBC)

5 RR222–RR223

BOEING AIRCRAFT HOLDING CO. (BHC)

1 RB693 RD181 RD451–RD454

6 RJ132

BOEING WICHITA MOD CENTER (WMC)

1 RD455

BULLFINCH LTD (BFN)

1 RB411–RB413

C.A.L. CARGO AIR LINES (CRG)

6 RJ331–RJ332

C.I.T. LEASING CORPORATION (TCI)

1 RB011 RD047

CAPITAL ASSET MANAGEMENT (CPG)

1 RD053

CARGAIR (CGL)

1 RD203

CARGOLUX AIRLINES (CLX)

2 RL551 RM881–RM890 RR722–RR724
 

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ALERT ALERT

CATHAY PACIFIC AIRWAYS (CAT)

2 RL581–RL586 RM856–RM859 RR951–RR952

CHINA AIRLINES (CHI)

2 RL411–RL412 RL414–RL430 RL481

CHINA CARGO (CIQ)

2 RL521–RL522

CHINA SOUTHERN AIRLINES (GUN)

2 RL751–RL752

DUBAI AIR WING (DAW)

2 RM852

4 RD622

EL AL ISRAEL AIRLINES (ELA)

5 RR225–RR226

ELITE AIRLINES S.A. (ETE)

4 RB696

EUREX AIRLINES (EXY)

5 RR552

EVA AIR (EVA)

2 RL401–RL403

EVERGREEN INTERNATIONAL A/L (EVR)

1 RA028 RA631 RA633 RD042

RD772–RD774

4 RB604 RB607 RD041 RD043

5 RR206

6 RJ131 RJ133

EVERGREEN TRADE INC. (EVG)

1 RA371 RD056–RD057 RD241 RD243

RD254–RD255 RD257

EXPORT RESTRICTED AIRPLANES (YWV)

1 RB711 RD681–RD682 RD791

3 RG101–RG104 RG141–RG142 RG171

4 RA101–RA103 RA112 RA161–RA163

5 RR001–RR004

6 RJ322

FINOVA (GRB)

1 RA651

G.A. TELESIS COMPONENT REPAIR (GTG)

1 RB692 RB697
 

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ALERT ALERT

GE (GEC)

1 RA016

GECAS (GEF)

1 RA007 RA013 RA027

GENERIC CUSTOMER/SUPPLIER (XXX)

1 RA749–RA750 RD104 RD531 RD592

5 RR202–RR203

GLOBAL PEACE INITIATIVE (GPI)

3 RG174

GLOBAL SUPPLY SYSTEMS (GSS)

2 RM891 RM894 RM896

GRACE CATHEDRAL INC. (GCI)

3 RG193

GRAND STAR (GCG)

2 RR861

GREAT WALL AIRLINES (GWL)

2 RM853 RR855

HELLENIC IMPERIAL AIRWAYS (HLE)

1 RD231–RD232 RD292 RD775

HORTA (HOB)

3 RG163

INTERNATIONAL AIR LEASES (IAL)

1 RB006

IRAQI AIRWAYS (IRQ)

3 RG095 RG172

6 RJ301–RJ303

JADE CARGO INTERNATIONAL (JDE)

2 RL511–RL516

JAL INTERNATIONAL (JAL)

2 RL461–RL462

JET AERO HOLDINGS (JHD)

3 RG122

JETT8 (JGP)

5 RR553

JOHNSON SPACE CENTER (ZBR)

1 RA908 RB601

3 RG091
 

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ALERT ALERT

JUMBO JET LEASING (JJL)

1 RA526 RA532–RA534 RA539

KABO AIR (KAB)

1 RA305 RA316 RA560 RB008

RD121 RD261–RD262

KALITTA AIR (KAC)

1 RA401–RA402 RA546 RD052 RD054

RD221 RD571 RD621

4 RA524 RA635 RA913 RD083

RD225 RD623

5 RR261–RR262 RR265–RR266 RR361–RR362 RR501

KLM - ROYAL DUTCH AIRLINES (KLM)

2 RL684

KOREAN AIR (KAL)

2 RL451–RL456 RM871–RM880 RR862

KUWAIT AIRWAYS (KUW)

1 RD202 RD204

L-3 COMMUNICATIONS (LCS)

1 RD352

LOADAIR CARGO (LRC)

2 RL571–RL572

LOGISTIC AIR, INC. (LGA)

1 RA015 RA217 RA266 RB722–RB723

4 RA910

5 RR342–RR343

MALAYSIA AIRLINES (MAS)

2 RL491–RL492

4 RD142 RD144

MARTINAIR HOLLAND (MTH)

2 RL681–RL683

MIDEX AIRLINES (MIX)

5 RR310

MK AIRLINES (MKA)

1 RD781

4 RD055 RD441

5 RR022–RR023 RR224 RR264 RR336

RR421 RR504

NEA HOLDINGS, INC. (NEA)

1 RB001 RD045–RD046
 

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ALERT ALERT

NIPPON CARGO AIRLINES (NCA)

2 RL471–RL480

4 RD461

NORTHWEST AIRLINES (NWA)

1 RD242 RD252–RD253 RD258–RD259

4 RD301–RD302

5 RR005 RR341 RR344–RR345 RR431–RR432

RR503 RR566

OCEAN AIRLINES (OCE)

1 RD658–RD659

OMAN ROYAL FLIGHT (RFO)

3 RG161

ORIENT THAI AIRLINES (OTH)

1 RA540 RA543–RA544

PAKISTAN INT'L AIRLINES (PIA)

1 RD701

POLAR AIR CARGO (PAO)

2 RL651–RL655 RM905

4 RD752

PRATT & WHITNEY ENGINE SERVICE (PWE)

3 RG213 RG222

PRONAIR (TXI)

5 RR221

RAYYAN AIR (RYY)

6 RJ321

ROYAL AIR MAROC (RAM)

1 RD671

S583 (583)

1 RD166–RD167

SAUDI ARABIAN AIRLINE (SRF)

3 RH101 RH122

SAUDI ARABIAN AIRLINES (SVA)

1 RB741–RB746 RB748

3 RH121

5 RR526

SIACARGO (SIT)

2 RL431–RL436 RM854–RM855 RR851–RR852 RR854

RR856
 

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ALERT ALERT

SINGAPORE AIRLINES (SIA)

2 RM851

SOUTHERN AIR (SOF)

1 RD751

4 RD411–RD412 RD583 RD642–RD643

5 RR024–RR025 RR302–RR305 RR551 RR554

STAR AIRLINES (SRQ)

1 RB421 RD426

SUO1 (UO1)

1 RB013–RB016

TIGER AIRCRAFT TRADING INC. (TGE)

4 RD233–RD235

TIGER AIRWAYS (TGR)

1 RD657

TNT AIRWAYS (TNB)

2 RL531–RL534

TRANSAERO AIRLINES (TRX)

1 RD226 RD356 RD471–RD475

TRANSATLANTIC INTL AIRLINES (TIB)

3 RG173

TRITON AVIATION SERVICES (TIA)

1 RA726

UNI-TOP AIRLINES (UTO)

1 RD782

UNKNOWN CUSTOMER (UNZ)

1 RA784 RB005

4 RD358

UPS (UPS)

1 RD051 RD058–RD059 RD593

2 RL561–RL568 RR701 RR721

4 RA026 RA029 RA033 RA902

RA912 RA915–RA916

US AIR FORCE (USF)

2 RM911

WINGS WORLD WIDE (WWW)

3 RG221

WORLDWIDE AIRCRAFT HOLDING CO. (WAH)

3 RG008
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

YANGTZE RIVER EXPRESS (YTH)

2 RL413

YEMENIA (YEM)

3 RG162

YONA (IOP)

3 RG009 RG191

IDENTIFICATION BY VARIABLE NUMBER

Variable Group

RA001–RA025 1

RA026 4

RA027–RA028 1

RA029 4

RA030–RA032 1

RA033 4

RA034 1

RA101–RA103 4

RA104–RA110 1

RA111–RA112 4

RA113–RA115 1

RA161–RA163 4

RA164 1

RA201–RA203 1

RA216–RA217 1

RA245–RA246 1

RA251–RA266 1

RA301–RA318 1

RA351–RA360 1

RA369–RA373 1

RA401–RA418 1

RA501–RA502 1

RA521–RA523 1

RA524 4

RA525–RA528 1

RA532–RA548 1

RA551–RA552 1

RA559–RA561 1

RA581–RA582 1

RA585 1
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

RA601–RA602 1

RA631 1

RA632 4

RA633 1

RA634–RA635 4

RA651–RA652 1

RA671–RA677 1

RA701–RA702 1

RA721–RA731 1

RA741–RA745 1

RA749–RA750 1

RA761–RA762 1

RA781–RA784 1

RA901–RA902 4

RA903–RA909 1

RA910–RA916 4

RB001–RB016 1

RB041 4

RB042 1

RB043 4

RB044 1

RB071–RB075 1

RB101–RB102 1

RB411–RB413 1

RB421 1

RB601–RB603 1

RB604–RB605 4

RB606 1

RB607 4

RB681–RB695 1

RB696 4

RB697 1

RB711 1

RB721–RB723 1

RB741–RB748 1

RD001–RD004 1

RD021–RD022 1

RD041 4

RD042 1

Variable Group
 

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ALERT ALERT

RD043–RD044 4

RD045–RD054 1

RD055 4

RD056–RD059 1

RD071–RD072 1

RD081 1

RD082–RD083 4

RD091–RD092 1

RD101–RD104 1

RD121–RD127 1

RD131–RD141 1

RD142 4

RD143 1

RD144 4

RD166–RD167 1

RD171–RD172 1

RD181–RD183 1

RD201–RD204 1

RD221–RD224 1

RD225 4

RD226 1

RD227 4

RD231–RD232 1

RD233–RD235 4

RD241–RD243 1

RD251–RD262 1

RD271–RD272 1

RD291–RD292 1

RD301–RD302 4

RD311 1

RD351–RD357 1

RD358 4

RD361–RD366 4

RD411–RD412 4

RD413–RD414 1

RD421–RD426 1

RD431–RD435 1

RD441–RD442 4

RD451–RD456 1

Variable Group
 

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ALERT ALERT

RD461 4

RD471–RD475 1

RD513–RD519 1

RD531–RD533 1

RD551 4

RD561 1

RD571 1

RD581–RD583 4

RD591–RD593 1

RD621 1

RD622–RD623 4

RD641–RD643 4

RD644–RD645 1

RD646 4

RD647–RD649 1

RD651–RD659 1

RD661 1

RD671 1

RD681–RD682 1

RD691 4

RD692 1

RD701–RD702 1

RD741–RD742 1

RD751 1

RD752 4

RD753–RD755 1

RD761 1

RD771–RD775 1

RD781–RD783 1

RD791–RD792 1

RE001 1

RG001–RG009 3

RG091 3

RG095 3

RG101–RG104 3

RG121–RG126 3

RG141–RG142 3

RG161–RG164 3

RG171–RG174 3

Variable Group
 

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ALERT ALERT

RG191–RG193 3

RG211–RG213 3

RG221–RG222 3

RH101–RH102 3

RH111–RH112 3

RH121–RH122 3

RJ131–RJ133 6

RJ151–RJ152 6

RJ301–RJ303 6

RJ321–RJ322 6

RJ331–RJ333 6

RL401–RL403 2

RL411–RL436 2

RL451–RL456 2

RL461–RL462 2

RL471–RL481 2

RL491–RL492 2

RL501–RL502 2

RL511–RL516 2

RL521–RL522 2

RL531–RL534 2

RL551 2

RL561–RL568 2

RL571–RL572 2

RL576–RL577 2

RL579 2

RL581–RL586 2

RL651–RL655 2

RL671–RL675 2

RL681–RL684 2

RL751–RL752 2

RM851–RM859 2

RM861–RM863 2

RM871–RM899 2

RM901–RM906 2

RM911 2

RR001–RR005 5

RR021–RR025 5

RR031 5

Variable Group
 

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ALERT ALERT

2. Spares Affected

None.

B. Concurrent Requirements

None.

C. Reason

Accomplishment of the work given in this Service Bulletin will make sure the tension ties and frames 

aft of the upper deck floor are not cracked. Cracks in tension ties and/or frames could cause the 

tension ties to become severed or disconnected from the frames. Severed or disconnected tension 

ties and/or frames at multiple locations could result in rapid in-flight decompression.

Tension ties are installed to connect the left and right hand sides of the body structure aft of the upper 

deck floor.

RR201–RR206 5

RR221–RR226 5

RR261–RR267 5

RR301–RR310 5

RR331–RR332 5

RR336 5

RR341–RR345 5

RR361–RR362 5

RR421–RR422 5

RR431–RR432 5

RR441–RR442 5

RR451 5

RR501–RR504 5

RR521–RR522 5

RR526 5

RR531 5

RR551–RR556 5

RR561 5

RR566 5

RR701 2

RR721–RR724 2

RR746–RR748 2

RR851–RR856 2

RR861–RR862 2

RR951–RR952 2

Variable Group
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

During routine maintenance of a 747-200F airplane one operator reported a crack in the tension tie, 

at the body station (STA) 820 frame connection. The crack was found to be 1/8 inch at a fastener hole. 

Inspection of the 747SR fatigue test airplane showed similar cracks in both the tension ties and frames 

at the tension tie to frame connections. The cracks were found at STA 800, 820, and 840 at 40,000 

flight cycles (20,000 operating cycles, 20,000 test cycles). Cracks in the frames were up to 1.25 inches 

long, and cracks in the tension ties were up to 0.20 inches long.

Revision 1: Subsequent to the release of the original issue of this service bulletin, an operator reported 

finding a total of twelve cracks on forward and aft tension tie channels at STA 740 and STA 760 on a 

747-400F airplane. After comparing the structure to the Boeing design configuration, it was 

determined that only seven fasteners were installed common to the frame at each end of the STA 760 

tension tie. A quantity of nine fasteners should have been installed common to the frame at each end 

of the tension tie. 

Revision 1: After investigation, it has been determined that the airplane on which the discrepancy was 

found was manufactured and delivered by Boeing with the incorrect tension tie configuration at STA 

760. Reduced load carrying capability of the STA 760 tension tie, due to cracks, subsequently lead 

to increased loads and premature fatigue cracks in the adjacent tension tie at STA 740.

Revision 1: 747-200F airplanes and Boeing modified 747 Special Freighter airplanes have a unique 

tension tie configuration at STA 760, and only 747-400F airplanes have tension ties at STA 720 and 

STA 740. Therefore, only 747-400F airplanes are affected by the new inspection for correct 

configuration which was added in Revision 1.

Revision 1: In addition, due to new analysis of the tension tie structure, Boeing has determined that 

stresses are higher in the STA 720, STA 740, and STA 760 tension ties on 747-400F airplanes. 

Therefore, even if the tension tie configurations are correct, the detailed and HFEC inspections given 

in this service bulletin should begin at an earlier time. This has resulted in a reduced flight cycle 

compliance time for the initial inspection threshold at STA 720, STA 740, and STA 760 tension ties on 

747-400F airplanes.

This service bulletin provides instructions for inspections and repair of the tension ties and frames aft 

of the upper deck floor. 

The tension ties and frames have been found to be structually significant in that it is critical to the 

structual integrity of the airplane. Tension tie and frame cracks not found before they reach critical 

crack lengths can cause in-flight depressurization. If the work given in this service bulletin is not done 

the airplane structure may not be able to withstand current regulatory fail-safe loads.

Boeing Service Related Problem (SRP) 747OP-SRP-53-0200 is related to this service bulletin.

Boeing Service Related Problem (SRP) 747-SRP-53-0349 is related to this service bulletin.

Boeing Fleet Team Digest (FTD) article 747-FTD-53-09008 is related to this service bulletin.

Modification Service Bulletin 747-53A2605 has been released to address Widespread Fatigue 

Damage (WFD) in the tension ties and adjacent frame structure. Accomplishment of the modification 

in accordance with Service Bulletin 747-53A2605 will terminate the repeat inspection requirements of 

this service bulletin.
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

Revision 1 is sent to reduce the initial inspection compliance time for Group 2 airplanes at STA 720, 

STA 740, and STA 760 and to add an inspection to ensure the correct tension tie configurations on 

Group 2 airplanes. Other changes have also been made in Revision 1. A list of Revision 1 changes 

can be found on the Revision Transmittal Sheet for Revision 1.

D. Description

Group 1, 3-6: Get access to all tension ties. Do detailed and HFEC inspections for cracks in all 

tension ties, adjacent frame structure, and adjacent structure that attaches to the tension ties. If any 

crack is found, repair as specified in this service bulletin, before further flight. Repeat inspections at 

the specified intervals.

Group 2: Do detailed and HFEC inspections for cracks in the tension ties and adjacent structure. If 

cracks are found, do the repair given in this service bulletin before further flight. Repeat inspections at 

the specified intervals. In addition, do a one-time general visual inspection at each tension tie location 

to determine if the correct design configuration is installed. At any tension tie where the correct 

configuration is not installed, do detailed and open hole HFEC inspections for cracks in the tension tie 

channels where they attach to the side of body frames. If no crack is found, install the correct tension 

tie configuration. If any crack is found, repair the tension tie in accordance with this service bulletin, 

or contact Boeing for repair instructions. 

All actions specified in this section should be done at the times given in paragraph 1.E., Compliance.

The basic airplanes have tension ties from STA 760 to STA 940. However, on some airplanes, some 

tension ties have been replaced by upper deck floor beams due to extended upper deck modifications, 

upper deck aft galley modification, or other modification. Operators should determine whether a floor 

beam or tension tie is installed at each station.

NOTE: This service bulletin recommends inspection of tension ties that are made up of back to back

channels, and the body frames that those tension ties connect to. On some airplanes, some

tension ties have been replaced by upper deck floor beams due to extended upper deck

modification, upper deck aft galley modification, or other modification. Due to the large

number of modifications available that each operator may have incorporated, this service

bulletin does not include groupings for airplanes incorporating all of these modifications.

Operators should determine whether a floor beam or a tension tie is installed at each station.

Refer to Appendix C, Figure B for an illustration of these configurations.

NOTE: Tension ties made from back to back aluminum channels have a steel plate installed at each

end of the tension tie at the connection to the frame. A distinction is made between "long"

steel plates and "short" steel plates. Long steel plates are approximately 20 inches long and

are installed at station 760 on 747-100, 747-SR, 747-200B, and 747-200 Combi airplanes

(that have not been modified by an extended upper deck modification). Long steel plates are

also installed at station 780 on 747-200 Freighter airplanes, and at station 920 on 747-200

convertible airplanes. Short steel plates are approximately 10 inches long and are typical at

all locations where long steel plates are not installed. Refer to Appendix C, Figure C for

illustrations of short and long steel plate configurations.
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

NOTE: An Airplane with an Extended Upper Deck is not the same as a Stretched Upper Deck. In an

Extended Upper Deck (EUD) Airplane, the upper deck contour extends aft to STA 1000.

Typically, EUD Airplanes have the tension ties at STA 760 and STA 780 replaced by floor

beams to extend the floor area of the upper deck. In a Stretched Upper Deck (SUD) Airplane,

the upper deck contour extends aft to STA 1283, as installed on 747-200 SUD Modified

Airplanes during production and 747-300 and 747-400 Passenger Airplanes. This service

bulletin does not apply to Stretched Upper Deck (SUD) Airplanes. Refer to Appendix C,

Figure A for an illustration of these configurations.

NOTE: Some Airplanes were delivered with Extended Upper Deck Modifications that installed floor

beams aft of Station 740. These Airplanes are not the same as Airplanes delivered with a

Stretched Upper Deck (SUD), which includes 747-300, 747-400 Passenger Airplanes, and

some 747-100 and 200 SUD Modified Airplanes.

NOTE: On 747-200 Freighter airplanes and Boeing modified 747 Special Freighter airplanes, the

tension tie at STA 760 is a built-up beam, made of an upper chord and a lower chord with a

shear web in between. This tension tie looks similar to a floor beam, but is considered a

tension tie, and should be inspected as specified in this service bulletin. Refer to Appendix

C, Figure B for an illustration of this configuration.

NOTE: Except for 747SP airplanes, airplanes modified from passenger to Special Freighter typically

have the life raft beams removed from above main entry door number 2. Removal of the life

raft beams changes the loads in the adjacent tension ties. For the purposes of this service

bulletin, airplanes modified to a Special Freighter or which have had the life raft beam

removed, are in airplane group 4 (This does not apply to 747SP airplanes because the

tension ties are not adjacent to a door).

NOTE: If the damaged area is more than the specified limits, write to Boeing for repair instructions.

Give the size and location of the damage. When possible, send sketches and photographs.

If the damage includes corrosion, send data on the length, width, and largest depth of clean

up.

Send to:

BOEING COMMERCIAL AIRPLANES GROUP

ATTENTION: MANAGER, AIRLINE SUPPORT

E. Compliance

Group 1, 3, 6: Table 1 - Compliance Times for Tension Tie Inspections.

Condition Action

Compliance Time

(Whichever Occurs Later)

Repeat Interval 

(Not to Exceed)

All airplanes. Do detailed and HFEC 

inspections of the tension 

ties in accordance with the 

INSPECTION steps of the 

Work Instructions.

Before 20,000 

total flight 

cycles.

Within 1,000 

flight cycles 

after the 

original issue 

date of this 

service bulletin.

4,000 flight cycles.
 

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Group 4-5: Table 2 - Compliance Times for Tension Tie Inspections.

Condition Action

Compliance Time

(Whichever Occurs Later)

Repeat Interval 

(Not to Exceed)

All airplanes. Do detailed and HFEC 

inspections of the tension 

ties in accordance with the 

INSPECTION steps of the 

Work Instructions.

Before 17,000 

total flight 

cycles

Within 1,000 

flight cycles 

after the 

original issue 

date of this 

service bulletin

3,000 flight cycles.

Group 2: Table 3 - Compliance Times for Tension Tie Inspections.

Condition Action

Compliance Time

(Whichever Occurs Later)

Repeat Interval 

(Not to Exceed)

All airplanes. At STA 720, 740, and 760, 

do detailed and HFEC 

inspections of the tension 

ties in accordance with the 

INSPECTION steps of the 

Work Instructions.

Before 8,000 

total flight 

cycles

Within 1,000 

flight cycles 

after the 

Revision 1 date 

of this service 

bulletin.

3,000 flight cycles.

At STA 780 through STA 

940, do detailed and HFEC 

inspections of the tension 

ties in accordance with the 

INSPECTION steps of the 

Work Instructions.

Before 17,000 

total flight 

cycles

Within 1,000 

flight cycles 

after the 

original issue 

date of this 

service bulletin

3,000 flight cycles.

Group 2: Table 4 - Compliance Times for One-Time Inspection for Correct Configuration.

Condition Action

Compliance Time

(Whichever Occurs Later)

All airplanes. Do a general visual inspection of the tension 

ties for correct configuration in accordance 

with the MORE WORK - ONE TIME 

INSPECTION FOR CORRECT 

CONFIGURATION section of paragraph 3.B., 

Work Instructions.

Before 8,000 

total flight 

cycles

Within 1,000 

flight cycles 

after the 

Revision 1 date 

of this service 

bulletin.

All tension ties have the 

correct configuration.

No more work is required for the one-time 

inspection for correct configuration.

- -
 

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ALERT ALERT

1. Life raft beams on passenger and convertible airplanes are installed over main entry door 

number 2.

a. Airplanes modified from passenger to Special Freighter typically have the life raft beams 

removed from above main entry door number 2.

b. Airplanes that do not have life raft beams over main entry door number 2 have higher loads 

in the adjacent tension ties than Airplanes with life raft beams installed. For the purpose of 

this Service Bulletin, Airplanes which do not have a life raft beam installed at main entry door 

number 2 (excluding group 3) should be inspected as shown for Airplane group 4.

Federal Aviation Administration (FAA) Airworthiness Directive AD 84-19-01 is related to this service 

bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 94-13-06 is related to this service 

bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 2004-07-22 R1 is related to this 

service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive AD 2006-01-07 is 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.

Incorrect configuration 

found.

Do detailed and HFEC inspections for cracks 

at tension tie locations where the incorrect 

configuration was found, in accordance with 

the MORE WORK - ONE TIME INSPECTION 

FOR CORRECT CONFIGURATION section 

of paragraph 3.B., Work Instructions.

Before further flight.

Any crack found. Do a repair, or contact Boeing for repair 

instructions, in accordance with the MORE 

WORK - ONE TIME INSPECTION FOR 

CORRECT CONFIGURATION section of 

paragraph 3.B., Work Instructions.

Before further flight.

No crack found. Install the correct configuration for the tension 

ties at locations where the incorrect 

configuration was found, in accordance with 

the MORE WORK - ONE TIME INSPECTION 

FOR CORRECT CONFIGURATION section 

of paragraph 3.B., Work Instructions.

Before further flight.

Group 2: Table 4 - Compliance Times for One-Time Inspection for Correct Configuration.

Condition Action

Compliance Time

(Whichever Occurs Later)
 

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ALERT ALERT

F. Approval

This service bulletin was examined by the Federal Aviation Administration (FAA). The changes 

specified in this service bulletin comply with the applicable regulations and are FAA approved, as well 

as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/

JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval 

were based on the airplane in its original Boeing delivery configuration or as modified by other 

approved Boeing changes.

If an airplane has a non-Boeing modification or repair that affects a component or system also affected 

by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency 

approval before incorporating this service bulletin.

The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the inspection and repair 

procedures with the corresponding compliance times specified in Service Bulletin 747-53A2502, 

Revision 1, as an Alternative Method of Compliance (AMOC) to the inspections and repairs required 

by paragraphs (h), (i), and (j) of AD 2004-07-22 R1, for the inspection of Structural Significant Item 

(SSI) F-19A of the Supplemental Structural Inspection Document (SSID) D6-35022, Revision G. This 

AMOC only applies to the areas inspected by this service bulletin. When this service bulletin specifies 

contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in 

accordance with paragraph (l) of the AD. All provisions of AD 2004-07-22 R1 that are not specifically 

referenced in this paragraph remain fully applicable and must be complied with.

The Manager of the FAA Seattle ACO approves the inspection and repair procedures with the 

corresponding compliance times specified in Service Bulletin 747-53A2502, Revision 1, as an AMOC 

to the inspections, repair and modification with the corresponding compliance times required by 

paragraphs A. and B. of AD 84-19-01. When this service bulletin specifies contacting Boeing for repair 

instructions, the repair instructions must be approved by the FAA in accordance with paragraph C. of 

the AD. All provisions of AD 84-19-01 that are not specifically referenced in this paragraph remain fully 

applicable and must be complied with.

The Manager of the FAA Seattle ACO approves the inspection and repair procedures with the 

corresponding compliance times specified in Service Bulletin 747-53A2502, Revision 1, as an AMOC 

to the inspections, repair and modification with the corresponding compliance times required by 

paragraphs (a) and (b) of AD 94-13-06. When this service bulletin specifies contacting Boeing for 

repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph 

(c) of the AD. All provisions of AD 94-13-06 that are not specifically referenced in this paragraph 

remain fully applicable and must be complied with.

The Manager of the FAA Seattle ACO approves the inspection and repair procedures with the 

corresponding compliance times specified in Service Bulletin 747-53A2502, Revision 1, as an AMOC 

to the inspections and corrective actions with the corresponding compliance times required by 

paragraph (f) of AD 2006-01-07. When this service bulletin specifies contacting Boeing for repair 

instructions, the repair instructions must be approved by the FAA in accordance with paragraph (g) of 

the AD. All provisions of AD 2006-01-07 that are not specifically referenced in this paragraph remain 

fully applicable and must be complied with.

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:
 

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— Time to adjust to the workplace

— Time to schedule the work

— Time to examine the work

— Time to cure the materials

— Time to make the parts

— Time to find the tools.

Group 1, Configuration 1: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 1 2 8.0 4.0

Figure 2 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) Most airplanes have ten tension tie locations. However, some airplanes could have 

six or eight tension tie locations.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 1, Configuration 2: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 3 2 8.0 4.0

Figure 4 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) Most airplanes have ten tension tie locations. However, some airplanes could have 

six or eight tension tie locations.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 1, Configuration 3: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 5 2 8.0 4.0

Figure 6 2 6.0 3.0

RESTORATION 2 2.0 1.0
 

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TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) There are 8 tension tie locations on each airplane.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 1, Configuration 4: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 7 2 8.0 4.0

Figure 8 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) Most airplanes have ten tension tie locations. However, some airplanes could have 

six or eight tension tie locations.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 2: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 0.50 0.25

Figure 9 2 1.5 0.75

Figure 10 2 8.0 4.0

Figure 11 2 6.0 3.0

Figure 12 2 1.5 0.75

RESTORATION 2 0.50 0.25

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) There are 12 tension tie locations on each airplane.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 1, Configuration 3: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours
 

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Group 3: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 13 2 8.0 4.0

Figure 14 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) There are 6 tension tie locations on each airplane.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 4: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 15 2 8.0 4.0

Figure 16 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) Most airplanes have nine tension tie locations. However, some airplanes could have 

six or eight tension tie locations.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 5: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 17 2 8.0 4.0

Figure 18 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) There are 9 tension tie locations on each airplane.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.
 

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ALERT ALERT

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not applicable.

J. References

1. Existing Data:

a. Engineering Change Memo PRR 85901-46RS

b. 747-100/200/300 Aircraft Maintenance Manual (AMM) 24-22-00, 25-14-02, 25-22-04, 

25-25-01

c. 747-100/200/300 Structural Repair Manual (SRM) 51-30-03, 51-30-05, 51-40-03, 53-10-04, 

53-10-11, 53-30-03

d. 747-400 Aircraft Maintenance Manual (AMM) 24-22-00, 25-21-04, 25-59-01

e. 747-400 Structural Repair Manual (SRM) 51-40-03

Group 6: Inspection for Fatigue Cracks

Task

Number of 

Persons Task-Hours Elapsed Hours

ACCESS 2 2.0 1.0

Figure 19 2 8.0 4.0

Figure 20 2 6.0 3.0

RESTORATION 2 2.0 1.0

TOTAL FOR EACH TENSION TIE LOCATION 

(a) (b)

18.0 9.0

(a) There are 8 tension tie locations on each airplane.

(b) It may not be necessary to do the work given in all Figures at all locations. Operators 

should refer to paragraph 1.E., Compliance and Appendix A - Logic Diagram, and total 

the number of hours required for each Figure as necessary.

Group 2: One-Time Inspection for Correct Configuration (Revision 1 - More Work)

Task

Number of 

Persons Task Hours Elapsed Hours

ACCESS 5 20.0 4.0

Figure 22 2 6.0 3.0

RESTORATION 5 20.0 4.0

TOTAL FOR EACH AIRPLANE 

(a)

46.0 11.0

(a) More time will be required if repairs are necessary, or if an incorrect 

configuration is found.
 

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f. 747-400F Structural Repair Manual (SRM) 51-40-03, 51-40-05, 51-70-11, 53-00-01, 

53-20-07, 53-20-30

g. 747-SP Structural Repair Manual (SRM) 51-30-03, 51-30-05, 51-40-03, 53-19-02, 53-19-11

h. 747 Non-Destructive Testing (NDT) Manual, Part 6, Subject 51-00-00, Figure 1, 11, or 16, 

Part 6, Subject 51-00-00, Figure 16, Part 6, Subject 51-00-00, Figure 19, Part 6, Subject 

51-00-00, Figure 4

i. Boeing Service Related Problem (SRP) 747-SRP-53-0349

j. Boeing Service Related Problem (SRP) 747OP-SRP-53-0200

k. Boeing Service Bulletin 747-53-2088, 747-53-2371, 747-53A2605

l. Federal Aviation Administration (FAA) Airworthiness Directive 2004-07-22 R1, 2006-01-07, 

84-19-01, 94-13-06

m. Standard Overhaul Practices Manual (SOPM) 20-41-05, 20-50-19

2. Data supplied with this Service Bulletin:

None.
 

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ALERT ALERT

3. Installation Drawings Used in the Preparation of this Service Bulletin:

These drawings were used to prepare this service bulletin. These drawings are not necessary to 

make the specified changes, and are not supplied with this service bulletin. These drawings may 

not be applicable to all airplane configurations or operators.

K. Publications Affected

1. Publications

Drawing Number Title

65B09631 Tension Tie Installation - STA 760 to STA 940, STA 1040 to STA 

1220. 747/100/200/SP Airplanes

142U1023 Tension Tie Installation - STA 720 to STA 940 747-400F Airplanes

65B24488 Tension Tie Installation - STA 760 to STA 940 - Mod Drawing.

65B01729 Body Station 720 Machined Fitting (400F only)

65B01730 Body Station 740 Machined Fitting (400F only)

65B01731 Body Station 760 Machined Fitting

65B01732 Body Station 780 Machined Fitting

65B01733 Body Station 800 Machined Fitting

65B01734 Body Station 820 Built Up Frame Section

65B01735 Body Station 840 Built Up Frame Section

65B01736 Body Station 860 Built Up Frame Section

65B01737 Body Station 880 Built Up Frame Section

65B01738 Body Station 900 Built Up Frame Section

65B01739 Body Station 920 Built Up Frame Section

65B01740 Body Station 940 Built Up Frame Section

65B01745 Body Station 1040 Built Up Frame Section (SP only)

65B01746 Body Station 1060 Built Up Frame Section (SP only)

65B01747 Body Station 1080 Built Up Frame Section (SP only)

65B01748 Body Station 1100 Built Up Frame Section (SP only)

65B01749 Body Station 1120 Built Up Frame Section (SP only)

65B18703 Body Station 1140 Built Up Frame Section (SP only)

65B38730 Installation of life raft beam over main entry door number 2.

65B12358 Installation of life raft beam over main entry door number 2.

65B38730 Built-up Tension Tie at STA 760

65B16291 Body Station 760 Tension Tie Beam Installation (Special Freighter)

65B16292 Body Station 780 Tension Tie Installation (Special Freighter)

Publication Chapter-Section

747 Structural Repair Manual 53-11

747 Illustrated Parts Catalog 53-12
 

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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 and new 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.
 

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ALERT ALERT

2. MATERIAL INFORMATION

A. Material - Price and Availability

Boeing can supply the parts shown in Paragraph 2.C., Parts Necessary For Each Airplane as shown 

below. If there is a limit to the quantity (QTY) of available parts, a supply sequence is given by Spares. 

More parts become available as shown in the Reorder Lead Time (ROLT). ROLT is calculated from 

the date Boeing gets the purchase order.

B. Industry Support Information

Boeing warranty remedies are not available for the inspection or repair procedures given in this 

service bulletin, except as specified below.

Group 2: Boeing warranty remedies are available for inspection and corrective actions related to the 

one-time inspection for incorrect configuration on 747-400F airplanes in warranty as of September 9, 

2009. For inspection task hour reimbursement for airplanes in warranty as of that date, send a 

warranty claim to Boeing Commercial Airplanes Group - Warranties. If the incorrect configuration 

condition described in this service bulletin is found during the inspection for airplanes in warranty as 

of that date and additional task hours and/or parts are required, send a warranty claim to Boeing 

Commercial Airplanes Group - Warranties. Please refer to this service bulletin number and reference 

the airplane variable number in your purchase order.

C. Parts Necessary For Each Airplane

1. Kits/Parts:

To get the parts shown below, refer to Paragraph 2.A., Material - Price and Availability.

Part Number Name Date QTY

ROLT 

(Weeks)

Unit Price thru

Dec 31/10

142U0105-4 Tension Tie Segment Jun 08/10 60 15 $580.00

142U0104-1 Tension Tie Splice Jun 04/10 60 15 $391.00

New Part Number QTY Name

Existing Part 

Number Notes

142U0105-4 2 Tension Tie Segment - (a) (b)

142U0104-1 2 Tension Tie Splice - (a) (b)

(a) This part is needed to perform SRM at STA 720, STA 740, and STA 760 on 747-400F 

airplanes. A limit number of these parts are available in Boeing Spares. The quantity 

shown is the number of parts necessary to do SRM repair at each end of the tension tie 

where. As an option to purchasing these parts from Boeing, operators can fabricate 

their own parts in accordance with the SRM.

(b) This part is identified to support the one-time inspection for correct configuration on 747-

400F airplanes.
 

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ALERT ALERT

2. Parts and Materials Supplied by the Operator:

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.

Part Number / 

Specification QTY Name Notes

BACB30NX( )K( ) 450 Hex Drive Bolt (a) (c) (d) (e)

BACN10YT( )CD 450 Nut (a) (c) (d) (e)

BACW10BP( )DP 450 Washer (a) (c) (d)

BMS 3-23, Type II 24 ounces Corrosion Inhibiting Compound (b) (c)

BMS 3-27 

(BMS 3-38 optional)

12 ounces Sealant (b) (c)

BMS 10-11 Type 1 12 ounces Primer (b) (c)

Alodine 1200 12 ounces Chemical Conversion Coating (b) (c)

(a) Refer to 747 Structural Repair Manual Chapter 51 for alternative fasteners.

(b) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.

(c) Quantities are approximate. The actual quantity required will vary depend the group and configuration 

of the airplane, inspection results, and if any repairs are accomplished.

(d) Operators should have access to standard, first and second over size 3/16 and 1/4 inch diameter 

fasteners, and 5/16 standard diameter fasteners in grip lengths ranging from -3 to -8.

(e) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts and 

BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at fastener 

locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is limited. 

Also, if fasteners are substituted, the same type of fastener should be used throughout each joint, as 

shown in Appendix C, Figure F.
 

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ALERT ALERT

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:

— Hole dimensions for standard solid rivets are given in 747 Structural Repair 

Manual, Chapter 51.

— Torque limits to tighten nuts and bolts are given in 747 Structural Repair Manual, 

Chapter 51.

4. Use the approved fastener and process material substitutions in accordance with 747 

SRM, Chapter 51. Alternate fasteners are listed in 747 SRM, Chapter 51 and Boeing 

Drawing 012W6100.

5. If the length of any fastener specified in this service bulletin does not meet the 

installation standards in SRM Chapter 51, then a fastener of the same specification, or 

an approved substitute, with a length which meets the installation standards in SRM 

Chapter 51 may be used.

6. The following Instructions apply to all tension ties that are made by fastening two 

aluminum channels back to back. Some of the tension ties also have an aluminum 

doubler sandwiched between the channels, and others have an additional aluminum 

channel fastened to the lower flanges of the back to back channels. Refer to Appendix 

C, Figure D for an illustration of these configurations.

7. This Service Bulletin recommends inspection of tension ties that are made up of backto-back channels, and the body frames that those tension ties connected to. On some 

Airplanes, some tension ties have been replaced by upper deck floor beams due to 

extended upper deck modifications, or other modifications. Due to the large number of 

modifications available that each operator may have incorporated, this service bulletin 

does not include groupings for Airplanes incorporating all of these modifications. 

Operators should determine whether a floor beam or tension tie is installed at each 

station. Refer to Appendix C, Figure B for an illustration of these configurations.

8. Some airplanes in Group 4 (Boeing-Modified Special Freighter) and Group 5 (747-200 

Freighter) have a built-up beam installed at STA 760 that looks similar to a floor beam, 

but is a tension tie. There are no floor panels attached to this built-up tension tie. For 

Group 4 and Group 5 airplanes that have a built-up tension tie installed at STA 760, an 

inspection of this tension tie is required in accordance with this service bulletin.
 

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

9. This service bulletin does not apply to locations where floor beams are installed instead 

of tension ties. For inspections of floor beams, refer to Boeing document D6-35022, 

Supplemental Structural Inspection Document for 747 airplanes and other applicable 

service documents.

10. The basic airplanes have tension ties from STA 760 to STA 940. However, on some 

airplanes, some tension ties have been replaced by upper deck floor beams due to 

extended upper deck modifications, upper deck aft galley modification, or other 

modification. Operators should determine whether a floor beam or tension tie is installed 

at each station.

11. 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.

12. In the instructions and Figures, the tension tie to frame joint configuration shown is a 

typical representative view. Actual configurations vary depending on location.

13. For Group 1 airplanes that have tension ties at STA 760 and STA 780, some airplanes 

could have been modified with a longer steel plate at STA 760 and/or STA 780 in 

accordance with Service Bulletin 747-53-2088. This modification would not be installed 

on airplanes with an extended upper deck modification. Refer to Appendix C, Figure E 

for an illustration of this configuration.

14. For 747 airplanes, line numbers 1 through 203, Service Bulletin 747-53-2088 and 

Service Bulletin 747-53-2371 inspections also apply if modifications in accordance with 

those service bulletins have not been accomplished.

15. In the Figures of this service bulletin, Right Buttock Line (RBL) and Left Buttock Line 

(LBL) are used as reference points. RBL is defined as the perpendicular distance in 

inches right of the fuselage vertical center line. LBL is defined as the perpendicular 

distance in inches left of the fuselage center line.

16. Some airplanes may have been modified with a longer steel plate at some locations, in 

accordance with Service Bulletin 747-53-2088. If longer steel plates are found, ensure 

that they conform to Service Bulletin 747-53-2088, and re-install them as necessary 

during accomplishment of this service bulletin.

17. Some airplanes may have been modified or repaired at some locations, in accordance 

with Service Bulletin 747-53-2371 or Service Bulletin 747-53-2088 optional modification, 

which trims the aft tension tie channel and installs a repair strap under the steel plate. If 

a repair strap is installed in accordance with Service Bulletin 747-53-2088 or Service 

Bulletin 747-53-2371, then re-install the short steel plate and repair strap. If an aft 

channel is being replaced by this service bulletin, it is not necessary to re-install the 

Service Bulletin 747-53-2088 or Service Bulletin 747-53-2371 repair strap.

18. In the following work instructions, it is acceptable to substitute fasteners in accordance 

with 747-100/200/300 SRM 51-30-03, or 747-400F SRM 51-40-03, or 747-SP SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be 

used throughout each joint in accordance with Appendix C, Figure F.
 

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ALERT ALERT

19. Instead of repairing tension ties, it is acceptable to replace tension ties from end to end, 

at operator’s discretion.

20. This note is deleted (Revision 1).

21. Appendix B shows tension tie disconnection methods.

22. These work instructions refer to procedures included on 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.

23. The instructions identified in Paragraph 3.B. Work Instructions and the Figures(s) give 

the recommended sequence of steps. The sequence of steps to do this service bulletin 

can be changed.

24. A General Visual Inspection is defined as: A visual examination of an interior or exterior 

area, installation or assembly to detect obvious damage, failure or irregularity. This level 

of inspection is made from within touching distance unless otherwise specified. A mirror 

may be necessary to ensure visual access to all surfaces in the inspection area. This 

level of inspection is made under normal available lighting conditions such as daylight, 

hangar lighting, flashlight or drop-light and may require removal or opening of access 

panels or doors. Stands, ladders or platforms may be required to gain proximity to the 

area being checked.

25. Where these work instructions state that a removed part must be kept and later installed, 

the operator may discard the part and install a new or serviceable part, with the same 

part number, in lieu of the kept/removed part, unless otherwise noted in the instructions.

B. WORK INSTRUCTIONS

Group 1: ACCESS

1. Remove electrical power and ground the airplane. Refer to 747-100/200/300 AMM 24-22-00 as 

an accepted procedure.

2. Remove seats as necessary between STA 760 and STA 940. Refer to 747-100/200/300 AMM 

25-25-01 as an accepted procedure.

3. Remove the ceiling panels as necessary to get access to the tension ties. Refer to 747-100/200/

300 AMM 25-22-04 as an accepted procedure.

4. Remove insulation as necessary to get access to the tension ties. Refer to 747-100/200/300 

AMM 25-14-02 as an accepted procedure.

Group 2: ACCESS

1. Remove electrical power and ground the airplane. Refer to 747-400 AMM 24-22-00 as an 

accepted procedure.

2. Remove ceiling panels as necessary between STA 720 and STA 940. Refer to Figure 9 for an 

accepted procedure.
 

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ALERT ALERT

3. Remove insulation as necessary to get access to the tension ties. Refer to 747-400 AMM 

25-21-04 as an accepted procedure.

Group 3: ACCESS

1. Remove electrical power and ground the airplane. Refer to 747-100/200/300 AMM 24-22-00 as 

an accepted procedure.

2. Remove seats as necessary between STA 1040 and STA 1140. Refer to 747-100/200/300 AMM 

25-25-01 as an accepted procedure.

3. Remove the ceiling panels as necessary to get access to the tension ties. Refer to 747-100/200/

300 AMM 25-22-04 as an accepted procedure.

4. Remove insulation as necessary to get access to the tension ties. Refer to 747-100/200/300 

AMM 25-14-02 as an accepted procedure.

Group 4-6: ACCESS

1. Remove electrical power and ground the airplane. Refer to 747-100/200/300 AMM 24-22-00 as 

an accepted procedure.

2. Remove the ceiling panels as necessary to get access to the tension ties. Refer to 747-100/200/

300 AMM 25-22-04 as an accepted procedure.

3. Remove the insulation as necessary to get access to the tension ties. Refer to 747-100/200/300 

AMM 25-14-02 as an accepted procedure.

Group 1, Configuration 1: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 1.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 1, and 

repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. On airplanes that have a tension tie at STA 760, but do not have an extended upper deck 

modification or other modifications, there is a full-length aluminum doubler installed at STA 760 

between the tension tie channels. If the doubler is cracked, before further flight, do one of the 

following steps:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.
 

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ALERT ALERT

b. If any crack is found in the doubler that cannot be removed by doing OVERSIZE HOLE 

REPAIR, repair in accordance with 747-100/200/300 SRM 53-10-11 Figure 2 Detail XI, or 

contact Boeing for repair instructions.

4. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2 Detail VIII, or contact Boeing for repair 

instructions.

5. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 - STA 840 or STA 840 - STA 860, depending on

the airplane.

6. On built-up frames, if a shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

7. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

8. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

9. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

10. Assemble parts with new fasteners in accordance with Figure 1. Where fasteners are not 

specified in Figure 1 or in a repair, install original size and type fasteners.

11. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 1, Configuration 2: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION
 

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ALERT ALERT

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 3.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 3, and 

repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. On airplanes that have a tension tie at STA 760, but do not have an extended upper deck 

modification or other modifications, there is a full-length aluminum doubler installed at STA 760 

between the tension tie channels. If the doubler is cracked, before further flight, do one of the 

following steps:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. If any crack is found in the doubler that cannot be removed by doing OVERSIZE HOLE 

REPAIR, repair in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact 

Boeing for repair instructions.

4. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2 Detail XI, or contact Boeing for repair 

instructions.

5. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 - STA 840 or STA 840 - STA 860, depending on

the Airplane.

6. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

7. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

8. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

9. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:
 

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ALERT ALERT

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

10. Assemble parts with new fasteners in accordance with Figure 3. Where fasteners are not 

specified in Figure 3 or in a repair, install original size and type fasteners.

11. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 1, Configuration 3: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 5.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 5, and 

repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tansion tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

4. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 - STA 840 or STA 840 - STA 860, depending on

the Airplane.

5. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie. 

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

6. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.
 

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ALERT ALERT

7. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

8. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

9. Assemble parts with new fasteners in accordance with Figure 5. Where fasteners are not 

specified in Figure 5 or in a repair, install original size and type fasteners.

10. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 1, Configuration 4: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 7.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 7, and 

repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. On airplanes that have a tension tie at STA 760, but do not have an extended upper deck 

modification or other modifications, there is a full-length aluminum doubler installed at STA 760 

between the tension tie channels. If the doubler is cracked, before further flight, do one of the 

following steps:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. If any crack is found in the doubler that cannot be removed by doing OVERSIZE HOLE 

REPAIR, repair in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact 

Boeing for repair instructions.
 

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ALERT ALERT

4. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

5. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 - STA 840 or STA 840 - STA 860, depending on

the Airplane.

6. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following: 

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

7. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

8. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

9. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

10. Assemble parts with new fasteners in accordance with Figure 7. Where fasteners are not 

specified in Figure 7 or in a repair, install original size and type fasteners.

11. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 2: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 10.
 

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NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 10, 

and repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-400F SRM 53-20-30 Repair 1, or contact Boeing for repair instructions.

4. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 780 to STA 800.

5. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-400F SRM 

53-20-07 Repairs 1 - 10, do the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

6. If a crack is found in the skin, repair the skin before further flight in accordance with 747-400F 

SRM 53-00-01, or contact Boeing for repair instructions.

7. If cracks are found in holes where insulation blanket studs go through the frames, repair before 

further flight. Repair in accordance with 747-400F SRM 53-20-07 Repairs 1 - 10, or contact 

Boeing for repair instructions.

8. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-400F SRM 53-20-30, Repair 1.

9. Assemble parts with new fasteners in accordance with Figure 10. Where fasteners are not 

specified in Figure 10 or in a repair, install original size and type fasteners.

10. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 3: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT
 

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ALERT ALERT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 13.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 13, 

and repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 1140, there is a full length aluminum reinforcing channel installed at the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-SP SRM 53-19-11 Figure 1 Detail II, or contact Boeing for repair 

instructions.

4. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 1040 to STA 1060.

5. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-SP SRM 53-19-02 

Figures 65 - 70, do the FRAME REPAIR steps, or contact Boeing for repair instructions.

6. If a crack is found in the skin, repair the skin before further flight. Repair in accordance with 

747-SP SRM 53-19-01 Figure 1, or contact Boeing for repair instructions.

7. If cracks are found in holes where insulation blanket studs go through the frames, repair before 

further flight. Repair in accordance with the FRAME REPAIR steps or contact Boeing for repair 

instructions.

8. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-SP SRM 53-19-11, Figure 1.

9. Assemble parts with new fasteners in accordance with Figure 13. Where fasteners are not 

specified in Figure 13 or in a repair, install original size and type fasteners.
 

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ALERT ALERT

10. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 4: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 15.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 15, 

and repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

4. On some airplanes, the tension tie at STA 760 is a built-up beam made from an upper chord, 

lower chord, and a shear web in between. This tension tie looks similar to a floor beam, but is 

considered a tension tie. Do a detailed inspection of the upper chord, lower chord, and web of 

the tension tie at STA 760 from end to end. If any crack is found on the built up beam, repair 

before further flight. If necessary, contact Boeing for Repair instructions.

5. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed either between STA 820 and STA 840, or between STA 840

and STA 860, depending on the airplane.

6. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

7. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

8. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.
 

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ALERT ALERT

9. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

10. Assemble parts with new fasteners in accordance with Figure 15. Where fasteners are not 

specified in Figure 15 or in a repair, install original size and type fasteners.

11. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 5: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 17.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 17, 

and repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2 or contact Boeing for repair 

instructions.

4. The tension tie at STA 760 is a built-up beam made from an upper chord, lower chord, and a 

shear web in between. This tension tie looks similar to a floor beam, but is considered a tension 

tie. Do a detailed inspection of the upper chord, lower chord, and web of the tension tie at STA 

760 from end to end. If any crack is found on the built up beam, repair before further flight. If 

necessary, contact Boeing for Repair instructions.

5. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 to STA 840.

6. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following: 
 

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ALERT ALERT

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie. 

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

7. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

8. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

9. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

10. Assemble parts with new fasteners in accordance with Figure 17. Where fasteners are not 

specified in Figure 17 or in a repair, install original size and type fasteners.

11. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 6: INSPECTION

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Inspect the tension ties, frames, and associated parts for cracks in accordance with Figure 19.

NOTE: If there are insulation blanket studs attached to the frames in the inspection area, check

to see if the studs are bonded on to the frames, or if they go through holes in the frames.

At locations where the studs go through holes in the frames, remove the stud and

inspect the hole in accordance with Figure 21.

2. If no cracks are found, install removed parts with new fasteners in accordance with Figure 19, 

and repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

3. At STA 940, there is a full length aluminum reinforcing channel installed on the bottom of the 

tension tie. If the aluminum channel is cracked, repair it before further flight. Repair in 

accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.
 

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ALERT ALERT

4. If any crack is found in a shear web component, contact Boeing for repair instructions.

NOTE: Shear webs are installed at STA 820 to STA 840.

5. On built-up frames, if the shear tie is cracked at the flange common to the skin, do the following:

a. Remove fasteners as required and do an open-hole HFEC inspection of the skin for cracks 

at all fastener locations common to the cracked shear tie.

b. Repair the shear tie before further flight. Repair in accordance with 747-100/200/300 SRM 

53-10-04 Figures 132 through 139, the FRAME REPAIR steps, or contact Boeing for repair 

instructions.

6. If a crack is found in the skin, repair the skin before further flight in accordance with 747-100/200/

300 SRM 53-30-03, or contact Boeing for repair instructions.

7. If cracks are found in holes where insulation blanket studs go through the frames, repair in 

accordance with 747-100/200/300 SRM 53-10-04 Figures 132 through 139, the FRAME REPAIR 

steps, or contact Boeing for repair instructions and install the repair before further flight.

8. If cracks are found in fastener holes in the tension ties or frames, before further flight, do the 

repair as follows:

a. For small cracks at hole locations that can be removed by oversizing the hole to a maximum 

hole diameter of 0.313 inch, do the OVERSIZE HOLE REPAIR steps.

b. For any frame crack that cannot be removed by doing OVERSIZE HOLE REPAIR, do the 

FRAME REPAIR steps.

c. For any tension tie crack that cannot be removed by doing OVERSIZE HOLE REPAIR, 

repair the tension tie in accordance with 747-100/200/300 SRM 53-10-11, Figure 2.

9. Assemble parts with new fasteners in accordance with Figure 19. Where fasteners are not 

specified in Figure 19 or in a repair, install original size and type fasteners.

10. Repeat the INSPECTION steps at the intervals specified in paragraph 1.E., Compliance.

Group 1, Configuration 1: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing the hole in accordance with Figure 2.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).
 

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ALERT ALERT

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 1, Configuration 2: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing the hole in accordance with Figure 4.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 1, Configuration 3: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove cracks in holes by oversizing hole in accordance with Figure 6.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 1, Configuration 4: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION
 

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ALERT ALERT

TIES.

1. Remove cracks in holes by oversizing hole in accordance with Figure 8.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 2: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing holes in accordance with Figure 11.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

Splice in a new segment of fail-safe chord in accordance with 747-400F SRM 51-70-11. The 

dimensions of the new chord should be increased to maintain minimum edge margin of 2D.

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-400F SRM 53-20-30 Repair 1, or contact Boeing for repair 

instructions.

Group 3: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing hole in accordance with Figure 14.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

Splice in a new segment of fail-safe chord in accordance with 747-SP SRM 51-40-03. The 

dimensions of the new chord should be increased to maintain minimum edge margin of 2D.

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-SP SRM 53-19-11 Figure 1, or contact Boeing for repair instructions.
 

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ALERT ALERT

Group 4: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove any small cracks at holes by oversizing hole in accordance with Figure 16.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 5: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing hole in accordance with Figure 18.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 6: OVERSIZE HOLE REPAIR

CAUTION: DO NOT REMOVE THE FASTENERS FROM ADJACENT TENSION TIE TO FRAME

JOINTS AT THE SAME TIME. IF FASTENERS ARE REMOVED FROM ADJACENT

TENSION TIES, DAMAGE TO THE AIRPLANE STRUCTURE MAY OCCUR. REFER

TO APPENDIX B FOR ALLOWABLE METHODS TO DISCONNECT THE TENSION

TIES.

1. Remove small cracks at holes by oversizing hole in accordance with Figure 20.

2. If any edge margin is less than 1.5D in the frame webs, do the FRAME REPAIR steps.
 

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ALERT ALERT

3. If any edge margin is less than 1.5D in the fail-safe chord, replace the chord. It is acceptable to 

splice in a new segment of fail-safe chord in accordance with 747-100/200/300 SRM 51-40-03. 

The dimensions of the new chord should be increased to maintain minimum edge margin of 2 

times fastener diameter (2D).

4. If any edge margin is less than 1.5D in the tension tie or tension tie steel plate, repair the tension 

tie in accordance with 747-100/200/300 SRM 53-10-11 Figure 2, or contact Boeing for repair 

instructions.

Group 1: FRAME REPAIR

1. For frame cracks at STA 820 through STA 940 (built up frames) repair in accordance with 

747-100/200/300 SRM 53-10-04 Figures 132 through 139.

2. For frame cracks at stations forward of STA 820 (machined frames), contact Boeing for repair 

instructions.

Group 2: FRAME REPAIR

1. For frame cracks at STA 820 through STA 940 (built up frames) repair in accordance with 

747-400F SRM 53-20-07 Repairs 1 through 10.

2. For frame cracks at stations forward of STA 820 (machined frames), contact Boeing for repair 

instructions.

Group 3: FRAME REPAIR

1. Repair frame cracks in accordance with 747-SP SRM 53-19-02 Figures 65 through 70.

Group 4-6: FRAME REPAIR

1. For frame cracks at STA 820 through STA 940 (built up frames) repair in accordance with 

747-100/200/300 SRM 53-10-04 Figures 132 through 139.

2. For frame cracks at stations forward of STA 820 (machined frames), contact Boeing for repair 

instructions.

Group 1: RESTORATION

1. Apply BMS 3-23, Type II, Corrosion Inhibiting Compound to all areas where fasteners were 

removed, and where repairs were done. Refer to SOPM 20-41-05 as an accepted procedure.

2. Install insulation. Refer to 747-100/200/300 AMM 25-14-02 as an accepted procedure.

3. Install ceiling panels. Refer to 747-100/200/300 AMM 25-22-04 as an accepted procedure.

4. Install seats between STA 760 and STA 940. Refer to 747-100/200/300 AMM 25-25-01 as an 

accepted procedure.

5. Return airplane to a Serviceable Condition.
 

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ALERT ALERT

Group 2: RESTORATION

1. Apply BMS 3-23, Type II, Corrosion Inhibiting Compound to all areas where fasteners were 

removed, and where repairs were done. Refer to SOPM 20-41-05 as an accepted procedure.

2. Install insulation. Refer to 747-400 AMM 25-21-04 as an accepted procedure

3. Install ceiling panels. Refer to Figure 12 for an accepted procedure.

4. Return airplane to a serviceable condition.

Group 3: RESTORATION

1. Apply BMS 3-23, Type II, Corrosion Inhibiting Compound to all areas where fasteners were 

removed, and where repairs were done. Refer to SOPM 20-41-05 as an accepted procedure.

2. Install insulation. Refer to 747-100/200/300 AMM 25-14-02 as an accepted procedure.

3. Install ceiling panels. Refer to 747-100/200/300 AMM 25-22-04 as an accepted procedure.

4. Install seats between STA 1040 and STA 1140. Refer to 747-100/200/300 AMM 25-25-01 as an 

accepted procedure.

5. Return airplane to a serviceable condition.

Group 4-6: RESTORATION

1. Apply BMS 3-23, Type II, Corrosion Inhibiting Compound to all areas where fasteners were 

removed, and where repairs were done. Refer to SOPM 20-41-05 as an accepted procedure.

2. Install insulation. Refer to 747-100/200/300 AMM 25-14-02 as an accepted procedure.

3. Install ceiling panels. Refer to 747-100/200/300 AMM 25-22-04 as an accepted procedure.

4. Return airplane to a serviceable condition.

Group 2: MORE WORK - ONE TIME INSPECTION FOR CORRECT CONFIGURATION (Revision 

1)

1. Do a general visual inspection of the tension ties to ensure all tension ties have the correct 

configuration where they attach to the side of body frames. Do this inspection in accordance with 

Figure 22. 

2. If all tension ties match the correct configurations shown in Figure 22, then no more work is 

required for this one time inspection.

3. If any tension tie does not match the correct configuration shown in Figure 22, do the following 

steps, as applicable:

a. Do the detailed and open hole HFEC inspections for cracks in the tension tie and frame in 

accordance with Figure 23. Do these inspections at both ends of any tension tie where the 

configuration did not match the correct configuration shown in Figure 22.
 

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ALERT ALERT

b. If any crack is found in a tension tie channel, repair the cracked tension tie in accordance 

with 747-400F SRM 53-20-30 Repair 1, or contact Boeing for repair instructions.

c. If any crack is found in a frame from STA 820 through STA 940, repair in accordance with 

747-400F SRM 53-20-07 Repairs 1 through 10.

d. If any crack is found in a frame forward of STA 820, contact Boeing for repair instructions.

e. If no crack is found, or if cracks have been repaired, install the correct configuration for the 

tension ties at locations where the incorrect configuration was found. If necessary, contact 

Boeing for installation instructions.
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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FIGURE 1: INSPECTION - Group 1, Configuration 1

760

STA

940

STA

760

STA

940

STA

FRAME (TYPICAL)

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

(TYPICAL)

TENSION TIE

SEE A SEE B

9

10

OR

SEE C

OR

SEE D

FWD

381593

(SHEET 1 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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ALERT ALERT

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

BL26

STRINGERS

AT ALL LOCATIONS)

VERTICAL POST (NOT PRESENT

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND CONFIGURATION

TO VERTICAL POST

FITTING COMMON

747-53-2371, FIGURE 3)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN

FRAME

SKIN

A A

8

1 4 6

UP

INBD

2

A

5

9

13 14

11

7

D36589

(SHEET 2 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

Original Issue: April 21, 2005

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

REMOVED STEEL PLATE (KEEP)

EXISTING FASTENERS

SURFACE HFEC

OPEN HOLE HFEC

TO VERTICAL POST

FITTING COMMON

SHEAR TIES

SKIN

CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN AND

BL26

STRINGERS

CHORD

FAILSAFE

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

747-53-2371 FIGURE 3)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN

VIEW LOOKING AFT

B B

7

1 4 6 2

B

UP

OUTBD

5

9

13 14

11

8

D36683

(SHEET 3 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN REMOVED ALUMINUM

REPAIR STRAP (KEEP)

BL26

STRINGERS

FRAME

FAILSAFE

CHORD VIEW LOOKING AFT

SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

747-53-2371 FIGURE 3, OR WITH OPTIONAL MODIFICATION PER SERVICE

BULLETIN 747-53-2088)

ALUMINUM REPAIR

STRAP

STEEL PLATE

VERTICAL POST 

(ACTUAL LOCATION

MAY VARY)

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

A-A

G

G

A A

E

E

8

6

1 4

UP

INBD

2

C

5

9

13

11

7

12

12

3 4

3 4

2

9

14

D36606

(SHEET 4 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE VIEW LOOKING AFT CHORD

SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

747-53-2371 FIGURE 3, OR WITH OPTIONAL MODIFICATION PER SERVICE

BULLETIN 747-53-2088)

ALUMINUM REPAIR

STRAP

STEEL PLATE

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

TENSION TIE

FORWARD CHANNEL

FRAME

TENSION TIE

AFT CHANNEL

B-B

G

G

B B

E

E

8

6

1 4

UP

INBD

2

D

5

9

13 14

11

7 3 12

2

4

9

D36686

(SHEET 5 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FRAME

ALUMINUM

CHANNEL

HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

C-C

E-E

(STA 940 ONLY)

(AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D

D-D D-D

G-G

2

1

2

1

2

1

2

1

9

9 9

9

2

1 3 4 12

9

9

10

D36690

(SHEET 6 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 1: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

3 Remove/Keep Aluminum Repair Strap - (n)

4 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

5 Inspect Steel Plates 65B09631-( ) (c)

6 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

7 Inspect Frame Structure (e)

8 Inspect Skin (f)

9 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

10 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661

(g)

11 Install (Kept) Steel Plates 65B09631-( ) (h)

12 Install (Kept) Aluminum Repair Strap - (n)

13 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout

each joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (i) (j) (l) 

(m) (o)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

14 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(i) (k) (l) (m) (p)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie. 

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(SHEET 7 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(c) One Steel Plate on each side of the airplane at each Tension Tie location. Open-hole HFEC 

inspect all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 

19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and 

around all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows 

inboard of the steel plates. Include all remaining fastener locations where fasteners have not been 

removed for inspection per step 4. Exclude areas around fasteners in the fittings common to the 

vertical posts at BL 39. Do inspections in accordance with 747 NDT Manual, Part 6, Subject 51-

00-00, Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of 

the stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and 

shear ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, 

remove fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC 

inspect the skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear 

webs where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no cracks indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) It is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

STEP TASK NAME Part Number NOTES

(SHEET 8 OF 9)
 FIGURE 1: INSPECTION - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(n) This part is only installed on Tension Ties that have been modified in accordance with Service 

Bulletin 747-53-2371, Figure 3. It is not necessary to re-install this part if the affected end of the 

Tension Tie aft channel is being replaced (either complete replacement of the channel, or a new 

segment spliced in).

(o) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

(p) If an aluminum repair strap was installed by Service Bulletin 747-53-2371, Figure 3, and is being 

re-installed, install BACB30NX( )K( ) bolts inboard of the steel plate, common to the aluminum 

repair strap plus three fastener rows inboard of the aluminum repair strap.

STEP TASK NAME Part Number NOTES

(SHEET 9 OF 9)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

760

STA

940

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE

(2 LOCATIONS)

SHEAR WEB WEB

HORIZONTAL

(2 LOCATIONS)

SLOPING SHEAR WEB

760

STA

940

STA

B

OR

A SEE

OR

SEE

SEE C SEE D

FWD

380701

(SHEET 1 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STEEL PLATE

SHEAR TIE

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

747-53-2371, FIGURE 3.)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

A A

1 2 3 4

A

UP

OUTBD

5 6

D36739

(SHEET 2 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

747-53-2371 FIGURE 3)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN

BL26

B B

1 2 3 4

B

UP

OUTBD

5 6

381991

(SHEET 3 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

FRAME

747-53-2088)

747-53-2371 FIGURE 3, OR OPTIONAL MODIFICATION PER SERVICE BULLETIN

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

A-A

A A

1 2 3 4

UP

INBD

C

5 6

380702

(SHEET 4 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

FRAME

BULLETIN 747-53-2088)

747-53-2371 FIGURE 3 OR PER OPTIONAL MODIFICATION PER SERVICE

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

B-B

B B

1 2 3 4

UP

INBD

D

5 6

D36708

(SHEET 5 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 1: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure.

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, in Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (g) (i) (j) Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for close 

ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within SRM 

limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(SHEET 6 OF 7)
 FIGURE 2: OVERSIZED HOLE REPAIR - Group 1, Configuration 1

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) It is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 7 OF 7)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 3: INSPECTION - Group 1, Configuration 2

760

STA

FRAME (TYPICAL)

(2 LOCATIONS)

SLOPING SHEAR WEB

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(TYPICAL)

TENSION TIE

800

STA

760

STA

940

STA

940

STA

FWD

9

D

OR

SEE

SEE B

SEE A

9

8

SEE F

SEE

OR

SEE C

E

381603

(SHEET 1 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

VERTICAL POST

FITTING

MACHINED FRAME

STRINGERS

REMOVED STEEL PLATE (KEEP)

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

BULLETIN 747-53-2088 MODIFICATION

LONG STEEL PLATE INSTALLED PER SERVICE

(STA 760 ONLY)

VIEW LOOKING AFT

D

A A

UP

INBD

A

1 4 13

6

14

5 11

9 2

7 8

D37308

(SHEET 2 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGERS

REMOVED STEEL PLATE (KEEP)

BL26

VERTICAL POST

MACHINED FRAME

FITTING

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

VIEW LOOKING AFT

(STA 760 ONLY)

LONG STEEL PLATE INSTALLED PER SERVICE

BULLETIN 747-53-2088 MODIFICATION

C

D C

E D

B B

E

1 4

B

13

6

14

UP

INBD

5 11

9 2

7 8

D36998

(SHEET 3 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TO VERTICAL POST

FITTING COMMON

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

SKIN

SHEAR TIES

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

MODIFICATION NOT DONE)

AND SERVICE BULLETIN 747-53-2088 OPTIONAL

(SERVICE BULLETIN 747-53-2371 MODIFICATION

A A

8

1 4 6

UP

INBD

2

C

5

9

7

11

13 14

D30804

(SHEET 4 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

REMOVED STEEL PLATE (KEEP)

FITTING COMMON

TO VERTICAL POST

SKIN

SHEAR TIES

FAILSAFE

CHORD

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

(SERVICE BULLETIN 747-53-2371 MODIFICATION

AND SERVICE BULLETIN 747-53-2088 OPTIONAL

MODIFICATION NOT DONE)

C

C

D

D

E

E

B B

8

6 1 4

UP

INBD

2

D

5

9

7

11

13 14

D30805

(SHEET 5 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE

FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

CHORD

VIEW LOOKING AFT

SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

747-53-2371 FIGURE 3 OR OPTIONAL MODIFICATION PER SERVICE

BULLETIN 747-53-2088)

ALUMINUM REPAIR

STRAP

STEEL PLATE

A-A

G

G

A A

E

E

8

6

1 4

UP

INBD

2

E

2

5

9

9

13 14

11

7

3 12

3 12

D38465

(SHEET 6 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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ALERT ALERT

TENSION TIE

FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

CHORD

VIEW LOOKING AFT

SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

ALUMINUM REPAIR

STRAP

STEEL PLATE

B-B

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

747-53-2371 FIGURE 3 OR OPTIONAL MODIFICATION PER SERVICE

BULLETIN 747-53-2088)

B B

G

G

E

E

8

6

1 4

UP

INBD

2

F

2

5

9

9

13 14

11

7

3 12

3 12

D38464

(SHEET 7 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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ALERT ALERT

ALUMINUM

CHANNEL

FRAME

HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

C-C

E-E

(STA 940 ONLY)

(AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D

D-D D-D

G-G

2

1

2

1

2

1

2

1

9

9 9

9

2

1 3

9

9

4 12

10

D37342

(SHEET 8 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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ALERT ALERT

This Figure applies to Group 1, Configuration 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

3 Remove/Keep Aluminum Repair Strap - (n)

4 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

5 Inspect Steel Plates 65B09631-( ) (c)

6 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

7 Inspect Frame Structure - (e)

8 Inspect Skin - (f)

9 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

10 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661

(g)

11 Install (Kept) Steel Plates 65B09631-( ) (h)

12 Install (Kept) Aluminum Repair Strap - (n)

13 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (i) (j) (l) 

(m) (o)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

14 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(i) (k) (l) (m) (p)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie. 

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(SHEET 9 OF 10)
 FIGURE 3: INSPECTION - Group 1, Configuration 2

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ALERT ALERT

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC inspect 

all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and around 

all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows inboard 

of the steel plates. Include all remaining fastener locations where fasteners have not been removed 

for inspection per step 4. Exclude areas around fasteners in the fittings common to the vertical 

posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of the 

stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and shear 

ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, remove 

fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC inspect the 

skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear webs 

where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 

125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) It is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) This part is only installed on Tension Ties that have been modified in accordance with Service 

Bulletin 747-53-2371, Figure 3. It is not necessary to re-install this part if the affected end of the 

Tension Tie aft channel is being replaced (either complete replacement of the channel, or a new 

segment spliced in).

(o) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

(p) If an aluminum repair strap was installed by Service Bulletin 747-53-2371, Figure 3, and is being reinstalled, install BACB30NX( )K( ) bolts inboard of the steel plate, common to the aluminum repair 

strap plus three fastener rows inboard of the aluminum repair strap.

STEP TASK NAME Part Number NOTES

(SHEET 10 OF 10)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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ALERT ALERT

FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

760

STA

940

STA

FRAME (TYPICAL)

(2 LOCATIONS)

SLOPING SHEAR WEB

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(TYPICAL)

TENSION TIE

800

STA

760

STA

940

STA

FWD

C

OR

SEE

D

OR

SEE

SEE B

SEE A

SEE F

SEE E

D37358

(SHEET 1 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGERS BL26

VERTICAL POST

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FSTENER PATTERN

FITTING

MACHINED FRAME

BULLETIN 747-53-2088 MODIFICATION

LONG STEEL PLATE INSTALLED PER SERVICE

RR201 ONLY)

(STA 760 OR STA 780 FOR AIRPLANE

VIEW LOOKING AFT

A A

UP

INBD

A

1 2 3 4 5 6

D37361

(SHEET 2 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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ALERT ALERT

STRINGERS BL26

VERTICAL POST

FITTING

MACHINED FRAME

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BULLETIN 747-53-2088 MODIFICATION

LONG STEEL PLATE INSTALLED PER SERVICE

RR201 ONLY)

(STA 760 OR STA 780 FOR AIRPLANE

VIEW LOOKING AFT

B B

B

UP

INBD

1 2 3 4 5 6

D37362

(SHEET 3 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

VIEW LOOKING AFT

SHEAR TIE

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

(SERVICE BULLETIN 747-53-2371 NOT DONE)

POST

VERTICAL

A A

1 2 3 4

UP

INBD

C

5 6

381607

(SHEET 4 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

(SERVICE BULLETIN 747-53-2371 NOT DONE)

SHEAR TIE

POST

VERTICAL

B B

1 2 3 4

D

UP

OUTBD

5 6

D30808

(SHEET 5 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

747-53-2088)

747-53-2371 FIGURE 3 OR OPTIONAL MODIFICATION PER SERVICE BULLETIN

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

POST

VERTICAL

A-A

A A

1 2 3 4

UP

INBD

5 6

E

D38458

(SHEET 6 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGER

CHORD

FAILSAFE

FRAME

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

BL26

B-B

POST

VERTICAL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

747-53-2088)

747-53-2371 FIGURE 3 OR OPTIONAL MODIFICATION PER SERVICE BULLETIN

(TYPICAL WITH REPAIR OR MODIFICATION PER SERVICE BULLETIN

B B

1 2 3 4

UP

INBD

F

5 6

D38459

(SHEET 7 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for close 

ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within SRM 

limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(SHEET 8 OF 9)
 FIGURE 4: OVERSIZED HOLE REPAIR - Group 1, Configuration 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) It is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 51-30-03. 

However, if fasteners are substituted the same type fasteners should be used throughout each 

joint, as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 9 OF 9)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 5: INSPECTION - Group 1, Configuration 3

800

STA 940

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

800

STA

940

STA

FWD

B

OR

A SEE

OR

SEE

10

SEE C SEE D

10 9

386272

(SHEET 1 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

TO VERTICAL POST

FITTING COMMON

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

FIGURE 3)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN 747-53-2371

A A

8

1 4 6

UP

INBD

2

A

5

9

13 14

11

7

386453

(SHEET 2 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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ALERT ALERT

BL26

STRINGERS

FAILSAFE

CHORD

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER SERVICE BULLETIN 747-53-2371

FIGURE 3)

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

C

C

D

D

E

E

B B

7

1 4

6 2

B

UP

OUTBD

5

9

13 14

11

8

386454

(SHEET 3 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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ALERT ALERT

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

CHORD SHEAR TIES VIEW LOOKING AFT

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

ALUMINUM REPAIR

STRAP

STEEL PLATE

BL26

TENSION TIE

FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

A-A

(TYPICAL WITH REPAIR OR MODIFICATION PER

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(AIRPLANES LINE 1-203 ONLY)

G

G

A A

E

E

8

6

1 4

UP

INBD

2

C

5

9

13 14

11

7

3 12

3 12

4

2

9

D37133

(SHEET 4 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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ALERT ALERT

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

VIEW LOOKING AFT CHORD SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

ALUMINUM REPAIR

STRAP

STEEL PLATE

TENSION TIE

FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

B-B

(TYPICAL WITH REPAIR OR MODIFICATION PER

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(AIRPLANES LINE 1-203 ONLY)

G

G

B B

E

E

8

6

1 4

UP

INBD

2

D

2

5

9

9

13 14

11

7

3

3 12

4 12

D37158

(SHEET 5 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

ALUMINUM

CHANNEL

FRAME

HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

C-C

E-E

(STA 940 ONLY)

(AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D

D-D D-D

G-G

2

1

2

1

2

1

2

1

9

9 9

9

2

1 3 12

9

9

9

10

D37159

(SHEET 6 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 3: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

3 Remove/Keep Aluminum Repair Strap - (n)

4 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

5 Inspect Steel Plates 65B09631-( ) (c)

6 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

7 Inspect Frame Structure - (e)

8 Inspect Skin - (f)

9 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

10 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

98B09661-( )

(g)

11 Install (Kept) Steel Plates 65B09631-( ) (h)

12 Install (Kept) Aluminum Repair Strap - (n)

13 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout each

joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (i) (j) (l) 

(m) (o)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

14 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. (i) 

(k) (l) (m) (p)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(SHEET 7 OF 8)
 FIGURE 5: INSPECTION - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC inspect 

all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and around 

all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows inboard 

of the steel plates. Include all remaining fastener locations where fasteners have not been removed 

for inspection per step 4. Exclude areas around fasteners in the fittings common to the vertical 

posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of the 

stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and shear 

ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, remove 

fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC inspect the 

skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear webs 

where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 

125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) This part is only installed on Tension Ties that have been modified in accordance with Service 

Bulletin 747-53-2371, Figure 3. It is not necessary to re-install this part if the affected end of the 

Tension Tie aft channel is being replaced (either complete replacement of the channel, or a new 

segment spliced in).

(o) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

(p) If an aluminum repair strap was installed by Service Bulletin 747-53-2371, Figure 3, and is being reinstalled, install BACB30NX( )K( ) bolts inboard of the steel plate, common to the aluminum repair 

strap plus three fastener rows inboard of the aluminum repair strap.

STEP TASK NAME Part Number NOTES

(SHEET 8 OF 8)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

800

STA

940

STA

800

STA

940

STA

FRAME (TYPICAL)

(TYPICAL)

(2 LOCATIONS) TENSION TIE

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

FWD

B

OR

A SEE

OR

SEE

SEE C SEE D

D37169

(SHEET 1 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

VIEW LOOKING AFT

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER

POST

VERTICAL

A A

FRAME

1 2 3 4

A

UP

OUTBD

5 6

D37175

(SHEET 2 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(TYPICAL WITHOUT REPAIR OR MODIFICATION PER

B B

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

1 2 3 4

B

UP

OUTBD

5 6

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

D37178

(SHEET 3 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

A-A

BL26

STRINGER

CHORD

FAILSAFE

FRAME

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

(AIRPLANES LINE 1-203 ONLY)

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(TYPICAL WITH REPAIR OR MODIFICATION PER

A A

1 2 3 4

UP

INBD

5 6

C

D37177

(SHEET 4 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

B-B

(AIRPLANES LINE 1-203 ONLY)

SERVICE BULLETIN 747-53-2371, FIGURE 3.)

(TYPICAL WITH REPAIR OR MODIFICATION PER

B B

BL26

STRINGER

CHORD

FAILSAFE

FRAME

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

1 2 3 4

VIEW LOOKING AFT

UP

INBD

D

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

5 6

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

D37181

(SHEET 5 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 3: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for close 

ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within SRM 

limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(SHEET 6 OF 7)
 FIGURE 6: OVERSIZED HOLE REPAIR - Group 1, Configuration 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 7 OF 7)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 7: INSPECTION - Group 1, Configuration 4

STA

760

STA

940

C

760

STA

940

STA

FRAME (TYPICAL)

9

(2 LOCATIONS)

SLOPING SHEAR WEB

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

SEE D

(TYPICAL)

TENSION TIE

SEE B

800

STA

SEE A

9

8

SEE

D38388

FWD

(SHEET 1 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

A A

STRINGERS

UP

INBD

REMOVED STEEL PLATE (KEEP)

D

BL26

VERTICAL POST

A

(STA 760 ONLY)

VIEW LOOKING AFT

1 3 11

5

12

FITTING

MACHINED FRAME

4 10

8 2

6 7

D38401

(SHEET 2 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

C

C

D

D

E

B B

E

STRINGERS

REMOVED STEEL PLATE (KEEP)

1 3

BL26

VERTICAL POST

B

VIEW LOOKING AFT

(STA 760 ONLY)

11

5

12

MACHINED FRAME

FITTING

UP

INBD

4 10

8 2

6 7

D38403

(SHEET 3 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TO VERTICAL POST

FITTING COMMON

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

SKIN

SHEAR TIES

A A

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

STA 780 TO STA 940

A-A

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

2

7

1 3 5

UP

INBD

2

C

4

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

8

6

10

11 12

8

D38414

(SHEET 4 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

C

C

D

D

E

E

FITTING COMMON

TO VERTICAL POST

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

SKIN

SHEAR TIES

B B

BL26

STRINGERS

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

FAILSAFE

CHORD

VIEW LOOKING AFT

STA 780 TO STA 940

B-B

TENSION TIE FORWARD CHANNEL

TENSION TIE AFT CHANNEL FRAME

2

7

5 1 3

UP

INBD

2

D

4

8

6

10

11 12

REMOVED STEEL PLATE (KEEP)

8

OPEN HOLE HFEC

SURFACE HFEC

D38415

(SHEET 5 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 4: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

FRAME

ALUMINUM

CHANNEL

HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

C-C

E-E

(STA 940 ONLY) (AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D D-D

D-D

2

1

2

1

2

1

2

1

8

8 8

8

8 8

8

8

9

D38416

(SHEET 6 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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ALERT ALERT

3 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

4 Inspect Steel Plates 65B09631-( ) (c)

5 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

6 Inspect Frame Structure - (e)

7 Inspect Skin - (f)

8 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

9 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661-( )

(g)

10 Install (Kept) Steel Plates 65B09631-( ) (h)

11 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout

each joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (i) (j) (l) 

(m) (n)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

12 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(i) (k) (l) (m)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC 

inspect all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 

19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and 

around all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows 

inboard of the steel plates. Include all remaining fastener locations where fasteners have not been 

removed for inspection per step 3. Exclude areas around fasteners in the fittings common to the 

vertical posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, 

Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of 

the stringer cut outs. On built-up frames, also pay special attention to the failsafe chords and 

shear ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, 

remove fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC 

inspect the skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

STEP TASK NAME Part Number NOTES

(SHEET 7 OF 8)
 FIGURE 7: INSPECTION - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear 

webs where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 8 OF 8)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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ALERT ALERT

FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

STA

760

STA

940

SEE C

760

STA

940

STA

FRAME (TYPICAL)

(2 LOCATIONS)

SLOPING SHEAR WEB

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

SEE D

(TYPICAL)

TENSION TIE

SEE B

800

STA

SEE A

D38421

FWD

(SHEET 1 OF 6)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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ALERT ALERT

A A

STRINGERS

UP

INBD

BL26

VERTICAL POST

A

(STA 760 ONLY)

VIEW LOOKING AFT

1 2

FITTING

MACHINED FRAME

3 4 5 6

D38441

B B

STRINGERS BL26

VERTICAL POST

B

FITTING

MACHINED FRAME

UP

INBD

(STA 760 ONLY)

VIEW LOOKING AFT

1 2 3 4 5 6

D38445

(SHEET 2 OF 6)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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ALERT ALERT

A-A

A A

BL26

STRINGER

CHORD

FAILSAFE

FRAME

STA 780 TO STA 940

1 2 3 4

VIEW LOOKING AFT

UP

INBD

C

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

5 6

SHEAR TIE

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

D38446

(SHEET 3 OF 6)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

B B

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

STA 780 TO STA 940

B-B

1 2 3 4

D

UP

OUTBD

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

5 6

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

D38448

(SHEET 4 OF 6)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 1, Configuration 4: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for 

close ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within 

SRM limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(SHEET 5 OF 6)
 FIGURE 8: OVERSIZE HOLE REPAIR - Group 1, Configuration 4

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ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) If required, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted the same type fasteners should be used 

throughout each joint, as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 6 OF 6)
 FIGURE 9: ACCESS - Group 2

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ALERT ALERT

FIGURE 9: ACCESS - Group 2

This Figure applies to Group 2: 

JC

232

LC

232

NC

232

QC

232

HC

231

KC

231

MC

231

JC

231

LC

231

NC

231

PC

231

QC

231

BC

242

AC

241

BC

231

DC

242

CC

241

DC

231

720

STA

960

STA

1

10

2

3

4

5

7 13 16

17

18

12 11 15 14

6

9

8

382760

(SHEET 1 OF 2)
 FIGURE 9: ACCESS - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

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 each airplane.

STEP TASK NAME PANEL NUMBER QTY NOTES

1 Remove/Keep Main Deck Ceiling 

Panel

232JC 1 (a)

2 Remove/Keep Main Deck Ceiling 

Panel

231HC 1 (a)

3 Remove/Keep Main Deck Ceiling 

Panel

231JC 1 (a)

4 Remove/Keep Main Deck Ceiling 

Panel

232LC 1 (a)

5 Remove/Keep Main Deck Ceiling 

Panel

231KC 1 (a)

6 Remove/Keep Main Deck Ceiling 

Panel

231LC 1 (a)

7 Remove/Keep Main Deck Ceiling 

Panel

232NC 1 (a)

8 Remove/Keep Main Deck Ceiling 

Panel

231MC 1 (a)

9 Remove/Keep Main Deck Ceiling 

Panel

231NC 1 (a)

10 Remove/Keep Main Deck Ceiling 

Panel

232QC 1 (a)

11 Remove/Keep Main Deck Ceiling 

Panel

231PC 1 (a)

12 Remove/Keep Main Deck Ceiling 

Panel

231QC 1 (a)

13 Remove/Keep Main Deck Ceiling 

Panel

242BC 1 (a)

14 Remove/Keep Main Deck Ceiling 

Panel

241AC 1 (a)

15 Remove/Keep Main Deck Ceiling 

Panel

231BC 1 (a)

16 Remove/Keep Main Deck Ceiling 

Panel

242DC 1 (a)

17 Remove/Keep Main Deck Ceiling 

Panel

241CC 1 (a)

18 Remove/Keep Main Deck Ceiling 

Panel

241DC 1 (a)

(a) Refer to 747-400 AMM 25-59-01 as an accepted procedure.

(SHEET 2 OF 2)
 FIGURE 10: INSPECTION - Group 2

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ALERT ALERT

FIGURE 10: INSPECTION - Group 2

720

STA

940

STA

FRAME (TYPICAL)

TENSION TIE (TYPICAL)

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

720

STA

940

STA

SEE A SEE B

8

9

FWD

383965

(SHEET 1 OF 6)
 FIGURE 10: INSPECTION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FORWARD CHANNEL

TENSION TIE

FRAME AFT CHANNEL

TENSION TIE

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

TO VERTICAL POST

FITTING COMMON

A A

A-A

7

1 3 5

UP

INBD

2

A

2

4

8

8

11 12

10

6

383966

(SHEET 2 OF 6)
 FIGURE 10: INSPECTION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE

FORWARD CHANNEL

FRAME

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

BL26

STRINGERS

FAILSAFE

CHORD

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

TENSION TIE

AFT CHANNEL

C

C

D

D

B B

B-B

E

E

6

1 3 5 2

8

B

UP

OUTBD

2

4

8

11 12

10

7

383967

(SHEET 3 OF 6)
 FIGURE 10: INSPECTION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

C-C

E-E

(STA 940 ONLY) (AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D D-D

D-D

FRAME HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

ALUMINUM

CHANNEL

2

1

2

1

2

1

2

1

8

8 8

8

8 8

8

8

9

383969

(SHEET 4 OF 6)
 FIGURE 10: INSPECTION - Group 2

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ALERT ALERT

3 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

4 Inspect Steel Plates 65B09631-( ) (c)

5 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

6 Inspect Frame Structure - (e)

7 Inspect Skin - (f)

8 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

9 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661-( )

(g)

10 Install (Kept) Steel Plates 65B09631-( ) (h)

11 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout

each joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

Steel Plates. Install washers 

under nuts.

(i) (j) (l) (m) (n)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

12 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to Steel Plates. 

Install washers under nuts. (i) 

(k) (l) (m)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC 

inspect all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 

19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and 

around all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows 

inboard of the steel plates. Include all remaining fastener locations where fasteners have not been 

removed for inspection per step 3. Exclude areas around fasteners in the fittings common to the 

vertical posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, 

Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of 

the stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and 

shear ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, 

remove fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC 

inspect the skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

STEP TASK NAME Part Number NOTES

(SHEET 5 OF 6)
 FIGURE 10: INSPECTION - Group 2

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ALERT ALERT

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear webs 

where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-400F SRM 51-40-05. Install fasteners wet with BMS 3-27 or BMS 3-38. 

Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-400F SRM 51-40-05.

(l) It is acceptable to substitute fasteners in accordance with 747-400F SRM 51-40-03. However, if 

fasteners are substituted, the same type of fastener should be used throughout each joint as 

shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 6 OF 6)
 FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

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ALERT ALERT

FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

720

STA

940

STA

FRAME (TYPICAL)

TENSION TIE (TYPICAL)

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

720

STA

940

STA

SEE B

FWD

A SEE

383971

(SHEET 1 OF 5)
 FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

A A

A-A

1 2 3 4

UP

INBD

A

5 6

383972

(SHEET 2 OF 5)
 FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

FRAME

VIEW LOOKING AFT

CHORD

FAILSAFE

B B

B-B

1 2 3 4

B

UP

OUTBD

5 6

383973

(SHEET 3 OF 5)
 FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure.

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for 

close ream holes in accordance with 747-400F SRM 51-40-05.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-400F SRM 51-40-05. If the holes are already within 

SRM limits for transition fit holes, do not further oversize.

(SHEET 4 OF 5)
 FIGURE 11: OVERSIZED HOLE REPAIR - Group 2

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ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, repair 

contact Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-400F SRM 51-40-05. Install fasteners wet with BMS 3-27 or BMS 3-38. 

Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-400F SRM 51-40-05.

(i) It is acceptable to substitute fasteners in accordance with 747-400F SRM 51-40-03. However, if 

fasteners are substituted, the same type of fastener should be used throughout each joint as 

shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 5 OF 5)
 FIGURE 12: CLOSE ACCESS - Group 2

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ALERT ALERT

FIGURE 12: CLOSE ACCESS - Group 2

This Figure applies to Group 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY 

JC

232

LC

232

NC

232

QC

232

HC

231

KC

231

MC

231

JC

231

LC

231

NC

231

PC

231

QC

231

BC

242

AC

241

BC

231

DC

242

CC

241

DC

231

720

STA

960

STA

1

10

2

3

4

5

7 13 16

17

18

12 11 15 14

6

9

8

384081

(SHEET 1 OF 2)
 FIGURE 12: CLOSE ACCESS - Group 2

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ALERT ALERT

numbers shown below are the number of parts necessary for each airplane.

STEP TASK NAME PANEL NUMBER QTY NOTES

1 Install (kept) Main Deck Ceiling 

Panel

232JC 1 (a)

2 Install (kept) Main Deck Ceiling 

Panel

231HC 1 (a)

3 Install (kept) Main Deck Ceiling 

Panel

231JC 1 (a)

4 Install (kept) Main Deck Ceiling 

Panel

232LC 1 (a)

5 Install (kept) Main Deck Ceiling 

Panel

231KC 1 (a)

6 Install (kept) Main Deck Ceiling 

Panel

231LC 1 (a)

7 Install (kept) Main Deck Ceiling 

Panel

232NC 1 (a)

8 Install (kept) Main Deck Ceiling 

Panel

231MC 1 (a)

9 Install (kept) Main Deck Ceiling 

Panel

231NC 1 (a)

10 Install (kept) Main Deck Ceiling 

Panel

232QC 1 (a)

11 Install (kept) Main Deck Ceiling 

Panel

231PC 1 (a)

12 Install (kept) Main Deck Ceiling 

Panel

231QC 1 (a)

13 Install (kept) Main Deck Ceiling 

Panel

242BC 1 (a)

14 Install (kept) Main Deck Ceiling 

Panel

241AC 1 (a)

15 Install (kept) Main Deck Ceiling 

Panel

231BC 1 (a)

16 Install (kept) Main Deck Ceiling 

Panel

242DC 1 (a)

17 Install (kept) Main Deck Ceiling 

Panel

241CC 1 (a)

18 Install (kept) Main Deck Ceiling 

Panel

241DC 1 (a)

(a) Refer to 747-400 AMM 25-59-01 as an accepted procedure.

(SHEET 2 OF 2)
 FIGURE 13: INSPECTION - Group 3

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ALERT ALERT

FIGURE 13: INSPECTION - Group 3

1040

STA

1140

STA

1040

STA 1140

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

FWD

A SEE B

9

SEE

9

9

384770

(SHEET 1 OF 6)
 FIGURE 13: INSPECTION - Group 3

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ALERT ALERT

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

TO VERTICAL POST

FITTING COMMON

FORWARD CHANNEL

TENSION TIE

AFT CHANNEL

TENSION TIE

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

FRAME

A A

A-A

7

1 3 5

UP

INBD

2

A

2

4

8

8

11 12

10

6

384779

(SHEET 2 OF 6)
 FIGURE 13: INSPECTION - Group 3

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ALERT ALERT

BL26

STRINGERS

FAILSAFE

CHORD

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

TENSION TIE

FORWARD CHANNEL

FRAME

TENSION TIE

AFT CHANNEL

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

C

C

D

D

B B

B-B

E

E

6

1 3 5 2

8

B

UP

OUTBD

2

4

8

11 12

10

7

384780

(SHEET 3 OF 6)
 FIGURE 13: INSPECTION - Group 3

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ALERT ALERT

This Figure applies to Group 3: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

C-C

E-E

(STA 1140 ONLY) (AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D D-D

D-D

FRAME HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

ALUMINUM

CHANNEL

2

1

2

1

2

1

2

1

8

8 8

8

8 8

8

8

9

384781

(SHEET 4 OF 6)
 FIGURE 13: INSPECTION - Group 3

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3 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

4 Inspect Steel Plates 65B09631-( ) (c)

5 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

6 Inspect Frame Structure - (e)

7 Inspect Skin - (f)

8 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

9 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661-( )

(g)

10 Install (Kept) Steel Plates 65B09631-( ) (h)

11 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout each

joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at locations common to Steel 

Plates. Install washers under 

nuts.

(i) (j) (l) (m) (n)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

12 Install (New) Hex Drive Bolts BACB30NX( )K( ) at locations NOT common to 

Steel Plates. Install washers 

under nuts. (j) (k) (l) (m) Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC 

inspect all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 

19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and 

around all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows 

inboard of the steel plates. Include all remaining fastener locations where fasteners have not been 

removed for inspection per step 3. Exclude areas around fasteners in the fittings common to the 

vertical posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, 

Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of 

the stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and 

shear ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, remove 

fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC inspect the 

skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

STEP TASK NAME Part Number NOTES

(SHEET 5 OF 6)
 FIGURE 13: INSPECTION - Group 3

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ALERT ALERT

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear webs 

where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-SP SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-38. Refer 

to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are installed 

with BMS 3-38, they must be installed with the following torque values applied to the nut: 3/16 inch 

bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 125 

pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-SP SRM 51-30-05.

(l) If necessary, it is acceptable to substitute fasteners in accordance with 747-SP SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 6 OF 6)
 FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

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ALERT ALERT

FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

1040

STA

1140

STA

1040

STA 1140

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

SEE A SEE B

FWD

384782

(SHEET 1 OF 5)
 FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

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ALERT ALERT

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

STEEL PLATE

A A

A-A

1 2 3 4

UP

INBD

A

5 6

384783

(SHEET 2 OF 5)
 FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

TENSION TIE AFT CHANNEL FRAME

STEEL PLATE

SHEAR TIE

BL26

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

B B

B-B

1 2 3 4

B

UP

OUTBD

5 6

384784

(SHEET 3 OF 5)
 FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 3: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure.

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to 

a maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for 

close ream holes in accordance with 747-SP SRM 51-30-05. If holes are already within SRM 

limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-SP SRM 51-30-05. If the holes are already within SRM 

limits for transition fit holes, do not further oversize.

(SHEET 4 OF 5)
 FIGURE 14: OVERSIZED HOLE REPAIR - Group 3

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ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained if edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-SP SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-38. Refer 

to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are installed 

with BMS 3-38, they must be installed with the following torque values applied to the nut: 3/16 

inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 

125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-SP SRM 51-30-05.

(i) If necessary, it is acceptable to substitute fasteners in accordance with 747-SP SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) 

bolts and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 5 OF 5)
 FIGURE 15: INSPECTION - Group 4

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ALERT ALERT

FIGURE 15: INSPECTION - Group 4

760

STA

940

STA

760

STA

940

STA

FRAME (TYPICAL)

ONLY

AT STA 760

TENSION TIE

BUILT-UP

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

(TYPICAL)

TENSION TIE

780

STA

FWD

B

OR

A SEE

OR

SEE

SEE E

SEE C SEE D

10

10

D37017

(SHEET 1 OF 9)
 FIGURE 15: INSPECTION - Group 4

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ALERT ALERT

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

TO VERTICAL POST

FITTING COMMON

A A

8

1 4 6

UP

INBD

2

A

5

9

13 14

11

7

D37018

(SHEET 2 OF 9)
 FIGURE 15: INSPECTION - Group 4

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ALERT ALERT

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

BL26

STRINGERS

FAILSAFE

CHORD

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

FRAME

C

C

D

D

E

B B

E

2

B

UP

OUTBD

8

6 1 4

5

9

13 14

11

7

D37019

(SHEET 3 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

A-A

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

CHORD

SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

ALUMINUM REPAIR

STRAP

STEEL PLATE

TENSION TIE

FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN

REMOVED ALUMINUM

REPAIR STRAP (KEEP)

VIEW LOOKING AFT

(TYPICAL WITH REPAIR PER SERVICE BULLETIN

747-53-2371 FIGURE 3)

(AIRPLANES LINE 1-203 ONLY)

G

G

A A

E

E

8

6

1 4

UP

INBD

2

C

2

5

9

9

13 14

11

7

3 12

3 12

D38635

(SHEET 4 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE

FORWARD CHANNEL

TENSION TIE AFT CHANNEL

REMOVED STEEL

PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

SKIN REMOVED ALUMINUM

REPAIR STRAP (KEEP)

BL26

STRINGERS

FRAME

VERTICAL POST

(ACTUAL LOCATION

MAY VARY)

FAILSAFE

CHORD SHEAR TIES

(TYPICAL)

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

ALUMINUM REPAIR

STRAP

STEEL PLATE

B-B

FRAME

VIEW LOOKING AFT

(TYPICAL WITH REPAIR PER SERVICE BULLETIN

747-53-2371 FIGURE 3)

(AIRPLANES LINE 1-203 ONLY)

G

G

B B

E

E

8

6

1 4

UP

INBD

2

D

2

5

9

9

13 14

11

7

3

3 12

12

D38638

(SHEET 5 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

H

H

H-H

E

9

9

9

9

9

BL

81

BL

81

WEB

UPPER CHORD

STA 760 ONLY

LOWER CHORD

D37020

(SHEET 6 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FRAME

ALUMINUM

CHANNEL

HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

C-C

E-E

(STA 940 ONLY)

(AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D

D-D D-D

G-G

2

1

2

1

2

1

2

1

2

1 3 12

9 9

9 9

9

9

9

9

9

10

D37021

(SHEET 7 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 4: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

3 Remove/Keep Aluminum Repair Strap - (n)

4 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

5 Inspect Steel Plates 65B09631-( ) (c)

6 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

7 Inspect Frame Structure - (e)

8 Inspect Skin - (f)

9 Inspect Tension Tie 65B09631-( ) (g)

10 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661

(g)

11 Install (Kept) Steel Plates 65B09631-( ) (h)

12 Install (Kept) Aluminum Repair Strap - (n)

13 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

Steel Plates. Install washers 

under nuts.

(i) (j) (l) (m) (o)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

14 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to Steel Plates. 

Install washers under nuts. (i) 

(k) (l) (m) (p)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC inspect 

all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 19.

(SHEET 8 OF 9)
 FIGURE 15: INSPECTION - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and around 

all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows inboard 

of the steel plates. Include all remaining fastener locations where fasteners have not been removed 

for inspection per step 4. Exclude areas around fasteners in the fittings common to the vertical 

posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of the 

stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and shear 

ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, remove 

fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC inspect the 

skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention at locations where shear 

webs and other structure attach to the Tension Tie channels. Also, do a detailed inspection of the 

shear webs where they attach to the tension tie. At STA 760, do a detailed inspection of the upper 

chord, lower chord, and web of the built up tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 

125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) It is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 51-30-03. 

However, if fasteners are substituted, the same type of fastener should be used throughout each 

joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) This part is only installed on Tension Ties that have been modified in accordance with Service 

Bulletin 747-53-2371, Figure 3. It is not necessary to re-install this part if the affected end of the 

Tension Tie aft channel is being replaced (either complete replacement of the channel, or a new 

segment spliced in).

(o) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

(p) If an aluminum repair strap was installed by Service Bulletin 747-53-2371, Figure 3, and is being reinstalled, install BACB30NX( )K( ) bolts inboard of the steel plate, common to the aluminum repair 

strap plus three fastener rows inboard of the aluminum repair strap.

STEP TASK NAME Part Number NOTES

(SHEET 9 OF 9)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

760

STA

940

STA

780

STA

940

STA

FRAME (TYPICAL)

(TYPICAL)

(2 LOCATIONS) TENSION TIE

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

FWD

B

OR

A SEE

OR

SEE

SEE C SEE D

386171

(SHEET 1 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

SHEAR TIE A A

1 2 3 4

UP

INBD

A

5 6

385928

(SHEET 2 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

B B

1 2 3 4

B

UP

OUTBD

5 6

385929

(SHEET 3 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGER

CHORD

FAILSAFE

(AIRPLANES LINE 1-203 ONLY)

747-53-2371 FIGURE 3)

(TYPICAL WITH REPAIR PER SERVICE BULLETIN

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

FRAME

A-A

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

PLATE

STEEL

BL26

A A

1 2 3 4

UP

INBD

5 6

C

D38641

(SHEET 4 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

FRAME

(ACTUAL LOCATION MAY VARY)

ALUMINUM REPAIR STRAP

(ACTUAL LOCATION MAY VARY)

TRIM LINE IN AFT TENSION CHANNEL

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

PLATE

STEEL

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

B-B

(AIRPLANES LINE 1-203 ONLY)

747-53-2371 FIGURE 3)

(TYPICAL WITH REPAIR PER SERVICE BULLETIN

VIEW LOOKING AFT

B B

1 2 3 4

UP

INBD

D

5 6

D38642

(SHEET 5 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 4: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: The oversize hole repair per this Figure does not apply to built-up Tension Tie located at STA 760 on

Group 4 and Group 6 Airplanes.

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (g) (i) (j) Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts. 

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for close 

ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within SRM 

limits for close ream holes, do not further oversize.

(SHEET 6 OF 7)
 FIGURE 16: OVERSIZED HOLE REPAIR - Group 4

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin or spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 7 OF 7)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 17: INSPECTION - Group 5

760

STA

940

STA

760

STA

940

STA

FRAME (TYPICAL)

ONLY

AT STA 760

TENSION TIE

BUILT-UP

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

(TYPICAL)

TENSION TIE

FWD

SEE A SEE B

9

9

SEE E

SEE C SEE D

380697

(SHEET 1 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

TO VERTICAL POST

FITTING COMMON

REMOVED STEEL PLATE (KEEP)

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

A A

7

1 3 5

UP

INBD

2

A

4

8

11 12

10

6

380698

(SHEET 2 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FAILSAFE

CHORD

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

C

C

D

D

E

E

B B

6

1 3

5 2

B

UP

OUTBD

4

8

11 12

10

7

381633

(SHEET 3 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

BL26

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

(STA 780 ONLY)

VIEW LOOKING AFT

REMOVED STEEL PLATE (KEEP)

VERTICAL POST

FITTING COMMON TO

STRINGERS

A-A

BL37.8

C

C

D

D

E

E

A A

2

6 7

1 3 11 12

5

8

4 10

C

2

D37034

(SHEET 4 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

STRINGERS

TENSION TIE FORWARD CHANNEL

TENSION TIE AFT CHANNEL FRAME

BL26 BL37.8

(STA 780 ONLY)

VIEW LOOKING AFT

REMOVED STEEL PLATE (KEEP)

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

VERTICAL POST

FITTING COMMON TO

B-B

C

C

D

D

E

E

B B

2

6 7

1 3 11 12 5 2

8

4 10

D

D37035

(SHEET 5 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

F

F

F-F

8

E

8

8

8

8

BL

81

BL

81

WEB

UPPER CHORD

STA 760 ONLY

LOWER CHORD

D30807

(SHEET 6 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 5: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

FRAME HORIZONTAL

SHEAR WEBS

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

ALUMINUM

CHANNEL C-C

E-E

(STA 940 ONLY) (AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D D-D

D-D

2

1

2

1

2

1

2

1

8

8 8

8

8 8

8

8

9

380700

(SHEET 7 OF 9)
 FIGURE 17: INSPECTION - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

3 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

4 Inspect Steel Plates 65B09631-( ) (c)

5 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

6 Inspect Frame Structure - (e)

7 Inspect Skin - (f)

8 Inspect Tension Tie 65B09631-( ) (g)

9 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

98B09661-( )

(g)

10 Install (Kept) Steel Plates 65B09631-( ) (h)

11 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout

each joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(i) (j) (l) (m) (n)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

12 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(i) (k) (l) (m)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie.

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC 

inspect all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 

19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and 

around all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows 

inboard of the steel plates. Include all remaining fastener locations where fasteners have not 

been removed for inspection per step 3. Exclude areas around fasteners in the fittings common to 

the vertical posts at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, 

Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of 

the stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and 

shear ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, 

remove fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC 

inspect the skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

STEP TASK NAME Part Number NOTES

(SHEET 8 OF 9)
 FIGURE 17: INSPECTION - Group 5

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ALERT ALERT

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention at locations where shear 

webs and other structure attach to the Tension Tie channels. Also, do a detailed inspection of the 

shear webs where they attach to the tension tie. At STA 760, do a detailed inspection of the upper 

chord, lower chord, and web of the built up tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) 

bolts and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 9 OF 9)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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ALERT ALERT

FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

760

STA

940

STA

780

STA

940

STA

FRAME (TYPICAL)

(TYPICAL)

(2 LOCATIONS) TENSION TIE

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

FWD

SEE SEE B

SEE D

SEE C

A

D38651

(SHEET 1 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

VIEW LOOKING AFT

SHEAR TIE

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

A A

1 2 3 4

UP

INBD

A

5 6

D38652

(SHEET 2 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

FRAME

VIEW LOOKING AFT

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

STRINGER

CHORD

FAILSAFE

B B

1 2 3 4

B

UP

OUTBD

5 6

D38654

(SHEET 3 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

BL26

VERTICAL POST

(STA 780 ONLY)

VIEW LOOKING AFT

FAILSAFE CHORD

SHEAR TIES

FRAME

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FSTENER PATTERN

STRINGERS

A-A

A A

UP

INBD

1 2

C

3 4 5 6

D37045

(SHEET 4 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

TENSION TIE AFT CHANNEL FRAME

BL26

VERTICAL POST

(STA 780 ONLY)

VIEW LOOKING AFT

SHEAR TIES

FRAME

STEEL PLATE

FAILSAFE CHORD

STRINGERS

TENSION TIE FORWARD CHANNEL

B-B

B B

1 2

D

3 4 5 6

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

UP

INBD

D37049

(SHEET 5 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 5: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: The oversize hole repair per this Figure does not apply to built-up Tension Tie located at STA 760 on

Group 4 and Group 6 Airplanes.

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts. (g) (i) (j) Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for 

close ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within 

SRM limits for close ream holes, do not further oversize.

(SHEET 6 OF 7)
 FIGURE 18: OVERSIZE HOLE REPAIR - Group 5

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ALERT ALERT

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin or spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to BSOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts 

are installed with BMS 3-38, they must be installed with the following torque values applied to the 

nut: 3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt 

= 90 to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 7 OF 7)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 19: INSPECTION - Group 6

940

STA

800

STA

800

STA

940

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

920

STA

FWD

9

8

9

SEE B

SEE A

SEE B

SEE D

SEE

SEE C

A

D36986

(SHEET 1 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FRAME

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

CHORD

FAILSAFE

VIEW LOOKING AFT

(TYPICAL)

SHEAR TIES

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN

TO VERTICAL POST

FITTING COMMON

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

SKIN

A A

7

1 3 5

UP

INBD

A

4

REMOVED STEEL PLATE (KEEP)

8

11 12

10

6

2

D36988

(SHEET 2 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

STRINGERS

FAILSAFE

CHORD

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

SURFACE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SHEAR TIES

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

C

C

D

D

E

E

B B

6

1 3

5 2

B

UP

OUTBD

4

8

11 12

10

7

D36989

(SHEET 3 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SURFACE HFEC

OPEN HOLE HFEC

EXISTING FASTENERS (REF)

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

BL26

ALL LOCATIONS)

(NOT PRESENT AT

VERTICAL POST

(STA 920 ONLY)

VIEW LOOKING AFT

REMOVED STEEL PLATE (KEEP)

VERTICAL POST

FITTING COMMON TO

STRINGERS

A-A

BL37.8

C

C

D

D

E

E

A A

2

6 7

1 3 11 12

5

8

4 10

C

2

D37211

(SHEET 4 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SURFACE HFEC

STRINGERS

TENSION TIE FORWARD CHANNEL

TENSION TIE AFT CHANNEL FRAME

BL26 BL37.8

VIEW LOOKING AFT

(STA 920 ONLY)

REMOVED STEEL PLATE (KEEP)

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

FITTING COMMON TO

VERTICAL POST

B-B

C

C

D

D

E

E

B B

2

6 7

1 3 11 12

5

2

8

4 10

D

D37212

(SHEET 5 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 6: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates 65B09631-( ) -

FRAME HORIZONTAL

SHEAR WEB

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

ALUMINUM

CHANNEL C-C

E-E

(STA 940 ONLY) (AT LOCATIONS WITH

A SHEAR WEB)

(AT ALL OTHER

LOCATIONS)

D-D D-D

D-D

2

1

2

1

2

1

2

1

8

8 8

8

8 8

8

8

9

D36991

(SHEET 6 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

3 Inspect Fastener Holes in the Frame 

and Frame doubler (if installed)

- (b)

Tension Tie channels, and all 

aluminum parts in the stackup.

65B09631-( ) (b)

4 Inspect Steel Plates 65B09631-( ) (c)

5 Inspect Tension Tie forward and aft 

channels 

65B09631-( ) (d)

6 Inspect Frame Structure - (e)

7 Inspect Skin - (f)

8 Inspect Tension Tie forward and aft 

channels and associated parts 

attached to the Tension Tie 

channels

65B09631-( ) (g)

9 Inspect Tension Ties, Shear Webs, 

Aluminum Channel

65B09631-( ) 

65B09661-( )

(g)

10 Install (Kept) Steel Plates 65B09631-( ) (h)

11 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout each

joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at locations common to the 

Steel Plates. Install washers 

under nuts.

(i) (j) (l) (m) (n)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

12 Install (New) Hex Drive Bolts BACB30NX( )K( ) at locations NOT common to 

the Steel Plates. Install 

washers under nuts.

(i) (k) (l) (m)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Remove all fasteners common to steel plates, plus six fasteners inboard of the steel plate at each 

end of the tension tie. 

(b) Open-hole HFEC inspect all holes in aluminum parts, in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16.

(c) One Steel Plate on each side of the Airplane at each Tension Tie location. Open-hole HFEC inspect 

all holes in the steel plates in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 19.

(d) Surface HFEC inspect the Tension Tie forward and aft channel vertical webs adjacent to and around 

all fastener heads and bucked tails between BL 26 and the outboard to three fastener rows inboard 

of the steel plates. Include all remaining fastener locations where fasteners have not been removed 

for inspection per step 3. Exclude areas around fasteners in the fittings common to the vertical posts 

at BL 39. Do inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 4.

(e) Do a detailed inspection for cracks in the Frames and associated parts from minimum (2) stringers 

above to a minimum (2) stringers below the Tension Ties. Pay special attention to the corners of the 

stringer cut outs. On built-up frames, also pay special attention to the fail-safe chords and shear 

ties.

(f) Do this step only if cracks were found in the shear tie. If cracks were found on the shear tie, remove 

fasteners in the fuselage skin common to the affected shear tie and open-hole HFEC inspect the 

skin in accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

STEP TASK NAME Part Number NOTES

(SHEET 7 OF 8)
 FIGURE 19: INSPECTION - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

(g) Do a detailed inspection of the Tension Tie forward and aft channels from end to end. At STA 940, 

do a detailed inspection of the Aluminum Channel. Pay special attention to where shear webs and 

other structure attach to the Tension Tie channels. Also, do a detailed inspection of the shear webs 

where they attach to the tension tie.

(h) Only reinstall the Steel Plates if step 4 inspections reveal no crack indications. If the Steel Plate is 

found cracked, before further flight, replace with new or contact Boeing for repair instructions.

(i) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(j) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 3/

16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 to 

125 pound-inches.

(k) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(l) If necessary, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted, the same type of fastener should be used 

throughout each joint as shown in Appendix C, Figure F.

(m) New fasteners are to be supplied by the operator.

(n) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at fastener 

locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is limited. 

Also, if fasteners are substituted, the same type of fastener should be used throughout each joint, as 

shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 8 OF 8)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

940

STA

800

STA

FRAME (TYPICAL)

(TYPICAL)

TENSION TIE (2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

920

STA

800

STA

940

STA

SEE D

SEE C

SEE D

SEE B

SEE C

SEE A

FWD

D36994

(SHEET 1 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

STRINGERS BL26

VERTICAL POST

(STA 920 ONLY)

VIEW LOOKING AFT

SHEAR TIES

FRAME

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

FAILSAFE CHORD

A A

UP

INBD

1 2

A

3 4 5 6

D36996

(SHEET 2 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

BL26

VERTICAL POST

(STA 920 ONLY)

VIEW LOOKING AFT

SHEAR TIES

FRAME

FAILSAFE CHORD

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

STRINGERS

STEEL PLATE

B B

1 2

B

3 4 5 6

UP

INBD

D37934

(SHEET 3 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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ALERT ALERT

BL26

STRINGER

CHORD

FAILSAFE

VIEW LOOKING AFT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

SHEAR TIE

STEEL PLATE

AND CONFIGURATION VARIES DEPENDING ON LOCATION

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

FRAME

A-A

A A

1 2 3 4

UP

INBD

C

5 6

D37002

(SHEET 4 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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ALERT ALERT

TENSION TIE FORWARD CHANNEL

FRAME TENSION TIE AFT CHANNEL

STEEL PLATE

SHEAR TIE

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

BL26

STRINGER

CHORD

FAILSAFE

FRAME

VIEW LOOKING AFT

B-B

B B

1 2 3 4

D

UP

OUTBD

5 6

D37004

(SHEET 5 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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ALERT ALERT

This Figure applies to Group 6: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

NOTE: Only do these steps at locations where crack indications are present in the Frame and/or Tension Tie

and can be cleaned up by oversizing the hole to a maximum hole size of 0.313 inch. If the crack is

larger, contact Boeing for repair instructions.

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME PART NUMBER NOTES

1 Oversize Holes in Tension Tie Channels, 

Frame, Steel Plate, associated 

parts in the stackup.

- (a)

2 Inspect Holes in Tension Tie Channels, 

Frame, and associated 

aluminum parts in the stack up.

- (b) (c)

3 Oversize Holes Tension Tie Channels, 

Frame, Steel Plate, and 

associated parts in the 

stackup.

- (d) (e)

NOTE: Holes can only be oversized to a maximum 0.313 inch diameter.

4 Measure Edge Margin and Spacing - (f)

5 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

the Steel Plates. Install 

washers under nuts.

(g) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

6 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to the Steel Plates. 

Install washers under nuts.

(h) (i)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) Oversize the minimum amount required to remove the cracks, in 0.0156 inches increments, up to a 

maximum hole size of 0.313 inch.

(b) Open-hole HFEC inspect holes in the aluminum parts in accordance with 747 NDT, Part 6, Subject 

51-00-00, Figure 16. 

(c) Repeat steps 1 to 2 if crack indications are still present, until there are no more crack indications. 

Once there are no more crack indications, go to step 3.

(d) Make the final hole diameters in the entire stackup common to the steel plates within limits for 

close ream holes in accordance with 747-100/200/300 SRM 51-30-05. If holes are already within 

SRM limits for close ream holes, do not further oversize.

(e) Make the final hole diameters in the stackup NOT common to the steel plates within limits for 

transition fit holes in accordance with 747-100/200/300 SRM 51-30-05. If the holes are already 

within SRM limits for transition fit holes, do not further oversize.

(SHEET 6 OF 7)
 FIGURE 20: OVERSIZE HOLE REPAIR - Group 6

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ALERT ALERT

(f) A minimum 1.5D edge margin (center of hole to edge of part) and 2.5D spacing (center of hole to 

center of hole) should be maintained. If edge margin and spacing cannot be maintained, contact 

Boeing for repair instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-100/200/300 SRM 51-30-05. Install fasteners wet with BMS 3-27 or BMS 3-

38. Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-100/200/300 SRM 51-30-05.

(i) If required, it is acceptable to substitute fasteners in accordance with 747-100/200/300 SRM 

51-30-03. However, if fasteners are substituted the same type fasteners should be used 

throughout each joint, as shown in Appendix C, Figure F.

(j) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME PART NUMBER NOTES

(SHEET 7 OF 7)
 FIGURE 21: HFEC INSPECTION OF HOLES FOR INSULATION BLANKET STUDS

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ALERT ALERT

FIGURE 21: HFEC INSPECTION OF HOLES FOR INSULATION BLANKET STUDS

FRAME (TYPICAL)

TENSION TIE (TYPICAL)

(2 LOCATIONS)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

SEE A SEE B

FWD

D72679

(SHEET 1 OF 3)
 FIGURE 21: HFEC INSPECTION OF HOLES FOR INSULATION BLANKET STUDS

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ALERT ALERT

STRINGERS

TRIPLER

DOUBLER, AND

FRAME WEB,

CHORD

FAILSAFE

VIEW LOOKING AFT

STRINGERS

CHORD

INNER

CHORD

INNER

TIE

TENSION

TIE

TENSION

ATTACH STUD

INSULATION BLANKET

CHORD

FAILSAFE

VIEW LOOKING AFT

TRIPLER

DOUBLER, AND

FRAME WEB,

PATTERN AND FRAME CONFIGURATION MAY VARY DEPENDING ON LOCATION.

NOTE: TYPICAL CONFIGURATION. ACTUAL INSULATION BLANKET STUD

(TYPICAL)

INSULATION BLANKET STUD

UP

INBD

A

UP

INBD

B

SEE C

1 3 2

C

1 3

D72703

(SHEET 2 OF 3)
 FIGURE 21: HFEC INSPECTION OF HOLES FOR INSULATION BLANKET STUDS

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. 

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1

Remove / Keep Insulation Blanket 

Stud

- 1 Only remove studs that are 

installed through the Frame 

Web in the inspection area. 

Studs that are bonded on to 

the Frame Web do not need 

to be removed.

2

Inspect Hole - 1 Do an open hole HFEC 

inspection of the hole in 

accordance with 747 NDT, 

Part 6, Subject 51-00-00, 

Figure 1, 11, or 16.

NOTE: If there is a crack indication during the HFEC inspection, contact Boeing for repair and/or 

re-installation instructions.

3 Install (Kept) Insulation Blanket 

Stud

- 1-

(SHEET 3 OF 3)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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ALERT ALERT

FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

STA

720

FRAME (TYPICAL)

TENSION TIE (TYPICAL)

STA

720

STA

940

STA 720

STA 740

STA 760

STA 780

STA 800

STA 820

STA 840

STA 860

STA 880

STA 900

STA 920

STA 940

A

B

C

D

E

F

G

H

I

J

K

L

FWD

1926501

(SHEET 1 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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ALERT ALERT

SKIN FRAME

TENSION

TIE

STA 720

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

720

A

A

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

1

A-A

A

1931561

(SHEET 2 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN FRAME

TENSION

TIE

STA 740

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

740

B

B

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

2

B-B

B

1931550

(SHEET 3 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 760

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

760

C

C

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

3

C-C

C

1931403

(SHEET 4 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

D

D

SKIN

FRAME

TENSION

TIE

STA 780

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

780

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

4

D-D

D

1930915

(SHEET 5 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 800

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

800

E

E

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

5

E-E

E

1930851

(SHEET 6 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 820

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

820

F

F

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

6

F-F

F

1930627

(SHEET 7 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 840

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

840

G

G

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

7

G-G

G

1930622

(SHEET 8 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN FRAME

TENSION

TIE

STA 860

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

860

H

H

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

8

H-H

H

1930466

(SHEET 9 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 880

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

880

I

I

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

9

I-I

I

1930364

(SHEET 10 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 900

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

900

J

J

10

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

J-J

J

1930279

(SHEET 11 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 920

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

920

K

K

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

11

K-K

K

1929844

(SHEET 12 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

SKIN

FRAME

TENSION

TIE

STA 940

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

FWD

INBD

STA

940

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

L-L

L

12

L

L

1929718

(SHEET 13 OF 14)
 FIGURE 22: ONE-TIME INSPECTION FOR CORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 2: 

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.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Inspect STA 720 Tension 

Tie

- - (a) (b)

2 Inspect STA 740 Tension 

Tie

- - (a) (b)

3 Inspect STA 760 Tension 

Tie

- - (a) (b)

4 Inspect STA 780 Tension 

Tie

- - (a) (b)

5 Inspect STA 800 Tension 

Tie

- - (a) (b)

6 Inspect STA 820 Tension 

Tie

- - (a) (b)

7 Inspect STA 840 Tension 

Tie

- - (a) (b)

8 Inspect STA 860 Tension 

Tie

- - (a) (b)

9 Inspect STA 880 Tension 

Tie

- - (a) (b)

10 Inspect STA 900 Tension 

Tie

- - (a) (b)

11 Inspect STA 920 Tension 

Tie

- - (a) (b)

12 Inspect STA 940 Tension 

Tie

- - (a) (b)

(a) Do a general visual inspection to ensure the configuration on the airplane matches the 

configuration shown in the illustration.

(b) Make sure that the number of fasteners on the airplane is the same as the number of fasteners 

shown. Do the inspection at both ends of the tension tie.

(SHEET 14 OF 14)
 FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

STA

720

STA

940

FRAME (TYPICAL)

TENSION TIE (TYPICAL)

HORIZONTAL SHEAR WEB

(2 LOCATIONS)

SLOPING SHEAR WEB

(2 LOCATIONS)

STA

720

STA

940

SEE A SEE B

FWD

1963631

(SHEET 1 OF 5)
 FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

Original Issue: April 21, 2005

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

REMOVED STEEL PLATE (KEEP)

EXISTING FASTENERS (REF)

OPEN HOLE HFEC

SKIN

STRINGERS

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

NOTE: TYPICAL CONFIGURATION, ACTUAL FASTENER PATTERN AND

CONFIGURATION VARIES DEPENDING ON LOCATION.

FITTING COMMON

TO VERTICAL POST

A

A

B

B

1 3

UP

INBD

2

A

4 5

6 5 7 8

1963637

(SHEET 2 OF 5)
 FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

Original Issue: April 21, 2005

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

REMOVED STEEL PLATE (KEEP)

OPEN HOLE HFEC

EXISTING FASTENERS

FITTING COMMON

TO VERTICAL POST

SKIN

NOTE: TYPICAL CONFIGURATION. ACTUAL FASTENER PATTERN

AND CONFIGURATION VARIES DEPENDING ON LOCATION.

STRINGERS

FRAME

VERTICAL POST

(NOT PRESENT AT

ALL LOCATIONS)

VIEW LOOKING AFT

A

A

B

B

B

1 3 6

B

UP

OUTBD

4

7 8 2

5

5

1963646

(SHEET 3 OF 5)
 FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

Original Issue: April 21, 2005

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BOEING SERVICE BULLETIN 747-53A2502

ALERT ALERT

This Figure applies to Group 2: 

The step numbers shown below agree with the numbers shown in the circle symbols in the Figure. 

CAUTION: UNLESS THE AIRPLANE IS SUPPORTED IN THE JIGGED POSITION, DO NOT REMOVE THE

FASTENERS FROM ADJACENT TENSION TIE TO FRAME JOINTS AT THE SAME TIME. IF

FASTENERS ARE REMOVED FROM ADJACENT TENSION TIES, DAMAGE TO THE

AIRPLANE STRUCTURE MAY OCCUR. REFER TO APPENDIX B FOR ALLOWABLE

METHODS TO DISCONNECT THE TENSION TIES.

STEP TASK NAME Part Number NOTES

1 Remove Fasteners - (a)

2 Remove/Keep Steel Plates - -

3 Inspect Fastener holes in aluminum 

parts.

- (b)

A-A

(STA 940 ONLY) (AT ALL OTHER

LOCATIONS)

B-B B-B

FRAME

TENSION TIE

AFT CHANNEL

(TYPICAL)

STEEL

PLATE

TENSION TIE

FWD CHANNEL

(TYPICAL)

ALUMINUM

CHANNEL

2

1

2

1

2

1

1963649

(SHEET 4 OF 5)
 FIGURE 23: ADDITIONAL INSPECTION OF INCORRECT CONFIGURATION - Group 2

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ALERT ALERT

4 Inspect Steel plates - (c)

5 Inspect Frame, tension tie, and steel 

plates.

- (d)

6 Install (Kept) Steel plates - (e)

7 CAUTION: If fasteners are substituted, the same type of fastener should be used throughout

each joint as shown in Appendix C, Figure F.

Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations common to 

Steel Plates. Install washers 

under nuts.

(f) (g) (i) (j) (k)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

8 Install (New) Hex Drive Bolts BACB30NX( )K( ) at hole locations NOT 

common to Steel Plates. 

Install washers under nuts. (f) 

(h) (i) (j)

Washers BACW10BP( )DP

Nuts BACN10YT( )CD

(a) At both ends of the tension tie, remove all fasteners common to steel plates, plus six fasteners 

inboard of the steel plates.

(b) At both ends of the tension tie, do open-hole high frequency eddy current (HFEC) inspection for 

cracks in the aluminum parts where fasteners were removed. Do the HFEC inspections in 

accordance with 747 NDT, Part 6, Subject 51-00-00, Figure 16.

(c) At both ends of the tension tie, do open-hole HFEC inspection for cracks in the steel plate at all 

fastener holes. Do the HFEC inspections in accordance with 747 NDT, Part 6, Subject 51-00-00, 

Figure 19.

(d) Do a detailed inspection for cracks in the tension tie and frame structure in the area shown. Also, 

do a detailed inspection for cracks in the steel plate.

(e) Only reinstall the kept steel plates if they are crack free. If they are cracked, install a new or 

serviceable plate with the same part number as the plate that was removed.

(f) Oversize undamaged holes up to 0.0312 inch over original as required to make holes round and to 

be within diameter limits for the specified hole size and fastener fit. If the holes need additional 

oversizing, do the OVERSIZE HOLE REPAIR steps as specified in the Work Instructions.

(g) At open hole locations common to the Steel Plates, install fasteners in close ream holes in 

accordance with 747-400F SRM 51-40-05. Install fasteners wet with BMS 3-27 or BMS 3-38. 

Refer to SOPM 20-50-19 wet fastener installation method 2. If BACB30NX hex-drive bolts are 

installed with BMS 3-38, they must be installed with the following torque values applied to the nut: 

3/16 inch bolt = 20 to 25 pound-inches. 1/4 inch bolt = 50 to 75 pound-inches. 5/16 inch bolt = 90 

to 125 pound-inches.

(h) At open hole locations not common to the Steel Plates, install fasteners in transition fit holes in 

accordance with 747-400F SRM 51-40-05.

(i) It is acceptable to substitute fasteners in accordance with 747-400F SRM 51-40-03. However, if 

fasteners are substituted, the same type of fastener should be used throughout each joint as 

shown in Appendix C, Figure F.

(j) New fasteners are to be supplied by the operator.

(k) To allow for easier removal during repeat inspections, it is optional to install BACB30MR( )K( ) bolts 

and BACW10BP( )CD washers, with BACN11Z( )CD nuts and BACW10BP( )DP washers at 

fastener locations common to the steel plates. However, availability of BACB30MR( )K( ) bolts is 

limited. Also, if fasteners are substituted, the same type of fastener should be used throughout 

each joint, as shown in Appendix C, Figure F.

STEP TASK NAME Part Number NOTES

(SHEET 5 OF 5)
 APPENDIX A: DELETED

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ALERT ALERT

APPENDIX A: DELETED

THIS APPENDIX IS DELETED.

1551112
 APPENDIX B: TENSION TIE DISCONNECTION METHODS

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APPENDIX B: TENSION TIE DISCONNECTION METHODS

SYMMETRICAL ABOUT

1

CL

1

OF AIRPLANE

VIEW LOOKING DOWN

CL

WEB

SHEAR

WEB

SHEAR

TENSION TIE AT BOTH ENDS.

METHOD 1: DISCONNECT EVERY OTHER

487858
 APPENDIX B: TENSION TIE DISCONNECTION METHODS

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METHOD TASK NOTES

1 With the airplane on its gear, disconnect every other Tension Tie from the 

Frame at both ends, as shown in the view for Method 1.

2 Deleted. (b)

3 

not 

shown

With the airplane on its gear, remove all but four fasteners at each end of 

each Tension Tie. Do the necessary Work Instructions specified in this 

service bulletin, and re-install fasteners. Remove the remaining four 

fasteners at each end of each Tension Tie and do the necessary Work 

Instructions at those locations.

4 

not 

shown

Deleted. (b)

(a) This note has been deleted.

(b) Method 2 and Method 4 have been deleted.
 APPENDIX C: GENERAL ILLUSTRATIONS

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APPENDIX C: GENERAL ILLUSTRATIONS

1000

STA

WITH OR WITHOUT EXTENDED UPPER DECK

747-100, -200, -400F

NON-SUD AIRPLANES

1283

STA

747-200 SUD MOD, 747-300, -400 PASSENGER

STRETCHED UPPER DECK (SUD) AIRPLANES

CONTOUR ENDS AT

UPPER DECK

FIGURE A

CONTOUR ENDS AT

UPPER DECK

D37011
 APPENDIX C: GENERAL ILLUSTRATIONS

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(REF)

CHANNELS

ALUMINUM

(REF)

THE TENSION TIES

OUTBOARD ENDS OF

INSTALLED AT THE

STEEL PLATES ARE

COVERED BY THIS SERVICE BULLETIN.

THIS IS THE CONFIGURATION THAT IS

ACTUAL CONFIGURATION MAY VARY.

TWO BACK-TO-BACK CHANNELS.

TYPICAL TENSION TIE CONFIGURATION:

(REF)

CHORD

UPPER

WEB (REF)

(REF)

CHORD

LOWER

DO NOT).

ATTACHED TO THEM, THE TENSION TIES

(NOTE: FLOOR BEAMS HAVE FLOOR PANELS

BEAMS ARE NOT.

COVERED BY THIS BULLENTIN, BUT FLOOR

THAT LOOK LIKE FLOOR BEAMS ARE

BS 760 TENSION TIES

ARE SIMILAR.

AND 747 SPECIAL FREIGHTER AIRPLANES

WEB. STA 760 TENSION TIE ON 747-200F

UPPER CHORD, LOWER CHORD, AND SHEAR

TYPICAL FLOOR BEAM CONFIGURATION:

FIGURE B

D37037
 APPENDIX C: GENERAL ILLUSTRATIONS

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FRAME

FRAME

STRINGER

LONG STEEL PLATE

CHORD

FAILSAFE

STRINGER

CHORD

FAILSAFE

PLATE

SHORT STEEL

CONFIGURATION AT STA 920.

GROUP 6 AIRPLANES HAVE THIS

CONFIGURATION AT STA 780.

GROUP 5 AIRPLANES HAVE THIS

MODIFICATION).

DUE TO EXTENDED UPPER DECK

BEEN REPLACED WITH A FLOOR BEAM

WHERE STA 760 TENSION TIE HAS

CONFIGURATION AT STA 760 (EXCEPT

203 AND ON WILL HAVE THIS

GROUP 1 AIRPLANES, LINE NUMBERS

MODIFICATION).

TO EXTENDED UPPER DECK

REPLACED WITH A FLOOR BEAM DUE

760 TENSION TIE HAS BEEN

747-53-2088 (EXCEPT WHERE STA

MODIFIED PER SERVICE BULLETIN

CONFIGURATION AT STA 760 IF

1 THRU 203 WILL HAVE THIS

GROUP 1 AIRPLANES, LINE NUMBERS

LONG STEEL PLATE CONFIGURATION

EXCEPT WHERE LONG STEEL PLATE IS INSTALLED.

SHORT STEEL PLATE CONFIGURATION - TYPICAL

FIGURE C

D37085
 APPENDIX C: GENERAL ILLUSTRATIONS

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OF TENSION TIE

RUNS FULL-LENGTH

ALUMINUM DOUBLER

0.025" 2024-T42 940

STA

OF TENSION TIE

RUNS FULL-LENGTH

ALUMINUM CHANNEL

0.051" 2024-T42

STA 780 ON GROUP 5 AIRPLANES

6 AIRPLANES.

STA 760 ON GROUP 1 AND GROUP

STA 1140 ON GROUP 3 AIRPLANES

AIRPLANES.

GROUP 4, GROUP 5 AND GROUP 6

STA 940 ON GROUP 1, GROUP 2,

FIGURE D

D37129

FRAME

STRINGER

(REF)

STEEL PLATE

END OF ORIGINAL

CHORD

FAILSAFE

HAS BEEN REPLACED WITH A LONGER STEEL PLATE.

BULLETIN 747-53-2088. THE ORIGINAL STEEL PLATE

STA 780 (DEPENDING ON THE AIRPLANE) PER SERVICE

MODIFIED CONFIGURATION AT STA 760 OR

FIGURE E

D37141
 APPENDIX C: GENERAL ILLUSTRATIONS

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ALERT ALERT

PLATE

STEEL

FRAME

STRINGER

CHORD

FAILSAFE

AREA SHOULD BE THE SAME TYPE.

THIS AREA, ALL FASTENERS IN THIS

IF FASTENERS ARE SUBSTITUTED IN

STEEL PLATE SHOULD BE THE SAME TYPE.

STEEL PLATE, ALL FASTENERS COMMON TO THE

IF FASTENERS ARE SUBSTITUTED COMMON TO THE

FIGURE F

D37193