### Commercial Airplanes 

# 747 Service Bulletin ALERT Number: 747-53A2688 Original Issue: August 21, 2008 Revision 1: September 19, 2012 ATA System: 5321 SUBJECT: FUSELAGE - Floors - Section 41 and Section 44 Upper Deck Floor Beam Upper Chord Inspection and Repair at Floor Panel Attachment Fastener Holes Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2008 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, DreamlinerTM, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. BOEING is a trademark of Boeing Management Company.

Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 1 of 163 6.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 2 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

BLANK PAGETable of Contents Revision Transmittal Sheet............................................ 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 29 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 29 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 31 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 35 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 FIGURE 1: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA [Group 1]. . . . . . . 50 FIGURE 2: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA [Group 2]. . . . . . . 51 FIGURE 3: SECTION 41 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 FIGURE 4: SECTION 41 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION. . . . . 55 FIGURE 5: SECTION 41 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION. . . . . . . . . . 59 FIGURE 6: SECTION 41 - HOLE MEASUREMENTS AFTER CRACK REMOVAL. . . . . . . . . . . 62 FIGURE 7: SECTION 41 - REPAIR STRAP INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . 65 FIGURE 8: SECTION 41 - UPPER CHORD TRIM. . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 FIGURE 9: SECTION 41 - UPPER CHORD REPAIR WITH STRAP. . . . . . . . . . . . . . . . . . . 72

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 3 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP. . . . . . . . . . . . . 76 FIGURE 11: SECTION 41 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 FIGURE 12: SECTION 41 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 FIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) . . 87 FIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) . . 92 FIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) . . . 97 FIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) . . 102 FIGURE 17: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA [Group 3]. . . . . . 107 FIGURE 18: SECTION 44 - UPPER DECK FLOOR BEAM INSPECTION AREA [Group 1]. . . . . . 108 FIGURE 19: SECTION 44 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS [Group 1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 FIGURE 20: SECTION 44 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION [Group 1] . 112 FIGURE 21: SECTION 44 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION [Group 1]. . . . 116 FIGURE 22: SECTION 44 - HOLE MEASUREMENTS AFTER CRACK REMOVAL [Group 1]. . . . . 119 FIGURE 23: SECTION 44 - REPAIR STRAP INSTALLATION [Group 1]. . . . . . . . . . . . . . . . 122 FIGURE 24: SECTION 44 - UPPER CHORD TRIM [Group 1]. . . . . . . . . . . . . . . . . . . . . . 126 FIGURE 25: SECTION 44 - UPPER CHORD REPAIR WITH STRAP [Group 1]. . . . . . . . . . . . 129 FIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP [Group 1]. . . . . . 133 FIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) [Group 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 FIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) [Group 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 FIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) [Group 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 FIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) [Group 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 FIGURE 31: SECTION 44 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR [Group 1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 FIGURE 32: SECTION 44 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE [Group 1]. . . . . . . . . . . . . . . . . . . . . . . . 161

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 4 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

### Commercial Airplanes 

# 747 Service Bulletin ALERT Revision Transmittal Sheet Number: 747-53A2688 Original Issue: August 21, 2008 Revision 1: September 19, 2012 ATA System: 5321 SUBJECT: FUSELAGE - Floors - Section 41 and Section 44 Upper Deck Floor Beam Upper Chord Inspection and Repair at Floor Panel Attachment Fastener Holes This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directives AD 2009-10-06 and AD 2004-07-22 R1 are related to this service bulletin. Group 1: More work is necessary on airplane(s) inspected or changed in accordance with the original issue of this service bulletin. Inspection of the Section 44 upper deck floor beam upper chords from Station (STA) 1000 to STA 1100 is necessary. Continue to do inspections of the Section 41 upper deck floor beam upper chords. No more work is necessary to change any repairs installed in accordance with the original issue of this service bulletin. Replace the upper deck floor beam upper chords at the compliance time given in paragraph 1.E., Compliance. Group 2-3: No more work is necessary on airplane(s) inspected or changed in accordance with the original issue of this service bulletin. Continue to do inspections of the Section 41 upper deck floor beam upper chords. No more work is necessary to change any repairs installed in accordance with the original issue of this service bulletin. Replace the upper deck floor beam upper chords at the compliance time given in paragraph 1.E., Compliance. REASON FOR REVISION This revision is sent to add inspections and repair of the Section 44 upper deck floor beam upper chords from STA 1000 to STA 1100 and also to add replacement of the upper deck floor beam upper chords at the time given in paragraph 1.E., Compliance. These sections were changed: 1. In Summary: Updated Background, Action, Compliance, Manpower, and Summary illustration. Also, added Planning Data table. 2. Paragraph 1.A., Effectivity: Airplanes RT021, RT031, RT032, RT033, RT061, RT161, RT164, RT461, RT519, RT526, RT530, RT576, RT577, RT578, RT579, RT642, RT752 and RT837 are moved from group 1 to group 2. Airplanes RT631, RT632, RT743 and RT876 are moved from group 1 to new group 3. Group 1 configurations are removed. 3. Paragraph 1.C., Reason: Revision information is added.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 5 of 1634. Paragraph 1.D., Description: Section 44 access information is added and maintenance zone tables are changed for group 1 airplanes. 5. Paragraph 1.E., Compliance: AD information is added. After-modification and after-repair inspection requirements are clarified in compliance tables 1 and 2. Some after repair/modification inspection compliance times are changed. Repairs are numbered. Compliance tables 3 and 4 are added for the inspection, repair and after-repair inspection of Section 44 upper deck floor beam upper chords. Compliance table 5 has been added for upper deck floor beam upper chord replacement. 6. Paragraph 1.F., Approval: New approval information is added. 7. Paragraph 1.G., Manpower: Manpower estimates are added for Section 44 inspections. 8. Paragraph 1.H., Weight and Balance Changes: Weight and balance information is added. 9. Paragraph 1.J., References: An AD is added to existing data. 10. Paragraph 1.K., Publications Affected: Damage Tolerance Inspection information is added. 11. Paragraph 2.C.2., Parts and Materials Supplied by the Operator: Part information is added for Section 44 repairs. 12. Paragraph 3.A., General Information: Notes are added. 13. Paragraph 3.B., Work Instructions: Modification and repair options are clarified. Repairs are added to PART 2 table 2 for upper chords made from BAC1506-2441 extrusion. After repair/modification inspection instructions are clarified. Existing repairs are numbered. Instruction is added for the inspection, repair and after-repair inspection of Section 44 upper deck floor beam upper chords. 14. Figure 8: Instruction is added to measure the depth of the trim. 15. Figures 13 to 16: New figures are added for the repair of upper chords made from BAC1506-2441 extrusion. 16. Figure 17: New figure added to show the inspection area for Large Cargo Freighter (LCF) configuration airplanes. 17. Figures 18 to 32: New figures are added for the inspection, repair and after-repair/modification inspection of Section 44 upper deck floor beam upper chords. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY August 21, 2008 Original Issue: September 19, 2012 Revision 1:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 6 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

### Commercial Airplanes 

# 747 Service Bulletin ALERT Summary Number: 747-53A2688 Original Issue: August 21, 2008 Revision 1: September 19, 2012 ATA System: 5321 SUBJECT: FUSELAGE - Floors - Section 41 and Section 44 Upper Deck Floor Beam Upper Chord Inspection and Repair at Floor Panel Attachment Fastener Holes THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None BACKGROUND This service bulletin gives instructions to do inspections of the floor panel attachment fastener holes in the Section 41 and Section 44 upper deck floor beam upper chords for fatigue cracks. Cracks in these chords that are not found and repaired could become large and cause the floor beam to become severed. This can lead to large deflection or deformation of the floor and of the body skin, frames, and stringers. This deflection or deformation could result in damage to wire bundles and unintended inputs to the flight control cables which could affect airplane controllability. Multiple adjacent severed floor beams could result in rapid decompression of the airplane. Flight critical wire bundles and control cables are routed through cutouts in the upper deck floor beams. Cracks have been found at open floor panel attach fastener holes in the upper chord of two Section 41 upper deck floor beam on three different 747-400D airplanes, which had flown 24,053, 24,783, and 25,631 flight-cycles. Boeing believes that these 747-400D airplanes were operated at reduced cabin differential pressures. Similar cracks were also found on the 747-400 Fatigue Test airplane. Accomplishment of the inspections given in this service bulletin will ensure the structural integrity of the upper chords of the Section 41 upper deck floor beams. A structural reassessment of the 747 airplane was conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure safe operation of 747 airplanes throughout their operational life. From this requirement, the Section 41 upper deck floor beam upper chords were determined to be significant, in that they are critical to airplane structural integrity. Therefore, a flight safety inspection program which will continue throughout the operational life of the airplane is specified in this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 7 of 163Between the original issue and Revision 1 of this service bulletin, Boeing has received two reports of cracking in upper deck floor beam upper chords in Section 44. The cracks were at STA 1000 and STA 1100. Due to these crack reports Boeing has determined that inspection of all upper deck floor beam upper chords in Section 44 (from STA 1000 to STA 1100) is required. Boeing Service Related Problem (SRP) 747-SRP-53-0293 and 747-SRP-53-0353 are related to this service bulletin. The upper deck floor beam upper chords have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). For more information about WFD, refer to Boeing Service Letter 747-SL-53-088A. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
Reference Affected Planning Data Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance Yes AD Related Paragraph 1.H., Weight and Balance Changes Yes Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts No Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator Yes Operator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

ACTION Group 1: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from Station (STA) 340 to STA 520 and to the upper chords of the Section 44 upper deck floor beams from STA 1000 to STA 1100. Group 2: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from STA 340 to STA 440. Group 3: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from STA 340 to STA 380.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 8 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE:On Group 2 airplanes, upper deck floor beams from STA 460 to STA 520 do not require inspection as given in this service bulletin because they were replaced with new floor beams during modification to Boeing Converted Freighter (BCF). The new floor beams have floor panel attachment fastener holes that have been cold-worked. Also, on Group 2 airplanes, inspection as given in this service bulletin are not necessary in Section 44 because all floor beams in Section 44 were replaced with tension ties during modification to BCF. On Group 3 airplanes, upper deck floor beams from STA 440 to STA 500 do not require inspection as given in this service bulletin because they were replaced with new floor beams during modification to Large Cargo Freighter (LCF). The new floor beams have floor panel attachment fastener holes that have been cold-worked. If access was gained from above, do open hole HFEC inspections of the floor panel attachment fastener holes in the upper chords for cracks. If access was gained from below, modify the clipnuts for the floor panel attachment fasteners as given in this service bulletin. Do surface HFEC inspections of the forward and aft horizontal flanges of the upper chord at floor panel attachment fastener holes. If cracks are found, repair before any more flights. Repair as given in this service bulletin, or ask Boeing for repair data. For areas repaired as given in this service bulletin, start to do repeat inspections at repaired locations as given in this service bulletin at the times given in Paragraph 1.E., Compliance. For any locations that have a repair that is different from those shown in this service bulletin, contact Boeing for an after-repair inspection plan. If no cracks are found, do the inspection again at the time given in Paragraph 1.E., Compliance. EFFECTIVITY All 747-400 and 747-400D airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-10-06 is related to this service bulletin. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection and repair procedures given in this service bulletin. MANPOWER Section 41 Inspections Elapsed Time (Hours)Total ManHours Airplanes

77.25 259 Passenger 72.25 241 Boeing Converted Freighter Large Cargo Freighter

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 9 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTSection 44 Inspections Elapsed Time (Hours)Total ManHours Airplanes

24.00 66.00 Passenger
MATERIAL INFORMATION None

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 10 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTExport Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 11 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTExport Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 12 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

BLANK PAGE

### Commercial Airplanes 

# 747 Service Bulletin ALERT Number: 747-53A2688 Original Issue: August 21, 2008 Revision 1: September 19, 2012 ATA System: 5321 SUBJECT: FUSELAGE - Floors - Section 41 and Section 44 Upper Deck Floor Beam Upper Chord Inspection and Repair at Floor Panel Attachment Fastener Holes THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes Refer to Service Bulletin Index Document D6-30300, Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. NOTE:This service bulletin is for the airplanes identified below. For Boeing Converted Freighter (BCF) configuration airplanes, the effectivity list shown below is complete for airplanes modified before November 01, 2011. For any Group 1 airplane that is modified to Boeing Converted Freighter (BCF) configuration on or after November 01, 2011, do the work as given for Group 2 airplanes in accordance with this service bulletin.
DESCRIPTION CONFIGURATION GROUP All 747-400 and 747-400D airplanes, except those modified to the Boeing Converted Freighter (BCF) and Large Cargo Freighter (LCF) configurations. - 1

747-400 and 747-400D airplanes that have been modified to the Boeing Converted Freighter (BCF) configuration. - 2
All 747-400 airplanes that have been modified to the Large Cargo Freighter (LCF) configuration. - 3

Airplane Models:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 13 of 163747-400, 747-400D Group Variable Number 1 RF001 - RF006 1 RM001 - RM007 1 RM010 - RM013 1 RM021 - RM024 1 RM026 - RM030 1 RM036 - RM045 1 RM051 - RM053 1 RM071 1 RM081 - RM084 1 RM091 1 RM096 - RM097 1 RM116 - RM117 1 RM126 - RM127 2 RM128 1 RM129 - RM132 1 RM136 - RM147 1 RM156 - RM158 1 RM166 - RM177 1 RM191 - RM192 1 RM231 - RM233 1 RM241 - RM246 1 RM261 - RM264 1 RM316 - RM318 1 RM331 - RM333 1 RM341 1 RM351 - RM355 1 RM366 - RM367 1 RM401 - RM403 1 RM426 1 RM431 1 RM441 - RM443 1 RM445

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 14 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup Variable Number 1 RM801 - RM803 1 RM811 - RM813 1 RT001 - RT014 2 RT021 - RT022 2 RT031 - RT033 1 RT034 - RT035 1 RT041 - RT047 2 RT061 2 RT071 - RT072 1 RT073 - RT074 2 RT075 1 RT101 - RT103 1 RT121 1 RT131 - RT137 1 RT151 - RT152 2 RT161 1 RT162 - RT163 2 RT164 1 RT165 - RT168 1 RT401 - RT412 1 RT431 - RT447 1 RT451 - RT455 2 RT456 1 RT457 - RT460 2 RT461 1 RT462 - RT469 1 RT471 - RT499 2 RT501 1 RT502 - RT505 2 RT506 - RT510 1 RT511 - RT512 2 RT513 1 RT514 - RT515

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 15 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup Variable Number 2 RT516 1 RT517 2 RT518 - RT520 1 RT521 - RT523 2 RT524 1 RT525 2 RT526 1 RT527 2 RT528 1 RT529 2 RT530 1 RT531 - RT535 1 RT551 - RT568 1 RT571 2 RT572 - RT579 1 RT580 - RT591 1 RT601 - RT630 3 RT631 - RT632 1 RT633 - RT641 2 RT642 1 RT643 - RT654 2 RT655 - RT657 1 RT671 - RT673 1 RT681 - RT682 1 RT691 - RT699 1 RT701 - RT704 1 RT711 - RT717 1 RT741 - RT742 3 RT743 1 RT744 - RT750 2 RT751 - RT752 1 RT753 - RT757 1 RT776 - RT777

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 16 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup Variable Number 2 RT781 - RT782 1 RT783 - RT784 1 RT801 - RT803 1 RT811 - RT814 1 RT831 - RT836 2 RT837 1 RT861 - RT864 3 RT876 1 RT877 - RT880 1 RT931 - RT932 1 RT945 - RT949 1 RT951 - RT955 1 RT966 2 RT967 1 RU001 - RU006 1 RU016 - RU017 1 RU031 - RU032 1 RU051 - RU052 1 RU059 - RU062 1 RU081 - RU083 1 RU101 - RU102 1 RU121 - RU132 1 RU801 - RU809 1 RU831 - RU841 2. Spares Affected None. B. Concurrent Requirements None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 17 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTC. Reason This service bulletin gives instructions to do inspections of the Section 41 and Section 44 upper deck floor beam upper chords for fatigue cracks. Cracks in these chords that are not found and repaired could become large and cause the floor beam to become severed. This can lead to large deflection or deformation of the floor and of the body skin, frames, and stringers. This deflection or deformation could result in damage to wire bundles and unintended inputs to the flight control cables which could affect airplane controllability. Multiple adjacent severed floor beams could result in rapid decompression of the airplane. Flight critical wire bundles and control cables are routed through cutouts in the upper deck floor beams. Cracks have been found at open floor panel attach fastener holes in the upper chord of two Section 41 upper deck floor beam on three different 747-400D airplanes, which had flown 24,053, 24,783, and 25,631 flight-cycles. Boeing believes that these 747-400D airplanes were operated at reduced cabin differential pressures. Similar cracks were also found on the 747-400 Fatigue Test airplane. Accomplishment of the inspections given in this service bulletin will ensure the structural integrity of the upper chords of the Section 41 upper deck floor beams. A structural reassessment of the 747 airplane was conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure safe operation of 747 airplanes throughout their operational life. From this requirement, the Section 41 upper deck floor beam upper chords were determined to be significant, in that they are critical to airplane structural integrity. Therefore, a flight safety inspection program which will continue throughout the operational life of the airplane is specified in this service bulletin. Between the original issue and Revision 1 of this service bulletin, the following cracks at upper deck floor beam fastener hole locations have been reported: Crack length Crack location Flight hours/cycles unknown STA 340,RBL 60 37,561 / 29,013 not reported STA 440, BL 0 32,855 / 24,783 1 inch (corrosion) STA 440, RBL 58 49,403 / 5,581 0.03 inch STA 1000, LBL 50 37,561 / 29,013 0.4 inch STA 1100, RBL 53 37,283 / 29,425 The cracks at STA 1000 and STA 1100 are at locations that are not common to the inspection area given in the original issue of this service bulletin. Due to these crack reports Boeing has determined that inspection of all upper deck floor beam upper chords in Section 44 (from STA 1000 to STA 1100) is required. Revision 1 is sent to add inspections and repair of the Section 44 upper deck floor beam upper chords from STA 1000 to STA 1100. NOTE: Inspections of Section 42 upper deck floor beam upper chords from STA 540 to STA 980 are not added to this service bulletin because the floor panel attachment holes in this area were cold worked in production.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 18 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTBoeing Service Related Problem (SRP) 747-SRP-53-0293 and 747-SRP-53-0353 are related to this service bulletin. The upper deck floor beam upper chords have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). For more information about WFD, refer to Boeing Service Letter 747-SL-53-088A. D. Description Group 1: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from STA 340 to STA 520 and to the upper chords of the Section 44 upper deck floor beams from STA 1000 to STA 1100. Group 2: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from STA 340 to STA 440. Group 3: Get access from above or below to the upper chords of the Section 41 upper deck floor beams from STA 340 to STA 380. NOTE:On Group 2 airplanes, upper deck floor beams from STA 460 to STA 520 do not require inspection as given in this service bulletin because they were replaced with new floor beams during modification to Boeing Converted Freighter (BCF). The new floor beams have floor panel attachment fastener holes that have been cold-worked. Also, on Group 2 airplanes, inspection as given in this service bulletin are not necessary in Section 44 because all floor beams in Section 44 were replaced with tension ties during modification to BCF. On Group 3 airplanes, upper deck floor beams from STA 440 to STA 500 do not require inspection as given in this service bulletin because they were replaced with new floor beams during modification to Large Cargo Freighter (LCF). The new floor beams have floor panel attachment fastener holes that have been cold-worked. If access was gained from above, do open hole HFEC inspections of the floor panel attachment fastener holes in the upper chords for cracks. If access was gained from below, modify the clipnuts for the floor panel attachment fasteners as given in this service bulletin. Do surface HFEC inspections of the forward and aft horizontal flanges of the upper chord at floor panel attachment fastener holes. If cracks are found, repair before any more flights. Repair as given in this service bulletin, or ask Boeing for repair data. For areas repaired as given in this service bulletin, start to do repeat inspections at repaired locations as given in this service bulletin at the times given in Paragraph 1.E., Compliance. For any locations that have a repair that is different from those shown in this service bulletin, contact Boeing for an after-repair inspection plan. If no cracks are found, do the inspection again at the time given in Paragraph 1.E., Compliance. Group 1: Revision 1 - More work is necessary on airplane(s) inspected or changed in accordance with the original issue of this service bulletin. Inspection of the Section 44 upper deck floor beam upper chords from Station (STA) 1000 to STA 1100 is necessary. Continue to do inspections of the Section 41 upper deck floor beam upper chords. No more work is necessary to change any repairs installed in accordance with the original issue of this service bulletin. Replace the upper deck floor beam upper chords at the compliance time given in paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 19 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup 2-3: Revision 1 - No more work is necessary on airplane(s) inspected or changed in accordance with the original issue of this service bulletin. Continue to do inspections of the Section 41 upper deck floor beam upper chords. No more work is necessary to change any repairs installed in accordance with the original issue of this service bulletin. Replace the upper deck floor beam upper chords at the compliance time given in paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1:
Affected Maintenance ZonesZone Model 211, 212, 221, 222, 223, 224, 225, 226, 231, 232, 241, 242 747-400, 747-400D

Group 2-3:
Affected Maintenance ZonesZone Model 211, 212, 221, 222, 223, 224, 231, 232 747-400 E. Compliance Federal Aviation Administration (FAA) Airworthiness Directives AD 2009-10-06 and AD 2004-07-22 R1 are related to this service bulletin.Table 1 - Section 41 Compliance Times for Upper Deck Floor Beam Upper Chord Initial and Repeat Inspections Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Last) Action Condition

- Within 2,000 flight-cycles ofthe last SSID inspection, if surface HFEC wasused in that inspection. Within6,000 flight-cycles of the last SSID inspection, if open hole HFEC was usedin that inspection. (a) Within 1,000 flight-cycles after June 17,2009 (the effective date of AD 2009- 10-06 ). Before 20,000 total flight-cycles.Do open hole or surface HFEC inspectionof the floor panel attachment fastener holes in the upper deck floor beam upper chords for cracks as given in Paragraph 3.B., PART 1.All affected airplanes.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 20 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 1 - Section 41 Compliance Times for Upper Deck Floor Beam Upper Chord Initial and Repeat Inspections Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Last) Action Condition

- Before further flight. Do the applicable repair procedures as given in Paragraph 3.B., PART 2, or contact Boeing for repair data. Any crack found inthe floor panel attachment fastener holes. 2,000 flight-cycles if surface HFEC inspection wasused; 6,000 flightcycles if openhole HFEC inspection was used.Within 2,000 flight-cycles if surface HFEC inspection was used, or within 6,000 flight-cycles if open hole HFEC inspection was used. Repeat open hole orsurface HFEC inspection of the floor panel attachment fastener holes in the upper deck floor beam upper chords for cracks as given in Paragraph 3.B., PART 1. No crack found inthe floor panel attachment fastener holes.

- Before further flight. As an option, do thehole modification procedure as given in FIGURE 5.

- Before further flight. As an option, do one of the repair procedures as a hole modification as given in Paragraph 3.B., PART 2. Refer to Table 2 in Paragraph 1.E., Compliance.Refer to Table 2 in Paragraph 1.E., Compliance. Refer to Table 2 inParagraph 1.E., Compliance.Location(s) modified or repaired as given in FIGURE 5 or Paragraph 3.B., PART 2.

- Before further flight. Do a repair. Contact Boeing for repair data. Any crack found in the repaired ormodified location(s). (a) Applicable only to airplanes that have been previously inspected as given in SSID SSI's F-19B, F-19G, or F-19K.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 21 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 2 - Section 41 Compliance Times for Inspection of Location(s) Repaired or Modified Repeat Interval (Not to Exceed) Compliance Time Action Condition 2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 15,000 flight-cycles after the modification was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 1. Location(s) modified as given in FIGURE 5 where edge margin after modification is 2.0D or more.

2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 10,000 flight-cycles after the modification was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 1. Location(s) modified as given in FIGURE 5 where edge margin after modification is 1.3D or more and less than 2.0D.

2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 15,000 flight-cycles after the repair was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 1. Location(s) where repair #1 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a)

2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 10,000 flight-cycles after the repair was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 1. Location(s) where repair #2 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a)

3,000 flight-cycles. Within 10,000 flight-cy- cles after the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 3. Location(s) where repair #3 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a) 3,000 flight-cycles. Within 5,000 flight-cyclesafter the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 1. Location(s) where repair #4 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a) 3,000 flight-cycles. Within 5,000 flight-cyclesafter the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 3. Location(s) where repair #5 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a) 6,000 flight-cycles. Within 10,000 flight-cy- cles after the repair was accomplished.Do open hole and surface HFEC inspections for cracks as given in Paragraph 3.B., PART 3. Location(s) where repair #6, #7, #8, #9, #11 or #12 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 22 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 2 - Section 41 Compliance Times for Inspection of Location(s) Repaired or Modified Repeat Interval (Not to Exceed) Compliance Time Action Condition Contact Boeing for after-repair inspection instructions and do the inspections at the compliance times specified by Boeing. Location(s) where repair #10 or#13 was done as given in Paragraph 3.B., PART 2 of this service bulletin. (a)

- Before further flight. Do a repair. Contact Boeing for repair data. Any crack found in the repaired or modified location(s). (a) Refer to Paragraph 3.B., Work Instructions, PART 2, Tables 1 and 2 for corresponding repair procedures. Group 1:Table 3 - Section 44 Compliance Times for Upper Deck Floor Beam Upper Chord Initial and Repeat Inspections Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Last) Action Condition

- Within 2,000 flight-cycles ofthe last SSID inspection, if surface HFEC wasused in that inspection. Within6,000 flight-cycles of the last SSID inspection, if open hole HFEC was usedin that inspection. (a) Within 1,000 flight-cyclesafter the Revision 1 date of this service bulletin. Before 20,000 total flight-cycles.Do open hole or surface HFEC inspectionof the floor panel attachment fastener holes in the upper deck floor beam upper chords for cracks as given in Paragraph 3.B., PART 4.All affected airplanes.

- Before further flight. Do the applicable repair procedures as given in Paragraph 3.B., PART 5, or contact Boeing for repair data. Any crack found inthe floor panel attachment fastener holes.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 23 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup 1:Table 3 - Section 44 Compliance Times for Upper Deck Floor Beam Upper Chord Initial and Repeat Inspections Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Last) Action Condition 2,000 flight-cycles if surface HFEC inspection wasused; 6,000 flightcycles if openhole HFEC inspection was used.Within 2,000 flight-cycles if surface HFEC inspection was used, or within 6,000 flight-cycles if open hole HFEC inspection was used. Repeat open hole orsurface HFEC inspection of the floor panel attachment fastener holes in the upper deck floor beam upper chords for cracks as given in Paragraph 3.B., PART 4. No crack found inthe floor panel attachment fastener holes.

- Before further flight. As an option, do thehole modification procedure as given in FIGURE 21.

- Before further flight. As an option, do one of the repair procedures as a hole modification as given in Paragraph 3.B., PART 5. Refer to Table 4 in Paragraph 1.E., Compliance.Refer to Table 4 in Paragraph 1.E., Compliance. Refer to Table 4 inParagraph 1.E., Compliance.Location(s) modified or repaired as given in FIGURE 21 or Paragraph 3.B., PART 5.

- Before further flight. Do a repair. Contact Boeing for repair data. Any crack found in the repaired ormodified location(s). (a) Applicable only to airplanes that have been previously inspected as given in SSID SSI's F-19B, F-19G, or F-19K. Group 1: Table 4 - Section 44 Compliance Times for Inspection of Location(s) Repaired or Modified Repeat Interval (Not to Exceed) Compliance Time Action Condition 2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 15,000 flight-cycles after the modification was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 4. Location(s) modified as given in FIGURE 21 where edge margin after modification is 2.0D or more.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 24 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup 1: Table 4 - Section 44 Compliance Times for Inspection of Location(s) Repaired or Modified Repeat Interval (Not to Exceed) Compliance Time Action Condition 2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 10,000 flight-cycles after the modification was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 4. Location(s) modified as given in FIGURE 21 where edge margin after modification 1.3D or more and less than 2.0D.

2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 15,000 flight-cycles after the repair was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 4. Location(s) where repair #1 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a)

2,000 flight-cycles if surface HFEC inspectionwas used; 6,000 flightcycles if open hole HFEC inspection was used.Within 10,000 flight-cycles after the repair was accomplished. Do open hole or surface HFEC inspection forcracks as given in Paragraph 3.B., PART 4. Location(s) where repair #2 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a)

3,000 flight-cycles. Within 10,000 flight-cy- cles after the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 6. Location(s) where repair #3 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a) 3,000 flight-cycles. Within 5,000 flight-cyclesafter the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 4. Location(s) where repair #4 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a) 3,000 flight-cycles. Within 5,000 flight-cyclesafter the repair was accomplished.Do open hole HFEC inspection for cracks as given in Paragraph 3.B., PART 6. Location(s) where repair #5 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a) 6,000 flight-cycles. Within 10,000 flight-cy- cles after the repair was accomplished.Do open hole and surface HFEC inspections for cracks as given in Paragraph 3.B., PART 6. Location(s) where repair #6, #7, #8, #9, #11 or #12 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a) Contact Boeing for after-repair inspection instructions and do the inspections at the compliance times specified by Boeing. Location(s) where repair #10 or#13 was done as given in Paragraph 3.B., PART 5 of this service bulletin. (a)

- Before further flight. Do a repair. Contact Boeing for repair data. Any crack found in the repaired or modified location(s). (a) Refer to Paragraph 3.B., Work Instructions, PART 5, Tables 3 and 4 for corresponding repair procedures.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 25 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 5 - Section 41 and 44 Upper Deck Floor Beam Upper Chord Replacement Compliance Time Action Condition After 15,000 total flight cycles and before 35,000 total flight cycles. (a) Replace upper deck floor beam upper chords inaccordance with Paragraph 3.B., PART 7. All airplanes

(a) Due to the post-replacement requirements, and the possibility that it will be necessary to replace the upper chords again, Boeing does not recommend upper chord replacement prior to 15,000 total flight-cycles. F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. This service bulletin has been approved by the Federal Aviation Administration (FAA). In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of the inspection and repair actions with corresponding compliance times specified in Tables 1, 2, 3, and 4 under paragraph 1.E., "Compliance", of Service Bulletin 747-53A2688, Revision 1, as an alternative method of compliance (AMOC) to the corresponding inspection and repair requirements of paragraphs (h), (i), and (j) of AD 2004-07-22 R1, for the inspection of Structural Significant Items (SSI) F-19B, F-19G, and F-19K of Supplemental Structural Inspection Document (SSID) D6-35022, Revision G, dated December 2000 and Revision TR-08-001, dated June 2006. This AMOC only applies to the areas where upper deck floor beam upper chords were inspected in accordance with 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, including the initial inspection threshold per paragraph (i) of AD 2004-07-22 R1, remain fully applicable and must be complied with. In addition, the manager of the Seattle Aircraft Certification Office (ACO) approves the accomplishment of the inspection and repair actions with corresponding compliance times specified in Tables 1 and 2 under paragraph 1.E., "Compliance," of Service Bulletin 747-53A2688, Revision 1, as an AMOC to the inspection and repair actions with corresponding compliance times specified in Tables 1 and 2 under paragraph 1.E.,"Compliance," of Service Bulletin 747-53A2688, original issue, dated August 21, 2008, required by paragraphs (g) and (h) of AD 2009-10-06 . Tables 3, 4 and 5 of Service Bulletin 747-53A2688, Revision 1, are not mandated by AD 2009-10-06 . This AMOC is only for upper deck floor beam upper chords that have been inspected and repaired in accordance with 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 (j) of AD 2009-10-06 . All provisions of AD 2009-10-06 that are not specifically referenced in this paragraph remain fully applicable and must be complied with.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 26 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTG. Manpower The table below shows an estimate of the man-hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator man-hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. Group 1: Section 41 Inspections Elapsed Hours Task Hours Number of Persons Task

24 96 4 Open Access 25 50 2 Inspect 28.25 113 4 Close Access 77.25 259 TOTAL FOR EACH AIRPLANE Group 2: Section 41 Inspections Elapsed Hours Task Hours Number of Persons Task

22.50 90 4 Open Access 24 48 2 Inspect 25.75 103 4 Close Access 72.25 241 TOTAL FOR EACH AIRPLANE Group 3: Section 41 Inspections Elapsed Hours Task Hours Number of Persons Task

11.25 45 4 Open Access 12 24 2 Inspect 12.75 51.5 4 Close Access 36.0 120.5 TOTAL FOR EACH AIRPLANE

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 27 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTGroup 1: Section 44 Inspections Elapsed Hours Task Hours Number of Persons Task

4.00 16.00 4 Open Access 15.00 30.00 2 Inspect 5.00 20.00 4 Close Access 24.00 66.00 TOTAL FOR EACH AIRPLANE
NOTE:More time will be necessary for repairs if cracks are found. H. Weight and Balance Changes The repairs in this service bulletin will affect the weight and balance of the airplane. However, because of the variation in weight, location and quantity of repairs, it is not possible to specify weight and balance changes in this service bulletin. It will be necessary for operators to calculate the weight and balance changes for each airplane based on the repairs that are accomplished. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Boeing Service Bulletin 747-53A2500 b. Boeing Service Letter 747-SL-53-088A c. Boeing Service Related Problem (SRP) 747-SRP-53-0353 d. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2004-07-22 R1, 2009-10-06 e. 747 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Part 6, 53-10-53, Part 6, 53-10-54 f. 747-400 Aircraft Maintenance Manual (AMM) 25-11-01, 25-11-03, 25-16-00, 25-19-03, 25-21-04, 25-22-01, 25-23-00, 25-24-18, 25-25-01, 25-27-05, 25-28-01, 25-28-02, 25-32-01, 25-40-03, 25-59-01, 25-59-05, 53-21-02 g. 747-400 Structural Repair Manual (SRM) 51-40-05 h. Supplemental Structural Inspection Document (SSID) D6-35022, Revision G 2. Data Supplied with this Service Bulletin: None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 28 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT3. Installation Drawings Used in the Preparation of this Service Bulletin: None. K. Publications Affected 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. M. Software Accomplishment Summary

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 29 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTExport Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 30 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

BLANK PAGE2. MATERIAL INFORMATION A. Material - Price and Availability None B. Industry Support Information Boeing warranty remedies are not available for the inspection and repair procedures given in this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: NOTE: The number in the QTY column in the tables that follow is the number of parts necessary to accomplish one repair. 1.
2. More than one repair may be necessary if cracks are found. 3. Refer to 747 Structural Repair Manual Chapter 51 for alternative fasteners. Table 1 - Section 41 or Section 44 Repair Strap Installation (Refer to Figure 7or Figure 23)
Name Part Number QTY Repair Strap A (a) 1 Bolt BACB30NW6K4 10 Collar BACC30M6 10 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD4 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 7 or FIGURE 23 . (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair. (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Table 2 - Section 41 or Section 44 Upper Chord Strap Repair (Refer to Figure 9or Figure 25)
Name Part Number QTY Repair Strap A (a) 1

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 31 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 2 - Section 41 or Section 44 Upper Chord Strap Repair (Refer to Figure 9or Figure 25)
Name Part Number QTY Filler B (a) 1 Bolt BACB30NW6K4 10 Collar BACC30M6 10 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD4 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 9 or FIGURE 25 . (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair. (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Table 3 - Section 41 or Section 44 Upper Chord Clip Repair (Refer to Figure 10or Figure 26)
Name Part Number QTY Repair Strap A (a) 1 Filler B (a) 1 Repair Clip C (a) 1 Bolt BACB30MY6K7X 3 Bolt BACB30NW6K4 10 Collar BACC30M6 13 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD4 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 10 or FIGURE 26 . (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair. (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 32 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 4 - Section 44 Upper Chord Clip Repair (Refer toFigure 13 or Figure 27)
Name Part Number QTY Repair Strap A (a) 1 Filler B (a) 1 Repair Strap C (a) 1 Bolt BACB30NW6K5 2 Bolt BACB30NW6K7 12 Collar BACC30M6 14 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD4 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 13 or FIGURE 27. (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair. (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Table 5 - Section 44 Upper Chord Clip Repair (Refer to Figure 14 or Figure 28)
Name Part Number QTY Repair Angle A (a) 1 Filler B (a) 1 Repair Strap C (a) 1 Bolt BACB30MY6K7X 14 Bolt BACB30NW6K5 2 Bolt BACB30NW6K7 12 Collar BACC30M6 28 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD3 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 14 or FIGURE 28. (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 33 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 5 - Section 44 Upper Chord Clip Repair (Refer to Figure 14 or Figure 28)
Name Part Number QTY (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Table 6 - Section 44 Upper Chord Clip Repair (Refer to Figure 15 or Figure 29)
Name Part Number QTY Repair Strap A (a) 1 Filler B (a) 1 Bolt BACB30NW6K3 12 Collar BACC30M6 12 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD3 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 15 or FIGURE 29. (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair. (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Table 7 - Section 44 Upper Chord Clip Repair (Refer to Figure 16 or Figure 30)
Name Part Number QTY Repair Angle A (a) 1 Filler B (a) 1 Bolt BACB30MY6K5 12 Bolt BACB30NW6K4 12 Collar BACC30M6 24 Nutplate BACN10JR3F (b) Rivet BACR15CE3AD3 (b) Pressure and Environmental Sealant - Chromate Type BMS 5-95 2 oz. (c)
Chemical and Solvent Resistant Finish BMS 10-11, Type I 2 oz. (c) (a) Make as given in FIGURE 16 or FIGURE 30. (b) Dependent upon the number of floor panel attachment fastener holes affected by the repair.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 34 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 7 - Section 44 Upper Chord Clip Repair (Refer to Figure 16 or Figure 30)
Name Part Number QTY (c) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.
3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 35 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTExport Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 36 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT

BLANK PAGE3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. 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 "as given in" are included in the instruction, the procedure in the Boeing document must be used. 8. For initial and repeat inspections of unrepaired and unmodified holes, either the open hole HFEC inspection method or the surface HFEC inspection method can be used. At hole locations where a repair or modification procedure has been done, do the type of inspection specified in paragraph 1.E., Compliance, depending on which repair was done.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 37 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT9. The affected areas are also visually inspected as given in Boeing Service Bulletin 747-53A2500, "FUSELAGE - Main Frame - Inspections Based on Fatigue Test Results". 10. If affected floor beams or floor beam upper chords have been previously replaced with new parts, the inspection threshold for the replaced part should be counted from the time of the replacement. 11. Fasteners may be oversized 1/64 or 1/32 inch in diameter as needed. Maintain 1.7D minimum edge margin on the upper chord and all adjacent parts. Edge margin is defined as the distance from the edge of the part to the center of the hole, and "D" is the hole diameter 12. Boeing Service Letter 747-SL-51-048, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 13. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 14. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. 15. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 16. Figures 9, 10, 25, and 26 are for upper chords that have forward and aft flanges of the same thickness. Figures 13, 14, 15, 16, 27, 28, 29, and 30 are for upper chords with forward and aft flanges with different thickness. All other figures are applicable to either configuration. 17. In Figures 13, 14, 15, 16, 27, 28, 29, and 30, the typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam. B. WORK INSTRUCTIONS PART 1 -SECTION 41 - INITIAL INSPECTION,REPEAT INSPECTION, and INSPECTION OF HOLES THAT HAVE ONLY BEEN REPAIRED OR MODIFIED BY OVERSIZING
1. Group 1: The area to be inspected is shown in FIGURE 1.
2. Group 2: The area to be inspected is shown in FIGURE 2.
3. Group 3: The area to be inspected is shown in FIGURE 17.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 38 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE: For airplane RT743, inspection is not required at STA 400 and STA 420. New floor beams were installed at STA 400 and STA 420 during RT743 conversion to Large Cargo Freighter. 4. If the open hole High Frequency Eddy Current (HFEC) inspection method will be used at the floor panel attach fastener holes: a. Remove equipment from the upper deck as given in the table that follows for access to the affected upper deck floor beams from above: Refer to as an accepted procedure Equipment

747-400 AMM 25-16-00 Flight Compartment Floor Covering747-400 AMM 25-11-01 Captain and First Officer Seat 747-400 AMM 25-11-03 Observer's Seat 747-400 AMM 25-19-03 Flight Deck Crew Rest Partitions 747-400 AMM 25-25-01 Upper Deck Passenger Seat 747-400 AMM 25-27-05 Upper Deck Floor Covering 747-400 AMM 25-40-03 Upper Deck Lavatories 747-400 AMM 25-24-18 Upper Deck Closets 747-400 AMM 25-32-01 Upper Deck Galleys 747-400 AMM 53-21-02 Upper Deck Floor Panels
NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the upper deck cabin on a typical 747 airplane. b. At all floor panel attach hole locations in the affected floor beam upper chords, do open hole HFEC inspections for cracks as given in FIGURE 3. c. Condition 1 - No crack indications found at floor panel attach hole locations: (1) Option 1: Install the floor panels and equipment that were removed for access to the area. Do inspections again, as given in Paragraph 1.E., Compliance. (2) Option 2: A new inspection threshold can be obtained by doing one of the following: (a) Do the fastener hole modification as given in FIGURE 5. After the modification, do inspections again, as given in Paragraph 1.E., Compliance. (b) Do one of the repair procedures as given in PART 2 to modify the hole. After the modification, do inspections again, as given in Paragraph 1.E., Compliance. d. Condition 2 - If crack indications are found at floor panel attach fastener holes, repair as given in PART 2 or ask Boeing for repair data. e. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 39 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 5. If the surface HFEC inspection method will be used at the floor panel attach fastener holes: a. Get access to the affected upper deck floor beams from below as follows: Group 1: Refer to as an accepted procedure Equipment

747-400 AMM 25-21-04 Ceiling Insulation 747-400 AMM 25-22-01 Ceiling Access Panels 747-400 AMM 25-23-00 Passenger Service Units 747-400 AMM 25-25-01 Passenger Seats 747-400 AMM 25-28-02 Center Overhead Stowage Compartments 747-400 AMM 25-28-01 Side Overhead Stowage Compartments Group 1: NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the main deck on a typical 747 Passenger airplane. Group 2-3: Refer to as an accepted procedure Equipment

747-400 AMM 25-59-01 Main Deck Cargo Compartment Ceiling Lining747-400 AMM 25-59-05 Main Deck Ceiling Insulation b. At all floor panel attach hole locations, modify the clipnuts and do surface HFEC inspections for cracks as given in FIGURE 4. c. If no crack indications are found, install the floor panels and equipment that were removed for access to the area. Do inspections again, as given in Paragraph 1.E., Compliance. d. If crack indications are found, repair as given in PART 2 or ask Boeing for repair data. e. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 40 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTPART 2 - SECTION 41 - REPAIR (Can also be accomplished as a modification) 1. If not already done, remove equipment and floor panels as necessary for access to the affected fastener hole from above. 2. For hole locations where this repair procedure is being accomplished as a modification (no crack has been found), make the fastener hole diameter 1/64 oversize, then go to step 4. 3. For hole locations where a crack indication was found during an inspection, do the following: NOTE: It is acceptable to skip this step at any fastener where the chord will be trimmed as given in FIGURE 8. For example, if the crack extends to the edge of the upper chord, or if you think that oversizing the crack will result in less edge margin less than 1.3D, then you can do a trim out as given in FIGURE 8 instead of doing this step. a. Make the affected fastener hole diameter 1/64 inch oversize. b. Do an open hole HFEC inspection of the hole as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00, Figure 1, 11, or 16 for cracks. c. If crack indications are found, repeat the hole oversize and open hole HFEC inspection until no crack indication is found. d. If no crack indication is found, continue to the next step. 4. Prior to any insurance cut, measure the edge margin and hole diameter as given in FIGURE 6. 5. Repair the hole as given in Table 1 - Hole Repair Instructions. NOTE:Before starting the repair, confirm that the damaged location meets all the repair requirements. Table 1 - Hole Repair Instructions Repair Procedure Edge Margin Crack-Free Hole Diam- eter Repair # Make hole 1/16 inch oversize (Insurance Cut) (a) 2.5D or more (before insurance cut)0.281 inch or less (before insurance cut) 1 Make hole 1/16 inch oversize (Insurance Cut) (a) 1.6D or more and lessthan 2.5D (before insurance cut)0.281 inch or less (before insurance cut) 2 Make hole 1/16 inch oversize (Insurance Cut) and install strap as given in FIGURE 7. (a) 1.3D or more and lessthan 1.6D (before insurance cut)0.281 inch or less (before insurance cut) 3 Trim the chord as given in FIGURE 8. Install the appropriate repair from Table 2 - Hole Trimout Repairs. Less than 1.3D 0.281 inch or less (Refer to Table 2) None (b) 1.3D or more 0.282 - 0.343 inch 4

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 41 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 1 - Hole Repair Instructions Repair Procedure Edge Margin Crack-Free Hole Diam- eter Repair # Install strap as given in FIGURE 7. (b) 1.1D or more and less than 1.3D 0.282 - 0.343 inch 5 Trim the chord as given in FIGURE 8. Install the appropriate repair from Table 2 - Hole Trimout Repairs. Less than 1.1D 0.282 - 0.343 inch (Refer to Table 2) Trim the chord as given in FIGURE 8. Install the appropriate repair from Table 2 - Hole Trimout Repairs. Any More than 0.343 inch (Refer to Table 2) (a) The hole diameter must not exceed 0.343 inch. (b) As an alternative it is acceptable to trim the chord as given in FIGURE 8 and then install the appropriate repair from Table 2 - Hole Trimout Repairs. Table 2 - Hole Trimout Repairs Repair as given in Condition Body Station (STA) Repair # FIGURE 10 Affected hole location is common to the fasteners that support any upper deck equipment support brackets. Affected floor beam locations where upper chord is not made from BAC1506-2441 extrusion 6
FIGURE 9 Affected hole location is not com- mon to the fasteners that support any upper deck equipment support brackets. 7

FIGURE 13 'f' is less than or equal to 0.75 inch. (a) Affected floor beam locations where upper chord is made from BAC1506-2441 extrusion and cracking is located on the thick flange of the upper chord. 8 FIGURE 14 'f' is more than 0.75 inch and less than or equal to 0.90 inch. (a) 9 Contact Boeing (c) 'f' is more than 0.90 inch. (a) 10 FIGURE 15 'a' is less than or equal to 0.60 inch. (b) Affected floor beam locations where upper chord is made from BAC1506-2441 extrusion and cracking is located on the thin flange of the upper chord. 11 FIGURE 16 'a' is more than 0.60 inch and less than or equal to 0.80 inch. (b) 12 Contact Boeing (c) 'a' is more than 0.80 inch. (b) 13 (a) 'f' is the depth of the trim from the edge of the thick flange of the upper chord. Refer to FIGURE 8. (b) 'a' is the depth of the trim from the edge of the thin flange of the upper chord. Refer to FIGURE 8. (c) Contact Boeing for repair instructions and do the repair instructed by Boeing. 6. Install all equipment that was removed for access to the repair area.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 42 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT7. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE: 1. Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 2. For any locations that have a repair that is different from those shown in this service bulletin, contact Boeing for an after-repair inspection plan. PART 3 - SECTION 41 -INSPECTION OF HOLES REPAIRED OR MODIFIED WITH STRAP OR ANGLE 1. Remove the equipment that follows from the upper deck for access to the upper chords of the upper deck floor beams from above: Refer to as an accepted procedure Equipment

747-400 AMM 25-16-00 Flight Compartment Floor Covering747-400 AMM 25-11-01 Captain and First Officer Seat 747-400 AMM 25-11-03 Observer's Seat 747-400 AMM 25-19-03 Flight Deck Crew Rest Partitions 747-400 AMM 25-25-01 Upper Deck Passenger Seat 747-400 AMM 25-27-05 Upper Deck Floor Covering 747-400 AMM 25-40-03 Upper Deck Lavatories 747-400 AMM 25-24-18 Upper Deck Closets 747-400 AMM 25-32-01 Upper Deck Galleys 747-400 AMM 53-21-02 Upper Deck Floor Panels
NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the upper deck cabin on a typical 747 airplane. 2. Do inspections of repaired locations as follows: a. For locations where repair #3 or #5 was done, inspect as given in FIGURE 11. b. For locations where repair #6, #7, #8, #9, #11 or #12 was done, inspect as given in FIGURE 12. c. For locations where repair #10 or #13 was done, contact Boeing for inspection instructions and do the inspections. 3. If no crack indications are found, install the equipment that were removed for access and put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 43 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 4. If crack indications are found, install a repair. Ask Boeing for repair data. 5. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. Group 1: PART 4 - SECTION 44 - INITIAL INSPECTION,REPEAT INSPECTION, and INSPECTION OF HOLES THAT HAVE ONLY BEEN REPAIRED OR MODIFIED BY OVERSIZING 1. The area to be inspected is shown in FIGURE 18. 2. If the open hole High Frequency Eddy Current (HFEC) inspection method will be used at the floor panel attach fastener holes: a. Remove equipment from the upper deck as given in the table that follows for access to the affected upper deck floor beams from above: Refer to as an accepted procedure Equipment

747-400 AMM 25-27-05 Upper Deck Floor Covering 747-400 AMM 25-32-01 Upper Deck Galleys 747-400 AMM 53-21-02 Upper Deck Floor Panels
NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the upper deck cabin on a typical 747 airplane. b. At all floor panel attach hole locations in the affected floor beam upper chords, do open hole HFEC inspections for cracks as given in FIGURE 19. c. Condition 1 - No crack indications found at floor panel attach hole locations: (1) Option 1: Install the floor panels and equipment that were removed for access to the area. Do inspections again, as given in Paragraph 1.E., Compliance. (2) Option 2: A new inspection threshold can be obtained by doing one of the following: (a) Do the fastener hole modification as given in FIGURE 21. After modification, do inspections again, as given in Paragraph 1.E., Compliance. (b) Do one of the repair procedures as given in PART 5. After repair, do inspections again, as given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 44 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTd. Condition 2 - If crack indications are found at floor panel attach fastener holes, repair as given in PART 5 or ask Boeing for repair data. e. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in Paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 3. If the surface HFEC inspection method will be used at the floor panel attach fastener holes: a. Get access to the affected upper deck floor beams from below as follows: Refer to as an accepted procedure Equipment

747-400 AMM 25-21-04 Ceiling Insulation 747-400 AMM 25-22-01 Ceiling Access Panels 747-400 AMM 25-23-00 Passenger Service Units 747-400 AMM 25-25-01 Passenger Seats 747-400 AMM 25-28-02 Center Overhead Stowage Compartments 747-400 AMM 25-28-01 Side Overhead Stowage Compartments
NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the main deck on a typical 747 Passenger airplane. b. At all floor panel attach hole locations, modify the clipnuts and do surface HFEC inspections for cracks as given in FIGURE 20. c. If no crack indications are found, install the floor panels and equipment that were removed for access to the area. Do inspections again, as given in Paragraph 1.E., Compliance. d. If crack indications are found, repair as given in PART 5 or ask Boeing for repair data. e. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in Paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. Group 1: PART 5 - SECTION 44 - REPAIR (Can also be accomplished as a modification) 1. If not already done, remove equipment and floor panels as necessary for access to the affected fastener hole from above.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 45 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT2. For hole locations where this repair procedure is being accomplished as a modification (no crack has been found), make the fastener hole diameter 1/64 oversize, then go to step 4. 3. For hole locations where a crack indication was found during an inspection, do the following: NOTE: It is acceptable to skip this step at any fastener where the chord will be trimmed as given in FIGURE 24. For example, if the crack extends to the edge of the upper chord, or if you think that oversizing the crack will result in less edge margin less than 1.3D, then you can do a trim out as given in FIGURE 24 instead of doing this step. a. Make the affected fastener hole diameter 1/64 inch oversize. b. Do an open hole HFEC inspection of the hole as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00, Figure 1, 11, or 16 for cracks. c. If crack indications are found, repeat the hole oversize and open hole HFEC inspection until no crack indication is found. d. If no crack indication is found, continue to the next step. 4. Prior to any insurance cut, measure the edge margin and hole diameter as given in FIGURE 22. 5. Repair the hole as given in Table 3 - Hole Repair Instructions. NOTE:Before starting the repair, confirm that the damaged location meets all the repair requirements. Table 3 - Hole Repair Instructions Repair Procedure Edge Margin Crack-Free Hole Diam- eter Repair # Make hole 1/16 inch oversize (Insurance Cut) (a) 2.5D or more (before insurance cut)0.281 inch or less (before insurance cut) 1 Make hole 1/16 inch oversize (Insurance Cut) (a) 1.6D or more and lessthan 2.5D (before insurance cut)0.281 inch or less (before insurance cut) 2 Make hole 1/16 inch oversize (Insurance Cut) and install strap as given in FIGURE 23. (a) 1.3D or more and lessthan 1.6D (before insurance cut)0.281 inch or less (before insurance cut) 3 Trim the chord as given in FIGURE 24. Installthe appropriate repair from Table 4 - Hole Trimout Repairs. Less than 1.3D 0.281 inch or less (Refer to Table 4) None (b) 1.3D or more 0.282 - 0.343 inch 4 Install strap as given in FIGURE 23. (b) 1.1D or more and less than 1.3D 0.282 - 0.343 inch 5 Trim the chord as given in FIGURE 24. Installthe appropriate repair from Table 4 - Hole Trimout Repairs. Less than 1.1D 0.282 - 0.343 inch (Refer to Table 4)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 46 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTTable 3 - Hole Repair Instructions Repair Procedure Edge Margin Crack-Free Hole Diam- eter Repair # Trim the chord as given in FIGURE 24. Installthe appropriate repair from Table 4 - Hole Trimout Repairs. Any More than 0.343 inch (Refer to Table 4) (a) The hole diameter must not exceed 0.343 inch. (b) As an alternative it is acceptable to trim the chord as given in FIGURE 24 and then install the appropriate repair from Table 4 - Hole Trimout Repairs. Table 4 - Hole Trimout Repairs Repair as given in Condition Location Repair # FIGURE 26 Affected hole location is common to the fasteners that support any upper deck equipment support brackets. Affected floor beam locations where upper chord is not made from BAC1506-2441 extrusion. 6
FIGURE 25 Affected hole location is not com- mon to the fasteners that support any upper deck equipment support brackets. 7

FIGURE 27 'f' is less than or equal to 0.75 inch. (a) Affected floor beam locations where upper chord is made from BAC1506-2441 extrusion and cracking is located on the thick flange of the upper chord. 8 FIGURE 28 'f' is more than 0.75 inch and less than or equal to 0.90 inch. (a) 9 Contact Boeing (c) 'f' is more than 0.90 inch. (a) 10 FIGURE 29 'a' is less than or equal to 0.60 inch. (b) Affected floor beam locations where upper chord is made from BAC1506-2441 extrusion and cracking is located on the thin flange of the upper chord. 11 FIGURE 30 'a' is more than 0.60 inch and less than or equal to 0.80 inch. (b) 12 Contact Boeing (c) 'a' is more than 0.80 inch. (b) 13 (a) 'f' is the depth of the trim from the forward edge of the thick flange of the upper chord. Refer to FIGURE 24. (b) 'a' is the depth of the trim from the aft edge of the thin flange of the upper chord. Refer to FIGURE 24. (c) Contact Boeing for repair instructions and do the repair instructed by Boeing. 6. Install all equipment that was removed for access to the repair area. 7. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 47 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE: 1. Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in Paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 2. For any locations that have a repair that is different from those shown in this service bulletin, contact Boeing for an after-repair inspection plan. Group 1: PART 6 - SECTION 44 - INSPECTION OF HOLES REPAIRED OR MODIFIED WITH STRAP OR ANGLE 1. Remove the equipment that follows from the upper deck for access to the upper chords of the upper deck floor beams from above: Refer to as an accepted procedure Equipment

747-400 AMM 25-27-05 Upper Deck Floor Covering 747-400 AMM 25-32-01 Upper Deck Galleys 747-400 AMM 53-21-02 Upper Deck Floor Panels
NOTE:All of the equipment listed above may not be installed on all affected airplanes. This list is only intended to show equipment typically installed in the upper deck cabin on a typical 747 airplane. 2. Do inspections of repaired locations as follows: a. For locations where repair #3 or #5 was done, inspect as given in FIGURE 31. b. For locations where repair #6, #7, #8, #9, #11 or #12 was done, inspect as given in FIGURE 32. c. For locations where repair #10 or #13 was done, contact Boeing for inspection instructions and do the inspections. 3. If no crack indications are found, install the equipment that were removed for access and put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in Paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. 4. If crack indications are found, install a repair. Ask Boeing for repair data. 5. Put the airplane back to a serviceable condition. Do inspections again, as given in Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 48 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in Paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole. PART 7 - SECTION 41 AND SECTION 44 UPPER DECK FLOOR BEAM UPPER CHORD REPLACEMENT
1. Group 1: Replace all upper deck floor beam upper chords with identical parts and restore all structure to original drawing requirements in the areas shown in FIGURE 1 and FIGURE 18 at the time given in Paragraph 1.E., Compliance.
2. Group 2: Replace all upper deck floor beam upper chords with identical parts and restore all structure to original drawing requirements in the area shown in FIGURE 2 at the time given in Paragraph 1.E., Compliance.
3. Group 3: Replace all upper deck floor beam upper chords with identical parts and restore all structure to original drawing requirements in the area shown in FIGURE 17 at the time given in Paragraph 1.E., Compliance. NOTE: For airplane RT743, replacement is not required at STA 400 and STA 420. New floor beams were installed at STA 400 and STA 420 during RT743 conversion to Large Cargo Freighter.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1: September 19, 2012 49 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 1: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA (SHEET 1 OF 1)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 50 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 2.

FIGURE 2: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA (SHEET 1 OF 1)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 51 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 3: SECTION 41 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 52 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 3: SECTION 41 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 53 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 affected floor panel attachment fastener hole. NOTE: As shown in FIGURE 2, the STA 460 - 520 floor beams are not affected on Group 2 airplanes. 1. 2. As shown in FIGURE 17 , the STA 440 - STA 520 floor beam is not affected on Group 3 airplanes. 3. Inspect all floor panel attachment fastener holes in each affected floor beam. Both the forward and aft horizontal flanges of each floor beam upper chord, from the left body frame to the right body frame, are affected. 4. If clipnuts are installed, move or remove the clipnuts to accomplish this inspection. Reinstall the clipnuts after the inspection is complete. Prior to clipnut reinstallation, touch up any areas of damaged finish with chemical film treatment and one coat of BMS 10-11, Type 1 primer.
MORE DATA QTY IDENTIFICATION NAME TASK STEP Open hole HFEC for cracks, as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. (a) (b) - - Fastener Hole Inspect 1

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23. (a) (b) - - Upper Chord Inspect 2

(a) Optional: As an alternative to open hole HFEC inspections, do surface HFEC inspections of the upper and lower surfaces of the horizontal flange of the upper chord at each affected floor panel attachment fastener hole. This option is NOT applicable if the floor panel attachment hole modification shown in Figure 5 is to be done. (b) On Group 2 airplanes, a portion of the STA 440 floor beam has a strap on the upper surface. However, this should not affect the inspection procedure.

FIGURE 3: SECTION 41 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 54 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 4: SECTION 41 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 55 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 4: SECTION 41 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 56 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: Inspect all floor panel attachment fastener holes in each affected floor beam. Both the forward and aft horizontal flanges of each floor beam upper chord, from the left body frame to the right body frame, are affected. 1.

2. Modify clipnuts in the affected area for access to the floor beam upper chord. This clipnut modification is only necessary the first time this inspection is done. 3. Steps 1 - 4 that follow give a suggested method for clipnut modification. Any clipnut modification procedure that allows access to the horizontal flange of the upper chord can be used, as long as the surface HFEC inspections in Steps 5 or 6, and in Step 7, can be accomplished. 4. Do the inspections in Steps 5, 6, and 7 in the area within 1 inch inboard and outboard of each floor panel attachment hole. CAUTION: WHEN CLIPNUTS ARE CUT, USE CAUTION TO AVOID DAMAGE TO THE FLOOR BEAM UPPER CHORD OR ITS FINISH. MORE WORK WILL BE NECESSARY FOR REPAIRS IF THE UPPER CHORD OR ITS FINISH IS DAMAGED. 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 affected fastener hole location..
MORE DATA QTY IDENTIFICATION NAME TASK STEP as close as possible to the top of the clipnut - - Clipnut Cut 1 down to expose the edge of the upper chord - - Clipnut Bend 2 On the clipnut lower flange - - Clipnut Cut 3

- - - Clipnut Flange Remove / Discard 4 Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 (a) (c) - Vertical Edge of Upper Chord Inspect 5

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 (b) (c) - Horizontal Edge of Upper Chord Inspect 6

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 (c) - Upper Chord Inspect 7

FIGURE 4: SECTION 41 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 57 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTMORE DATA QTY IDENTIFICATION NAME TASK STEP (a) As an alternative if adequate access to the vertical edge of the horizontal flange cannot be gained, do the inspection of the horizontal edge of the horizontal flange as given in Step 6. (b) This inspection is not necessary if the inspection of the vertical edge of the horizontal flange can be done as given in Step 5. (c) On Group 2 airplanes, a portion of the STA 440 floor beam has a strap on the upper surface. However, this should not affect the inspection procedure.

FIGURE 4: SECTION 41 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 58 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 5: SECTION 41 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 59 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 5: SECTION 41 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 60 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: This modification can only be used if no cracks are detected using the open hole HFEC inspection. (The surface HFEC inspection option shown in Figure 4 is not allowed.) 1.
2. This modification should not be used if the hole that exists is larger than 0.281 inch diameter. 3. This modification makes the diameter of the floor panel attachment fastener hole in the upper chord 1/16 inch oversize. It is not necessary to make the floor panel attachment fastener oversize. 4. After oversizing in step 1, if the edge margin at the fastener hole is less than 1.3D, repair as given in Paragraph 3.B., Work Instructions, PART 2 - REPAIR, or contact Boeing for repair instructions and do the repair.
MORE DATA QTY IDENTIFICATION NAME TASK STEP By 1/16 inch diameter

- - Fastener Hole Oversize 1 Edge margin must be greater than or equal to 1.3D - - Edge Margin Measure 2

FIGURE 5: SECTION 41 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 61 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 6: SECTION 41 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 62 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 6: SECTION 41 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 63 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure.
MORE DATA QTY IDENTIFICATION NAME TASK STEP Distance from center of hole to the edge of the upper chord - - Edge margin Measure 1

Hole diameter

- - "D" Measure 2

FIGURE 6: SECTION 41 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 64 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 7: SECTION 41 - REPAIR STRAP INSTALLATION (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 65 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 7: SECTION 41 - REPAIR STRAP INSTALLATION (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 66 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the area to be covered by the repair strap - - Clipnuts Remove / Discard 1 (a) (b) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair strap 1 BACN10JR3F Nutplate Install 3

- 1 A Repair Strap Install 4 (a) Length as necessary to install at least five bolts on either side of the affected fastener hole. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (b) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 7: SECTION 41 - REPAIR STRAP INSTALLATION (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 67 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size is given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K4 Bolt B BACC30M6 Collar

FIGURE 7: SECTION 41 - REPAIR STRAP INSTALLATION (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 68 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 8: SECTION 41 - UPPER CHORD TRIM (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 69 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 8: SECTION 41 - UPPER CHORD TRIM (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 70 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the area to be covered by the repair strap - - Clipnuts Remove / Discard 1
Maintain a minimum trim radius of 0.5 inch (a) 1

- Upper Chord Trim 2 (b)

- - Depth of trim Measure 3 (a) Do the steps that follow: 1. Trim to remove the crack. Do a surface HFEC inspection along the edge of the trimmed surface as given in 747 NDT Manual D6-7170, Part 6, Subject 51-00-00, Figure 4 or 23 to confirm that there is no crack. 2. Remove an additional 0.03 inch of material as an "insurance cut" to ensure crack removal. Do not trim beyond any point within 0.25 inch of the vertical flange. Ask Boeing for repair data if crack removal requires trimming beyond any point within 0.25 inch of the vertical flange. (b) If the upper chord is made from BAC1506-2441 extrusion, measure the depth of the trim from the edge of the thick flange ("f") or from the edge of the thin flange ("a") as shown.

FIGURE 8: SECTION 41 - UPPER CHORD TRIM (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 71 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 9: SECTION 41 - UPPER CHORD REPAIR WITH STRAP (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 72 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 9: SECTION 41 - UPPER CHORD REPAIR WITH STRAP (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 73 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 (b) (c) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair strap 1 BACN10JR3F Nutplate Install 3

- 1 B Filler Install 4

- 1 A Repair Strap Install 5 (a) Size to match the trimmed area, the same thickness as the upper chord. (b) Length as necessary to install at least five bolts on either side of the trimmed area. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (c) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 9: SECTION 41 - UPPER CHORD REPAIR WITH STRAP (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 74 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size is given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K4 Bolt B BACC30M6 Collar

FIGURE 9: SECTION 41 - UPPER CHORD REPAIR WITH STRAP (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 75 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 76 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 77 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 78 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the vertical flange of the upper chord 3

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (a) 1 B Filler Make 2 (b) (d) 1 A Repair Strap Make 3 (c) 1 C Repair Clip Make 4 On repair strap A or repair clip C, as necessary, for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 5

- 1 A Repair Strap Install 6

- 1 C Repair Clip Install 7

- 1 B Filler Install 8 (a) Size to match the trimmed area, the same thickness as the upper chord. (b) Length as necessary to install at least five bolts on either side of the trimmed area. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (c) Make from 2024-T3511 AND10134-1206, AND10134-1407, or AND10134-1602 aluminum extrusion 0.125 inch thick, length as necessary to install one bolt on either side of the trimmed area and three bolts common to the vertical flange, width to match the flanges of the upper chord. (d) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 79 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size may be given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (a) 0.187 - 0.190 BACB30MY6K7 Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (a) 0.200 - 0.203 BACB30MY6K7X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (a) 0.216 - 0.219 BACB30MY6K7Y Bolt BACC30R6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 10: SECTION 41 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 80 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 11: SECTION 41 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 81 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 11: SECTION 41 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 82 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.
MORE DATA QTY IDENTIFICATION NAME TASK STEP

- 2

- Fastener Remove / Discard 1 (a) for cracks 2

- Fastener Hole Inspect 2 (a) for cracks

- - Floor Panel Attach Fastener Hole Inspect 3 1/64 inch diameter (b) 2

- Fastener Hole Oversize 4 (c) if no cracks are found 2

- Fastener Install (a) Do open hole HFEC inspections as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. (b) If necessary to meet the hole size and quality criteria shown in 747-400 SRM 51-40-05. (c) Install fasteners of the same type and size as was removed, or 1/64 inch oversize as necessary.

FIGURE 11: SECTION 41 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 83 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 12: SECTION 41 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 84 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 12: SECTION 41 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 85 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.
MORE DATA QTY IDENTIFICATION NAME TASK STEP

- 1 B Filler Remove / Keep 1 (a) for cracks

- - Upper Chord Inspect 2 (b) for cracks

- - Floor Panel Attach Fastener Hole Inspect 3

- 2

- Fastener Remove / Discard 4 (b) for cracks 2

- Fastener Hole Inspect 5 If no cracks are found, wet with BMS 5-95 sealant 1

- Filler (Kept) Install 6 1/64 inch diameter (c) 2

- Fastener Hole Oversize 7 (d) if no cracks are found 2

- Fastener Install (a) Do a surface HFEC inspections along the edge of the trimmed surface as given in 747 NDT Part 6, 53- 10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23. (b) Do open hole HFEC inspections as shown in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. (c) If necessary to meet the hole size and quality criteria shown in 747-400 SRM 51-40-05. (d) Install fasteners of the same type and size as was removed, or 1/64 inch oversize as necessary.

FIGURE 12: SECTION 41 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 86 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 87 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 88 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 89 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 From 2024-T3 aluminum (b) 1 A Repair Strap Make 2 From 2024-T3 aluminum (c) (d) 1 C Repair Strap Make 3 On repair strap A or C, as necessary, for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 4

- 1 A Repair Strap Install 5

- 1 C Repair Strap Install 6

- 1 B Filler Install 7 (a) Size to match the trimmed area, 0.180 inch thick to match the flange of the upper chord. (b) 0.100 inch thick, 1.125 inch wide, length as necessary to install at least 7 bolts on either side of the trimmed area. Radius strap corner (0.15R) as necessary to nest into the radius of the upper chord. (c) 0.125 inch thick, 1.125 inch wide, length as necessary to install at least 6 bolts on either side of the trimmed area. (d) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 90 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar

FIGURE 13: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 91 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 92 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 93 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 94 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP

- (a)

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (b) 1 B Filler Make 2 From 2024-T3 aluminum (c) 1 A Repair Angle Make 3 From 2024-T3 aluminum (d) (e) 1 C Repair Strap Make 4 On repair angle A or repair strap C, as necessary, foreach floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 5

- 1 A Repair Angle Install 6

- 1 C Repair Strap Install 7

- 1 B Filler Install 8 (a) At approximately 14 locations, as necessary to properly size repair angle A. (b) Size to match the trimmed area, 0.180 inch thick to match the flange of the upper chord. (c) 0.080 inch thick sheet, width as necessary to match the upper flange and the vertical flange of the upper chord. Length as necessary to install at least 7 bolts in the horizontal flange and 7 bolts in the vertical flange on either side of the trimmed area. (d) 0.160 inch thick, width as necessary to match the upper flange, length as necessary to install at least 6 bolts on either side of the trimmed area.

FIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 95 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTES QTY PART NUMBER NAME TASK STEP (e) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE (a)

- BACR15CE3AD() Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (b) 0.187 - 0.190 BACB30MY6K7 Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (b) 0.200 - 0.203 BACB30MY6K7X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (b) 0.216 - 0.219 BACB30MY6K7Y Bolt BACC30R6 Collar (a) For nutplates in repair strap C use BACR15CE3AD5 rivets. For nutplates in repair angle A use BACR15CE3AD3 rivets. (b) Typical. Longer bolts may be necessary in some locations.

FIGURE 14: SECTION 41 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 96 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 97 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 98 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 99 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 From 2024-T3 aluminum (b) (c) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 3

- 1 A Repair Strap Install 4

- 1 B Filler Install 5 (a) Size to match the trimmed area, 0.063 inch thick to match the flange of the upper chord. (b) 0.071 inch thick, 1.0 inch wide, length as necessary to install at least 6 bolts on either side of the trimmed area. (c) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 100 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD3 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 15: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 101 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 102 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 103 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 104 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP

- (a)

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (b) 1 B Filler Make 2 From 2024-T3 aluminum (c) (d) 1 A Repair Angle Make 3 On repair angle A for eachfloor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 4

- 1 A Repair Angle Install 5

- 1 B Filler Install 6 (a) Approximately 12 locations, as necessary to properly size repair angle A. (b) Size to match the trimmed area, 0.063 inch thick to match the flange of the upper chord. (c) 0.071 inch thick sheet, width as necessary to match the upper flange and the vertical flange of the upper chord. Length as necessary to install at least 6 bolts in the horizontal flange and 6 bolts in the vertical flange on either side of the trimmed area. (d) Any floor panel attachment fastener hole under the repair angle that is not repaired or modified (as given in FIGURE 5 or as given in Paragraph 3.B., Part 2) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 105 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD3 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (a) 0.187 - 0.190 BACB30MY6K() Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (a) 0.200 - 0.203 BACB30MY6K()X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (a) 0.216 - 0.219 BACB30MY6K()Y Bolt BACC30R6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 16: SECTION 41 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 106 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 3.

FIGURE 17: SECTION 41 - UPPER DECK FLOOR BEAM INSPECTION AREA (SHEET 1 OF 1)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 107 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 18: SECTION 44 - UPPER DECK FLOOR BEAM INSPECTION AREA (SHEET 1 OF 1)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 108 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 19: SECTION 44 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 109 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 19: SECTION 44 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 110 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 affected floor panel attachment fastener hole. NOTE: Inspect all floor panel attachment fastener holes in each affected floor beam. Both the forward and aft horizontal flanges of each floor beam upper chord, from the left body frame to the right body frame, are affected. 1.

2. If clipnuts are installed, move or remove the clipnuts to accomplish this inspection. Reinstall the clipnuts after the inspection is complete. Prior to clipnut reinstallation, touch up any areas of damaged finish with chemical film treatment and one coat of BMS 10-11, Type 1 primer.
MORE DATA QTY IDENTIFICATION NAME TASK STEP open hole HFEC for cracks, as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. - - Fastener Hole Inspect 1

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23. (a) - - Upper Chord Inspect 2

(a) Optional: As an alternative to open hole HFEC inspections, do surface HFEC inspections of the upper and lower surfaces of the horizontal flange of the upper chord at each affected floor panel attachment fastener hole. This option is NOT applicable if the floor panel attachment hole modification shown in FIGURE 21 is to be done.

FIGURE 19: SECTION 44 - OPEN HOLE HFEC INSPECTION AT FLOOR PANEL ATTACHMENT FASTENER LOCATIONS (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 111 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 20: SECTION 44 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 112 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 20: SECTION 44 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 113 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: Inspect all floor panel attachment fastener holes in each affected floor beam. Both the forward and aft horizontal flanges of each floor beam upper chord, from the left body frame to the right body frame, are affected. 1.

2. Modify clipnuts in the affected area for access to the floor beam upper chord. This clipnut modification is only necessary the first time this inspection is done. 3. Steps 1 - 4 that follow give a suggested method for clipnut modification. Any clipnut modification procedure that allows access to the horizontal flange of the upper chord can be used, as long as the surface HFEC inspections in Steps 5 or 6, and in Step 7, can be accomplished. 4. Do the inspections in Steps 5, 6, and 7 in the area within 1 inch inboard and outboard of each floor panel attachment hole. CAUTION: WHEN CLIPNUTS ARE CUT, USE CAUTION TO AVOID DAMAGE TO THE FLOOR BEAM UPPER CHORD OR ITS FINISH. MORE WORK WILL BE NECESSARY FOR REPAIRS IF THE UPPER CHORD OR ITS FINISH IS DAMAGED. 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 affected fastener hole location.
MORE DATA QTY IDENTIFICATION NAME TASK STEP as close as possible to the top of the clipnut - - Clipnut Cut 1 down to expose the edge of the upper chord - - Clipnut Bend 2 On the clipnut lower flange - - Clipnut Cut 3

- - - Clipnut Flange Remove / Discard 4 Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 (a) - Vertical Edge of Upper Chord Inspect 5

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 (b) - Horizontal Edge of Upper Chord Inspect 6

Surface HFEC for cracks, as given in 747 NDT Part 6, 53-10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23 - Upper Chord Inspect 7

FIGURE 20: SECTION 44 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 114 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTMORE DATA QTY IDENTIFICATION NAME TASK STEP (a) As an alternative if adequate access to the vertical edge of the horizontal flange cannot be gained, do the inspection of the horizontal edge of the horizontal flange as given in Step 6. (b) This inspection is not necessary if the inspection of the vertical edge of the horizontal flange can be done as given in Step 5.

FIGURE 20: SECTION 44 - CLIPNUT MODIFICATION AND SURFACE HFEC INSPECTION (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 115 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 21: SECTION 44 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 116 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 21: SECTION 44 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 117 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: This modification can only be used if no cracks are detected using the open hole HFEC inspection. (The surface HFEC inspection option shown in FIGURE 20 is not allowed.) 1.
2. This modification should not be used if the hole that exists is larger than 0.281 inch diameter. 3. This modification makes the diameter of the floor panel attachment fastener hole in the upper chord 1/16 inch oversize. It is not necessary to make the floor panel attachment fastener oversize. 4. After oversizing in step 1, if the edge margin at the fastener hole is less than 1.3D, repair as given in Paragraph 3.B., Work Instructions, PART 5 - REPAIR, or contact Boeing for repair instructions and do the repair.
MORE DATA QTY IDENTIFICATION NAME TASK STEP By 1/16 inch diameter

- - Fastener Hole Oversize 1 Edge margin must be greater than or equal to 1.3D. - - Edge Margin Measure 2

FIGURE 21: SECTION 44 - FLOOR PANEL ATTACHMENT HOLE MODIFICATION (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 118 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 22: SECTION 44 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 119 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 22: SECTION 44 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 120 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure.
MORE DATA QTY IDENTIFICATION NAME TASK STEP Distance from center of hole to the edge of the upper chord - - Edge margin Measure 1

Hole diameter

- - "D" Measure 2

FIGURE 22: SECTION 44 - HOLE MEASUREMENTS AFTER CRACK REMOVAL (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 121 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 23: SECTION 44 - REPAIR STRAP INSTALLATION (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 122 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 23: SECTION 44 - REPAIR STRAP INSTALLATION (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 123 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the area to be covered by the repair strap - - Clipnuts Remove / Discard 1 (a) (b) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair strap 1 BACN10JR3F Nutplate Install 3

- 1 A Repair Strap Install 4 (a) Length as necessary to install at least five bolts on either side of the affected fastener hole. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (b) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 23: SECTION 44 - REPAIR STRAP INSTALLATION (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 124 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size is given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K4 Bolt B BACC30M6 Collar

FIGURE 23: SECTION 44 - REPAIR STRAP INSTALLATION (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 125 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 24: SECTION 44 - UPPER CHORD TRIM (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 126 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 24: SECTION 44 - UPPER CHORD TRIM (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 127 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the area to be covered by the repair strap - - Clipnuts Remove / Discard 1
Maintain a minimum trim radius of 0.5 inch (a) 1

- Upper Chord Trim 2 (b)

- - Depth of trim Measure 3 (a) Do the steps that follow: 1. Trim to remove the crack. Do a surface HFEC inspection along the edge of the trimmed surface as given in 747 NDT Manual D6-7170, Part 6, Subject 51-00-00, Figure 4 or 23 to confirm that there is no crack. 2. Remove an additional 0.03 inch of material as an "insurance cut" to ensure crack removal. Do not trim beyond any point within 0.25 inch of the vertical flange. Ask Boeing for repair data if crack removal requires trimming beyond any point within 0.25 inch of the vertical flange. (b) If the upper chord is made from BAC1506-2441 extrusion, measure the depth of the trim from the edge of the thick flange ("f") or from the edge of the thin flange ("a") as shown.

FIGURE 24: SECTION 44 - UPPER CHORD TRIM (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 128 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 25: SECTION 44 - UPPER CHORD REPAIR WITH STRAP (SHEET 1 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 129 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 25: SECTION 44 - UPPER CHORD REPAIR WITH STRAP (SHEET 2 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 130 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 (b) (c) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair strap 1 BACN10JR3F Nutplate Install 3

- 1 B Filler Install 4

- 1 A Repair Strap Install 5 (a) Size to match the trimmed area, the same thickness as the upper chord. (b) Length as necessary to install at least five bolts on either side of the trimmed area. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (c) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 25: SECTION 44 - UPPER CHORD REPAIR WITH STRAP (SHEET 3 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 131 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size is given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K4 Bolt B BACC30M6 Collar

FIGURE 25: SECTION 44 - UPPER CHORD REPAIR WITH STRAP (SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 132 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 133 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 134 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 135 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe step numbers shown below agree with the numbers shown in the circle symbols in the figure. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch.
MORE DATA QTY IDENTIFICATION NAME TASK STEP From the vertical flange of the upper chord 3

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (a) 1 B Filler Make 2 (b) (d) 1 A Repair Strap Make 3 (c) 1 C Repair Clip Make 4 On repair strap A or repair clip C, as necessary, for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 5

- 1 A Repair Strap Install 6

- 1 C Repair Clip Install 7

- 1 B Filler Install 8 (a) Size to match the trimmed area, the same thickness as the upper chord. (b) Length as necessary to install at least five bolts on either side of the trimmed area. Material, thickness, and width to match the horizontal flange of the trimmed upper chord. (c) Make from 2024-T3511 AND10134-1206, AND10134-1407, or AND10134-1602 aluminum extrusion 0.125 inch thick, length as necessary to install one bolt on either side of the trimmed area and three bolts common to the vertical flange, width to match the flanges of the upper chord. (d) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 136 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. NOTE: In the table that follows, for bolt locations, a transition-fit hole size and a close-ream hole size may be given for each affected fastener code. If the transition-fit hole size is used, it may be necessary to make the hole oversize and install oversize fasteners after each repeated open hole HFEC inspection. If the close-ream hole size is used, it should not be necessary to make the fastener hole oversize.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 or 0.1895 - 0.1905 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (a) 0.187 - 0.190 BACB30MY6K7 Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (a) 0.200 - 0.203 BACB30MY6K7X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (a) 0.216 - 0.219 BACB30MY6K7Y Bolt BACC30R6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 26: SECTION 44 - UPPER CHORD REPAIR WITH STRAP AND CLIP (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 137 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 138 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 139 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 140 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 From 2024-T3 aluminum (b) 1 A Repair Strap Make 2 From 2024-T3 aluminum (c) (d) 1 C Repair Strap Make 3 On repair strap A or C, as necessary, for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 4

- 1 A Repair Strap Install 5

- 1 C Repair Strap Install 6

- 1 B Filler Install 7 (a) Size to match the trimmed area, 0.180 inch thick to match the flange of the upper chord. (b) 0.100 inch thick, 1.125 inch wide, length as necessary to install at least 7 bolts on either side of the trimmed area. Radius strap corner (0.15R) as necessary to nest into the radius of the upper chord. (c) 0.125 inch thick, 1.125 inch wide, length as necessary to install at least 6 bolts on either side of the trimmed area. (d) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 141 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD4 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar

FIGURE 27: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH STRAP (REPAIR 8) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 142 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 143 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 144 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 145 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP

- (a)

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (b) 1 B Filler Make 2 From 2024-T3 aluminum (c) 1 A Repair Angle Make 3 From 2024-T3 aluminum (d) (e) 1 C Repair Strap Make 4 On repair angle A or repair strap C, as necessary, foreach floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 5

- 1 A Repair Angle Install 6

- 1 C Repair Strap Install 7

- 1 B Filler Install 8 (a) At approximately 14 locations, as necessary to properly size repair angle A. (b) Size to match the trimmed area, 0.180 inch thick to match the flange of the upper chord. (c) 0.080 inch thick sheet, width as necessary to match the upper flange and the vertical flange of the upper chord. Length as necessary to install at least 7 bolts in the horizontal flange and 7 bolts in the vertical flange on either side of the trimmed area. (d) 0.160 inch thick, width as necessary to match the upper flange, length as necessary to install at least 6 bolts on either side of the trimmed area.

FIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 146 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTNOTES QTY PART NUMBER NAME TASK STEP (e) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE (a)

- BACR15CE3AD() Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (b) 0.187 - 0.190 BACB30MY6K7 Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (b) 0.200 - 0.203 BACB30MY6K7X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (b) 0.216 - 0.219 BACB30MY6K7Y Bolt BACC30R6 Collar (a) For nutplates in repair strap C use BACR15CE3AD5 rivets. For nutplates in repair angle A use BACR15CE3AD3 rivets. (b) Typical. Longer bolts may be necessary in some locations.

FIGURE 28: SECTION 44 - UPPER CHORD THICK FLANGE REPAIR WITH ANGLE (REPAIR 9) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 147 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 148 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 149 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 150 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP From 2024-T3 aluminum (a) 1 B Filler Make 1 From 2024-T3 aluminum (b) (c) 1 A Repair Strap Make 2 On repair strap A for each floor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 3

- 1 A Repair Strap Install 4

- 1 B Filler Install 5 (a) Size to match the trimmed area, 0.063 inch thick to match the flange of the upper chord. (b) 0.071 inch thick, 1.0 inch wide, length as necessary to install at least 6 bolts on either side of the trimmed area. (c) Any floor panel attachment fastener hole under the repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 151 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD3 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 29: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH STRAP (REPAIR 11) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 152 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 1 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 153 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 2 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 154 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 3 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 155 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE: The number in the QTY column is the number of parts necessary for one repair. 1. 2. Break all sharp edges 0.015 - 0.030 inch. 3. Maintain a 125 microinch finish on all cut or trimmed surfaces. 4. The maximum gap allowed without installation of a shim is 0.010 inch. 5. Install all parts wet with BMS 5-95 faying surface sealant. 6. Finish all bare aluminum with chemical film treatment and one coat of BMS 10-11, Type I primer. 7. At new fastener locations, maintain 0.75 - 1.125 inch between fasteners and a minimum edge margin of 0.33 inch. NOTE:The typical illustrations show the thick flange on the forward side of the floor beam. However, at STA 1000, the thick flange is on the aft side of the floor beam.
NOTES QTY PART NUMBER NAME TASK STEP

- (a)

- Fasteners Remove / Discard 1 From 2024-T3 aluminum (b) 1 B Filler Make 2 From 2024-T3 aluminum (c) (d) 1 A Repair Angle Make 3 On repair angle A for eachfloor panel attach fastener location covered by the repair 1 BACN10JR3F Nutplate Install 4

- 1 A Repair Angle Install 5

- 1 B Filler Install 6 (a) Approximately 12 locations, as necessary to properly size repair angle A. (b) Size to match the trimmed area, 0.063 inch thick to match the flange of the upper chord. (c) 0.071 inch thick sheet, width as necessary to match the upper flange and the vertical flange of the upper chord. Length as necessary to install at least 6 bolts in the horizontal flange and 6 bolts in the vertical flange on either side of the trimmed area. (d) Any floor panel attachment fastener hole under the repair angle that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.

FIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 4 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 156 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
NOTES HOLE DIA PART NUMBER NAME CODE

- - BACR15CE3AD3 Rivet A

- 0.187 - 0.190 BACB30NW6K() Bolt C BACC30M6 Collar Use at existing 5/32 inch rivet locations (a) 0.187 - 0.190 BACB30MY6K() Bolt D BACC30M6 Collar Use at existing 3/16 inch bolt locations (a) 0.200 - 0.203 BACB30MY6K()X Bolt BACC30M6 Collar Use at existing 3/16 inch rivet locations (a) 0.216 - 0.219 BACB30MY6K()Y Bolt BACC30R6 Collar (a) Typical. Longer bolts may be necessary in some locations.

FIGURE 30: SECTION 44 - UPPER CHORD THIN FLANGE REPAIR WITH ANGLE (REPAIR 12) (SHEET 5 OF 5)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 157 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 31: SECTION 44 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 158 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 31: SECTION 44 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 159 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.
MORE DATA QTY IDENTIFICATION NAME TASK STEP

- 2

- Fastener Remove / Discard 1 (a) for cracks 2

- Fastener Hole Inspect 2 (a) for cracks

- - Floor Panel Attach Fastener Hole Inspect 3 1/64 inch diameter (b) 2

- Fastener Hole Oversize 4 (c) if no cracks are found 2

- Fastener Install (a) Do open hole HFEC inspections as given in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. (b) If necessary to meet the hole size and quality criteria shown in 747-400 SRM 51-40-05. (c) Install fasteners of the same type and size as was removed, or 1/64 inch oversize as necessary.

FIGURE 31: SECTION 44 - AFTER-REPAIR INSPECTION FOR LOCATIONS WITH THE STRAP REPAIR (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 160 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThis Figure applies only to: Group 1.

FIGURE 32: SECTION 44 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 1 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 161 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTFIGURE 32: SECTION 44 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 2 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 162 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERTThe 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 repair. NOTE:Any floor panel attachment fastener hole under a repair strap that is not repaired or modified (as given in FIGURE 21 or as given in paragraph 3.B., Part 5) and is not at least five fasteners away from the end of the repair strap is not considered a repaired hole.
MORE DATA QTY IDENTIFICATION NAME TASK STEP

- 1 B Filler Remove / Keep 1 (a) for cracks

- - Upper Chord Inspect 2 (b) for cracks

- - Floor Panel Attach Fastener Hole Inspect 3

- 2

- Fastener Remove / Discard 4 (b) for cracks 2

- Fastener Hole Inspect 5 If no cracks are found, wet with BMS 5-95 sealant 1

- Filler (Kept) Install 6 1/64 inch diameter (c) 2

- Fastener Hole Oversize 7 (d) if no cracks are found 2

- Fastener Install (a) Do a surface HFEC inspections along the edge of the trimmed surface as given in 747 NDT Part 6, 53- 10-53 or 747 NDT Part 6, 51-00-00 Figure 4 or 23. (b) Do open hole HFEC inspections as shown in 747 NDT Part 6, 53-10-54 or 747 NDT Part 6, 51-00-00 Figure 1, 11, or 16. (c) If necessary to meet the hole size and quality criteria shown in 747-400 SRM 51-40-05. (d) Install fasteners of the same type and size as was removed, or 1/64 inch oversize as necessary.

FIGURE 32: SECTION 44 - AFTER-REPAIR INSPECTIONS FOR LOCATIONS WITH UPPER CHORD TRIM REPAIR WITH STRAP OR ANGLE (SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 21, 2008 747-53A2688 Revision 1 September 19, 2012 163 of 163 BOEING SERVICE BULLETIN 747-53A2688 ALERT ALERT