# Boeing Alert Service Bulletin 747-53A2500: Revision 1 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2009-0655; AD 2010-01-01 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 747-53A2500](https://openairdocs.org/service-documents/boeing/747-53a2500.md) - Title as filed: U.S. DOT/FAA - Boeing Service Bulletin - Pages: 173 - PDF: https://openairdocs.org/files/sha256/ca/6f/ca6f623090be117c16544c537a030c4a8dc3a944c56109063483d9d08a70b78a - Page: https://openairdocs.org/service-documents/boeing/747-53a2500/file/ca6f623090be ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 173 ALERT ALERT Commercial Airplane Group 747 ALERTALERT Service Bulletin Number: 747-53A2500 Date: December 21, 2004 Revision 1: September 25, 2008 ATA System: 5311 5312 5321 5211 SUBJECT: FUSELAGE - Main Frame - Inspections Based on Fatigue Test Results BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2004 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, 707, 717, 727, 737, 747, 757, 767, 777, BBJ, BOEING BUSINESS JET, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-90, the Boeing logo and the Boeing livery are among the trademarks owned by Boeing or its subsidiaries. No intellectual property license (express or implied) is granted in connection with this document or otherwise. ### Page 2 BLANK PAGE December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT BLANK PAGE ### Page 3 Table of Contents December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT Table of Contents Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 32 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 32 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 32 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 33 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 33 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES . . . . . . . . . . . . 57 FIGURE 4: INSPECTION OF AREA 4 - SECTION 42 LOWER LOBE FRAMES . . . . . . . . . . . . 68 FIGURE 5: INSPECTION OF AREA 5 - SECTION 46 UPPER LOBE FRAMES - GROUP 1 AND 5 AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 FIGURE 6: INSPECTION OF AREA 6 - MAIN ENTRY DOOR CUTOUTS - GROUP 1, 3, 5, 6, 7, and 8 AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 FIGURE 7: INSPECTION OF AREA 7 - BODY STATION 260, 340, AND 400 BULKHEADS AND NOSE ### Page 4 Table of Contents December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT WHEEL WELL SIDEWALLS FROM STATION 340 TO STATION 400 . . . . . . . . . . 90 F I G U R E 8 : I N S P E C T I O N O F A R E A 8 - M A I N E N T R Y D O O R S - G R O U P 1 , 3 , 5 , 6 , 7 , 8 , A N D 1 0 AIRPLANES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 FIGURE 9: INSPECTION OF AREA 9 - MAIN ELECTRONICS BAY ACCESS DOOR CUTOUT . . . 103 FIGURE 10: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 2 AND 9 AIRPLANES 105 FIGURE 11: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 3 AND 10 AIRPLANES 110 FIGURE 12: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 4 AIRPLANES . 115 FIGURE 13: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 2, 3, 4, 9, AND 10 AIRPLANES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9 FIGURE 14: INSPECTION OF AREA 6 - MAIN ENTRY DOOR CUTOUTS - GROUP 2 and 4 AIRPLANES 125 FIGURE 15: INSPECTION OF AREA 8 - MAIN ENTRY DOORS - GROUP 2, 4, AND 9 AIRPLANES 130 FIGURE 16: INSPECTION OF AREA 5 - SECTION 46 UPPER LOBE FRAMES - GROUP 2, 4, AND 9 AIRPLANES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 FIGURE 17: INSPECTION OF AREA 5 - SECTION 46 UPPER LOBE FRAMES - GROUP 3, 6, 7, AND 10 AIRPLANES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 FIGURE 18: INSPECTION OF AREA 1 - FRAM E INSPECTION COMMON TO UPPER DECK FLOOR BEAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 FIGURE 19: INSPECTION OF AREA 6 - MAIN ENTRY DOOR CUTOUTS - GROUP 9 AIRPLANES 157 FIGURE 20: INSPECTION OF AREA 6 - MAIN ENTRY DOOR CUTOUTS - GROUP 10 AIRPLANES 161 FIGURE 21: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 8 AIRPLANES . 168 APPENDIX A: LOGIC DIAGRAM - GROUP 1 AND 6 AIRPLANES . . . . . . . . . . . . . . . . . . 172 APPENDIX B: LOGIC DIAGRAM - GROUP 2, 3, 4, 5, 7, 9, AND 10 AIRPLANES. . . . . . . . . . . 173 ### Page 5 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 173 ALERT ALERT Commercial Airplane Group 747 ALERTALERT Service Bulletin Number: 747-53A2500 Revision Transmittal Sheet Date: December 21, 2004 Revision 1: September 25, 2008 ATA System: 5311 5312 5321 5211 SUBJECT: FUSELAGE - Main Frame - Inspections Based on Fatigue Test Results This Revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION More work is necessary on airplanes inspected as given in the original issue of this service bulletin. Operators should incorporate the additional inspection requirements for Area 1 and Area 6 during the next scheduled inspection. No airplanes have been added to the service bulletin effectivity. However, 747 Large Cargo Freighter (LCF) airplanes RT631-RT632, RT743, and RT876 were moved from Group 1 to new Group 8. 747-200F airplanes through line number 685 were moved from Group 2 to new Group 9. 747-200C airplanes through line number 685 were moved from Group 3 to new Group 10. Federal Aviation Administration (FAA) Airworthiness Directives 2006-05-02 and 2004-07-22 R1 are related to this service bulletin. REASON FOR REVISION This revision is sent to add new inspection requirements for Area 1, and to add to and to clarify some inspection requirements for Area 6. Inspection Area 1 (upper deck floor beams) has been changed to include inspections of the fuselage frames in the areas where the upper deck floor beams are attached. Inspection Area 6 has been changed to include inspection of more fuselage frames in the area above Main Entry Door 1 on 747-200C and 747-200F airplanes after line number 685, and on all 747-400, 747-400D, and 747-400F airplanes. For 747- 200C and 747-200F airplanes through line number 685, this inspection area is included in Boeing Service Bulletin 747-53A2732. In addition, Compliance information and inspection area requirements for 747 Large cargo Freighter (LCF) airplanes have been added. These sections were changed: 1. In Summary Background section and in Reason, Paragraph 1.C., referenced Boeing Service Related Problem (SRP) 747-SRP-53-0311. Also, updated Summary illustration. 2. In Description Paragraph 1.D., a description of the inspections required on Group 8 airplanes has been added. ### Page 6 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 3. In Compliance, Paragraph 1.E., Compliance information for new Group 8 airplanes has been added. Related airworthiness directives have also been added. 4. In Approval, Paragraph 1.F., the approval statement has been updated and Alternative Method of Compliance information for related airworthiness directives has been added. 5. In Manpower, Paragraph 1.G., the estimate has been updated to include inspection of the frames in the upper deck floor beam attachment areas in Area 1. 6. In References, Paragraph 1.J., updated references list. 7. In Work Instructions, Paragraph 3.B., descriptions of the inspections required in the various Inspection Areas for Group 8 airplanes have been added. 8. In Work Instructions, Paragraph 3.B., Area 1 inspection, instructions were added for detailed inspection of the frame inner chord, the frame outer chord, and the frame web in the area between the upper and lower chords of the upper deck floor beams. Instructions were added to inspect Group 8 airplanes as given in Figure 21. 9. In Work Instructions, Paragraph 3.B., Area 5 inspection, step 5 has been revised to refer to Figure 17 (was Figure 19). 10. In Work Instructions, Paragraph 3.B., Area 6 inspection, instructions were added to inspect Group 9 airplanes as given in Figure 19. Instructions were added to inspect Group 10 airplanes as given in Figure 20. 11. Figures 6 and 14 (for Area 6) have been revised to clarify and add inspection requirements for the area above the Main Entry Door No. 1 cutout. On these airplanes, also do detailed inspections of the body frames at STA 400 through STA 500, from the top of the upper deck floor to Stringer 8. 12. Figure 18 (for Area 1) has been added for detailed inspection of the frame inner chord, the frame outer chord, and the frame web in the area between the upper and lower chords of the upper deck floor beams. This inspection is necessary on both sides of the airplane at each frame from body station 260 to body station 520. 13. Figure 19 (for Area 6 on Group 9 airplanes) has been added to show that on these airplanes it is not necessary to do inspections of the frames above the upper deck floor above Main Entry Door 1 left. 14. Figure 20 (for Area 6 on Group 10 airplanes) has been added to show that on these airplanes it is not necessary to do inspections of the frames above the upper deck floor above Main Entry Door 1 left and right. 15. Figure 21 (for Area 1 on Group 8 airplanes) has been added to show the detailed inspection requirements for the upper deck floor beams on Group 8 airplanes. Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. ### Page 7 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT REVISION HISTORY Original Issue: December 21, 2004 Revision 1: September 25, 2008 ### Page 8 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT BLANK PAGE ### Page 9 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 173 ALERT ALERT Commercial Airplane Group 747 ALERTALERT Service Bulletin Number: 747-53A2500 Summary Date: December 21, 2004 Revision 1: September 25, 2008 ATA System: 5311 5312 5321 5211 SUBJECT: FUSELAGE - Main Frame - Inspections Based on Fatigue Test Results 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 data for the inspection and repair, if necessary, of certain fuselage structure. These inspections and repairs are necessary for safe operation of 747-400 airplanes and nose cargo door 747 airplanes past the design life goal. Tests by Boeing have determined that the structure shown in this service bulletin is subject to fatigue cracks. Boeing has completed extended pressure fatigue tests on a 747SR and a 747-400 fuselage test article. Boeing has also used updated analysis methods on the 747 fuselage structure. The tests and analysis have identified areas of the fuselage where fatigue cracks can occur. Inspection and repair of these areas is necessary for safe operation of 747 airplanes past the design life goal. The inspections in this service bulletin will make sure that fatigue cracks in the areas of fuselage internal structure shown do not become critical. Additional service bulletins will be required to be accomplished in certain specific areas, as a result of fatigue crack findings in the 747 fleet. Also, Supplemental Structural Inspection Document (SSID), D6-35022 Revision G and Federal Aviation Administration (FAA) Airworthiness Directive 2004-07-22 R1 require inspections to be accomplished, starting at 20,000 total flight-cycles. Boeing Service Related Problem (SRP) 747-SRP-53-0211 is related to this service bulletin. Boeing Service Related Problem (SRP) 747-SRP-53-0311 is related to this service bulletin. ACTION (PRR 85901-44RS) Do internal detailed inspections for cracks in these areas of internal fuselage structure: ### Page 10 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 1. Upper deck floor beams. 2. Section 42 frames. 3. Section 46 frames. 4. Nose wheel well bulkheads, sidewall panels, and the STA 360 and 380 main deck floor beams. 5. Section 41 frame structure in the area between the upper deck floor beam chords, from STA 260 to 520. Do internal and external detailed inspections of the main entry doors and door cutouts for cracks. Do internal and external detailed inspections of the fuselage skin for cracks at all four corners of the main electronics bay access door cutout. If cracks are found, refer to the structural repair manual for repair instructions. If the damage is beyond the limits shown in the structural repair manual, ask Boeing for repair data. Also, ask Boeing for repair data if an applicable repair is not included in the structural repair manual. EFFECTIVITY All 747-200C, 747-200F, 747-400, 747-400D, and 747-400F series airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. COMPLIANCE The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directives 2006-05-02 and 2004-07-22 R1 are related to this service bulletin. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection or repair procedures given in this service bulletin. MANPOWER MATERIAL INFORMATION None. Airplanes Total Task Hours Elapsed Hours All 1990 322 ### Page 11 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT FRAMES LOWER LOBE SECTION 42 INSPECT THE 1000 STA 520 STA 260 BULKHEAD 140 STA INSPECT THE BODY STATION INSPECT THE BODY WHEEL WELL STRUCTURE BULKHEADS AND NOSE STATION 340 AND 400 ENTRY DOORS AND DOOR CUTOUTS INSPECT THE MAIN INSPECT THE UPPER DECK FLOOR BEAMS AND INSPECT THE FRAMES IN THE AREA COMMON TO THE UPPER DECK FLOOR BEAMS520 STA UPPER DECK FLOOR BEAMS INSPECT THE INSPECT THE UPPER LOBE FRAMES SECTION 42 ACCESS DOOR CUTOUT ELECTRONICS BAY AT THE MAIN INSPECT THE SKIN DECK FLOOR BEAMS 360 AND 380 MAIN INSPECT THE STA DOORS AND DOOR INSPECT THE MAIN ENTRY CUTOUTS DOORS AND DOOR CUTOUTS MAIN ENTRY INSPECT THE 1000 STA 1480 STA 1480 STA 2360 STA DOORS AND DOOR SECTION 46 SECTION 46 FRAMES LOWER LOBE CUTOUTS MAIN ENTRY INSPECT THE UPPER LOBE FRAMES INSPECT THE INSPECT THE DECK FLOOR BEAMS INSPECT THE UPPER RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SECTION 42 RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SECTION 41 RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SECTION 46 RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SECTION 44 FWD FWD FWD FWD W59427 ### Page 12 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT BLANK PAGE ### Page 13 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 173 ALERT ALERT Commercial Airplane Group 747 ALERTALERT Service Bulletin Number: 747-53A2500 Date: December 21, 2004 Revision 1: September 25, 2008 ATA System: 5311 5312 5321 5211 SUBJECT: FUSELAGE - Main Frame - Inspections Based on Fatigue Test Results 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. Refer to PRR 85901-44RS for data about this change. NOTE: This service bulletin is for the airplanes identified below. The effectivity list shown below is complete for airplanes through line number 1413. However, airplanes after line number 1413 are also affected by this service bulletin. GROUP CONFIGURATION DESCRIPTION 1 - All 747-400 airplanes line number 758 and on, except Combi and 747-400F airplanes and airplanes modified by Boeing to the Large Cargo Freighter (LCF) configuration. 2 - All 747-200F airplanes line number 686 and on. 3 - All 747-200C airplanes line number 686 and on. 4 - All 747-400F airplanes. 5 - All 747-400 airplanes through line number 757, except Combi and 747-400F airplanes. ### Page 14 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT Airplane models: 747-200C 747-200F 747-400 747-400D 747-400F IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER AEROLINEAS ARGENTINAS (ARG) 1 RT701–RT702 RT704 AIR ATLANTA ICELANDIC (AID) 1 RT515 RT751 2 RR206 9 RR204 RR332 AIR CHINA (BEJ) 1 RM341 RT878–RT880 2 RR451 6 RM811–RM813 RT032–RT035 7 RT031 AIR CHINA CARGO (CGC) 4 RL501–RL502 6 RT101 RT103 AIR FRANCE (AFA) 1 RM401–RM403 RT711–RT716 2 RR308–RR309 4 RL671–RL675 5 RT591 6 RT071–RT075 RT121 9 RR306 AIR INDIA (AIN) 1 RT749 RU001–RU006 6 - All 747-400 Combi airplanes line number 758 and on. 7 - All 747-400 Combi airplanes through line number 757. 8 - All 747-400 airplanes line number 758 and on, modified by Boeing to the Large Cargo Freighter (LCF) configuration. 9 - All 747-200F airplanes through line number 685. 10 - All 747-200C airplanes through line number 685. GROUP CONFIGURATION DESCRIPTION ### Page 15 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT AIR NEW ZEALAND (ANZ) 1 RM082 RM191–RM192 RT672–RT673 RT703 RT932 5 RT671 AIR PACIFIC (APC) 5 RT502 RT504 AIR PULLMANTUR (PUL) 1 RT525 AIRBRIDGE CARGO (ABM) 2 RR556 4 RL576–RL577 RL579 9 RR552 ALL NIPPON AIRWAYS (ANA) 1 RM231 RM233 RT753–RT756 RT776–RT777 RU831–RU841 AMIRI FLIGHT (ABD) 1R M 0 8 4 6 RT137 ASIANA AIRLINES (AAR) 1 RM071 RU032 4 RM861–RM863 RR746–RR747 6 RT131–RT136 ATLAS AIR (TLS) 1 RT752 10 RJ333 4 RM891–RM899 RM901–RM906 RR748 9 RR301 AVION AIRCRAFT TRADING H.F. (VNG) 1 RT633–RT634 AWAS (AWW) 10 RJ321 3 RJ322 BAHRAIN ROYAL FLIGHT (BHR) 1R M 4 2 6 BOEING (TBC) 9 RR222–RR223 BOEING AIRCRAFT HOLDING CO. (BHC) 10 RJ132 ### Page 16 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT BRITISH AIRWAYS (BAB) 1 RM096–RM097 RM136–RM145 RM261–RM264 RT476–RT499 RU121–RU132 5 RT471–RT475 C.A.L. CARGO AIR LINES (CRG) 10 RJ331–RJ332 CARGO 360, INC. (CGN) 2 RR024–RR025 CARGO B AIRLINES (CBO) 2 RR307 9 RR561 CARGOLUX AIRLINES (CLX) 4 RL551 RM881–RM890 RR701 RR721–RR724 CATHAY PACIFIC AIRWAYS (CAT) 1 RT453–RT469 RT508 RT511–RT512 RT514 RT517–RT518 RT522 RT528–RT529 RT781–RT782 2 RR441–RR442 4 RL581–RL583 RM856–RM859 RR951–RR952 5 RT451–RT452 CHINA AIRLINES (CHI) 1 RM021–RM024 RM441–RM443 RM445 RT636–RT640 4 RL411–RL430 RL481 CHINA CARGO (CIQ) 4 RL521–RL522 CHINA SOUTHERN AIRLINES (GUN) 4 RL751–RL752 CORSAIR (COR) 1 RT613–RT614 RT616 RT618–RT619 RT621 DRAGONAIR (DRG) 1 RT510 RT513 RT516 RT524 2 RR522 DUBAI AIR WING (DAW) 1 RM167–RM168 6 RT102 EL AL ISRAEL AIRLINES (ELA) 1 RM091 RU081–RU083 10 RJ152 9 RR225–RR226 EMIRATES (EAD) 4 RL533–RL534 ### Page 17 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT EVA AIR (EVA) 1 RM116–RM117 RT951–RT952 RT955 4 RL401–RL403 6 RT162–RT163 RT165–RT168 RT953–RT954 EVERGREEN INTERNATIONAL A/L (EVR) 10 RJ131 RJ133 8 RT631–RT632 RT743 RT876 EXPORT RESTRICTED AIRPLANES (YWV) 1 RT412 RT606 RT615 RT620 RT622 5 RT602 9 RR001–RR004 GARUDA INDONESIA (GIA) 1 RT931 RU061–RU062 GENERIC CUSTOMER/SUPPLIER (XXX) 2 RR310 9 RR202–RR203 GOVERNMENT OF JAPAN (JAG) 1 RT681–RT682 GRAND STAR (GCG) 4 RR861 GREAT WALL AIRLINES (GWL) 1 RT520 IRAQI AIRWAYS (IRQ) 10 RJ301–RJ303 JADE CARGO INTERNATIONAL (JDE) 4 RL511–RL516 JAL INTERNATIONAL (JAL) 1 RM126–RM132 RM316–RM318 RT641–RT657 RT861–RT864 RT966–RT967 RU801–RU809 4 RL461–RL462 9 RR265–RR266 KALITTA AIR (KAC) 7 RT021–RT022 9 RR261–RR262 RR361–RR362 RR501 RR521 KINGDOM HOLDING COMPANY (KBA) 1 RT877 ### Page 18 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT KLM - ROYAL DUTCH AIRLINES (KLM) 1 RT533–RT535 4 RL681–RL684 5 RT531–RT532 6 RM801–RM803 RT003–RT014 7 RT001–RT002 KOREAN AIR (KAL) 1 RM011–RM013 RT574–RT588 RT590 RT811–RT814 4 RL451–RL456 RM871–RM880 RR862 5 RT571–RT573 6 RT061 KUWAIT AIRWAYS (KUW) 6 RT151 LUFTHANSA GERMAN AIRLINES (DLH) 1 RM001–RM007 RT434–RT439 RT441–RT447 5 RT431–RT433 6 RT044–RT047 7 RT041–RT043 MALAYSIA AIRLINES (MAS) 1 RM036–RM040 RM366–RM367 RT744 RT746 RT748 RT750 RU016–RU017 4 RL491–RL492 MARTINAIR HOLLAND (MTH) 1 RT506–RT507 RT509 5 RT501 MK AIRLINES (MKA) 9 RR022–RR023 RR224 RR336 RR421 NIPPON CARGO AIRLINES (NCA) 2 RR555 4 RL471–RL479 9 RR553 NORTHWEST AIRLINES (NWA) 1 RM241–RM246 RT407–RT410 2 RR566 5 RT401–RT406 9 RR005 RR341–RR342 RR344–RR345 RR431–RR432 RR503 OASIS HONG KONG AIRLINES (OHK) 1 RM232 RT505 5 RT503 OMAN ROYAL FLIGHT (RFO) 1R M 0 1 0 ### Page 19 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT ORIENT THAI AIRLINES (OTH) 9 RR264 PHILIPPINE AIRLINES (PAL) 1 RU059 6 RT152 POLAR AIR CARGO (PAO) 4 RL651–RL655 9 RR504 PRONAIR (TXI) 9 RR221 QANTAS (QAN) 1 RF001–RF006 RM331–RM333 RT554–RT568 RT741–RT742 RU031 5 RT551–RT553 ROYAL AIR MAROC (RAM) 1 RT717 SAUDI ARABIAN AIRLINES (SVA) 1 RM156–RM157 RU101–RU102 2 RR526 SAUDI ROYAL FLIGHT (SRF) 1R M 1 5 8 SIACARGO (SIT) 4 RL431–RL436 RM851–RM855 RR851–RR856 SINGAPORE AIRLINES (SIA) 1 RM041–RM045 RT519 RT521 RT523 RT526–RT527 RT530 RT747 RT831–RT835 RT837 SOUTH AFRICAN AIRWAYS (SAA) 1 RM081 RM083 RM146–RM147 RT784 SOUTHERN AIR (SOF) 2 RR554 9 RR267 RR302–RR305 RR551 THAI AIRWAYS INTERNATIONAL (TII) 1 RM026–RM030 RM431 RT691–RT699 RT801–RT803 THE SULTAN'S FLIGHT (BWN) 1 RT440 TNT AIRWAYS (TNB) 4 RL531–RL532 ### Page 20 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT TRANSAERO AIRLINES (TRX) 1 RT783 UNITED AIR LINES (UAL) 1 RM166 RM169–RM177 RT411 RT603–RT605 RT607–RT612 RT617 RT623–RT630 5 RT601 UPS (UPS) 4 RL561–RL568 6 RT161 RT164 US AIR FORCE (USF) 4R M 9 1 1 VIRGIN ATLANTIC AIRWAYS (VAA) 1 RM051–RM053 RM351–RM355 RT945–RT949 WILMINGTON TRUST COMPANY (WBT) 1 RU051–RU052 RU060 WORLD AIRWAYS, INC. (WLD) 1 RT745 YANGTZE RIVER EXPRESS (YTH) 1 RT757 IDENTIFICATION BY VARIABLE NUMBER Variable Group RF001–RF006 1 RJ131–RJ133 10 RJ151–RJ152 10 RJ301–RJ303 10 RJ321 10 RJ322 3 RJ331–RJ333 10 RL401–RL403 4 RL411–RL436 4 RL451–RL456 4 RL461–RL462 4 RL471–RL479 4 RL481 4 RL491–RL492 4 RL501–RL502 4 RL511–RL516 4 RL521–RL522 4 ### Page 21 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT RL531–RL534 4 RL551 4 RL561–RL568 4 RL576–RL577 4 RL579 4 RL581–RL583 4 RL651–RL655 4 RL671–RL675 4 RL681–RL684 4 RL751–RL752 4 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–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 1 Variable Group ### Page 22 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT RM801–RM803 6 RM811–RM813 6 RM851–RM859 4 RM861–RM863 4 RM871–RM899 4 RM901–RM906 4 RM911 4 RR001–RR005 9 RR021–RR023 9 RR024–RR025 2 RR031 9 RR201–RR205 9 RR206 2 RR221–RR226 9 RR261–RR267 9 RR301–RR306 9 RR307–RR310 2 RR331–RR332 9 RR336 9 RR341–RR345 9 RR361–RR362 9 RR421–RR422 9 RR431–RR432 9 RR441–RR442 2 RR451 2 RR501–RR504 9 RR521 9 RR522 2 RR526 2 RR531 9 RR551–RR553 9 RR554–RR556 2 RR561 9 RR566 2 RR701 4 RR721–RR724 4 RR746–RR748 4 RR851–RR856 4 RR861–RR862 4 Variable Group ### Page 23 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT RR951–RR952 4 RT001–RT002 7 RT003–RT014 6 RT021–RT022 7 RT031 7 RT032–RT035 6 RT041–RT043 7 RT044–RT047 6 RT061 6 RT071–RT075 6 RT101–RT103 6 RT121 6 RT131–RT137 6 RT151–RT152 6 RT161–RT168 6 RT401–RT406 5 RT407–RT412 1 RT431–RT433 5 RT434–RT447 1 RT451–RT452 5 RT453–RT469 1 RT471–RT475 5 RT476–RT499 1 RT501–RT504 5 RT505–RT530 1 RT531–RT532 5 RT533–RT535 1 RT551–RT553 5 RT554–RT568 1 RT571–RT573 5 RT574–RT590 1 RT591 5 RT601–RT602 5 RT603–RT630 1 RT631–RT632 8 RT633–RT657 1 RT671 5 RT672–RT673 1 RT681–RT682 1 Variable Group ### Page 24 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 2. Spares Affected None. B. Concurrent Requirements None. RT691–RT699 1 RT701–RT704 1 RT711–RT717 1 RT741–RT742 1 RT743 8 RT744–RT757 1 RT776–RT777 1 RT781–RT784 1 RT801–RT803 1 RT811–RT814 1 RT831–RT837 1 RT861–RT864 1 RT876 8 RT877–RT880 1 RT931–RT932 1 RT945–RT949 1 RT951–RT952 1 RT953–RT954 6 RT955 1 RT966–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 1 Variable Group ### Page 25 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT C. Reason This service bulletin gives data for the inspection and repair, if necessary, of certain fuselage structure. These inspections and repairs are necessary for safe operation of 747-400 airplanes and nose cargo door 747 airplanes past the design life goal. Tests by Boeing have determined that the structure shown in this service bulletin is subject to fatigue cracks. Boeing has completed extended pressure fatigue tests on a 747SR and a 747-400 fuselage test article. Boeing has also used updated analysis methods on the 747 fuselage structure. The tests and analysis have identified areas of the fuselage where fatigue cracks can occur. Inspection and repair of these areas is necessary for safe operation of 747 airplanes past the design life goal. The inspections in this service bulletin will make sure that fatigue cracks in the areas of fuselage internal structure shown do not become critical. Additional service bulletins will be required to be accomplished in certain specific areas, as a result of fatigue crack findings in the 747 fleet. Also, Supplemental Structural Inspection Document (SSID), D6-35022 Revision G and Federal Aviation Administration (FAA) Airworthiness Directive 2004-07-22 R1 require inspections to be accomplished, starting at 20,000 total flight-cycles. Boeing Service Related Problem (SRP) 747-SRP-53-0211 is related to this service bulletin. Boeing Service Related Problem (SRP) 747-SRP-53-0311 is related to this service bulletin. Revision 1 is sent to add new inspection requirements for Area 1, and to add to and to clarify some inspection requirements for Area 6. Inspection Area 1 (upper deck floor beams) has been changed to include inspections of the fuselage frames in the areas where the upper deck floor beams are attached. Inspection Area 6 has been changed to include inspection of more fuselage frames in the area above Main Entry Door 1 on 747-200C and 747-200F airplanes after line number 685, and on all 747-400, 747-400D, and 747-400F airplanes. For 747-200C and 747-200F airplanes through line number 685, this inspection area is included in Boeing Service Bulletin 747-53A2732. In addition, Compliance information and inspection area requirements for 747 Large cargo Freighter (LCF) airplanes have been added. These sections were changed as part of Revision 1: 1. In Summary Background section and in Reason, Paragraph 1.C., referenced Boeing Service Related Problem (SRP) 747-SRP-53-0311. Also, updated Summary illustration. 2. In Description Paragraph 1.D., a description of the inspections required on Group 8 airplanes has been added. 3. In Compliance, Paragraph 1.E., Compliance information for new Group 8 airplanes has been added. Related airworthiness directives have also been added. 4. In Approval, Paragraph 1.F., the approval statement has been updated and Alternative Method of Compliance information for related airworthiness directives has been added. 5. In Manpower, Paragraph 1.G., the estimate has been updated to include inspection of the frames in the upper deck floor beam attachment areas in Area 1. 6. In References, Paragraph 1.J., updated references list. ### Page 26 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 7. In Work Instructions, Paragraph 3.B., descriptions of the inspections required in the various Inspection Areas for Group 8 airplanes have been added. 8. In Work Instructions, Paragraph 3.B., Area 1 inspection, instructions were added for detailed inspection of the frame inner chord, the frame outer chord, and the frame web in the area between the upper and lower chords of the upper deck floor beams. Instructions were added to inspect Group 8 airplanes as given in Figure 21. 9. In Work Instructions, Paragraph 3.B., Area 5 inspection, step 5 has been revised to refer to Figure 17 (was Figure 19). 10. In Work Instructions, Paragraph 3.B., Area 6 inspection, instructions were added to inspect Group 9 airplanes as given in Figure 19. Instructions were added to inspect Group 10 airplanes as given in Figure 20. 11. Figures 6 and 14 (for Area 6) have been revised to clarify and add inspection requirements for the area above the Main Entry Door No. 1 cutout. On these airplanes, also do detailed inspections of the body frames at STA 400 through STA 500, from the top of the upper deck floor to Stringer 8. 12. Figure 18 (for Area 1) has been added for detailed inspection of the frame inner chord, the frame outer chord, and the frame web in the area between the upper and lower chords of the upper deck floor beams. This inspection is necessary on both sides of the airplane at each frame from body station 260 to body station 520. 13. Figure 19 (for Area 6 on Group 9 airplanes) has been added to show that on these airplanes it is not necessary to do inspections of the frames above the upper deck floor above Main Entry Door 1 left. 14. Figure 20 (for Area 6 on Group 10 airplanes) has been added to show that on these airplanes it is not necessary to do inspections of the frames above the upper deck floor above Main Entry Door 1 left and right. 15. Figure 21 (for Area 1 on Group 8 airplanes) has been added to show the detailed inspection requirements for the upper deck floor beams on Group 8 airplanes. D. Description Group 1-7, 9-10: 1. Do internal detailed inspections for cracks in these areas of internal fuselage structure: a. Upper deck floor beams. b. Section 42 frames. c. Section 46 frames. d. Nose wheel well bulkheads, sidewall panels, and the STA 360 and 380 main deck floor beams. e. Section 41 frame structure in the area between the upper deck floor beam chords, from STA 260 to 520. ### Page 27 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 2. Do internal and external detailed inspections of the main entry doors and door cutouts for cracks. 3. Do internal and external detailed inspections of the fuselage skin for cracks at all four corners of the main electronics bay access door cutout. Group 8: 1. Do internal detailed inspections for cracks in these areas of internal fuselage structure: a. Upper deck floor beams. b. Section 42 lower lobe frames. c. Section 46 lower lobe frames. d. Nose wheel well bulkheads, sidewall panels, and the STA 360 and 380 main deck floor beams. e. Section 41 frame structure in the area between the upper deck floor beam chords, from STA 260 to 520. 2. Do internal and external detailed inspections of Main Entry Door 1 left and right and the Main Entry Door 1 cutouts for cracks. 3. Do internal and external detailed inspections of the fuselage skin for cracks at all four corners of the main electronics bay access door cutout. If cracks are found, refer to the structural repair manual for repair instructions. If the damage is beyond the limits shown in the structural repair manual, ask Boeing for repair data. Also, ask Boeing for repair data if an applicable repair is not included in the structural repair manual. The airplane effectivity is divided in ten groups. Revision 1 - More work is necessary on airplanes inspected as given in the original issue of this service bulletin. Operators should incorporate the additional inspection requirements for Area 1 and Area 6 during the next scheduled inspection. E. Compliance The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. ### Page 28 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT On Groups 1 - 7 and 9 - 10 airplanes, for inspections that were added to this service bulletin in Revision 1 (i.e., in Areas 1 and 6), start the new inspections at 22,000 total flight-cycles or within 1,000 flight-cycles after the date on Revision 1 of this service bulletin, whichever is later. On Groups 1 - 7 and 9 - 10 airplanes, these inspections include the frame inspections in Figure 18 from body station 260 to 520, between the upper and lower chords of the upper deck floor beams. On Groups 1 - 7 airplanes, these inspections also include the frame inspections in Figures 6 and 14 from body station 400 to 500, from the upper chord of the upper deck floor beams to Stringer 8. For all the existing inspections, refer to TABLE 1 for compliance times. NOTE: On Group 8 airplanes, this service bulletin does not include Area 2 and Area 5 inspections. Federal Aviation Administration (FAA) Airworthiness Directives 2006-05-02 and 2004-07-22 R1 are related to this service bulletin. Group 1-7, 9-10: TABLE 1: Group Area Action Compliance Time (Whichever is later) Repeat Interval 1 and 6 1, 3, 4, 6, 7, 8, and 9 Inspect 22,000 total flight-cycles 1,000 flight-cycles after the date on the original issue of this service bulletin. 3,000 flight-cycles 2 and 5 Inspect 25,000 total flight-cycles 1,000 flight-cycles after the date on the original issue of this service bulletin. 3,000 flight-cycles 2, 3, 4, 5, 7, 9, and 10 1, 2, 3, 4, 6, 7, 8, and 9 Inspect 22,000 total flight-cycles 1,000 flight-cycles after the date on the original issue of this service bulletin. 3,000 flight-cycles 5 Inspect 25,000 total flight-cycles 1,000 flight-cycles after the date on the original issue of this service bulletin. 3,000 flight-cycles Group 8: TABLE 2: Condition Action Compliance Time (Whichever occurs later) Repeat Interval (Not to Exceed) All Group 8 airplanes Inspect Area 1 as given in Paragraph 3.B. 20,000 total flight-cycles 1,000 flight-cycles after the date on Revision 1 of this service bulletin. 2,500 flight-cycles All Group 8 airplanes Inspect Area 3, Area 4, and Area 8 as given in Paragraph 3.B. 22,000 total flight-cycles 1,000 flight-cycles after the date on Revision 1 of this service bulletin. 3,000 flight-cycles All Group 8 airplanes Inspect Area 6 and Area 9 as given in Paragraph 3.B. 15,000 total flight-cycles 1,000 flight-cycles after the date on Revision 1 of this service bulletin. 1,500 flight-cycles All Group 8 airplanes Inspect Area 7 as given in Paragraph 3.B. 18,000 total flight-cycles 1,000 flight-cycles after the date on Revision 1 of this service bulletin. 2,500 flight-cycles ### Page 29 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/ JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the accomplishment of the applicable inspection and repair procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraph (f) of AD 2006-05-02. This AMOC only applies to the areas inspected as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be in accordance with FAA-approved procedures as required by paragraph (g) of the AD. All provisions of AD 2006-05-02 that are not specifically referenced in the preceding statement remain fully applicable and must be complied with. The Manager of the FAA Seattle ACO also approves the accomplishment of the applicable inspection and repair procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraphs (h), (i), and (j) of FAA AD 2004-07-22 R1 for SSI F-21A, F-21B, F-24A, F-24C, F-41A, and F-41B of Supplemental Structural Inspection Document (SSID) D6-35022, Revision G. This AMOC only applies to the areas inspected as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be in accordance with FAA-approved procedures as required by paragraph (j) of the AD. All provisions of AD 2004-07-22 R1 that are not specifically referenced in the preceding statement, including the initial inspection threshold per paragraph (i) of AD 2004-07-22 R1, remain fully applicable and must be complied with. G. Manpower The table below shows an estimate of the task-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 task-hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to cure the materials — Time to make the parts ### Page 30 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT — Time to find the tools. Group 1-7, 9-10: TABLE 1: Area Task Number of Persons Task-Hours Elapsed Hours 1 Open Access 8 120 15 Inspect Floor Beams 4 132 33 Inspect Frames at Upper Deck Floor Beams 26 3 Close Access 8 160 20 Test 3 18 6 TOTAL FOR AREA 1 436 77 2 Open Access 8 176 22 Examine 6 72 12 Close Access 8 240 30 Test 4 28 7 TOTAL FOR AREA 2 516 71 3 Open Access 8 96 12 Examine 4 16 4 Close Access 8 144 18 Test 4 20 5 TOTAL FOR AREA 3 276 39 4 Open Access 4 28 7 Examine 2 8 4 Close Access 4 40 10 Test 1 1 1 TOTAL FOR AREA 4 77 22 5 Open Access 6 66 11 Examine 2 8 4 Close Access 6 96 16 Test 2 8 4 TOTAL FOR AREA 5 178 35 6 Open Access 2 10 5 Examine 1 2 2 Close Access 2 14 7 Test 1 2 2 TOTAL FOR EACH DOOR 28 16 TOTAL FOR AREA 6 280 28 ### Page 31 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 31 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT NOTE: More time will be necessary for repairs if cracks are found. H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Engineering Change Memo PRR85901-44RS b. Service Related Problem (SRP) 747-SRP-53-0211 c. Service Related Problem (SRP) 747-SRP-53-0311 d. 747 Maintenance Manual (AMM) Subject 25-21-02, 25-21-03, 25-21-04, 25-22-01, 25-22-03, 25-25-01, 25-28-01, 25-28-02, 25-52-01, 25-52-04, 25-53-15, 25-55-02, 25-55-03, 25-59-01, 25-59-05, 52-11-02, 53-21-02 e. 747-400 Maintenance Manual (AMM) Subject 25-21-02, 25-21-03, 25-21-04, 25-22-01, 25-22-03, 25-25-01, 25-28-01, 25-28-02, 25-52-01, 25-52-04, 25-53-15, 25-55-02, 25-55-03, 25-59-01, 25-59-05, 52-11-02, 53-21-02 f. 747 Structural Repair Manual (SRM) Subject 52-00-03, 52-10-02, 53-00-01, 53-10-03, 53- 10-04, 53-10-04, 53-10-07, 53-30-03 7 Open Access 4 50 12.5 Examine 2 20 10 Close Access 4 62 15.5 Test 2 4 2 TOTAL FOR AREA 7 136 40 8 Open Access 1 3 3 Examine 1 1 1 Close Access 1 4 4 Test 1 1 1 TOTAL FOR EACH DOOR 9 9 TOTAL FOR AREA 8 90 9 9E x a m i n e 1 1 1 TOTAL FOR AREA 9 1 1 TOTAL FOR EACH AIRPLANE 1990 322 Group 1-7, 9-10: TABLE 1: Area Task Number of Persons Task-Hours Elapsed Hours ### Page 32 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 32 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT g. 747-400 Structural Repair Manual (SRM) Subject 52-10-01, 52-10-02, 53-00-01, 53-00-03, 53-00-51, 53-10-07, 53-10-08, 53-10-51, 53-20-07, 53-20-51, 53-60-07, 53-60-15 h. 747-400F Structural Repair Manual (SRM) Subject 52-10-01, 52-10-02, 53-00-01, 53-00- 03, 53-10-07, 53-10-08, 53-20-07, 53-60-07, 53-60-15 i. Boeing Service Bulletins 747-53-2358, "Fuselage - Main Entry Doors Number 1, 2, 3, and 4 - Forward Edge Stop Support Fitting Inspection and Replacement,"; 747-53A2396, "Fuselage - Skins - Skin and Internal Doubler Inspection, Repair, and Modification Above Main Entry Door 1 at Station 460,"; 747-53A2414, "Fuselage - Main Entry Door 1 Cutout - Door Frame Aft Edge at Station 488 - Inspection and Repair,"; 747-53A2416, "Fuselage - Center Section - Body Station 1265 Frame Inspection, Repair, and Modification,"’ 747- 53A2417, "Fuselage - Main Entry Door Number 1 Cutout - Door Frame Forward Edge at Station 434 - Inspection and Repair,"; 747-53A2450, "Fuselage - Section 46 - Body Station 2231 Frame Inspection - Stringers 23 through 31"; 747-53A2451, "Fuselage - Section 42 - Door Number 2 Forward Edge Frame at Body Station 800 - Inspection and Repair"; and 747-53A2512, Fuselage - Main Entry Door Number 3 Cutout - Lower Forward Corner and Upper Aft Corner - Inspection and Repair at Left and Right Side Skin and Bearstrap. j. Boeing Service Letter 747-SL-53-088-A k. 747 Supplemental Structural Inspection Document (SSID) D6-35022, Items F-21A, F-21B, F-24A, F-24B, F-24C, F-41A and F-41B l. FAA Airworthiness Directives 2004-07-22 R1 and 2006-05-02 m. Boeing Parts Standards Document D-590 n. Boeing Drawing 012W6100 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. K. Publications Affected None. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. ### Page 33 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 33 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are not available for the inspections or repair procedures given in this service bulletin. C. Parts Necessary For Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: None. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin, but maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, may be necessary. Examine operator tool supply to make sure all necessary tools are available. ### Page 34 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT BLANK PAGE ### Page 35 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: — 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 are given in 747, 747-400, or 747-400F Structural Repair Manual, Chapter 51 — Torque limits to tighten nuts and bolts are given in 747, 747-400, or 747-400F Structural Repair Manual, Chapter 51. 4. For approved fastener and process material substitutions, refer to 747, 747-400, or 747- 400F Structural Repair Manual, Chapter 51. Alternate fasteners are given in 747, 747- 400, or 747-400F Structural Repair Manual Chapter 51 and Boeing Drawing 012W6100. 5. If the length of fasteners specified in this service bulletin do not meet the installation standards, fasteners of the same specification, or an approved substitute, one grip length longer or shorter may be used. 6. Start to do inspections at the time shown in Paragraph 1.E., Compliance. 7. 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 a mirror, magnifying lenses, etc., may be necessary. Surface cleaning procedures may be required. Inspection aids such as 10X magnifying lenses may be required. 8. Figures 1 - 18 show Group 1, 2, 3, 4, 5, 6, 7, 9, and 10 airplanes. Group 8 airplanes are similar, except as described below in each affected inspection area. B. WORK INSTRUCTIONS AREA 1 - UPPER DECK FLOOR BEAMS 1. Remove the equipment that follows from the main deck passenger cabin for access from below ### Page 36 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT to the upper deck floor beams. Use the AMM subjects that follow: NOTE: All upper deck floor beam inspections are to be performed from below. Group 1, 5-7: The upper deck floor beams to be inspected are from STA 260 to STA 1100. Group 2, 9: The upper deck floor beams to be inspected are from STA 260 to STA 740. Group 3, 10: The upper deck floor beams to be inspected are from STA 260 to STA 780. Group 4: The upper deck floor beams to be inspected are from STA 260 to STA 700. Group 8: The upper deck floor beams to be inspected are from STA 260 to STA 500. 2. If necessary, loosen and remove air conditioning ducts for access to the inspection area. 3. Group 1, 5-7: Do inspections of the upper deck floor beams for cracks as shown in Figure 1. 4. Group 2, 9: Do inspections of the upper deck floor beams for cracks as shown in Figure 10. 5. Group 3, 10: Do inspections of the upper deck floor beams for cracks as shown in Figure 11. 6. Group 4: Do inspections of the upper deck floor beams for cracks as shown in Figure 12. 7. Group 8: Do inspections of the upper deck floor beams for cracks as shown in Figure 21. 8. For each frame from body station 260 to body station 520, do a detailed inspection for cracks in the frame inner chord, the frame outer chord, and the frame web in the area between the upper and lower chords of the upper deck floor beam as shown in Figure 18. Do these detailed inspections on both the left side and right side of the airplane. 9. If floor beam web cracks are found, repair before any more flights. Repair as shown in 747-400 SRM 53-00-51, Figure 201, 747-400 SRM 53-10-51, Figure 201, 747 SRM 53-10-07, Figure 11, or ask Boeing for repair data. Equipment AMM Subject Ceiling Insulation 747-100/200/300 AMM 25-21-04/401 747-400 AMM 25-21-04/401 Main Passenger Cabin Ceiling Panels 747-100/200/300 AMM 25-22-01/401 747-400 AMM 25-22-01/401 Main Deck Track Mounted Passenger Seats 747-100/200/300 AMM 25-25-01/401 747-400 AMM 25-25-01/401 Center Overhead Stowage Compartments 747-100/200/300 AMM 25-28-01/201 747-400 AMM 25-28-02/401 Side Overhead Stowage Compartments 747-100/200/300 AMM 25-28-01/201 747-400 AMM 25-28-01/201 Main Deck Cargo Compartment Ceiling Lining 747-100/200/300 AMM 25-59-01/401 747-400 AMM 25-59-01/401 Main Deck Cargo Compartment Ceiling Insulation 747-100/200/300 AMM 25-59-05/405 747-400 AMM 25-59-05/401 ### Page 37 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 10. If any other floor beam cracks are found, repair before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-07 Figure 21 or 23, 747-400 SRM 53-10-51 Figure 205, 747-400 SRM 53-20-51 Figure 204, or ask Boeing for repair data. 11. If frame inner chord, frame outer chord, or frame web cracks are found, repair them as given in the structural repair manual, or contact Boeing for repair instructions. 12. After repair, install all equipment that was removed for access. 13. If no cracks are found, install all equipment that was removed for access. 14. Put the airplane back to a serviceable condition. Do the Area 1 inspection again at the time shown in Paragraph 1.E., Compliance. Group 1-7, 9-10: AREA 2 - SECTION 42 UPPER LOBE FRAMES 1. Remove the equipment that follows from the main deck passenger cabin and the upper deck passenger cabin for access to the Section 42 upper lobe frames, from the main deck floor to the top of the crown. Use the AMM subjects that follow: 2. If necessary, loosen and remove air conditioning ducts for access to the inspection area. 3. Group 1, 5-7: Do inspections of Area 2 for cracks as shown in Figure 2. 4. Group 2-4, 9-10: Do inspections of Area 2 for cracks as shown in Figure 13. 5. If cracks are found, repair before any more flights as follows: a. Remove and replace cracked stringer clips before any more flights. Use 747-100/200/300 SRM 53-10-03, or 747-400 SRM 53-00-03, or 747-400 SRM 53-00-03. Equipment AMM Subject Sidewall and Ceiling Insulation 747-100/200/300 AMM 25-21-04/401 747-400 AMM 25-21-04/401 Main Deck Track Mounted Passenger Seats 747-100/200/300 AMM 25-25-01/401 747-400 AMM 25-25-01/401 Side Overhead Stowage Compartments 747-100/200/300 AMM 25-28-01/401 747-400 AMM 25-28-01/201 Upper Deck Ceiling Panel 747-100/200/300 AMM 25-22-03/401 747-400 AMM 25-22-03/401 Upper Deck Window Reveal Panel 747-100/200/300 AMM 25-21-02/401 747-400 AMM 25-21-02/401 Main Deck Sidewall Lining Doorway Panels 747-100/200/300 AMM 25-21-03/401 747-400 AMM 25-21-03/401 Main Deck Cargo Compartment Sidewall Lining 747-100/200/300 AMM 25-59-01/401 747-400 AMM 25-59-01/401 Main Deck Cargo Compartment Sidewall Insulation 747-100/200/300 AMM 25-59-05/401 747-400 AMM 25-59-05/401 ### Page 38 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT b. Repair frame cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04, 747-400 SRM 53-20-07, 747-400F SRM 53-20-07, or ask Boeing for repair data. c. If any other cracks are found, repair before any more flights. Repair as shown in the SRM, or ask Boeing for repair data. d. After repair, install all equipment that was removed for access. 6. If no cracks are found, install all equipment that was removed for access. 7. Put the airplane back to a serviceable condition. Do the Area 2 inspection again at the time given in Paragraph 1.E., Compliance. AREA 3 - SECTION 46 LOWER LOBE FRAMES 1. Remove the equipment that follows for access to the Section 46 lower lobe frames, from the main deck floor down. Use the AMM subjects that follow: NOTE: On Group 8 airplanes, it is not necessary to inspect the Section 46 lower lobe frames aft of STA 1940. On the left side of the airplane, it is not necessary to inspect the Section 46 lower lobe frames above Stringer 34. On the right side of the airplane, it is not necessary to inspect the Section 46 lower lobe frames above Stringer 34, except at STA 1810 and STA 1920. At STA 1810 and STA 1920 on the right side of the airplane, the inspection area is from the main deck floor down. Equipment AMM Subject Sidewall Insulation 747-100/200/300 AMM 25-21-04/401 747-400 AMM 25-21-04/401 Main Deck Track Mounted Passenger Seats 747-100/200/300 AMM 25-25-01/401 747-400 AMM 25-25-01/401 Main Deck Sidewall Lining Doorway Panels 747-100/200/300 AMM 25-21-03/401 747-400 AMM 25-21-03/401 Cargo Compartment Lining Panels 747-100/200/300 AMM 25-52-01/401 747-400 AMM 25-52-01/401 Cargo Compartment Insulation 747-100/200/300 AMM 25-52-04/401 747-400 AMM 25-52-04/401 Ball Transfer Panels 747-100/200/300 AMM 25-53-15/401 747-400 AMM 25-53-15/401 Main Deck Floor Panels (a) 747-100/200/300 AMM 53-21-02/401 747-400 AMM 53-21-02/401 Bulk Cargo Compartment Lining 747-100/200/300 AMM 25-55-02/401 747-400 AMM 25-55-02/401 Main Deck Cargo Compartment Sidewall Lining 747-100/200/300 AMM 25-59-01/401 747-400 AMM 25-59-01/401 Main Deck Cargo Compartment Sidewall Insulation 747-100/200/300 AMM 25-59-05/401 747-400 AMM 25-59-05/401 Bulk Cargo Compartment Insulation 747-100/200/300 AMM 25-55-03/401 747-400 AMM 25-55-03/401 Bulk Cargo Compartment Floor Panels -- (a) From STA 2180 to STA 2360 for access to the lower lobe frames aft of the bulk cargo compartment. ### Page 39 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 2. If necessary, loosen and remove air conditioning ducts for access to the inspection area. 3. Do inspections of Area 3 for cracks as shown in Figure 3. 4. If cracks are found, repair before any more flights as follows: a. Remove and replace cracked stringer clips before any more flights. Use 747-100/200/300 SRM 53-10-03, or 747-400 SRM 53-00-03, or 747-400 SRM 53-00-03. b. Repair frame cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04, 747-400 SRM 53-60-07, 747-400F SRM 53-60-07, or ask Boeing for repair data. c. If any other cracks are found, repair before any more flights. Repair as shown in the SRM, or ask Boeing for repair data. d. After repair, install all equipment that was removed for access. 5. If no cracks are found, install all equipment that was removed for access. 6. Put the airplane back to a serviceable condition. Do the Area 3 inspection again at the time given in Paragraph 1.E., Compliance. AREA 4 - SECTION 42 LOWER LOBE FRAMES 1. Remove the equipment that follows for access to the Section 42 lower lobe frames, from the main deck floor down. Use the AMM subjects that follow: NOTE: On Group 8 airplanes, it is not necessary to inspect the STA 540 lower lobe frame from S-26L to S-39R. On the left side of the airplane, it is not necessary to inspect the Section 42 lower lobe frames above Stringer 34. On the right side of the airplane, it is not necessary to inspect the Section 42 lower lobe frames above Stringer 28 from STA 580 to STA 660, or above Stringer 34 from STA 680 to STA 980. 2. If necessary, loosen and remove air conditioning ducts for access to the inspection area. 3. Do inspections of Area 4 for cracks as shown in Figure 4. 4. If cracks are found, repair before any more flights as follows: a. Remove and replace cracked stringer clips before any more flights. Use 747-100/200/300 SRM 53-10-03, or 747-400 SRM 53-00-03, or 747-400 SRM 53-00-03. b. Repair frame cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04, 747-400 SRM 53-20-07, 747-400F SRM 53-20-07, or ask Boeing for repair data. c. If any other cracks are found, repair before any more flights. Repair as shown in the SRM, or ask Boeing for repair data. Equipment AMM Subject Cargo Compartment Lining Panels 747-100/200/300 AMM 25-52-01/401 747-400 AMM 25-52-01/401 Cargo Compartment Insulation 747-100/200/300 AMM 25-52-04/401 747-400 AMM 25-52-04/401 Ball Transfer Panels 747-100/200/300 AMM 25-53-15/401 747-400 AMM 25-53-15/401 ### Page 40 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT d. After repair, install all equipment that was removed for access. 5. If no cracks are found, install all equipment that was removed for access. 6. Put the airplane back to a serviceable condition. Do the Area 4 inspection again at the time given in Paragraph 1.E., Compliance. Group 1-7, 9-10: AREA 5 - SECTION 46 UPPER LOBE FRAMES 1. Remove the equipment that follows for access to the Section 46 upper lobe frames, from the main deck floor to Stringer 20. Use the AMM subjects that follow: 2. If necessary, loosen and remove air conditioning ducts for access to the inspection area. 3. Group 1, 5: Do inspections of Area 5 for cracks as shown in Figure 5. 4. Group 2, 4, 9: Do inspections of Area 5 for cracks as shown in Figure 16. 5. Group 3, 6-7, 10: Do inspections of Area 5 for cracks as shown in Figure 17. 6. If cracks are found, repair before any more flights as follows: a. Remove and replace cracked stringer clips before any more flights. Use 747-100/200/300 SRM 53-10-03, or 747-400 SRM 53-00-03, or 747-400 SRM 53-00-03. b. Repair frame cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04, 747-400 SRM 53-60-07, 747-400F SRM 53-60-07, or ask Boeing for repair data. c. If any other cracks are found, repair before any more flights. Repair as shown in the SRM, or ask Boeing for repair data. d. After repair, install all equipment that was removed for access. 7. If no cracks are found, install all equipment that was removed for access. 8. Put the airplane back to a serviceable condition. Do the Area 5 inspection again at the time given in Paragraph 1.E., Compliance. Equipment AMM Subject Sidewall Insulation 747-100/200/300 AMM 25-21-04/401 747-400 AMM 25-21-04/401 Main Deck Track Mounted Passenger Seats 747-100/200/300 AMM 25-25-01/401 747-400 AMM 25-25-01/401 Side Overhead Stowage Compartments 747-100/200/300 AMM 25-28-01/401 747-400 AMM 25-28-01/201 Main Deck Sidewall Lining Doorway Panels 747-100/200/300 AMM 25-21-03/401 747-400 AMM 25-21-03/401 Main Deck Cargo Compartment Sidewall Lining 747-100/200/300 AMM 25-59-01/401 747-400 AMM 25-59-01/401 Main Deck Cargo Compartment Sidewall Insulation 747-100/200/300 AMM 25-59-05/401 747-400 AMM 25-59-05/401 ### Page 41 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT AREA 6 - MAIN ENTRY DOOR CUTOUTS 1. Open each Main Entry Door. At each Main Entry Door, remove the equipment that follows for access to the door cutout. Also remove and keep the threshold and scuff plate at each Main Entry Door. NOTE: Do inspections of the cutouts of all of the main entry doors. This includes any door that may have been deactivated. 2. Group 1, 3, 5-8: Do inspections of Area 6 for cracks as shown in Figure 6. NOTE: On Group 8 airplanes, only the cutouts for Main Entry Door 1 left and right are affected. 3. Group 2, 4: Do inspections of Area 6 for cracks as shown in Figure 14. 4. Group 9: Do inspections of Area 6 for cracks as shown in Figure 19. 5. Group 10: Do inspections of Area 6 for cracks as shown in Figure 20. 6. If cracks are found, repair before any more flights as follows: a. Repair frame cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04, 747-400 SRM 53-10-07, 747-400 SRM 53-20-07747-400 SRM 53-60-07, 747- 400F SRM 53-10-07, or 747-400F SRM 53-60-07, or ask Boeing for repair data. b. Repair other door surround structure cracks before any more flights. Repair as shown in 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-60-15 or 747-400F SRM 53-60-15, or ask Boeing for repair data. c. If any other cracks are found, repair before any more flights. Repair as shown in the SRM, or ask Boeing for repair data. d. After repair, install all equipment that was removed for access. 7. If no cracks are found, install all equipment that was removed for access. 8. Put the airplane back to a serviceable condition. Do the Area 6 inspection again at the time shown in Paragraph 1.E., Compliance. Equipment AMM Subject Sidewall Insulation 747-100/200/300 AMM 25-21-04/401 747-400 AMM 25-21-04/401 Main Deck Sidewall Lining Doorway Panels 747-100/200/300 AMM 25-21-03/401 747-400 AMM 25-21-03/401 Cargo Compartment Ceiling and Sidewall Lining 747-100/200/300 AMM 25-52-01/401 747-400 AMM 25-52-01/401 Cargo Compartment Insulation 747-100/200/300 AMM 25-52-04/401 747-400 AMM 25-52-04/401 Main Deck Cargo Compartment Sidewall Lining 747-100/200/300 AMM 25-59-01/401 747-400 AMM 25-59-01/401 Main Deck Cargo Compartment Sidewall Insulation 747-100/200/300 AMM 25-59-05/401 747-400 AMM 25-59-05/401 ### Page 42 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT AREA 7 - SECTION 41 STA 260, 340, AND 400 BULKHEADS, AND NOSE WHEEL WELL SIDEWALL FROM STA 340 TO STA 400 1. Remove the insulation blankets from the STA 260, 340, and 400 bulkheads and the sidewall panels from STA 340 to STA 400. Also remove the insulation blankets from the nose wheel well top panel in the area of the STA 360 and 380 floor beams. Keep the insulation blankets for later installation. 2. Do inspections of Area 7 for cracks as shown in Figure 7. 3. If cracks are found, repair before any more flights. Repair as shown in 747-100/200/300 SRM 53-10-04747-400 SRM 53-10-08, or 747-400F SRM 53-10-08, or ask Boeing for repair data. After repair, install all equipment that was removed for access. 4. If no cracks are found, install all equipment that was removed for access. 5. Put the airplane back to a serviceable condition. Do the Area 7 inspection again at the time given in Paragraph 1.E., Compliance. AREA 8 - MAIN ENTRY DOORS 1. Remove the lining and insulation from all Main Entry Doors. Use 747 AMM 52-11-02/401. NOTE: On Group 8 airplanes, only Main Entry Door 1 left and right is affected. CAUTION: Group 1, 3, 5-8, 10: DO STRUCTURAL INSPECTIONS OF ALL MAIN ENTRY DOORS AS SHOWN IN THIS SERVICE BULLETIN, INCLUDING DOORS THAT HAVE BEEN DEACTIVATED. DEACTIVATED MAIN ENTRY DOORS ARE SUBJECT TO THE TYPES OF FATIGUE CRACKS SHOWN IN THIS SERVICE BULLETIN. 2. Group 1, 3, 5-8, 10: Do inspections of Area 8 for cracks as shown in Figure 8. CAUTION: Group 2, 4, 9: DO STRUCTURAL INSPECTIONS OF ALL MAIN ENTRY DOORS AS SHOWN IN THIS SERVICE BULLETIN, INCLUDING DOORS THAT HAVE BEEN DEACTIVATED. DEACTIVATED MAIN ENTRY DOORS ARE SUBJECT TO THE TYPES OF FATIGUE CRACKS SHOWN IN THIS SERVICE BULLETIN. 3. Group 2, 4, 9: Do inspections of Area 8 for cracks as shown in Figure 15. 4. If cracks are found, repair before any more flights. Repair as shown in 747-100/200/300 SRM 52-00-03, 747-100/200/300 SRM 52-10-02, 747-400 SRM 52-10-01, 747-400 SRM 52-10-02, 747-400F SRM 52-10-01, or 747-400F SRM 52-10-02, or ask Boeing for repair data. After repair, install all equipment that was removed for access. 5. If no cracks are found, install all equipment that was removed for access. 6. Put the airplane back to a serviceable condition. Do the Area 8 inspection again at the time given in Paragraph 1.E., Compliance. AREA 9 - MAIN ELECTRONICS BAY ACCESS DOOR CUTOUT 1. Open the Main Electronics Bay access door, just aft of the nose wheel well. ### Page 43 December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT 2. Do internal and external detailed inspections of Area 9 for cracks as shown in Figure 9. 3. If cracks are found, repair before any more flights. Repair skin cracks as shown in 747-100/200/ 300 SRM 53-00-01, 747-400 SRM 53-00-01, or 747-400F SRM 53-00-01, or ask Boeing for repair data. 4. If no cracks are found, close the Main Electronics Bay access door. 5. Put the airplane back to a serviceable condition. Do the Area 9 inspection again at the time given in Paragraph 1.E., Compliance. ### Page 44 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIR- PLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIRPLANES (TYPICAL) FLOOR BEAMS ALL UPPER DECK FASEE THROUGH 1 W59452 (SHEET 1 OF 5) ### Page 45 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIR- PLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN (RIGHT SIDE OPPOSITE) (RIGHT SIDE OPPOSITE) LEFT SIDE SHOWN BL 0 LBL 24.17 LBL 46.83 LBL 60 LBL 80 520 STA 500 STA STA 480 460 STA 440 STA 420 STA BL 0 LBL 20 LBL 40 LBL 60 LBL 80 STA 340 STA 330 STA 320 STA 302 STA 287 STA 270 STA 360 STA 380 STA 400 A B FWD UP FWD UP W59472 (SHEET 2 OF 5) ### Page 46 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIR- PLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN (RIGHT SIDE OPPOSITE) LBL 100 80 LBL 60 LBL 40 LBL 20 LBL 0 BL STA 720 STA 700 STA 680 STA 660 STA 640 STA 620 STA 600 STA 580 STA 560 STA 540 C FWD UP W59530 (SHEET 3 OF 5) ### Page 47 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIR- PLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT CARTLIFT ACCESS 880 STA 860 STA 840 STA 820 STA 800 STA 780 STA 760 STA 740 STA 900 STA 920 STA 940 STA 960 STA 980 STA BL 80 BL 60 BL 40 BL 20 BL 0 RIGHT SIDE LEFT SIDE 920 STA940 STA960 STA980 STA 880 STA 860 STA 840 STA 820 STA 800 STA 780 STA 760 STA 740 STA LBL 100 LBL 80 LBL 60 LBL 40 LBL 20 900 STA ACCESS STAIRWAY FWD UP FWD UP E D 480179 (SHEET 4 OF 5) ### Page 48 FIGURE 1: INSPECTION OF AREA 1 - UPPER DECK FLOOR BEAMS - GROUP 1, 5, 6, AND 7 AIR- PLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 48 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT This Figure applies to Group 1, 5-7: The step number shown below agrees with the number shown in the circle symbol in the figure. NOTE: If necessary, loosen and remove air conditioning ducts for access to the inspection area. STEP TASK NAME PROCEDURE REFERENCES NOTES 1 Inspect Upper Chord Detailed - From below the floor beams (a)Floor Beam Web Lower Chord Cab Floor Web (a) The inspection area is from STA 260 to STA 1100. Pay particular attention to all nutplate locations, cutout locations, and to the floor beam connections to the frames. Also inspect the cab floor web (in the plane of the floor) from STA 260 to STA 330. Pay particular attention to all cutouts and nutplate locations. NOTE: At STA 260, inspect the chord that is common to the cab floor web. Also inspect the adjacent 2 inches of the vertical web. STA 1100 STA 1080 STA 1060 STA 1040 STA 1020 1000 STA LBL 80.56 LBL 54.00 24.17 LBL 7.50 LBL (RIGHT SIDE OPPOSITE) LEFT SIDE SHOWN INBD F FWD UP W59575 (SHEET 5 OF 5) ### Page 49 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES 540 STA STA 720 STA 980 S-0 S-39 S-22 S-10ASEE A FSEE SEE C BSEE SEE E DSEE W59603 (SHEET 1 OF 8) ### Page 50 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 50 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT (RIGHT SIDE OPPOSITE) LEFT SIDE SHOWN STA 720 STA 700 STA 680 STA 660 STA 540STA 560STA 580STA 600STA 620STA 640 S-2A S-2 S-1 S-0 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-10A FWD 1 A W59621 (SHEET 2 OF 8) ### Page 51 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN (RIGHT SIDE OPPOSITE) STA STA STA STA STA STA STA STA STA STA 720 700 680 660 620 640 600 580 560 540 S-11 S-12 S-13 S-14 S-15 S-16 S-17 S-18 S-19 S-20 S-21 S-22 B 1 W59638 FWD (SHEET 3 OF 8) ### Page 52 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN DOOR CUTOUT IS BELOW S-26) (RIGHT SIDE OPPOSITE, EXCEPT THE CARGO S-27 S-26 S-28 S-29 S-23 S-24 S-25 720 STA 700 STA 680 660 STA STA 640 620 STA STA 600 580 STA STA 560 540 STA STA C 1 W59639 FWD (SHEET 4 OF 8) ### Page 53 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN (RIGHT SIDE OPPOSITE) S-10AS-10 S-9S-8 S-7S-6 S-5S-4 S-3AS-3 S-2AS-2 S-0 S-1 STA STA STA STA 980 960 920 900 940 STA 780 STA STA STA STA STA STA 860 840 820 800 880 STA STA 760 740 FWD 1 D W59645 (SHEET 5 OF 8) ### Page 54 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 54 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT LEFT SIDE SHOWN SHOWN FOR CLARITY UPPER DECK FLOOR BEAMS NOT (RIGHT SIDE OPPOSITE) STA 980 960 STA STA940 STA 900STA920 STA 880 STA 860 STA 820STA 840 STA 800 STA 780 STA 760 STA 740 S-22 S-21 S-20 S-18 S-17 S-16 S-15 S-14 S-13 S-12 S-11 S-19 FWD 1 E W59651 (SHEET 6 OF 8) ### Page 55 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT S-27 S-26 LEFT SIDE SHOWN (RIGHT SIDE OPPOSITE) S-23 S-24 S-25 S-28 S-29 S-30 S-31 S-32 S-33 S-34 840 STA STA 820 STA 980 960 STA 940 STA STA 920 STA 900 STA 880 860 STA STA 800 STA 780 STA 760 STA 740 FWD 1 F W59666 (SHEET 7 OF 8) ### Page 56 FIGURE 2: INSPECTION OF AREA 2 - SECTION 42 UPPER LOBE FRAMES - GROUP 1, 5, 6, AND 7 AIRPLANES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT This Figure applies to Group 1, 5-7: The step number shown below agrees with the number shown in the circle symbols in the figure. STEP TASK NAME PROCEDURE REFERENCES NOTES 1 Inspect Upper Lobe Frames Detailed - (a) (b) (a) The inspection area is from STA 520 to STA 1000, from the main deck floor to the top of the crown. (b) Pay particular attention to frame inner chords at the last fastener in a reinforcing strap, frame webs, fail-safe chords, and stringer cutouts. (SHEET 8 OF 8) ### Page 57 FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES S-39R S-39L STA 1500 S-0 2160 STA 1720 STA 1980 STA 2360 STA INSTALLED ON SOME AIRPLANES. MAIN DECK SIDE CARGO DOOR TYPICAL AIRPLANE SHOWN, GDSEE B SEE A SEE FSEE H CSEE E I W59671 (SHEET 1 OF 11) ### Page 58 FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT S-24 S-23S-22 S-39 S-38 S-37 S-36 S-35 S-34 S-33 S-31 S-29 S-28 S-32 S-30 S-27 STA S-16 S-25 S-8 S-9 S-10 S-11 S-12 S-13 S-14 S-15 S-17 S-18 S-19 S-20 S-2S-1 S-3 S-4 S-5 S-6 S-7 STA 1520 STA 1560 STA 1600 1580 STA 1540 STA 1500 STA 1640 STA 1680 STA 1620 STA 1660 STA 1700 STA 1720 LEFT SIDE SHOWN POSTS NOT SHOWN FOR CLARITY MAINDECK FLOOR BEAMS AND (RIGHT SIDE OPPOSITE) 1 A FWD W59676 (SHEET 2 OF 11) ### Page 59 FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT SIDE SHOWN LEFT AND RIGHT S-42R S-40R S-44R S-46R S-48R S-50R S-51R S-51L S-48L S-46L S-44L S-42L S-40L S-50L 1580 STA STA 1540 STA 1500 STA 1600 STA 1560 1520 STA STA 1620 STA 17001720 STA STA 1660 STA 1640 STA 1680 FWD B 1 W59699 (SHEET 3 OF 11) ### Page 60 FIGURE 3: INSPECTION OF AREA 3 - SECTION 46 LOWER LOBE FRAMES December 21, 2004 Revision 1: September 25, 2008 747-53A2500 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 60 of 173 BOEING SERVICE BULLETIN 747-53A2500 ALERT ALERT S22 S21 S23 S25 S26S27 S28 S34 S32 POSTS NOT SHOWN FOR CLARITY MAIN DECK FLOOR BEAMS AND LEFT SIDE SHOWN S2 S4 S6 S8 S10 S12 S9 S7 S5 S3 S1 S11 S13 S15 S17 S19 S30 S36 S38 S20 S29 S31 S33 S37 S39 STA 1840 STA1800 STA1760 1860 STA 1820 STA 1780 STA 1740 STA 18801960 STA 1920 STA STA 1940 STA 1900 STA1980STA S35 S18 S16 S14 FWD C 1 W59850 (SHEET 4 OF 11) The text continues at https://openairdocs.org/service-documents/boeing/747-53a2500/file/ca6f623090be.md?from=61 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.