# Boeing Alert Service Bulletin 747-53A2305: Revision 2 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2010-0674; AD 2010-26-07 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 747-53A2305](https://openairdocs.org/service-documents/boeing/747-53a2305.md) - Title as filed: U.S. DOT/FAA - Service Bulletin - Pages: 102 - PDF: https://openairdocs.org/files/sha256/83/e2/83e238b49c5667b6a657c8a37fe114e5e6b50de0346ea65caef89f3b07250eb6 - Page: https://openairdocs.org/service-documents/boeing/747-53a2305/file/83e238b49c56 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplane Group 747 Service Bulletin ALERT Number: 747-53A2305 Date: June 27, 1991 Revision 2: January 15, 2009 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Nose Wheel Well Aft Corner Skin Panel Inspection and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). 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all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1991 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P .O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 1 of 102 9.0 ### Page 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 2 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 Summary ..................................................... 7 1. PLANNING INFORMATION ........................................ 1 1 A. Effectivity ............................................... 1 1 1. Airplanes ............................................ 1 1 2. Spares Affected ........................................ 2 2 B. Concurrent Requirements ...................................... 2 2 C. Reason ................................................ 2 2 D. Description .............................................. 2 3 E. Compliance .............................................. 2 5 F . Approval ............................................... 3 1 G. Manpower .............................................. 3 2 H. Weight and Balance Changes .................................... 3 4 I. Electrical Load Data ......................................... 3 4 J. References .............................................. 3 4 1. Existing Data: .......................................... 3 4 2. Data supplied with this Service Bulletin: ........................... 3 5 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 7 K. Publications Affected ......................................... 3 7 L. Interchangeability and Intermixability of Parts ........................... 3 7 2. MATERIAL INFORMATION ........................................ 3 9 A. Material - Price and Availability ................................... 3 9 B. Industry Support Information .................................... 3 9 C. Parts Necessary For Each Airplane ................................. 3 9 1. Kits/Parts: ............................................ 3 9 2. Parts and Materials Supplied by the Operator: ........................ 3 9 3. Parts Modified and Reidentified: ................................ 3 9 4. Parts Removed and Not Replaced: .............................. 4 0 D. Parts Necessary to Change Spares ................................. 4 0 E. Special Tooling - Price and Availability ............................... 4 0 F . Special Tooling Necessary to do this Service Bulletin ....................... 4 0 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 4 1 A. GENERAL INFORMATION ..................................... 4 1 B. WORK INSTRUCTIONS ....................................... 4 2 FIGURE 1: LOGIC DIAGRAM - GROUP 1 - 3 AIRPLANES NOT CHANGED AS GIVEN IN SERVICE BULLETIN 747-53-2150 OR SRM 53-30-03, FIGURE 35 (DELETED) ........... 4 8 FIGURE 2: LOGIC DIAGRAM - GROUP 1 - 3 AIRPLANES CHANGED/REPAIRED AS GIVEN IN SERVICE BULLETIN 747-53-2150 OR SRM 53-30-03, FIGURE 35 (DELETED) ........... 4 9 FIGURE 3: LOGIC DIAGRAM - GROUP 4 - 7 AIRPLANES (DELETED) ................. 5 0 FIGURE 4: INSPECTION - GROUP 1-3 AIRPLANES [Group 1-3] .................... 5 1 FIGURE 5: INSPECTION - GROUP 4-8 AIRPLANES [Group 4-8] .................... 5 5 FIGURE 6: MODIFICATION - GROUP 1 AIRPLANES [Group 1] ..................... 5 8 FIGURE 7: MODIFICATION - GROUP 2 AIRPLANES [Group 2] ..................... 6 1 FIGURE 8: MODIFICATION - GROUP 3 AIRPLANES [Group 3] ..................... 6 4 FIGURE 9: MODIFICATION - GROUP 4 AIRPLANES [Group 4] ..................... 6 7 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 3 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 4 FIGURE 10: MODIFICATION - GROUP 5 AIRPLANES [Group 5] ..................... 7 0 FIGURE 11: MODIFICATION - GROUP 6 AIRPLANES [Group 6] ..................... 7 3 FIGURE 12: MODIFICATION - GROUP 7, 8 AIRPLANES [Group 7] ................... 7 6 FIGURE 13: POST -MODIFICATION INSPECTION - GROUP 1 AIRPLANES [Group 1] ......... 7 9 FIGURE 14: POST -MODIFICATION INSPECTION - GROUP 2 AIRPLANES [Group 2] ......... 8 2 FIGURE 15: POST -MODIFICATION INSPECTION - GROUP 3 AIRPLANES [Group 3] ......... 8 5 FIGURE 16: POST -MODIFICATION INSPECTION - GROUP 4 AIRPLANES [Group 4] ......... 8 8 FIGURE 17: POST -MODIFICATION INSPECTION - GROUP 5 AIRPLANES [Group 5] ......... 9 1 FIGURE 18: POST -MODIFICATION INSPECTION - GROUP 6 AIRPLANES [Group 6] ......... 9 4 FIGURE 19: POST -MODIFICATION INSPECTION - GROUP 7, 8 AIRPLANES [Group 7-8] ....... 9 7 FIGURE 20: BS 400 BULKHEAD OUTER CHORD INSPECTION .................... 1 0 0 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 4 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 5 Commercial Airplane Group 747 Service Bulletin ALERT Revision Transmittal SheetNumber: 747-53A2305Date: June 27, 1991 Revision 2: January 15, 2009 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Nose Wheel Well Aft Corner Skin Panel Inspection and Modification This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION More work is necessary on airplanes changed as shown in the initial release or revision 1 of this service bulletin as follows: Group 1-3 airplanes: add post-modification inspections and add inspections of the BS 400 bulkhead outer chord. Group 4-7 airplanes: add steel doublers to modification, add post-modification inspections and add inspections of the BS 400 bulkhead outer chord. Line number 686 and subsequent airplanes were added to the service bulletin effectivity as group 8 airplanes. The effectivity of this service bulletin now includes future airplanes. With this revision, some airplanes were moved from group 5 to group 4. REASON FOR REVISION This revision is sent to give added inspections (all airplanes) and added modification work (group 4-7 airplanes), and to extend the effectivity of the service bulletin to include all 747 airplanes. After the release of revision 1 of this service bulletin, skin cracks were found at both aft corners of the nose wheel well on two 747 airplanes that were built after line number 685. Based on these findings, the inspections, repair and modification given in this service bulletin have been made applicable to 747 airplanes built after line number 685 and changes have been made to the modification for group 4-7 airplanes (steel doublers added). Also, for all airplanes, instruction to do post-modification inspections has been added. Also, subsequent to the previous release of this service bulletin, small cracks have been found in the outer chord of the BS 400 bulkhead on airplanes with less than 20,000 flight-cycles. Based on these findings, instruction to do inspection of the outer chord has been added to this service bulletin.These inspections replace existing SSID F-4 inspections. All sections of this service bulletin were changed with this revision. Paragraph I.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 5 of 102 ### Page 6 Vertical lines are put on the left edge of each page, except in Paragraph I.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY June 27, 1991Original Issue: May 22, 1997Revision 1: January 15, 2009Revision 2: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 6 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 7 Commercial Airplane Group 747 Service Bulletin ALERT SummaryNumber: 747-53A2305Date: June 27, 1991 Revision 2: January 15, 2009 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Nose Wheel Well Aft Corner Skin Panel Inspection and Modification THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY . IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None. BACKGROUND This inspection and doubler installation will make sure that there are no unrepaired cracks in the aft corner of the nose wheel well. These cracks occur in the fuselage skin and skin splice plate at Body Station (BS) 400 near Stringer (STR) 44, left and right side. Service Bulletin 747-53-2150, "Nose Wheel Well Aft Bulkhead External Doubler Installation" told operators of cracks in the skin splice plate for airplane line numbers 1-314. Operators were told to stop drill any cracks in the skin splice plate and to install two external doublers. A thicker skin splice plate was provided in production for airplane line numbers 315 and on. Subsequently, two operators told Boeing of two incidents of cracks in the fuselage skin. These cracks occurred forward of BS 400 at STR 44 near the external repair doublers for the skin splice plate. The cracks were found on airplanes with 10,539 and 15,178 flight-cycles. These airplanes had been changed as shown in Service Bulletin 747-53-2150 or by means of the Structural Repair Manual 53-30-03, Figure 35. After line number 685, airplanes were delivered with an improved internal skin doubler and fit-up of the structure was improved. After the release of revision 1 to this service bulletin, skin cracks were found at both aft corners of the nose wheel well on two 747 airplanes built after line number 685. Based on these findings, instruction to do post-modification inspections were added to this service bulletin and the effectivity was extended to include airplanes built after line number 685. Also, subsequent to the release of revision 1 to this service bulletin, small cracks were found in the outer chord of the BS 400 bulkhead on airplanes with less than 20,000 flight-cycles. As a result of these findings, instruction to do inspections of the bulkhead outer chord are included this service bulletin. These outer chord inspections replace SSID F-4 inspections. This item is identified in Boeing Structural Item Interim Advisory (SIIA) 747-48 and 747-87. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 7 of 102 ### Page 8 ACTION (PRR 85901-84RS) For all airplanes, a Detailed inspection for cracks in the skin at/around the aft corners of the nose wheel well is to be done. On specified airplanes, a Detailed inspection for cracks in the skin splice plate at the aft corners of the nose wheel well is also to be done. If a crack in the skin or the skin splice plate is found, the modification and the post-modification inspections given in this service bulletin are to be done. If no cracks are found, repeat Detailed inspections are to be done, or alternatively, the modification and the post-modification inspections given in this service bulletin can be done. Also, for all airplanes, a surface HFEC inspection of the bulkhead outer chord is to be done. If a crack is found, the chord is to be repaired as given in this service bulletin. EFFECTIVITY All 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F , 747-300, 747-400, 747-400D, 747-400F , 747SP , 747SR series airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. COMPLIANCE Refer to Paragraph 1.E., Compliance. Federal Aviation Administration (FAA) Airworthiness Directives 86-09-07, 94-12-04, 94-17-01, 2004-07-22 R1, and 2006-22-09 are related to this service bulletin. INDUSTRY SUPPORT INFORMATION This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether you ever filed a warranty claim with Boeing on this service bulletin. MANPOWER Refer to Paragraph 1.G., Manpower. MATERIAL INFORMATION Refer to Paragraph 2.A., Material - Price and Availability. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 8 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 9 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT S-44 STA + + + +j 380 71 SEE ¡+| + SKIN SPLICE INSPECT SKIN, SPLICE PLATE, FRAME + PLATE CHORD AND RADIUS FILLER IN THE AFT CORNER OF THE NOSE WHEEL WELL INSTALL SPLICE PLATE DOUBLERS BULKHEAD CHORD DRAIN • HOLE 777+++ STA 400 ++ + + + + + + INSTALL SKIN MODIFICATION DOUBLERS FWD LEFT SIDE SHOWN INBD 746682 RIGHT SIDE OPPOSITE June 27, 1991 Revision 2: January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 102 ### Page 10 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 10 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT BLANK PAGE ### Page 11 Commercial Airplane Group 747 Service Bulletin ALERT Number: 747-53A2305 Date: June 27, 1991 Revision 2: January 15, 2009 ATA System: 5331 SUBJECT: FUSELAGE - Skin - Nose Wheel Well Aft Corner Skin Panel Inspection and Modification THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY . IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes 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 referred to in PRR82284R. NOTE: 747-8 and 747-8F series airplanes are not affected by this service bulletin. NOTE: This Service Bulletin is for the airplanes identified below. The Effectivity list shown below is complete for airplanes through line number 1419. Airplanes after line number 1419 are also affected by this service bulletin, and are in Group(s): 8 DESCRIPTIONCONFIGURATIONGROUP Airplanes with line numbers 1-26 (modification installation 141U1099-1/-2 (LS/RS) applicable) -1 747-100 airplanes with line numbers 27-314 (modification installation 141U1099-3/-4 (LS/RS) applicable) -2 747-200 airplanes with line numbers 27-314 (modification installation 141U1099-5/-6 (LS/RS) applicable) -3 747-100 airplanes with line numbers 315-579 (modification installation 141U1099-43/-44 (LS/RS) applicable) -4 747-200,-300 airplanes with line numbers 315-579 (modification installation 141U1099-45/-46 (LS/RS) applicable) -5 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 11 of 102 ### Page 12 DESCRIPTIONCONFIGURATIONGROUP 747-100 airplanes with line numbers 580-685 (modification installation 141U1099-49/-50 (LS/RS) applicable) -6 747-200,-300 airplanes with line numbers 580-685 (modification installation 141U1099-51/-52 (LS/RS) applicable) -7 Airplanes built after line number 685 (modification installation 141U1099-51/-52 (LS/RS) applicable -8 Airplane Models: 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F , 747-300, 747-400, 747-400D, 747-400F , 747SP , 747SR GroupVariable Number 1RA001 - RA017 2RA018 - RA034 1RA101 - RA105 2RA106 - RA115 2RA161 - RA164 1RA201 2RA202 - RA203 3RA216 - RA217 3RA245 - RA246 1RA251 - RA252 2RA253 - RA266 1RA301 2RA302 - RA318 2RA351 - RA360 3RA369 - RA373 2RA401 - RA418 2RA501 - RA502 2RA521 - RA528 3RA532 - RA543 5RA544 - RA548 2RA551 - RA552 3RA559 - RA561 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 12 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 13 GroupVariable Number 2RA581 - RA582 3RA585 2RA601 - RA602 2RA631 - RA635 3RA651 - RA652 3RA671 - RA677 3RA701 - RA702 3RA721 - RA725 5RA726 - RA731 2RA741 - RA745 3RA749 5RA750 2RA761 - RA762 3RA781 - RA783 5RA784 2RA901 - RA916 3RB001 - RB016 2RB041 - RB044 3RB071 - RB075 2RB101 - RB102 7RB411 - RB412 8RB413 8RB421 2RB601 - RB607 4RB681 - RB697 4RB711 4RB721 - RB722 6RB723 4RB741 - RB748 3RD001 - RD004 3RD021 - RD022 3RD041 - RD047 5RD048 - RD059 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 13 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 14 GroupVariable Number 3RD071 - RD072 5RD081 - RD083 5RD091 - RD092 3RD101 - RD104 3RD121 5RD122 - RD127 3RD131 - RD133 5RD134 - RD144 7RD166 - RD167 5RD171 - RD172 5RD181 - RD183 5RD201 - RD204 5RD221 - RD225 7RD226 - RD227 7RD231 - RD234 8RD235 5RD241 - RD243 5RD251 - RD257 7RD258 - RD262 5RD271 - RD272 7RD291 - RD292 7RD301 - RD302 7RD311 5RD351 - RD356 7RD357 - RD358 5RD361 - RD365 7RD366 5RD381 - RD383 5RD411 - RD414 5RD421 - RD426 5RD431 - RD435 5RD441 - RD442 5RD451 - RD455 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 14 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 15 GroupVariable Number 7RD456 5RD461 5RD471 - RD475 3RD513 5RD514 - RD519 3RD531 5RD532 - RD533 5RD551 5RD561 5RD571 5RD581 - RD583 3RD591 5RD592 - RD593 3RD601 - RD602 5RD603 - RD607 3RD621 - RD623 3RD641 - RD642 5RD643 - RD649 3RD651 - RD652 5RD653 - RD658 7RD659 5RD661 5RD671 3RD681 - RD682 3RD691 - RD692 5RD701 - RD702 5RD721 - RD722 5RD741 - RD742 5RD751 - RD753 7RD754 - RD755 5RD761 5RD771 7RD772 - RD775 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 15 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 16 GroupVariable Number 7RD781 - RD783 7RD791 8RD792 5RE001 8RF001 - RF006 3RG001 - RG005 4RG006 - RG009 3RG091 4RG095 3RG101 - RG103 4RG104 3RG121 - RG126 3RG141 - RG142 4RG161 - RG164 3RG171 4RG172 - RG174 4RG191 - RG193 4RG211 - RG213 4RG221 - RG222 4RH101 7RH102 4RH111 - RH112 4RH121 - RH122 3RJ131 - RJ133 3RJ151 5RJ152 3RJ301 - RJ302 5RJ303 7RJ321 8RJ322 5RJ331 - RJ333 8RL401 - RL403 8RL411 - RL436 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 16 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 17 GroupVariable Number 8RL451 - RL456 8RL461 - RL462 8RL471 - RL481 8RL491 - RL492 8RL501 - RL502 8RL511 - RL516 8RL521 - RL522 8RL531 - RL534 8RL551 8RL561 - RL568 8RL571 - RL572 8RL576 - RL577 8RL579 8RL581 - RL586 8RL651 - RL655 8RL671 - RL675 8RL681 - RL684 8RL751 - RL752 8RM001 - RM007 8RM010 - RM013 8RM021 - RM024 8RM026 - RM030 8RM036 - RM045 8RM051 - RM053 8RM071 8RM081 - RM084 8RM091 8RM096 - RM097 8RM116 - RM117 8RM126 - RM132 8RM136 - RM147 8RM156 - RM158 8RM166 - RM177 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 17 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 18 GroupVariable Number 8RM191 - RM192 8RM231 - RM233 8RM241 - RM246 8RM261 - RM264 8RM316 - RM318 8RM331 - RM333 8RM341 8RM351 - RM355 8RM366 - RM367 8RM401 - RM403 8RM426 8RM431 8RM441 - RM443 8RM445 8RM801 - RM803 8RM811 - RM813 8RM851 - RM859 8RM861 - RM863 8RM871 - RM899 8RM901 - RM906 8RM911 5RR001 - RR005 5RR021 - RR023 8RR024 - RR025 5RR031 3RR201 5RR202 - RR203 7RR204 - RR205 8RR206 3RR221 - RR222 5RR223 - RR226 3RR261 5RR262 - RR265 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 18 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 19 GroupVariable Number 7RR266 - RR267 3RR301 - RR302 5RR303 - RR306 8RR307 - RR310 5RR331 - RR332 5RR336 3RR341 - RR344 5RR345 5RR361 - RR362 5RR421 - RR422 7RR431 - RR432 8RR441 - RR442 8RR451 5RR501 - RR504 5RR521 8RR522 8RR526 5RR531 7RR551 - RR553 8RR554 - RR556 5RR561 8RR566 8RR701 8RR721 - RR724 8RR746 - RR748 8RR851 - RR856 8RR861 - RR862 8RR951 - RR952 6RS001 - RS002 5RS201 5RS211 - RS212 7RS221 - RS222 7RS231 - RS241 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 19 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 20 GroupVariable Number 7RS251 - RS258 8RS259 8RS263 8RS265 - RS268 7RS271 - RS276 7RS291 - RS292 7RS301 - RS304 8RS305 - RS306 7RS311 - RS320 8RS331 - RS333 7RS341 8RS342 7RS699 5RS701 - RS702 8RS703 7RS711 - RS713 7RS721 - RS722 8RS731 - RS732 7RS741 - RS743 7RS751 - RS752 7RS761 8RS762 7RS771 8RS781 - RS782 8RS786 8RT001 - RT014 8RT021 - RT022 8RT031 - RT035 8RT041 - RT047 8RT061 8RT071 - RT075 8RT101 - RT103 8RT121 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 20 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 21 GroupVariable Number 8RT131 - RT137 8RT151 - RT152 8RT161 - RT168 8RT401 - RT412 8RT431 - RT447 8RT451 - RT469 8RT471 - RT499 8RT501 - RT535 8RT551 - RT568 8RT571 - RT591 8RT601 - RT657 8RT671 - RT673 8RT681 - RT682 8RT691 - RT699 8RT701 - RT704 8RT711 - RT717 8RT741 - RT757 8RT776 - RT777 8RT781 - RT784 8RT801 - RT803 8RT811 - RT814 8RT831 - RT837 8RT861 - RT864 8RT876 - RT880 8RT931 - RT932 8RT945 - RT949 8RT951 - RT955 8RT966 - RT967 8RU001 - RU006 8RU016 - RU017 8RU031 - RU032 8RU051 - RU052 8RU059 - RU062 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 21 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 22 GroupVariable Number 8RU081 - RU083 8RU101 - RU102 8RU121 - RU132 8RU801 - RU809 8RU831 - RU841 2. Spares Affected None B. Concurrent Requirements None. C. Reason This inspection and doubler installation will make sure that there are no unrepaired cracks in the aft corner of the nose wheel well. These cracks occur in the fuselage skin and skin splice plate at Body Station (BS) 400 near Stringer (STR) 44, left and right side. Service Bulletin 747-53-2150, "Nose Wheel Well Aft Bulkhead External Doubler Installation", told operators of cracks in the skin splice plate for airplane line numbers 1-314. Operators were told to stop drill any cracks in the skin splice plate and to install two external doublers. A thicker skin splice plate was provided in production for airplane line numbers 315 and on. Subsequently, two operators told Boeing of two incidents of cracks in the fuselage skin. These cracks occurred forward of BS 400 at STR 44 near the external repair doublers. The cracks were found on airplanes with 10,539 and 15,178 flight-cycles.These airplanes had been changed as shown in Service Bulletin 747-53-2150 or by means of the Structural Repair Manual 53-30-03, Figure 35. After line number 685, airplanes were delivered with an improved internal skin doubler and fit-up of the structure was improved. Subsequent to the release of revision 1 to this service bulletin, skin cracks were found at both aft corners of the nose wheel well on two 747 airplanes built after line number 685. Based on these findings, the inspections, repair and modification given in this service bulletin has been made applicable to 747 airplanes built after line number 685 and changes have been made to the modification given in this service bulletin for group 4-7 airplanes (steel doublers added). Also, for all airplanes, instruction to do post-modification inspections has been added. Also, after the release of revision 1 to this service bulletin, small cracks were found in the outer chord of the BS 400 bulkhead on airplanes with less than 20,000 flight-cycles. As a result of these findings, instruction to do inspections of the bulkhead outer chord have been included this service bulletin. These outer chord inspections replace SSID F-4 inspections. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 22 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 23 Revision 1 is sent to tell operators about a change in the doubler installation. Sheets PL, 1 - 7, and 9 of Drawing 141U1099 have been changed to show the location of a drain hole for the nose wheel well torque box. These revised drawing sheets were previously sent with Notice of Status Change 747-53-2305 NSC 5. The data given in Notice of Status Change 747-53-2305 NSC 1 through NSC 4 are also included in Revision 1. NSC 1 was issued to send Sheet PL of Drawing 141U1099 to all affected operators. NSC 2 was issued to clarify that the initial inspection should be done using close visual inspection methods and to add reference to the Zone 9 modification in Boeing Service Bulletin 747-53-2272 because of common access. NSC 3 was issued to correct a typographical error in the logic diagram in Figure 1. NSC 4 was issued to send Sheet PL, DCN A, of Drawing 141U1099 to all affected operators. This revised drawing showed optional skin doublers that were made larger to improve short edge margin conditions that were found in service. Revision 2 is sent to give added inspections (post-modification inspection and bulkhead outer chord inspection for all airplanes) and added modification work (added steel doublers to modification applicable to Group 4-7 airplanes), and to extend the effectivity of the service bulletin to include Group 8 for affected 747 airplanes built after line number 685. With revision 2, some airplanes were moved from Group 5 to Group 4. Boeing Structural Item Interim Advisory (SIIA) 747-48 and 747-87 are related to this service bulletin. D. Description For all airplanes, a Detailed inspection for cracks in the skin at/around the aft corners of the nose wheel well is to be done. On specified airplanes, a Detailed inspection for cracks in the skin splice plate at the aft corners of the nose wheel well is also to be done. If a crack in the skin or the skin splice plate is found, the modification and the post-modification inspections given in this service bulletin are to be done. If no cracks are found, repeat Detailed inspections are to be done, or alternatively, the modification and the post-modification inspections given in this service bulletin can be done. Also, for all airplanes, a surface HFEC inspection of the bulkhead outer chord is to be done. If a crack is found, the chord is to be repaired as given in this service bulletin. More work is necessary on airplanes changed by Service Bulletin 747-53-2150 or Structural Repair Manual 53-30-03, Figure 35. Do inspections by means of this service bulletin of the skin panels and skin splice plate in the aft corners of the nose wheel well. Revision 2 - More work is necessary on airplanes changed as shown in the initial release or revision 1 of this service bulletin. For Group 1-3 airplanes, post-modification inspections and inspections of the BS 400 bulkhead outer chord are necessary. For Group 4-7 airplanes, steel doublers are to be added to complete the modification, and post-modification inspections and inspections of the BS 400 bulkhead outer chord are necessary. Airplane effectivity is divided in eight groups due to configuration differences in the area of the modification. NOTE: Inspection and maintenance alternatives are shown in Paragraph 1.E., Compliance. Do not count flight cycles at 2.0 psi or less cabin differential pressure. 1. 2. If the damaged area is more than the specified limits, write to Boeing for repair instructions. Give the size and location of the damage.When possible, send sketches and photographs. If the damage includes corrosion, send data on the length, width, and largest depth of clean up. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 23 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 24 Send to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, AIRLINE SUPPORT 3. It is recommended that this bulletin be done at the same time with Service Bulletin 747-53-2272, Zone 4 and Zone 9, because of common access and the same fasteners. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 113, 114747-100 Group 2: Affected Maintenance Zones ZoneModel 113, 114747-100, 747SR Group 3: Affected Maintenance Zones ZoneModel 113, 114747-200B, 747-200C, 747-200F , 747SP Group 4: Affected Maintenance Zones ZoneModel 113, 114747-100B, 747SP , 747SR Group 5: Affected Maintenance Zones ZoneModel 113, 114747-200B, 747-200C, 747-200F , 747-300 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 24 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 25 Group 6: Affected Maintenance Zones ZoneModel 113, 114747-100B, 747-100B SUD Group 7: Affected Maintenance Zones ZoneModel 113, 114747-200B, 747-200C, 747-200F , 747-300, 747SP Group 8: Affected Maintenance Zones ZoneModel 113, 114747-200B, 747-200C, 747-200F , 747-300, 747-400, 747-400D, 747-400F E. Compliance Table 1: Group 1-3 Airplanes - Inspection/Repair/Modification Repeat Interval (Not to Exceed) Compliance TimeActionCondition (d) -Before 3,000 total flight-cycles or 1,500 flight-cycles after the date of the initial release of this service bulletin, whichever occurs later. Do an external Detailed inspection for cracks in the body skin and the skin splice plate as given in Accomplishment Instruction paragraph 3.B. Airplane does not have the modification given in service bulletin 747-53-2150, the repair given in 747-100/200/300 SRM 53-30-03, Figure 35, or the modification given in this service bulletin. -Before 6,000 flight-cycles after the modification or SRM repair, or 1,500 flight-cycles after the date of the initial release of this service bulletin, whichever occurs later. Do an external Detailed inspection for cracks in the body skin and the skin splice plate as given in Accomplishment Instruction paragraph 3.B. Airplane has the modification given in service bulletin 747-53-2150 or the repair given in 747-100/200/300 SRM 53-30-03, Figure 35. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 25 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 26 Table 1: Group 1-3 Airplanes - Inspection/Repair/Modification Repeat Interval (Not to Exceed) Compliance TimeActionCondition (d) -See Table 4. Data below in this table is not applicable. Do post-modification Inspections as given in Table 4. Airplane has the modification given in this service bulletin. (a) 1,500 flight-cycles1,500 flight-cycles after the initial Detailed inspection. Repeat the external Detailed inspection for cracks in the body skin and the skin splice plate as given in Accomplishment Instruction paragraph 3.B. No cracks found. -(b)As an alternative to the repeat Detailed inspection, do the modification as given in Accomplishment Instruction paragraph 3.B. (c) -Before further flight. Do the modification as given in Accomplishment Instruction paragraph 3.B. Crack is found in the skin or the skin splice plate. (c) (a) This condition is applicable to airplanes that were modified as given in service bulletin 747-53-2150, and modified as given in this service bulletin subsequently. (b) The modification can be done at any time as an alternative to continued/repeat Detailed inspections. (c) The post-modification inspections given in Table 4 are applicable. (d) To know which actions given in this table are applicable, the condition of the airplane with regards to modification and/or repairs at the aft corner of the nose wheel must be known. If the condition of the airplane with regards to modification and/or repairs at the aft corner of the nose wheel well is not known, it will be necessary to determine the condition of the airplane before the earliest of the possibly applicable compliance times given in this table - early enough to allow compliance with the earliest of the possibly applicable times. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 26 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 27 Table 2: Group 4-7 Airplanes - Inspection/Repair/Modification Repeat Interval (Not to Exceed) Compliance TimeActionCondition (b) -Before 3,000 total flight-cycles or 1,500 flight-cycles after the date of revision 2 of this service bulletin, whichever occurs later. Do an external Detailed inspection for cracks in the body skin as given in Accomplishment Instruction paragraph 3.B. Airplane does not have the modification given in this service bulletin. -Before 1,000 flight-cycles after the date of revision 2 of this service bulletin. Do an external General Visual inspection to find if steel, cross-shaped doublers have been installed on the larger aluminum doublers as given in Accomplishment Instruction paragraph 3.B. Airplane has the modification given in this service bulletin before Revision 2. -Before 1,500 flight-cycles after the date of revision 2 of this service bulletin. Install steel doublers on the existing modification doublers as given in Accomplishment Instruction paragraph 3.B. Airplane has the modification as given in this service bulletin before Revision 2 and steel cross-shaped doublers have not been installed. (a) -See Table 4. Data below in this table is not applicable. Do post-modification inspections as given in Table 4. Airplane has the modification given in this service bulletin including the steel cross-shaped doublers. 1,500 flight-cycles1,500 flight-cycles after the initial Detailed inspection. Repeat the external Detailed inspection for cracks in the body skin as given in Accomplishment Instruction paragraph 3.B. No cracks found. -(c)As an alternative to the repeat Detailed inspection, do the modification as given in Accomplishment Instruction paragraph 3.B. -Before further flight.Do the modification as given in Accomplishment Instruction paragraph 3.B. Crack is found. (a) (a) The post-modification inspections given in Table 4 are applicable. (b) To know which actions given in this table are applicable, the condition of the airplane with regards to modification and/or repairs at the aft corner of the nose wheel must be known. If the condition of the airplane with regards to modification and/or repairs at the aft corner of the nose wheel well is not known, BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 27 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 28 Table 2: Group 4-7 Airplanes - Inspection/Repair/Modification Repeat Interval (Not to Exceed) Compliance TimeActionCondition (b) it will be necessary to determine the condition of the airplane before the earliest of the possibly applicable compliance times given in this table - early enough to allow compliance with the earliest of the possibly applicable times. (c) The modification can be done at any time as an alternative to continued/repeat Detailed inspections. Table 3: Group 8 Airplanes - Inspection/Repair/Modification Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 3,000 total flight-cycles or 1,500 flight-cycles after the date of revision 2 of this service bulletin, whichever occurs later. Do an external Detailed inspection for cracks in the body skin as given in Accomplishment Instruction paragraph 3.B. All Group 8 airplanes. 1,500 flight-cycles1,500 flight-cycles after the initial Detailed inspection. Repeat the external Detailed inspection for cracks in the body skin as given in Accomplishment Instruction paragraph 3.B. No crack found. -(a)As an alternative to the repeat Detailed inspection, do the modification as given in Accomplishment Instruction paragraph 3.C. (b) Before Further flight. Do the modification as given in Accomplishment Instruction paragraph 3.B. Crack found (b) (a) The modification can be done at any time as an alternative to continued/repeat Detailed inspections (b) The post-modification inspections given in Table 4 are applicable. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 28 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 29 Table 4: Group 1 - 8 Airplanes - Post-Modification Inspection Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 15,000 flight-cycles after the modification or 1,500 flight-cycles after the date of revision 2 of this service bulletin, whichever occurs later. Conduct external LFEC post-modification inspection for skin cracks around the fasteners at periphery of the modification doublers as given in Accomplishment Instruction paragraph 3.B. Airplane has the modification given in this service bulletin and the edge row fastener holes common to the external doublers were zero-timed as given in Accomplishment Instruction paragraph 3.B. (a) -Before 15,000 total flight-cycles or 1,500 flight-cycles after the date of revision 2 of this service bulletin, whichever occurs later. Conduct external LFEC post-modification inspection for skin cracks around the fasteners at periphery of the modification doublers as given in Accomplishment Instruction paragraph 3.B. Airplane has the modification given in this service bulletin and the edge row fastener holes common to the external doublers were not zero-timed as given in Accomplishment Instruction paragraph 3.B. (a) 1,500 flight-cyclesBefore 1,500 flight-cycles after the initial post-modification inspection. Repeat external LFEC inspection for skin cracks around the periphery of the doublers modification doublers as given in Accomplishment Instruction paragraph 3.B. No crack found. -Before further flight.Contact Boeing for special repair instruction and make repair. Crack found. (a) For a fastener hole to be zero-timed, a sequence of two steps are necessary: (1) open hole HFEC inspection is done with no crack indication, and (2) hole diameter is increased by 1/16 inch (minimum insurance cut) to remove a possible undetected crack. Also, the fastener edge margin must be be more than a specified minimum value. If it cannot be determined whether or not the fastener holes were zero-timed, the compliance time for a modification without zero-timed fastener holes should be used. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 29 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 30 Table 5: Group 1 - 8 Airplanes -Bulkhead Outer Chord Inspection Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 20,000 total flight-cycles, or 3,000 flight-cycles after SSID F-4B HFEC inspection, or 1,500 flight-cycles after the date of revision 2 of this service bulletin, whichever occurs later. From inside the airplane, do a surface HFEC inspection for cracks in the BS 400 bulkhead outer chord, skin splice plate, and the outer chord radius filler as given in Accomplishment Instruction paragraph 3.B. Also do a detailed inspection for cracks in the bulkhead frame web and body skin in the same area. Group 1-8 airplanes. 3,000 flight-cyclesBefore 6,000 flight-cycles after the initial detailed and surface HFEC inspection. Repeat the surface HFEC inspection for cracks in the BS 400 bulkhead outer chord, skin splice plate and outer chord radius filler between stringers S-41L and S-41R as given in Accomplishment Instruction paragraph 3.B. Also, in the same area, repeat the detailed inspection for cracks in the bulkhead frame web and body skin as given in Accomplishment Instruction paragraph 3.B. No cracks found. -Before further flight.Repair as given in Accomplishment Instruction paragraph 3.B. Crack found. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 30 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 31 Table 5: Group 1 - 8 Airplanes -Bulkhead Outer Chord Inspection Repeat Interval (Not to Exceed) Compliance TimeActionCondition 3,000 flight-cyclesBefore 6,000 flight-cycles after the previous detailed and surface HFEC inspection. Repeat the surface HFEC inspection for cracks in the BS 400 bulkhead outer chord, skin splice plate and outer chord radius filler between stringers S-41L and S-41R as given in Accomplishment Instruction paragraph 3.B. Also, in the same area, repeat the detailed inspection for cracks in the bulkhead frame web and body skin as given in Accomplishment Instruction paragraph 3.B. BS 400 bulkhead outer chord and/or skin splice plate and/or the outer chord radius filler has been repaired as given in Accomplishment Instruction paragraph 3.B. Federal Aviation Administration (FAA) Airworthiness Directives 86-09-07, 94-12-04, 94-17-01, 2004-07-22 R1, and 2006-22-09 are related to this service bulletin. F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA).The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of the applicable inspection, repair and modification procedures of this service bulletin as an alternative method of compliance (AMOC) to the corresponding inspection and repair requirements of paragraphs (h), (i) and (j) of FAA AD 2004-07-22 R1 for SSI F-4A, F-4B, and F-25H of Supplement Structural Inspection Document (SSID) D6-35022, Revision G, dated December 2000. 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. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 31 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 32 The Manager of the FAA Seattle ACO also approves the accomplishment of the applicable modification procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraphs (f), (g) and (h) of AD 2006-22-09.This AMOC only applies to the areas modified as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved in accordance with paragraph (j) of the AD. All provisions of AD 2006-22-09 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 modification procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraphs (a), (b) and (c) of AD 94-12-04. This AMOC only applies to the areas modified as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved in accordance with paragraph (d) of the AD. All provisions of AD 94-12-04 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 modification procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraphs (a), (b) and (c) of AD 94-17-01. This AMOC only applies to the areas modified as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved in accordance with paragraph (d) of the AD. All provisions of AD 94-17-01 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 modification procedures of this service bulletin as an AMOC to the corresponding inspection and repair requirements of paragraphs A., B. and C. of AD 86-09-07 R1.This AMOC only applies to the areas modified as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved in accordance with paragraph F . of the AD. All provisions of AD 86-09-07 R1 that are not specifically referenced in the preceding statement remain fully applicable and must be complied with NOTE: The skin inspections given in this service bulletin satisfy the requirements of the 747 RAG (Boeing Document D6-36181, "Repair Assessment Guidelines - Model 747") in the area of the repair/modification given in this service bulletin. G. Manpower Approximately one man-hour and one person are necessary to do the Detailed inspection of the skin and skin splice plate for each airplane. The tables below give estimates of the man-hours necessary to do the modification, post-modification inspection and the BS 400 bulkhead outer chord 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. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 32 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 33 Skin and Splice Plate Doubler Installation for Group 1, 2, and 3 Airplanes That Have Not Done Service Bulletin 747-53-2150 or SRM 53-30-03, Figure 35 Task Elapsed Time (Hours) Man-HoursNumber of Persons Task 10202Open Access 451804Change 10202Close Access 65220TOTAL Skin and Splice Plate Doubler Installation for Group 1, 2, and 3 Airplanes That Have Done Service Bulletin 747-53-2150 or SRM 53-30-03, Figure 35 Elapsed Time (Hours) Man-HoursNumber of Persons Task 10202Open Access 803204Change 10202Close Access 100360TOTAL Skin and Splice Plate Doubler Installation for Group 4-8 Airplanes Elapsed Time (Hours) Man-HoursNumber of Persons Task 10202Open Access 451804Change 10202Close Access 65220TOTAL Supplemental Modification - Splice Plate Doubler Installation for Group 4-7 Airplanes Changed Before Revision 2 to this Service Bulletin Elapsed Time (Hours) Man-HoursNumber of Persons Task 10.0020.002Open Access 10.0040.004Change 10.0020.002Close Access 30.0080.00TOTAL BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 33 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 34 NOTE: Add more time if it is necessary to do the other service bulletins specified in Paragraph I.C., Description. Post-Modification LFEC Inspection Elapsed HoursTask HoursNumber of Persons Task 661Inspect BS 400 Bulkhead Outer Chord Inspection Elapsed HoursTask HoursNumber of Persons Task 10202Open Access 441Inspect 10202Close Access 2444TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes Change in Moment (Pound-Inches) Change in Weight (Pounds) Airplane +5,134.0 lb-in+12.9lbsGroup 1 +5,357.0 lb-in+13.5lbsGroup 2 +5,357.0 lb-in+13.5Group 3 +5040.0 lb-in+12.6 lbsGroup 4 +5040.0 lb-in+12.6 lbsGroup 5 +3280.0 lb-in+8.2 lbsGroup 6 +3280.0 lb-in+8.2 lbsGroup 7, 8 I. Electrical Load Data Not changed J. References 1. Existing Data: a. Engineering Change Memo PRR 85901-84RS b. Standard Overhaul Practices Manual (SOPM) 20-20-02 c. 747 Non-Destructive Testing (NDT) Manual 747 NDT 51-00-00, Figures 1, 4, 11, and 16; 53-30-00, Figure 5; and 53-10-37 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 34 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 35 d. 747-100/200/300 Aircraft Maintenance Manual (AMM) 7 e. 747-100/200/300 Structural Repair Manual (SRM) 51-10-08, 53-30-03 f. 747-400 Aircraft Maintenance Manual (AMM) 7 g. 747-400 Structural Repair Manual (SRM) 51-20-07 h. 747-400F Structural Repair Manual (SRM) 51-20-07 i. 747-400LCF Structural Repair Manual (SRM) 51-20-07 j. 747-400SF Structural Repair Manual (SRM) 51-20-06 k. 747-SP Structural Repair Manual (SRM) 51-10-08 l. Engineering Change Memo PRR 78724, 82284R m. 747 Structural Item Interim Advisory 747-48 and 747-87 n. Boeing Service Bulletin 747-53-2150, "NOSE WHEEL WELL AFT BULKHEAD EXTERNAL DOUBLER INSTALLATION" o. Boeing Service Bulletin 747-53A2267, "FUSELAGE - SKIN - LOWER BODY LONGITUDINAL SKIN LAP JOINT AND ADJACENT BODY FRAME INSPECTION AND REPAIR p. Boeing Service Bulletin 747-53-2272 "FUSELAGE - NOSE SECTION 41 BODY FRAME STRUCTURE REPLACEMENT AND REINFORCEMENT" q. Boeing Service Letter 747-SL-53-080 r. 747 RAG (Repair Assessment Guideline Document D6-36181) s. FAA Airworthiness Directives 86-09-07, 94-12-04, 94-17-01, 2004-07-22 R1, 2006-22-09 2. Data supplied with this Service Bulletin: a. Drawings: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 35 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 36 ADCNDCN/REVSheetTitleDrawing No --14DOUBLER INSL - S-44, STA 400, NWW RETROFIT KIT 141U1099 --15 --16 --17 --18 --19 --20 --21 --22 --23 --24 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-41 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-42 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-43 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-44 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-45 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-46 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-47 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-48 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-49 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-50 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-51 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-52 -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-53 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 36 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 37 ADCNDCN/REVSheetTitleDrawing No -AKPLTOP KIT, RETROFIT - DOUBLER INSTL - S-44, STA400, NWW 141U1099-54 --1Nose Wheel Well Torque Box Disassembly and Reassembly 624U0011 --2 --3 --4 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number Doubler Installation - S-44, Sta 400, NWW141U1099 K. Publications Affected None. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 37 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 38 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 38 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT BLANK PAGE ### Page 39 2. MATERIAL INFORMATION A. Material - Price and Availability Boeing is developing kits to support the modification given in drawing 141U1099. Contact Boeing Spares for the price and availability of the kits. The availability of kits will be added in a later revision of this service bulletin. Contact Boeing Spares by one of the methods that follow: 1. Fax to: (206) 662-7145 2. Mail to: Spares Customer Support - MC 36-65 Boeing Spares Department P .O. Box 3707 Seattle, Washington 98124-2207 USA B. Industry Support Information This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether you ever filed a warranty claim with Boeing on this service bulletin. C. Parts Necessary For Each Airplane 1. Kits/Parts: Boeing is developing kits to support the modification given in drawing 141U1099. The details of the kits will be added in a later revision of this service bulletin. 2. Parts and Materials Supplied by the Operator: NOTE: Boeing is developing kits to support the modification given in drawing 141U1099. The details of the kits will be added in a later revision of this service bulletin. Operators can choose to get kits from Boeing or make the modification parts shown on drawing 141U1099. NamePart Number or SpecificationQuantity AdhesiveBMS 5-92, Type 1 (a)1 pint SealantBMS 5-95, Class C (a)1 quart See the Qualified Products List (QPL) at the end of the Boeing Material Specification (BMS) for supplier data. (a) 3. Parts Modified and Reidentified: None. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 39 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 40 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 I.K., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 40 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 41 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. The instructions identified in Paragraph 3.B., Work Instructions and the Figures give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. 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 the SRM, Chapter 51 – Torque limits to tighten nuts and bolts are given in the SRM, Chapter 51 5. For approved fastener and process material substitutions, refer to SRM, Chapter 51. Alternate fasteners are given in SRM Chapter 51 and Boeing Drawing 012W6100. 6. If the length of any fastener specified in this service bulletin does not meet the 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. 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 mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 8. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 41 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 42 9. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "as given in" are included in the instruction, the procedure in the Boeing document must be used. 10. The inspection figure shows an example configuration of the aft corner of the nose wheel well. On some airplanes, fastener quantities and locations will be different than shown in the figure. 11. As applied in this service bulletin, edge margin is defined as the distance from the center of the fastener hole to the edge of the part. B. WORK INSTRUCTIONS ACCESS - INSPECTION WARNING: RAPID ACTION OF DOORS MAY INJURE PERSONNEL OR DAMAGE EQUIPMENT IF NOSE GEAR DOOR LOCKS ARE NOT INSTALLED PROPERL Y . 1. Get access to the aft corners of the nose wheel well from outside the airplane. ONE-TIME INSPECTION AND SUPPLEMENTAL MODIFICATION FOR MODIFIED GROUP 4-7 AIRPLANES 1. For group 4-7 airplanes that were modified as given in this service bulletin before Revision 2: Do a one-time, external, general visual inspection at the aft corners of the nose wheel well to find if steel cross-shaped doublers have been installed on the larger aluminum doublers. Refer to the drawing identified in the table below to see where the steel cross-shaped doublers are installed. If the steel cross-shaped doublers have been installed, the supplemental modification is not necessary and only post-modification inspections are applicable. Post-modification inspections are to be done by the times given in paragraph 1.E., Compliance. If the steel cross-shaped doublers have not been installed, install the steel cross-shaped doublers in accordance with the applicable data in the table below. The steel cross-shaped doublers are to be installed by the time given in paragraph 1.E., Compliance. Also, post-modification inspections are to be done by the times given in paragraph 1.E., Compliance. Supplemental ModificationAirplane Make left side doubler installation 141U1099-41 and right side doubler installation 141U1099-42 in accordance with drawing 141U1099 sheet 14. Group 4, 5 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 42 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 43 Supplemental ModificationAirplane Make left side doubler installation 141U1099-53 and right side doubler installation 141U1099-54 in accordance with drawing 141U1099 sheet 22. Group 6 Make left side doubler installation 141U1099-47 and right side doubler installation 141U1099-48 in accordance with drawing 141U1099 sheet 18. Group 7 INSPECTION 1. For airplanes that have not been modified in accordance with this service bulletin: Do Detailed inspections for cracks as given in the figure identified in the table below. Compliance times for the Detailed inspections are given in paragraph 1.E., Compliance. NOTE: To know which inspection compliance time is applicable, the condition of the airplane with regards to modification/repairs at the aft corner of the nose wheel well must be known. Inspection FigureAirplane 4Group 1-3 5Group 4-8 NOTE: For airplanes that have been modified in accordance with this service bulletin, post-modification inspections are necessary by the times given in paragraph 1.E., Compliance. 2. If no cracks are found with the Detailed inspection, do either (a) or (b) below: a. Do repeat Detailed inspections as given in the figure identified in the table above. Compliance times for the repeat inspections are given in paragraph 1.E., Compliance. b. Do the modification given in this service bulletin and then do post-modification inspections. Compliance times for the post-modification inspections are given in paragraph 1.E., Compliance. 3. If a crack is found with the inspection, do the modification given in this service bulletin as a repair/modification and then do post-modification inspections. Compliance times for the repair/modification and post-modification inspections are given in paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 43 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 44 JACK / ACCESS FOR REPAIR/MODIFICATION 1. Jack and stabilize the airplane without using the nose jack point. Refer to 747-100/200/300 AMM 7 or 747-400 AMM 7 (as applicable), except do not use the nose jack point (Jack VI). Deflate the nose gear so that no load can be transmitted through it - and the weight of the wheels, truck, and inner cylinder rest on the ground. Keep the gear upper valve open and connected to a container of the same oil by way of a tube. 2. Get access to the fasteners between Station 380 - 410 and stringers S-41L to S-41R, left and right sides. Drawing 624U0011 shows how this can be done. 3. If there is an existing repair in the modification area, remove the repair parts. MODIFICATION 1. If a crack was found in the skin splice plate with the Detailed inspection, drill a 1/4 inch diameter stop hole through the skin splice plate at the end of the crack. If the crack in the splice plate extends to/under the bulkhead outer chord, contact Boeing to get special instruction. 2. All airplanes: Do an open hole HFEC inspection for cracks at fasteners common to the bulkhead outer chord as given in the modification figure identified in the table in step 4 below. If a repair has previously been made in the inspection area, contact Boeing for special instruction. If a skin crack was indicated with this open hole inspection, or a skin crack was found with the Detailed inspection, do a surface HFEC inspection of the skin to find the end(s) of the crack as given in 747 NDT 51-00-00, figure 4, or alternatively, do a penetrant inspection of the skin as given in SOPM 20-20-02. If a skin crack has extended aft past the aft edge of the bulkhead outer chord, contact Boeing to get special repair instruction. For other skin cracks, before the modification doublers are installed, do one of the applicable alternatives (a-c) below: a. If a skin crack is indicated with the open hole inspection but not indicated with the subsequent surface inspection, and a minimum edge margin requirement is satisfied for all parts in the stackup, oversize the fastener hole as necessary to remove the crack. The edge margin (at the final oversize) is to be 1.7D or more for all the parts in the stackup. b. Oversize the hole through only the skin as necessary to remove the crack and install a freeze plug in the oversize hole. Install the freeze plug as given in the applicable SRM (747-100/200/300 SRM 51-10-08, 747-400 SRM 51-20-07, 747-400F SRM 51-20-07, 747-SP SRM 51-10-08, 747-400SF SRM 51-20-06, or 747-400LCF SRM 51-20-07). c. Drill a 1/4 inch diameter stop hole through the skin at the end of the crack, or preferably, remove the crack from the skin with a cutout. Cut material containing the crack from the skin panel and replace the removed skin with a 2024-T3 filler of the same thickness as the removed skin (a filler is not necessary between stringers and forward or aft of the frame chord). Locate the cut lines on the skin panel so that the edge margin for all fasteners adjacent to the edge BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 44 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 45 of the cutout is not less than 1.7D. For rectangular cutouts, position the edges of the cutout to be parallel or perpendicular to the stringer/frame chord and make the corner radius 0.5 inch or more. Chamfer or break all sharp edges to 0.015 - 0.030 inch radius. Make the surface finish of the cut edges of the skin and filler 125 micro-inches or smoother and apply chemical conversion coating and BMS 10-11, Type 1 primer to all bare aluminum surfaces. NOTE: After the work given in (b) or (c) above, it is possible that the modification doubler installed over the freeze plug, stop hole, or cutout will need to be extended from (be larger than) the configuration given on the drawing supplied with this service bulletin. The doubler must be extended if there is less than a specified distance between the freeze plug, stop hole, or cutout and the edge of the doubler. Data/instruction about extending the doublers is given in the modification figure identified in the table in step 4 below. 1. 2. More inspection work is given in step 3 below and the results of the inspection given below could affect the skin repair. It is recommended that skin repairs be accomplished after the inspection given in step 3 below. If a crack is indicated in the outer chord of the bulkhead, skin splice plate, or radius filler, and a minimum edge margin requirement is satisfied for all parts in the stackup, oversize the fastener hole as necessary to remove the crack. The edge margin (at the final oversize) is to be 1.7D or more for all the parts in the stackup. If this edge margin requirement cannot be satisfied, contact Boeing to get special repair instruction. 3. Do an open hole HFEC inspection for cracks at existing fastener holes that will contain edge row fasteners through the modification doublers. Do this inspection as given in the modification figure identified in the table in step 4 below. If a skin crack is indicated with this open hole inspection, do a surface HFEC inspection of the skin to find the end(s) of the crack as given in 747 NDT 51-00-00, figure 4, or alternatively, do a penetrant inspection of the skin as given in SOPM 20-20-02. For these skin cracks, before the modification doublers are installed, do one of the applicable alternatives (a-c) below: a. If a skin crack is indicated with the open hole inspection but not indicated with the subsequent surface inspection, and a minimum edge margin requirement can be satisfied for all parts in the stackup, oversize the fastener hole as necessary to remove the crack. The edge margin (at the final oversize) is to be 1.7D or more for all the parts in the stackup. b. Oversize the hole through only the skin as necessary to remove the crack and install a freeze plug in the oversize hole. Install the freeze plug as given in the applicable SRM (747-100/200/300 SRM 51-10-08, 747-400 SRM 51-20-07, 747-400F SRM 51-20-07, 747-SP SRM 51-10-08, 747-400SF SRM 51-20-06, or 747-400LCF SRM 51-20-07). c. Drill a 1/4 inch diameter stop hole through the skin at the end of the crack, or preferably, remove the crack from the skin with a cutout. Cut material containing the crack from the skin panel and replace the removed skin with a 2024-T3 filler of the same thickness as the removed skin (a filler is not necessary between stringers and forward or aft of the frame chord). Locate the cut lines on the skin panel so that the edge margin for all fasteners adjacent to the edge BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 45 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 46 of the cutout is not less than 1.7D. For rectangular cutouts, position the edges of the cutout to be parallel or perpendicular to the stringer/frame chord and make the corner radius 0.5 inch or more. Chamfer or break all sharp edges to 0.015 - 0.030 inch radius. Make the surface finish of the cut edges of the skin and filler 125 micro-inches or smoother and apply chemical conversion coating and BMS 10-11, Type 1 primer to all bare aluminum surfaces. NOTE: After the work given in (b) or (c) above, it will be necessary to extend the modification doubler installed over the freeze plug, stop hole, or cutout (extend from the configuration given in the drawing supplied with this service bulletin). Data/instruction about extending the doublers is given in the modification figure identified in the table in step 4 below. If a crack is found in the stack-up in a stringer or frame, contact Boeing for repair instruction. 4. Install the modification doublers as given in the applicable figure identified in the table below. Modification FigureAirplane Group 61 72 83 94 105 116 127,8 NOTE: Boeing is developing the kits required to support the modification given in drawing 141U1099. Contact Boeing Spares for the price and availability of the kits.The availability of kits will be added in a later revision of this service bulletin. POST-MODIFICATION INSPECTION 1. For modified airplanes do post-modification inspections as given in the applicable figure identified in the table below. Compliance times for the post-modification inspections are given in paragraph 1.E., Compliance. NOTE: The inspection given in this service bulletin satisfies the inspection requirements of Repair Assessment Guideline Document D6-36181 in the area of the repair/modification given in this service bulletin. Post-Modification Inspection Figure Airplane Group 131 142 153 164 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 46 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 47 Post-Modification Inspection Figure Airplane Group 175 186 197,8 BS 400 BULKHEAD OUTER CHORD INSPECTION 1. All airplanes: do a surface HFEC inspection for cracks in the BS 400 bulkhead outer chord, skin splice plate, and the outer chord radius filler between stringers S-41L and S-41R as given in figure 20. In addition, do a Detailed inspection for cracks in the bulkhead frame web and body skin in the same area as given in figure 20. Compliance times for these inspections are given in paragraph 1.E., Compliance. If no cracks are found, repeat the inspection as given in paragraph 1.E., Compliance. If a crack is indicated in the outer chord of the bulkhead, skin splice plate or radius filler, and a minimum edge margin requirement is satisfied for all parts in the stackup, oversize the fastener hole as necessary to remove the crack. Install oversize fastener(s) of the same type as the removed fastener. The edge margin is to be 1.7D or more for all the parts in the stackup. If this edge margin requirement cannot be satisfied, contact Boeing to get special repair instruction. If a crack is found in the bulkhead frame web or body skin, contact Boeing for repair instruction. The compliance time for the repair is given in paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2: January 15, 2009 47 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 48 The data from this figure was moved into the Accomplishment Instructions and Paragraph 1.E., Compliance with revision 2 to the service bulletin. FIGURE 1: LOGIC DIAGRAM - GROUP 1 - 3 AIRPLANES NOT CHANGED AS GIVEN IN SERVICE BULLETIN 747-53-2150 OR SRM 53-30-03, FIGURE 35 (DELETED) (SHEET 1 OF 1) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 48 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 49 The data from this figure was moved into the Accomplishment Instructions and Paragraph 1.E., Compliance with revision 2 to the service bulletin. FIGURE 2: LOGIC DIAGRAM - GROUP 1 - 3 AIRPLANES CHANGED/REPAIRED AS GIVEN IN SERVICE BULLETIN 747-53-2150 OR SRM 53-30-03, FIGURE 35 (DELETED) (SHEET 1 OF 1) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 49 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 50 The data from this figure was moved into the Accomplishment Instructions and Paragraph 1.E., Compliance with revision 2 to the service bulletin. FIGURE 3: LOGIC DIAGRAM - GROUP 4 - 7 AIRPLANES (DELETED) (SHEET 1 OF 1) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 50 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 51 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT This Figure applies only to: Group 1-3. S-44 SEE 77FFF777709 STA 380 SEE SKIN SPLICE PLATE DOUBLERS (IF INSTALLED AS GIVEN IN (1 SERVICE BULLETIN 747-53-2150 OR SRM 53-03-03, FIGURE 35). BULKHEAD CHORD DRAIN HOLE STA 400 + + ++++ F WD INBD < LEFT SIDE SHOWN A—A GROUP 1, 2 AND 3 AIRPLANES CHANGED BY SERVICE BULLETIN 747-53-2150 936492 OR SRM 53-03-03, FIGURE 35. FIGURE 4: INSPECTION - GROUP 1-3 AIRPLANES (SHEET 1 OF 4) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 102 ### Page 52 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT S-44 STA 380 C=FFFF77777EN I++ ++ SKIN SPLICE 1++ PLATE DOUBLERS (IF INSTALLED 1++ AS GIVEN IN SERVICE BULLETIN I+! 747-53-2150 OR SM 53-03-03, FIGURE 35). BULKHEAD CHORD DRAIN HOLE STA 400 + + + FWD — INBD RIGHT SIDE SHOWN A-A GROUP 1, 2 AND 3 AIRPLANES CHANGED BY SERVICE BULLETIN 747-53-2150 OR SRM 53-03-03, FIGURE 35. FIGURE 4: INSPECTION - GROUP 1-3 AIRPLANES (SHEET 2 OF 4) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 102 ### Page 53 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT TYPICAL CRACK LEFT SIDE INBD →FWD TYPICAL CRACK RIGHT SIDE FWD * - INBO The step numbers shown below agree with the numbers shown in the circle symbols in the figure. FIGURE 4: INSPECTION - GROUP 1-3 AIRPLANES (SHEET 3 OF 4) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 102 ### Page 54 MORE DATAQTYIDENTIFICATIONNAMETASKSTEP (a)--SkinInspect1 (b)--Skin splice plateInspect2 (a) Do a Detailed inspection for cracks within a ten inch radius centered at the corner of the nose wheel well. (b) Do a Detailed inspection for cracks in the visible surfaces of the skin splice plate. FIGURE 4: INSPECTION - GROUP 1-3 AIRPLANES (SHEET 4 OF 4) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 54 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 55 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT This Figure applies only to: Group 4-8. S-44 STA 380 +j SKIN SPLICE ¡+| PLATE BULKHEAD CHORD DRAIN • HOLE STA 400 + + FWD LEFT SIDE SHOWN INBD A-A 946044 FIGURE 5: INSPECTION - GROUP 4-8 AIRPLANES (SHEET 1 OF 3) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 102 ### Page 56 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT S-44 STA 380 7++++++++|+ |+| ++ ++ |++ I+l 1+ + SKIN SPLICE + + PLATE + + + 1++ BULKHEAD DRAIN HOLE\ CHORD STA 400 + + FWD RIGHT SIDE SHOWN • INBD A—A 1550385 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. FIGURE 5: INSPECTION - GROUP 4-8 AIRPLANES (SHEET 2 OF 3) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 102 ### Page 57 MORE DATAQTYIDENTIFICATIONNAMETASKSTEP (a)--SkinInspect1 (a) Do a Detailed inspection for cracks within a ten inch radius centered at the corner of the nose wheel well. FIGURE 5: INSPECTION - GROUP 4-8 AIRPLANES (SHEET 3 OF 3) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 57 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT ### Page 58 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT This Figure applies only to: Group 1. S-44 S-43 STA 380 • OUTER CHORD 2X SKIN FWD- REPAIR STRAP DOUBLER (S) B—B B STA 400 ￾ B STA 409.75 FWD S-45 £7-S INBD LEFT SIDE 1550850 A-A FIGURE 6: MODIFICATION - GROUP 1 AIRPLANES (SHEET 1 OF 3) June 27, 1991 Revision 2 January 15, 2009 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 102 ### Page 59 (OCR) BOEING SERVICE BULLETIN 747-53A2305 ALERT ALERT OUTER CHORD STA 380 SKIN →FWD STRAP REPAIR C-C DOUBLER (S) STA._ 400 STA 1++7 409.75 FWD S-43 S-45 (2) 3 S-46 > INBD RIGHT SIDE 1550750 A-A The step numbers shown below agree with the numbers shown in the circle symbols in the figure. FIGURE 6: MODIFICATION - GROUP 1 AIRPLANES (SHEET 2 OF 3) June 27, 1991 Revision 2 January 15, 2009 747-53A2305 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 102 ### Page 60 NOTE: As part of this modification, existing fastener holes that contain edge row fasteners through the modification doublers are to be zero-timed. For a fastener hole to be zero-timed, an open hole HFEC inspection (with no crack indication) is done at the fastener hole and then the fastener hole diameter is increased by 1/16 inch (minimum insurance cut) to remove a possible undetected crack. Where doubler edge row fasteners are installed through existing fastener holes that have been zero-timed, it will be necessary to install a larger diameter fastener than is specified on the modification drawing included with this service bulletin. — — If a skin crack has been found and a stop hole, freeze plug hole, or cutout has been made in the skin, it will be necessary to extend the modification doubler(s) up/down if the distance between the upper/lower edge of the doubler(s) and the hole or cutout in the skin is not sufficient. Between the upper/lower edge of the doubler and the nearest edge of a cutout, stop hole, or freeze plug hole, there must be a minimum of four (horizontal) rows of the fasteners common to the modification doubler and the bulkhead outer chord. If this is not the case, the modification doubler(s) are to be expanded up/down as necessary to put sufficient distance between the edge of the doubler(s) and the hole or cutout in the skin. — This figure includes instruction for open hole inspection at fastener holes common to the modification doubler(s) and the bulkhead outer chord, and also at any existing fastener holes that contain edge row fasteners through the modification doublers. If the modification doublers have been expanded up/down from the configuration given in the drawings included with this service bulletin, the inspection given in this figure is to be expanded to include the added fastener holes common to the (extended) modification doubler(s) and the bulkhead outer chord. Also, open hole inspection and zero-timing should be done at any existing fastener holes that contain edge row fasteners through the expanded modification doublers instead of at the locations identified in this figure. — A fastener hole common to a modification doubler can be moved from the location given on the drawing supplied with this service bulletin as necessary to align the hole with a fastener hole from an existing/removed repair. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP (a)--Stack-up (d)Inspect1 (a) & (b)--SkinInspect2 (c)--Fastener holeChange3 (e)--ModificationInstall (New)4 (a) Do an open hole HFEC inspection for cracks as given in 747 NDT D6-7170, Part 6, 51-00-00, Figure 1, 11 or 16. (b) Plus other structure (Stringer, frame, etc) in the stack-up were applicable. (c) Increase hole diameter 1/16 inch after open hole inspection. This can be done when the doubler edge row fasteners are installed. (d) Bulkhead outer chord + radius filler+ skin splice plate (between S-43 and S-45) + skin (e) Install modification parts as given in drawing 141U1099, sheet 1 (LS) and sheet 2 (RS). FIGURE 6: MODIFICATION - GROUP 1 AIRPLANES (SHEET 3 OF 3) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. June 27, 1991 747-53A2305Revision 2 January 15, 2009 60 of 102 BOEING SERVICE BULLETIN 747-53A2305 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/747-53a2305/file/83e238b49c56.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.