# Boeing Alert Service Bulletin 747-53A2478: Revision 3 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2013-0540; AD 2013-26-12 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 747-53A2478](https://openairdocs.org/service-documents/boeing/747-53a2478.md) - Title as filed: U.S. DOT/FAA - SB-747-53A2478-03 - Pages: 52 - PDF: https://openairdocs.org/files/sha256/c5/37/c53707eb7b3f66171cc23b63b4ad03816fcf0b44f1f525399f0b278907b9b652 - Page: https://openairdocs.org/service-documents/boeing/747-53a2478/file/c53707eb7b3f ## 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 Airplanes 747 Service Bulletin ALERT Number: 747-53A2478 Original Issue: February 07, 2002 Revision 3: October 17, 2011 ATA System: 5361 SUBJECT: FUSELAGE - Section 46 and Section 48 - Vertical Stabilizer Seal - Skin Damage Protection at Seal Interface - Inspection and Repair 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all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2002 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 1 of 52 2.0 ### Page 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 2 of 52 BOEING SERVICE BULLETIN 747-53A2478 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 0 B. Concurrent Requirements ...................................... 2 0 C. Reason ................................................ 2 1 D. Description .............................................. 2 3 E. Compliance .............................................. 2 4 F. Approval ............................................... 3 1 G. Manpower .............................................. 3 1 H. Weight and Balance Changes .................................... 3 2 I. Electrical Load Data ......................................... 3 2 J. References .............................................. 3 2 1. Existing Data: ......................................... 3 2 2. Data supplied with this Service Bulletin: ........................... 3 3 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 3 K. Publications Affected ........................................ 3 3 L. Interchangeability and Intermixability of Parts ........................... 3 4 2. MATERIAL INFORMATION ........................................ 3 5 A. Material - Price and Availability ................................... 3 5 B. Industry Support Information .................................... 3 5 C. Parts Necessary For Each Airplane ................................. 3 5 1. Kits/Parts: ........................................... 3 5 2. Parts and Materials Supplied by the Operator: ........................ 3 5 3. Parts Modified and Reidentified: ............................... 3 5 4. Parts Removed and Not Replaced: .............................. 3 5 D. Parts Necessary to Change Spares ................................. 3 5 E. Special Tooling - Price and Availability ............................... 3 6 F. Special Tooling Necessary to do this Service Bulletin ....................... 3 6 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 7 A. GENERAL INFORMATION ..................................... 3 7 B. WORK INSTRUCTIONS ....................................... 3 8 FIGURE 1: LOGIC DIAGRAM ....................................... 4 6 FIGURE 2: ACCESS / RESTORATION .................................. 4 7 FIGURE 3: FUSELAGE SKIN INSPECTION ............................... 4 9 FIGURE 4: FUSELAGE SKIN REWORK .................................. 5 1 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 3 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 4 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 4 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT BLANK PAGE ### Page 5 Commercial Airplanes 747 Service Bulletin ALERT Revision Transmittal SheetNumber: 747-53A2478Original Issue: February 07, 2002 Revision 3: October 17, 2011 ATA System: 5361 SUBJECT: FUSELAGE - Section 46 and Section 48 - Vertical Stabilizer Seal - Skin Damage Protection at Seal Interface - Inspection and Repair This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION More work is necessary on the airplane(s) changed in accordance with Revision 1 or Revision 2 of this service bulletin. Do repeat inspections in accordance with Revision 3. Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-14-02 is related to this service bulletin. REASON FOR REVISION This revision is sent to change the repeat inspection requirements for all airplanes, to add the requirement for rub strip installation for airplanes with wear or blend that exceeds Structural Repair Manual limits and to add the requirement to clean the skin at each inspection interval. Since the release of Revision 2 of this service bulletin, one operator has reported wear through the fuselage skin between Body Station (STA) 2598 and STA 2638, stringers S-2L to S-3L. The wear developed in less than 3,657 flight hours since the previous inspection, which was less than the repeat inspection interval given in Revision 2 of the service bulletin. The wear occurred through both the Teflon filled coating and the full thickness of the 0.050 inch thick skin to create a hole approximately 16 inches in length. These sections were changed: 1. Paragraph 1.C., Reason: Revision information is added. 2. Paragraph 1.D., Description: Revision information is added. 3. Paragraph 1.E., Compliance: Conditions, compliance times and repeat inspection intervals are changed. Requirement for rub strip installation is added. Requirement to clean skin is added. 4. Paragraph 1.F., Approval: Approval information information is updated. 5. Paragraph 1.G., Manpower: Manpower estimates are changed. 6. Paragraph 1.J., References: New references are added to existing data. 7. Paragraph 3.A., General Information: Note allowing sequence of steps to be changed is removed. New notes are added. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 5 of 52 ### Page 6 8. Paragraph 3.B., Work Instructions: Alternative access method is added. HFEC inspection requirement is clarified. Repair options are clarified. Rub strip installation requirement is added. Instruction to apply Teflon filled coating is changed. Instruction to clean the skin is added. Optional economic based additional inspections and procedures are added. 9. Figure 3: HFEC inspection requirement is clarified. 10. Figure 4: Teflon filled coating minimum thickness requirement is added. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY February 07, 2002Original Issue: March 27, 2008Revision 1: July 15, 2010Revision 2: October 17, 2011Revision 3: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 6 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 7 Commercial Airplanes 747 Service Bulletin ALERT SummaryNumber: 747-53A2478Original Issue: February 07, 2002 Revision 3: October 17, 2011 ATA System: 5361 SUBJECT: FUSELAGE - Section 46 and Section 48 - Vertical Stabilizer Seal - Skin Damage Protection at Seal Interface - Inspection and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None. BACKGROUND Accomplishment of this service bulletin will detect cracks and accelerated skin wear damage from the vertical stabilizer seal beyond allowable limits. The fuselage skin is subject to wear damage in the area of the vertical stabilizer seal interface in Section 46 (Section 47 on 747-400 Large Cargo Freighter, LCF) and Section 48, which causes thinning of the skin and could lead to cracking. Undetected cracking in the pressurized Section 46 could reach sufficient length to cause in-flight depressurization of the airplane. Prior to the release of Revision 1 of this service bulletin, BMS 10-86 Teflon filled coating along with primer has shown to reduce wear caused by the movement of the vertical stabilizer seal on the fuselage skin. Boeing has determined that primer and BMS 10-86 Teflon filled coating does not provide the required wear resistance. Service Bulletin 747-53-2192, "Body-To-Vertical Fin Interface Seal Chafing Protection", dated July 21, 1981 provided operators of line numbers 0001 - 0414 with the option to apply enamel coating or BMS 10-86 Teflon filled coating. Service bulletin 747-53-2192 was released after two operators reported seal wear damage on four airplanes ranging in service time from 15,332 to 27,204 flight hours. Subsequent to Service Bulletin 747-53-2192 three operators reported seal wear damage on three airplanes ranging in service time from 8,265 to 40,805 flight hours. Service Bulletin 747-53-2192 is being replaced by this service bulletin, thereby eliminating the option of enamel coating under the vertical stabilizer seal for airplane line numbers 0001 - 0414. On airplanes after line number 1264, BMS 10-86 Teflon filled coating along with primer was applied at the vertical stabilizer seal interface in Section 46 and Section 48 during production. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 7 of 52 ### Page 8 BMS 10-86 Teflon filled coating was applied in Service Bulletin 747-53-2192 and the original issue of this service bulletin to prevent skin wear damage, but is no longer terminating action for Revision 1 of this service bulletin. Subsequent to the release of the original issue of this service bulletin, an operator reported seal wear damage on three airplanes. The airplanes had received BMS 10-86 Teflon filled coating during production. The wear damage had occurred on airplanes ranging in service time between from 21,318 to 26,432 flight hours. The maximum depth of wear damage reported was 0.018 inches and was found on airplane line number 1300 with a service time of 21,371 flight hours. Application of BMS 10-86 Teflon filled coating per Service Bulletin 747-53-2192 and the original issue of this service bulletin is no longer terminating action for this service bulletin. Since the release of Revision 2 of this service bulletin, one operator has reported wear through the fuselage skin between Body Station (STA) 2598 and STA 2638, stringers S-2L to S-3L. The wear developed in less than 3,657 flight hours since the previous inspection, which was less than the repeat inspection interval given in Revision 2 of the service bulletin. The wear occurred through both the Teflon filled coating and the full thickness of the 0.050 inch thick skin to create a hole approximately 16 inches in length. Accomplishment of this service bulletin will ensure detection of crack and wear damage and provide proper fuselage skin coating at the vertical stabilizer seal interface in Section 46 and Section 48. Boeing Service Related Problem (SRP) 747-SRP-53-0161, 747-SRP-53-0296 and 747 FTD 53-06007 are related to this service bulletin. ACTION Get access to the fuselage skin at the vertical stabilizer seal interface. Do a detailed inspection of the fuselage skin for wear damage and cracks at the vertical stabilizer seal interface. In addition, if skin is blended in Section 46 and not reinforced, inspect the blended area with surface HFEC for cracks. If damage exists, repair in accordance with the structural repair manual (SRM) or Boeing Service Bulletin 747-53-2721 . If any crack is found or if wear exceeds SRM limits, also install rub strips in accordance with Boeing Service Bulletin 747-53-2721 . Apply BMS 10-86 Teflon filled coating as necessary. Clean the skin at the vertical stabilizer seal interface. Follow-up with repeat visual or HFEC inspections. Optional: replace the seals and inspect for and repair paint blistering at the vertical stabilizer seal interface. As an alternative to repeated inspections, install CRES rub strips on the affected skin panels in accordance with 747-53-2721. The skin panels affected by this service bulletin are divided into the following zones: – Zone 1: STA 2280 to STA 2360 (STA 2340+40 to STA 2360 for 747LCF, STA 2072 to STA 2360 for 747SP) – Zone 2: STA 2360 to STA 2397 – Zone 3: STA 2397 to STA 2417 – Zone 4: STA 2517 to STA 2557 – Zone 5: STA 2557 to STA 2598 – Zone 6: STA 2598 to STA 2638 NOTE: The SRM subjects referenced in this service bulletin have been updated to reflect new allowable damage limits. EFFECTIVITY All 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, and 747SR series airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 8 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 9 COMPLIANCE The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-14-02 is related to this service bulletin. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are available for the original release of this service bulletin only for Group 1 airplanes in warranty as of July 12, 2001. For inspection labor hour reimbursement for Group 1 airplanes in warranty as of that date, send a warranty claim to Boeing Warranty. If the condition described in the original release of this service bulletin is found during the inspection for Group 1 airplanes in warranty as of that date and additional labor hours are required, send a warranty claim to Boeing Warranty. Please refer to this service bulletin number and reference the airplane variable numbers in your purchase order. Boeing warranty remedies are not available for either Group 1 or Group 2 airplanes for the additional work required by Revision 1, Revision 2 or Revision 3 of this service bulletin. MANPOWER Elapsed HoursTotal Task Hours Airplanes 16.7533.50Group 1 and Group 2 airplanes. MATERIAL INFORMATION Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 9 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 10 (OCR) BOEING SERVICE BULLETIN 747-53A2478 ALERT ALERT INSPECT THE FUSELAGE SKIN FOR WEAR AND CRACKS AT THE VERTICAL STABILIZER SEAL INTERFACE. IF DAMAGE EXISTS, REPAIF IN ACCORDANCE WITH SRM OR SB 747-53-2721 IF CRACK IS FOUND OR IF WEAR EXCEEDS SRM LIMITS, ALSO INSTALL RUB STRIPS IN ACCORDANCE WITH SB 747-53-2721. APPLY BMS 10-86 TEFLON FILLED COATING AS NECESSARY. CLEAN THE SKIN. DO REPEAT INSPECTIONS. AFT TORQUE BOX ACCESS RUDDER PANEL -ORWARL ORQUE BOX ACCESS PANEL STA 2628 DORSAL STA FIN 2521 VERTICAL STABILIZER STA SEAL STA 1 2416 2360 STA : 2280 1 (STA 2072 ON 747SP) (STA 2340+40 ON 747LCF) VERTICAL HORIZONTAL STABILIZER STABILIZER SEAL AFT PRESSURE BULKHEAD TYPICAL PASSENGER AIRPLANE SHOWN, SP AND BOEING LCF SIMILAR (LEFT SIDE SHOWN RIGHT SIDE OPPOSITE) V71088 Original Issue: February 07, 2002 Revision 3: October 17, 2011 747-53A2478 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 52 ### Page 11 Commercial Airplanes 747 Service Bulletin ALERT Number: 747-53A2478 Original Issue: February 07, 2002 Revision 3: October 17, 2011 ATA System: 5361 SUBJECT: FUSELAGE - Section 46 and Section 48 - Vertical Stabilizer Seal - Skin Damage Protection at Seal Interface - Inspection and Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. NOTE: 747-8 and 747-8F series airplanes are not affected by this service bulletin. DESCRIPTIONCONFIGURATIONGROUP Line number 0001 - 1264 Airplanes that are in the effectivity of service bulletin 747-53A2478 R0. -1 Line number 1265 and on. Airplanes that have received BMS 10-86 Teflon Filled Coating in production. -2 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 - RA034 1RA101 - RA115 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 11 of 52 ### Page 12 GroupVariable Number 1RA161 - RA164 1RA201 - RA203 1RA216 - RA217 1RA245 - RA246 1RA251 - RA266 1RA301 - RA318 1RA351 - RA360 1RA369 - RA373 1RA401 - RA418 1RA501 - RA502 1RA521 - RA528 1RA532 - RA548 1RA551 - RA552 1RA559 - RA561 1RA581 - RA582 1RA585 1RA601 - RA602 1RA631 - RA635 1RA651 - RA652 1RA671 - RA677 1RA701 - RA702 1RA721 - RA731 1RA741 - RA745 1RA749 - RA750 1RA761 - RA762 1RA781 - RA784 1RA901 - RA916 1RB001 - RB016 1RB041 - RB044 1RB071 - RB075 1RB101 - RB102 1RB411 - RB413 1RB421 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 12 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 13 GroupVariable Number 1RB601 - RB607 1RB681 - RB697 1RB711 1RB721 - RB723 1RB741 - RB748 1RD001 - RD004 1RD021 - RD022 1RD041 - RD059 1RD071 - RD072 1RD081 - RD083 1RD091 - RD092 1RD101 - RD104 1RD121 - RD127 1RD131 - RD144 1RD166 - RD167 1RD171 - RD172 1RD181 - RD183 1RD201 - RD204 1RD221 - RD227 1RD231 - RD235 1RD241 - RD243 1RD251 - RD262 1RD271 - RD272 1RD291 - RD292 1RD301 - RD302 1RD311 1RD351 - RD358 1RD361 - RD366 1RD381 - RD383 1RD411 - RD414 1RD421 - RD426 1RD431 - RD435 1RD441 - RD442 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 13 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 14 GroupVariable Number 1RD451 - RD456 1RD461 1RD471 - RD475 1RD513 - RD519 1RD531 - RD533 1RD551 1RD561 1RD571 1RD581 - RD583 1RD591 - RD593 1RD601 - RD607 1RD621 - RD623 1RD641 - RD649 1RD651 - RD659 1RD661 1RD671 1RD681 - RD682 1RD691 - RD692 1RD701 - RD702 1RD721 - RD722 1RD741 - RD742 1RD751 - RD755 1RD761 1RD771 - RD775 1RD781 - RD783 1RD791 - RD792 1RE001 2RF001 - RF006 1RG001 - RG009 1RG091 1RG095 1RG101 - RG104 1RG121 - RG126 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 14 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 15 GroupVariable Number 1RG141 - RG142 1RG161 - RG164 1RG171 - RG174 1RG191 - RG193 1RG211 - RG213 1RG221 - RG222 1RH101 - RH102 1RH111 - RH112 1RH121 - RH122 1RJ131 - RJ133 1RJ151 - RJ152 1RJ301 - RJ303 1RJ321 - RJ322 1RJ331 - RJ333 1RL401 2RL402 - RL403 1RL411 - RL414 2RL415 - RL436 2RL451 - RL456 2RL461 - RL462 2RL471 - RL481 2RL491 - RL492 2RL501 - RL502 2RL511 - RL516 2RL521 - RL522 2RL531 - RL534 2RL551 2RL561 - RL568 2RL571 - RL572 2RL576 - RL577 2RL579 2RL581 - RL586 1RL651 - RL653 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 15 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 16 GroupVariable Number 2RL654 - RL655 2RL671 - RL675 2RL681 - RL684 2RL751 - RL752 1RM001 - RM005 2RM006 - RM007 2RM010 1RM011 - RM012 2RM013 1RM021 - RM024 1RM026 - RM027 2RM028 - RM030 1RM036 - RM039 2RM040 1RM041 2RM042 - RM045 1RM051 2RM052 - RM053 1RM071 1RM081 - RM084 1RM091 1RM096 - RM097 1RM116 - RM117 1RM126 - RM131 2RM132 1RM136 - RM147 1RM156 - RM157 2RM158 1RM166 - RM177 1RM191 - RM192 1RM231 - RM233 1RM241 - RM244 2RM245 - RM246 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 16 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 17 GroupVariable Number 1RM261 - RM264 1RM316 - RM318 1RM331 - RM333 1RM341 2RM351 - RM355 2RM366 - RM367 2RM401 - RM403 2RM426 2RM431 2RM441 - RM443 2RM445 1RM801 - RM802 2RM803 1RM811 - RM813 1RM851 - RM853 2RM854 - RM855 1RM856 2RM857 - RM859 1RM861 2RM862 - RM863 1RM871 - RM873 2RM874 - RM880 1RM881 - RM885 2RM886 - RM890 1RM891 - RM899 1RM901 - RM903 2RM904 - RM906 1RM911 1RR001 - RR005 1RR021 - RR025 1RR031 1RR201 - RR206 1RR221 - RR226 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 17 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 18 GroupVariable Number 1RR261 - RR267 1RR301 - RR310 1RR331 - RR332 1RR336 1RR341 - RR345 1RR361 - RR362 1RR421 - RR422 1RR431 - RR432 1RR441 - RR442 1RR451 1RR501 - RR504 1RR521 - RR522 1RR526 1RR531 1RR551 - RR556 1RR561 1RR566 1RR701 1RR721 - RR724 1RR746 - RR748 1RR851 - RR856 1RR861 - RR862 1RR951 - RR952 1RS001 - RS002 1RS201 1RS211 - RS212 1RS221 - RS222 1RS231 - RS241 1RS251 - RS259 1RS263 1RS265 - RS268 1RS271 - RS276 1RS291 - RS292 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 18 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 19 GroupVariable Number 1RS301 - RS306 1RS311 - RS320 1RS331 - RS333 1RS341 - RS342 1RS699 1RS701 - RS703 1RS711 - RS713 1RS721 - RS722 1RS731 - RS732 1RS741 - RS743 1RS751 - RS752 1RS761 - RS762 1RS771 1RS781 - RS782 1RS786 1RT001 - RT014 1RT021 - RT022 1RT031 - RT035 1RT041 - RT047 1RT061 1RT071 - RT075 1RT101 - RT103 1RT121 1RT131 - RT137 1RT151 - RT152 1RT161 - RT168 1RT401 - RT412 1RT431 - RT447 1RT451 - RT469 1RT471 - RT499 1RT501 - RT535 1RT551 - RT568 1RT571 - RT591 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 19 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 20 GroupVariable Number 1RT601 - RT657 1RT671 - RT673 1RT681 - RT682 1RT691 - RT699 1RT701 - RT704 1RT711 - RT717 1RT741 - RT757 1RT776 - RT777 1RT781 - RT784 1RT801 - RT803 1RT811 - RT814 1RT831 - RT837 1RT861 - RT864 1RT876 - RT880 1RT931 - RT932 1RT945 - RT949 1RT951 - RT955 1RT966 - RT967 1RU001 - RU006 1RU016 - RU017 1RU031 - RU032 1RU051 - RU052 1RU059 - RU062 1RU081 - RU083 1RU101 - RU102 1RU121 - RU132 1RU801 - RU809 1RU831 - RU841 2. Spares Affected None. B. Concurrent Requirements None. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 20 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 21 C. Reason Accomplishment of this service bulletin will detect cracks and accelerated skin wear damage from the vertical stabilizer seal beyond allowable limits. The fuselage skin is subject to wear damage in the area of the vertical stabilizer seal interface in Section 46 (Section 47 on 747-400 Large Cargo Freighter, LCF) and Section 48, which causes thinning of the skin and could lead to cracking. Undetected cracking in the pressurized Section 46 could reach sufficient length to cause in-flight depressurization of the airplane. The vertical stabilizer seals are located at the interface between vertical stabilizer and fuselage skin between Body Station (BS) 2280 to BS 2416 and BS 2521 to BS 2598. Small movements of the vertical stabilizer seal cause wear through the enamel coating or primer. Prior to the release of Revision 1 of this service bulletin, BMS 10-86 Teflon filled coating along with primer has shown to reduce wear caused by the movement of the vertical stabilizer seal on the fuselage skin. Boeing has determined that primer and BMS 10-86 Teflon filled coating does not provide the required wear resistance. Service Bulletin 747-53-2192, "Body-To-Vertical Fin Interface Seal Chafing Protection", dated July 21, 1981 provided operators of line numbers 0001 - 0414 with the option to apply enamel coating or BMS 10-86 Teflon filled coating. Service Bulletin 747-53-2192 was released after two operators reported seal wear damage on four airplanes ranging in service time from 15,332 to 27,204 flight hours. Subsequent to Service Bulletin 747-53-2192 three operators reported seal wear damage on three airplanes ranging in service time from 8,265 to 40,805 flight hours. Service Bulletin 747-53-2192 is being replaced by this service bulletin, thereby eliminating the option of enamel coating under the vertical stabilizer seal for airplane line numbers 0001 - 0414. On airplanes after line number 1264, BMS 10-86 Teflon filled coating along with primer was applied at the vertical stabilizer seal interface in Section 46 and Section 48 during production. BMS 10-86 Teflon filled coating was applied in Service Bulletin 747-53-2192 and the original issue of this service bulletin to prevent skin wear damage, but is no longer terminating action for Revision 1 of this service bulletin. Subsequent to the release of the original issue of this service bulletin, an operator reported seal wear damage on three airplanes. The airplanes had received BMS 10-86 Teflon filled coating during production. The wear damage had occurred on airplanes ranging in service time between from 21,318 to 26,432 flight hours. The maximum depth of wear damage reported was 0.018 inches and was found on airplane line number 1300 with a service time of 21,371 flight hours. Application of BMS 10-86 Teflon filled coating per Service Bulletin 747-53-2192 and the original issue of this service bulletin is no longer terminating action for Revision 1 of this service bulletin. Since the release of Revision 2 of this service bulletin, one operator has reported wear through the fuselage skin between Body Station (STA) 2598 and STA 2638, stringers S-2L to S-3L. The wear developed in less than 3,657 flight hours since the previous inspection, which was less than the repeat inspection interval given in Revision 2 of the service bulletin. The wear occurred through both the Teflon filled coating and the full thickness of the 0.050 inch thick skin to create a hole approximately 16 inches in length. Accomplishment of this service bulletin will ensure detection of cracks and wear damage and / or cracks and provide proper fuselage skin coating at the vertical stabilizer seal interface in Section 46 and Section 48. Boeing Service Related Problem (SRP) 747-SRP-53-0161, 747-SRP-53-0296 and 747 FTD 53-06007 are related to this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 21 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 22 Revision 1 was sent to tell operators that recent service history indicates that application of BMS 10-86 Teflon filled coating is no longer terminating action for the prevention of wear damage in Section 46 and Section 48 of the vertical stabilizer seal interface. Changes to this service bulletin include: — Paragraph 1.A., Effectivity. Airplanes line number 1265 and on have been added to the effectivity of this service bulletin. — Paragraph 1.A., Effectivity. Group effectivity has been revised. Group 2 in the original issue of this service bulletin has been added to Group 1 in this service bulletin. Airplanes through line number 1265 and on have been added to Group 2 of this service bulletin — Paragraph 1.E., Compliance. Compliance times have been revised and repeat inspections have been added for all airplanes. A note is also added to inform operators that application of BMS 10-86 Teflon filled coating is no longer terminating action. — Paragraph 1.F., Manpower. The manpower table has been revised to account for the time taken to accomplish inspection for wear damage of Group 2 airplanes. — Paragraph 3.B.3., Work Instructions. Work has been added for airplanes that do not have wear damage. — Figure 1 has been deleted to remove the logic diagram. — In Figure 3, Step 2 has been added to show an inspection for skin cracks in blended areas forward of STA 2360. Revision 2 was sent to add references to Boeing Service Bulletin 747-53-2721, which gives instructions to install CRES steel rub strips in areas affected by this service bulletin. The inspections in this service bulletin are no longer necessary after the modification in Service Bulletin 747-53-2721 has been installed. In addition, references to skin repairs, including kits, that are in Service Bulletin 747-53-2721 have been included. The Summary illustration and the locators in Figures 2, 3 and 4 have been changed to more clearly show that the inspections in this service bulletin should be done up to STA 2628, not STA 2598. The location wrongly identified as STA 2598 in the previous releases of this service bulletin is actually STA 2628. The Action paragraph in the Summary, Paragraph 1.D., Description, Paragraph 1.E., Compliance, and FIGURE 3 have been changed to make it clear that affected areas of skin in Section 46 (areas forward of STA 2360) that have been blended without reinforcement should be inspected for cracks with external surface High Frequence Eddy Current (HFEC), in addition to external detailed inspections. Instructions for repair of fasteners with wear damage have been added to new PART 2 in Paragraph 3.B., Work Instructions. References to FAA AD 2009-14-02 have been added. AD 2009-14-02 superseded AD 2002-26-15. The data given in Information Notice 747-53A2478 IN 01 is included in this revision. IN 01 was sent to clarify footnote (b) in Figure 3, which describes the surface HFEC inspections required in blended skin areas. Revision 3 is sent to change the repeat inspection requirements for all airplanes, to add the requirement for rub strip installation for airplanes with wear or blend that exceeds Structural Repair Manual limits and to add the requirement to clean the skin at each inspection interval. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 22 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 23 D. Description Get access to the fuselage skin at the vertical stabilizer seal interface. Do a detailed inspection of the fuselage skin for wear damage and cracks at the vertical stabilizer seal interface. In addition, if skin is blended in Section 46 and not reinforced, inspect the blended area with surface HFEC for cracks. If damage exists, repair in accordance with the structural repair manual (SRM) or Boeing Service Bulletin 747-53-2721 . If any crack is found or if wear exceeds SRM limits, also install rub strips in accordance with Boeing Service Bulletin 747-53-2721 . Apply BMS 10-86 Teflon filled coating as necessary. Clean the skin at the vertical stabilizer seal interface. Follow-up with repeat visual or HFEC inspections. Optional: replace the seals and inspect for and repair paint blistering at the vertical stabilizer seal interface. As an alternative to repeated inspections, install CRES rub strips on the affected skin panels in accordance with 747-53-2721. The skin panels affected by this service bulletin are divided into the following zones: – Zone 1: STA 2280 to STA 2360 (STA 2340+40 to STA 2360 for 747LCF, STA 2072 to STA 2360 for 747SP) – Zone 2: STA 2360 to STA 2397 – Zone 3: STA 2397 to STA 2417 – Zone 4: STA 2517 to STA 2557 – Zone 5: STA 2557 to STA 2598 – Zone 6: STA 2598 to STA 2638 NOTE: The SRM subjects referenced in this service bulletin have been updated to reflect new allowable damage limits. Revision 1 - More work is necessary on airplanes changed in accordance with the original issue of this service bulletin. Repeat inspections are necessary for all airplanes. Application of BMS 10-86 Teflon filled coating is no longer terminating action for the inspections given in this service bulletin. Revision 2 - No more work is necessary on airplanes inspected in accordance with Revision 1 of this service bulletin. Continue to do repeat inspections in accordance with Revision 2. Revision 3 - More work is necessary on the airplane(s) changed in accordance with Revision 1 or Revision 2 of this service bulletin. Do repeat inspections in accordance with Revision 3. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 311, 312, 313, 314747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, 747SR BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 23 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 24 Group 2: Affected Maintenance Zones ZoneModel 311, 312, 313, 314747-400, 747-400F E. Compliance The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directive AD 2009-14-02 is related to this service bulletin. Table 1 - Inspection for wear damage and cracks Repeat Interval (Not to Exceed) Compliance TimeActionCondition -In accordance with Table 2. Do initial inspection and modi- fy/repair as necessary in accor- dance with Table 2. (b) (c) All airplanes. (a) Refer to Table 3In accordance with Table 3. Do repeat inspections and modify/repair as necessary in accordance with Table 3. (c) Refer to Table 4In accordance with Table 4. Do inspections and modify/re- pair in accordance with Table 4. (c) Airplanes with fuselage skin blended without external rein- forcement in Section 46. (a) Refer to Boeing Service Bulletin 747-53-2721 or contact Boeing if CRES rub strips are installed. (b) For airplanes that have started inspections in accordance with the original issue, Revision 1 or Revision 2 of this service bulletin, initial inspections in accordance with Revision 3 of this service bulletin are nec- essary unless terminating action has been accomplished. (c) It is acceptable to install rub strips in accordance with Boeing Service Bulletin 747-53-2721 at any time. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in this service bulletin at the locations of rub strip installation only. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 24 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 25 Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled coating. Compliance TimeActionCondition Whichever Occurs Later:Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes that have not started inspections in accordance with the original issue, Revision 1 or Revision 2 of this service bul- letin. (c) Within 6,000 flight hours after the effec- tive date of FAA AD 2009-14-02 or within 2,000 flight hours af- ter the Revision 3 date of this service bulletin, whichever occurs first. Before 20,000 total flight hours. (a) (b) (d) (e) (h) Whichever Occurs First:Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes that have started in- spections in accordance with the original issue, Revision 1 or Revision 2 of this service bul- letin and, after the last work in accordance with this service bulletin, one of the following conditions applied in the fuse- lage skin at the vertical stabilizer seal interface: - there were no blend repairs Within 2,000 flight hours after the Revi- sion 3 date of this service bulletin, or within 3,000 flight hours after the previ- ous inspection in ac- cordance with the original issue, Revi- sion 1 or Revision 2, whichever occurs lat- er. Within 7,500 flight hours after the previ- ous inspection in ac- cordance with the original issue, Revi- sion 1 or Revision 2 of this service bul- letin. (a) (b) (d) (e) (h)or - the maximum blend repair depth was 0.006 inches or less. (c) (j) (k) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 25 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 26 Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled coating. Compliance TimeActionCondition Whichever Occurs First:Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes that have started in- spections in accordance with the original issue, Revision 1 or Revision 2 of this service bul- letin and, after the last work in accordance with this service bulletin, one of the following conditions applied in the fuse- lage skin at the vertical stabilizer seal interface: - the maximum blend repair depth was more than 0.006 inches Within 2,000 flight hours after the Revi- sion 3 date of this service bulletin. Within 7,500 flight hours after the previ- ous inspection in ac- cordance with the original issue, Revi- sion 1 or Revision 2 of this service bul- letin. (a) (b) (d) (e) (h) or - the maximum blend repair depth was not recorded or - it is not known if there were any blend repairs. (c) (j) (k) Before further flight.Repair wear damage and apply BMS 10-86 Teflon filled coating in accordance with Paragraph 3.B., Work Instructions , PART 1. Wear damage is found that is less than or equal to the rework limit allowed in the SRM. (f) (g) (h) (i) Before further flight.Repair wear damage and/or crack, and apply BMS 10-86 Teflon filled coating in accor- dance with Paragraph 3.B., Work Instructions , PART 1. Wear damage is found that is more than the rework limit al- lowed in the SRM. (f) OR Crack is found. (g) (h) AND Within 24 months after finding the condition.Install rub strips at all locations in accordance with Boeing Ser- vice Bulletin 747-53-2721. (e) (h) Before further flight.Apply BMS 10-86 Teflon filled coating in accordance with Paragraph 3.B., Work Instruc- tions , PART 1. No wear damage or crack is found. (g) (h) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 26 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 27 Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled coating. Compliance TimeActionCondition Before further flight.Repair skin and apply BMS 10- 86 Teflon filled coating in accor- dance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is repaired using blend method and, after the re- pair, the blend depth is more than the rework limit allowed in the SRM. (f) (g) (h) AND Within 24 months after finding the condition.Install rub strips at all locations in accordance with Boeing Ser- vice Bulletin 747-53-2721. (e) (h) (a) Application of BMS 10-86 Teflon filled coating is no longer terminating action for the inspections. (b) If repair doubler is installed in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, 747-SP SRM 53-39-01, or 747-400LCF SRM 53- 00-01, inspections in accordance with the SRM are also required. (c) Refer to Boeing Service Bulletin 747-53-2721 or contact Boeing if CRES rub strips are installed. (d) If skin thickness in Section 46 is reduced by blending without reinforcement, Table 4 also applies. (e) In areas repaired or modified in accordance with Boeing Service Bulletin 747-53-2721, continue inspections in the repaired or modified areas in accordance with Boeing Service Bulletin 747-53-2721. (f) Refer to 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01 for rework limits. (g) It is not necessary to apply BMS 10-86 Teflon filled coating at locations where rub strips are installed in accordance with Boeing Service Bulletin 747-53-2721 before further flight. (h) It is acceptable to install rub strips in accordance with Boeing Service Bulletin 747-53-2721 at any time. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in this service bulletin at the locations of rub strip installation only. (i) The repeat inspection conditions given in Table 3 are dependent on maximum blend depth after repair. If blend repair is used, it is recommended to record the maximum blend depth after blend repair so that the next repeat interval can be determined. (j) (j) Maximum blend repair depth is the depth of the blend repair at the location where the blend depth is largest. The blend depth is the total depth of material removed from the skin, based on the original skin thickness. (k) This condition applies to the time after the last work was done in accordance with this service bulletin before starting inspections in accordance with Revision 3 of this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 27 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 28 Table 3 - Repeat inspections for wear damage and cracks, and application of BMS 10-86 Teflon filled coating Repeat Interval (Not to Exceed) (j) Compliance Time (j)ActionCondition 3,000 flight hours (h) (i) Within 3,000 flight hours after the previous inspec- tion in accordance with this service bulletin. Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes for which, in the fuse- lage skin at the vertical stabilizer seal interface: - there are no blend repairs or - the maximum blend repair depth is 0.006 inches or less. (c) (k) (a) (b) (d) (e) (i) 2,000 flight hours (h) (i) Within 2,000 flight hours after the previous inspec- tion in accordance with this service bulletin. Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes for which, in the fuse- lage skin at the vertical stabilizer seal interface: - the maximum blend repair depth is more than 0.006 inches and less than or equal to the rework limit allowed in the SRM. (f) or - the maximum blend repair depth is not known (a) (b) (d) (e) (i)or - it is not known if there are any blend repairs. (c) (k) 2,000 flight hours (i) Within 2,000 flight hours after the previous inspec- tion in accordance with this service bulletin. Do a detailed inspection of the fuselage skin at the vertical sta- bilizer seal interface for wear damage and cracks, and clean the skin, in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. Where skin re- pair doubler is present, inspect the surface of the repair dou- bler. Removal of the repair dou- bler is not necessary. Airplanes for which, in the fuse- lage skin at the vertical stabilizer seal interface: - there has been skin wear or blend repair greater than the rework limit allowed in the SRM since the release of Revision 3 of this service bulletin. (f) (c) (a) (b) (d) (e) (i) AND -Within 24 months after finding the condition. Install rub strips at all locations in accordance with Boeing Ser- vice Bulletin 747-53-2721. (e) (i) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 28 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 29 Table 3 - Repeat inspections for wear damage and cracks, and application of BMS 10-86 Teflon filled coating Repeat Interval (Not to Exceed) (j) Compliance Time (j)ActionCondition -Before further flight.Repair wear damage and apply BMS 10-86 Teflon filled coating, in accordance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is found that is less than or equal to the rework limit allowed in the SRM. (f) (g) (j) (i) -Before further flight.Repair wear damage and/or crack, and apply BMS 10-86 Teflon filled coating, in accor- dance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is found that is more than the rework limit al- lowed in the SRM. (f) OR Crack is found. (g) (i) AND -Within 24 months after finding the condition. Install rub strips at all locations in accordance with Boeing Ser- vice Bulletin 747-53-2721. (e) (i) -Before further flight.Apply BMS 10-86 Teflon filled coating in accordance with Paragraph 3.B., Work Instruc- tions, PART 1. No wear damage or crack is found. (g) (i) -Before further flight.Repair skin and apply BMS 10- 86 Teflon filled coating in accor- dance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is repaired using blend method and, after the re- pair, the blend is more than the rework limit allowed in the SRM. (f) (g) (i) AND -Within 24 months after finding the condition. Install rub strips at all locations in accordance with Boeing Ser- vice Bulletin 747-53-2721. (e) (i) (a) Application of BMS 10-86 Teflon filled coating is no longer terminating action for the repeat inspections (b) If repair doubler is installed in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, 747-SP SRM 53-39-01, or 747-400LCF SRM 53- 00-01, inspections in accordance with the SRM are also required. (c) Refer to Boeing Service Bulletin 747-53-2721 or contact Boeing if CRES rub strips are installed. (d) If skin thickness in Section 46 is reduced by blending without reinforcement, Table 4 also applies. (e) In areas repaired or modified in accordance with Boeing Service Bulletin 747-53-2721, continue inspections in the repaired or modified areas in accordance with Boeing Service Bulletin 747-53-2721. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 29 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 30 Table 3 - Repeat inspections for wear damage and cracks, and application of BMS 10-86 Teflon filled coating Repeat Interval (Not to Exceed) (j) Compliance Time (j)ActionCondition (f) Refer to 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01 for rework limits. (g) It is not necessary to apply BMS 10-86 Teflon filled coating at locations where rub strips are installed in accordance with Boeing Service Bulletin 747-53-2721 before further flight. (h) This repeat inspection is terminated if the blend depth becomes more than is stated in the condition. Refer to the new applicable Condition for the required Action, Compliance Time and Repeat Interval. (i) It is acceptable to install rub strips in accordance with Boeing Service Bulletin 747-53-2721 at any time. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in this service bulletin at the locations of rub strip installation only. (j) The repeat inspection conditions are dependent on maximum blend depth after repair. If blend repair is used, it is recommended to record the maximum blend depth after blend repair so that the next repeat interval can be determined. (k) (k) Maximum blend repair depth is the depth of the blend repair at the location where the blend depth is largest. The blend depth is the total depth of material removed from the skin, based on the original skin thickness. Table 4 - Inspection for cracks on airplanes that have reduced skin thickness in Section 46 due to blending without reinforcement Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 6,000 flight cy- cles. (d) Within 1,000 flight cycles af- ter the effective date of FAA AD 2009-14-02 Before 20,000 total flight cy- cles, or within 6,000 flight cy- cles after the initial blend, whichever oc- curs later. Do an external surface HFEC inspection of the blended area of the fuselage skin for cracks, in accordance with Paragraph 3.B., Work Instructions , PART 1. Where skin repair doubler is present, inspect the surface of the repair doubler. Removal of the repair doubler is not neces- sary. (a) (b) (c) (d) Fuselage skin blended without external reinforce- ment. -Before further flight.Repair crack and apply BMS 10- 86 Teflon filled coating, in accor- dance with Paragraph 3.B., Work Instructions , PART 1. Crack is found. (d) -Before further flight.Apply BMS 10-86 Teflon filled coating, in accordance with Paragraph 3.B., Work Instruc- tions , PART 1. No crack is found. (d) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 30 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 31 Table 4 - Inspection for cracks on airplanes that have reduced skin thickness in Section 46 due to blending without reinforcement Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition (a) If there is a knife edge condition at any fastener hole in the blended area (i.e. countersink depth greater than 2/3 of the existing skin thickness), repair in accordance with Paragraph 3.B., Accomplishment Instruc- tions, before further flight. After the repair, continue inspection in accordance with Table 1. (b) Repeat this inspection until repair doubler is installed in the blended area as given 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, 747-SP SRM 53-39-01 or 747-400LCF SRM 53-00-01. After an SRM repair, if no rub strip was installed, continue in- spections in the repaired area in accordance with Table 1. (c) In areas repaired or modified in accordance with Boeing Service Bulletin 747-53-2721, continue inspections in the repaired or modified areas in accordance with Boeing Service Bulletin 747-53-2721. (d) It is acceptable to install rub strips in accordance with Boeing Service Bulletin 747-53-2721 at any time. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in this service bulletin at the locations of rub strip installation only. F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. This service bulletin has been approved by the Federal Aviation Administration (FAA). In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the inspection, repair, and modification procedures with the corresponding compliance times specified in Tables 1, 2, 3 and 4 under paragraph 1.E., "Compliance" of Service Bulletin 747-53A2478, Revision 3, as an Alternative Method of Compliance (AMOC) to the inspections, corrective actions, and terminating actions required by paragraphs (f), (i), (k), and (l) of AD 2009-14-02. This AMOC only applies to the areas inspected, repaired, or modified in accordance with this service bulletin. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in AD 2009-14-02 at the locations of rub strip installation only. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph (m) of the AD. All provisions of AD 2009-14-02 that are not specifically referenced in this paragraph remain fully applicable and must be complied with. G. Manpower The following table shows an estimate of the task-hours necessary to do this change for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task-hour data if necessary. The estimate does not include lost time. These are some examples of lost time: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 31 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 32 — 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. Elapsed HoursTask HoursNumber of Per- sons Task 2.505.002Open access 1.002.002Visually inspect for wear 3.006.002Apply BMS 10-86 Teflon filled coating 6.2512.502Replace seals (b) 0.751.502Inspect for soften- ing/blistering of fin- ish (b) 0.751.502Clean skin 2.505.002Close access 16.7533.50TOTAL FOR EACH AIRPLANE (a) (a) Estimate does not include time for repairs. (b) These task are optional. H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. 747 Maintenance Manual (AMM) Subjects 51-24-04, 55-30-10 b. 747-SP Structural Repair Manual (SRM) 51-30-08, 53-31-00, 53-39-01 c. 747-100/200/300 Structural Repair Manual (SRM) 51-30-08, 53-30-01, 53-30-03 d. 747-400 Structural Repair Manual (SRM) 51-40-08, 53-00-01 e. 747-400F Structural Repair Manual (SRM) 51-40-08, 53-00-01 f. 747-400LCF Structural Repair Manual (SRM) 51-40-08, 53-00-01 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 32 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 33 g. 747-400SF Structural Repair Manual (SRM) 51-40-08, 53-00-01 h. Boeing Service Bulletin 747-53-2192, 747-53-2721 i. Boeing Service Related Problem (SRP) 747-SRP-53-0161, 747-SRP-53-0296 j. Federal Aviation Administration (FAA) Airworthiness Directive 2002-26-15, 2009-14-02 k. 747-400SF Structural Repair Manual (SRM) 51-40-08, 53-00-01 l. 747-400LCF Structural Repair Manual (SRM) 53-00-01 m. 747 NDT Part 6, 51-00-00, Figure 4 or 23 n. 747 Repair Assessment Guidelines (RAG) D6-36181 o. Boeing Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-41-02, 20-44-01 p. 747 Fleet Team Digest (FTD) 53-06007 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number Skin Panel Assembly - STA 2181.10 to 2360, Str 4L to Str 4R146U3910 Panel Instl - S-1 to S-11, STA 2360 - 259865B02706 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. K. Publications Affected 1. Publications: Chapter-SectionPublication 53-30-01, 53-30-03747-100/-200/-300 Structural Repair Manual 53-00-01747-400 Structural Repair Manual 53-31-00, 53-39-01747 SP Structural Repair Manual 53-00-01747-400F Structural Repair Manual 53-30-01, 53-30-03747 E4B Structural Repair Manual 53-00-01747LCF Structural Repair Manual BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 33 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 34 Chapter-SectionPublication 53-00-01747SF Structural Repair Manual 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin revision for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin revision affects FCS but no new DTIs are necessary. 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. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 34 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 35 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are available for the original release of this service bulletin only for Group 1 airplanes in warranty as of July 12, 2001. For inspection labor hour reimbursement for Group 1 airplanes in warranty as of that date, send a warranty claim to Boeing Warranty. If the condition described in the original release of this service bulletin is found during the inspection for Group 1 airplanes in warranty as of that date and additional labor hours are required, send a warranty claim to Boeing Warranty. Please refer to this service bulletin number and reference the airplane variable numbers in your purchase order. Boeing warranty remedies are not available for either Group 1 or Group 2 airplanes for the additional work required by Revision 1, Revision 2 or Revision 3 of this service bulletin. C. Parts Necessary For Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: NotesNameQTYPart Number / Specification (c)Primer16 oz(a) (c)Teflon Filled Coating16 oz(b) (a) Use one of the following primers; BMS 10-79 Type III, BMS 10-79 Type II, or BMS 10-11 Type I. (b) Use one of the following Teflon filled coatings; BMS 10-86 Type I or BMS 10-86 Type II. (c) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 35 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 36 E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 36 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 37 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 SRM, Chapter 51 – Torque limits to tighten nuts and bolts are given in 747 SRM, Chapter 51 4. Use the approved fastener and process material substitutions in accordance with the 747 SRM 51. 5. 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. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 8. Boeing Service Letter 747-SL-51-048, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 37 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 38 9. This service bulletin contains instructions to remove and keep parts for installation. However, before installation of any removed and kept part, the part must be in a serviceable condition. Replacement of the removed and kept part with a new or serviceable part of the same part number/specification is an acceptable alternative unless otherwise stated in the service bulletin instructions. 10. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 11. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. 12. Boeing has determined that the condition of the seals and the skin finish (or paint) in the vertical stabilizer seal interface area may contribute to skin wear. Degraded seals and contaminants/debris at the vertical stabilizer seal interface, from softening, blistering or flaking of the skin finish, can accelerate skin wear. Excessive skin wear will require extensive repairs. To make sure that excessive wear does not occur between inspections Boeing recommends operator accomplish Paragraph 3.B., Work Instructions, Part 3 - Economic Based Additional Inspections and Procedures (Operator Option), at each skin inspection. 13. It is acceptable to install rub strips in accordance with Boeing Service Bulletin 747-53-2721 at any time. Installation of rub strips in accordance with Boeing Service Bulletin 747-53-2721 is terminating action for the work given in this service bulletin at the locations of rub strip installation only. B. WORK INSTRUCTIONS PART 1 - INSPECTION 1. Get access. Refer to FIGURE 2 as an accepted procedure. NOTE: It is also acceptable to get access for inspections by lifting the seal with a finger or plastic instrument. 2. Do a detailed inspection of the fuselage skin for wear and cracks at the vertical stabilizer seal interface in accordance with FIGURE 3. If skin is blended forward of STA 2360 without external reinforcement, also do external surface High Frequency Eddy Current (HFEC) inspections for cracks in accordance with FIGURE 3. a. If wear is found, measure and record the depth of the wear and location. (1) FOR WEAR IN SECTION 46 (FORWARD OF STA 2360) (Zone 1): BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 38 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 39 (a) If the head of any fastener in the affected area is worn beyond 0.002 inch deep (not including paint and primer), replace the fastener in accordance with PART 2. (b) If depth of wear in fuselage skin has exceeded the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do the following: 1) Do one of the following to repair the wear damage: a) Repair the wear damage in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01. b) Install a full-length repair in Zone 1 in accordance with Boeing Service Bulletin 747-53-2721. c) Repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. 2) Install rub strips at all locations in accordance with Boeing Service Bulletin 747-53-2721. (c) If depth of wear in fuselage skin is within the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do one of the following options: 1) Option 1 - Blend repair: Do the following: NOTE: Depending on the extent and location of the wear, it might not be possible to accomplish a blend repair and comply with the rework limits given in the applicable SRM. If the rework limits in the applicable SRM are exceeded, more repair work will be necessary. Refer to Paragraph 3.B., Work Instructions PART 1 step 2.a.(1)(c)1)b). a) Repair the skin panel using the blend method in accordance with 747-100/200/300 SRM 53-30-01, Figure 1, Flagnote D, 747-400 SRM 53-00-01, Allowable Damage 1, Flagnote F, 747-SP SRM 53-31-00, Figure 1, Flagnote F, 747-400F SRM 53-00-01, Allowable Damage 1, Flagnote F, 747-400SF SRM 53-00-01, Allowable Damage 1, Flagnote F, or 747-400LCF SRM 53-00-01, Allowable Damage 1, Flagnote F. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 39 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 40 NOTE: 1. Observe minimum distance of cleanout boundary from fastener holes as stated in the SRM. 2. Based on the original nominal design skin thickness, for any rework the total depth of material removed from the skin must not exceed the "MAXIMUM ALLOWABLE REWORK DEPTH" given in the applicable SRM. 3. It is recommended to record the maximum blend depth after blend repair so that the next repeat interval can be determined. 4. The maximum blend depth after blend repair is the depth of the blend repair at the location where the blend depth is largest. The blend depth is the total depth of material removed from the skin, based on the original skin thickness. b) After doing the blend repair, if the blend depth is not within the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do the following: {1} Repair the skin panel in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01, or install a full-length repair in Zone 1 in accordance with Boeing Service Bulletin 747-53-2721, or repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. {2} Install rub strips at all locations in accordance with Boeing Service Bulletin 747-53-2721. 2) Option 2 - Non-blend repair: Do one of the following to repair the wear damage: a) Repair the wear damage in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01. b) Install a full-length repair in Zone 1 in accordance with Boeing Service Bulletin 747-53-2721. c) Repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. (d) If countersinking after blending would result in a knife edge condition (i.e. countersink depth greater than 2/3 of the existing skin thickness), do not increase the countersink depth. Repair in accordance with PART 2. (2) FOR WEAR IN SECTION 48 (AFT OF STA 2360) (Zone 2 - Zone 6): BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 40 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 41 (a) If the head of any fastener in the affected area is worn beyond 0.002 inch deep (not including paint and primer), replace the fastener in accordance with PART 2. (b) If depth of wear in fuselage skin has exceeded the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do the following: 1) Do one of the following: a) Repair the skin panel in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01. b) Install a full-length repair in Zone 1 in accordance with Boeing Service Bulletin 747-53-2721. c) Install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. 2) Install rub strips at all locations in accordance with Boeing Service Bulletin 747-53-2721. (c) If depth of wear in fuselage skin is within the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do one of the following options: 1) Option 1 - Blend repair: Do the following: NOTE: Depending on the extent and location of the wear, it might not be possible to accomplish a blend repair and comply with the rework limits given in the applicable SRM. If the rework limits in the applicable SRM are exceeded, more repair work will be necessary. Refer to Paragraph 3.B., Work Instructions PART 1 step 2.a.(1)(c)1)b). a) Repair the skin panel using the blend method in accordance with 747-100/200/300 SRM 53-30-01, Figure 1, Flagnote D, 747-400 SRM 53-00-01, Allowable Damage 1, Flagnote F, 747-SP SRM 53-31-00, Figure 1, Flagnote F, 747-400F SRM 53-00-01, Allowable Damage 1, Flagnote F, 747-400SF SRM 53-00-01, Allowable Damage 1, Flagnote F, or 747-400LCF SRM 53-00-01, Allowable Damage 1, Flagnote F. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 41 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 42 NOTE: 1. Observe minimum distance of cleanout boundary from fastener holes as stated in the SRM. 2. Based on the original nominal design skin thickness, for any rework the total depth of material removed from the skin must not exceed the "MAXIMUM ALLOWABLE REWORK DEPTH" given in the applicable SRM. 3. It is recommended to record the maximum blend depth after blend repair so that the next repeat interval can be determined. 4. The maximum blend depth after blend repair is the depth of the blend repair at the location where the blend depth is largest. The blend depth is the total depth of material removed from the skin, based on the original skin thickness. b) After doing the blend repair, if the blend depth is not within the rework limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01, do the following: {1} Repair the skin panel in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01 or install a full-length repair in the affected zone in accordance with Boeing Service Bulletin 747-53-2721 or repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. {2} Install rub strips at all locations in accordance with Boeing Service Bulletin 747-53-2721. 2) Option 2 - Non-blend repair: Do one of the following to repair the wear damage: a) Repair the wear damage in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01 or 747-400LCF SRM 53-00-01. b) Install a full-length repair in the affected zone in accordance with Boeing Service Bulletin 747-53-2721. c) Repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. (3) If cracks are found, do the following: (a) Do one of the following to repair the crack: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 42 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 43 1) Repair the skin in accordance with 747-100/200/300 SRM 53-30-03, 747-400 SRM 53-00-01, 747-SP SRM 53-39-01, 747-400F SRM 53-00-01, 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01 2) Install a full-length repair in the affected skin Zone in accordance with Boeing Service Bulletin 747-53-2721. 3) Repair the wear damage and install rub strips in the affected areas in accordance with Boeing Service Bulletin 747-53-2721. (b) Install rub strips at all locations in accordance with Boeing Service Bulletin 747-53-2721. (4) Apply BMS 10-86 Teflon filled coating, in accordance with FIGURE 4, over the repair, in areas where there is no Teflon filled coating and in areas where existing Teflon filled coating is not intact. (a) If Teflon filled coating exists and is intact, do not apply another coat. (b) If Teflon filled coating exists and is not intact, do one of the following to repair the coating: 1) Option 1 (Boeing recommends): Remove all of the existing Teflon filled coating apply new Teflon filled coating in accordance with FIGURE 4. 2) Option 2: Remove the existing Teflon filled coating that is not intact and apply new Teflon filled coating in accordance with FIGURE 4, but only to the following area: – Length from 2 inches forward to 2 inches aft of where the existing Teflon filled coating was removed. – Width in accordance with FIGURE 4. b. If no wear or crack is found, apply BMS 10-86 Teflon filled coating in accordance with FIGURE 4. (1) If Teflon filled coating exists and is intact, do not apply another coat. (2) If Teflon filled coating exists and is not intact, do one of the following to repair the coating: (a) Option 1 (Boeing recommends): Remove all of the existing Teflon filled coating apply new Teflon filled coating in accordance with FIGURE 4. (b) Option 2: Remove the existing Teflon filled coating that is not intact and apply new Teflon filled coating in accordance with FIGURE 4, but only to the following area: – Length from 2 inches forward to 2 inches aft of where the existing Teflon filled coating was removed. – Width in accordance with FIGURE 4. 3. Optional: Do PART 3 - ECONOMIC BASED ADDITIONAL INSPECTIONS AND PROCEDURES (OPERATOR OPTION) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 43 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 44 4. Clean the skin within five inches of the vertical stabilizer seals to remove hydraulic fluid and other dirt and debris. Refer to SOPM 20-30-03 as an accepted procedure. 5. Restore access. Refer to FIGURE 2 as an accepted procedure if necessary. 6. Put the airplane back to a serviceable condition. 7. Repeat inspections at times given in Paragraph 1.E., Compliance. As an alternative to repeated inspections, install CRES rub strips on the affected skin panels in accordance with 747-53-2721. PART 2 - REPAIR OF FASTENERS WITH HEAD WEAR 1. If the head of any fastener in the affected area is worn beyond 0.002 inch deep (not including paint and primer), do the following: a. Remove the fastener. b. If necessary, clean up skin damage. Blendout repairs in the skin cannot exceed the limits given in 747-100/200/300 SRM 53-30-01, 747-SP SRM 53-31-00, 747-400 SRM 53-00-01, 747-400F SRM 53-00-01, or 747-400SF SRM 53-00-01, or 747-400LCF SRM 53-00-01. c. Do not deepen the countersink that exists. Install a countersink repair washer in accordance with 747-100/200/300 SRM 51-30-08, 747-SP SRM 51-30-08, 747-400 SRM 51-40-08, 747-400F SRM 51-40-08, 747-400SF SRM 51-40-08, or 747-400LCF SRM 51-40-08. d. Install a new, protruding shear head fastener, made from A286 CRES or titanium, the same size as was removed. The fastener can be first or second oversize in diameter, as necessary. Install the fastener wet with BMS 5-95 sealant. Refer to the applicable SRM for acceptable fastener type and hole sizes. NOTE: Examples of acceptable A286 CRES fasteners that can be installed are BACB30FM( )AK( ), BACB30FP( )AK( ), and BACB30KK( )AK( ). Example of acceptable titanium fasteners that can be installed are BACB30MY( )K( ) and BACB30VT( )K( ). PART 3 - ECONOMIC BASED ADDITIONAL INSPECTIONS AND PROCEDURES (OPERATOR OPTION) 1. If wear was found in the fuselage skin at the vertical stabilizer seal interface, or if the seal is degraded, Boeing recommends replacing the seals: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 44 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 45 a. To replace the seals between STA 2288 and STA 2416: Remove the existing seal from the forward vertical stabilizer seal panel assembly and install a new seal on the forward vertical stabilizer seal panel assembly. b. To replace the seals between STA 2521 and STA 2628: Punch 0.218 - 0.229 inch diameter holes in a new seal at each applicable fastener location. Use the existing structure or the removed seal as a template for fastener locations. Install the new seal when restoring access in accordance with FIGURE 2. 2. Do a detailed inspection of the skin for softening or blistering of the finish within 5 inches of the vertical stabilizer seals. If any softening or blistering is found, do the following: a. Remove all finish within 5 inches of the affected area. b. Restore finish. Refer to SOPM 20-41-02 as an accepted procedure. c. If Teflon filled coating was removed, do one of the following to repair the coating: (1) Option 1 (Boeing recommends): Remove all of the existing Teflon filled coating apply new Teflon filled coating in accordance with FIGURE 4. (2) Option 2: Remove the existing Teflon filled coating that is not intact and apply new Teflon filled coating in accordance with FIGURE 4, but only to the following area: – Length from 2 inches forward to 2 inches aft of where the existing Teflon filled coating was removed. – Width in accordance with FIGURE 4. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3: October 17, 2011 45 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 46 (OCR) BOEING SERVICE BULLETIN 747-53A2478 ALERT ALERT THIS FIGURE IS DELETED. FIG SHEET TO DIAGRAM Revision October 47, 201102 747-53A2478 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 52 ### Page 47 (OCR) BOEING SERVICE BULLETIN 747-53A2478 ALERT ALERT AFT TORQUE BOX RUDDER 3 8 FORWARD TORQUE BOX STA X10 2628 DORSAL STA FIN- 2521 STA 1 2416 STA 2360 2280 i SIA (STA 2072 ON 747SP) (STA 2340+40 ON 747LCF) VERTICAL HORIZONTAL STABILIZER SEAL AFT STABILIZER PRESSURE BULKHEAD TYPICAL PASSENGER AIRPLANE SHOWN, SP AND BOEING LCF SIMILAR (LEFT SIDE SHOWN RIGHT SIDE OPPOSITE) V71503 FIGURE 2: ACCESS / RESTORATION (SHEET 1 OF 2) Original Issue: February 07, 2002 Revision 3 October 17, 2011 BOEING PROPRIETARY - 747-53A2478 Copyright © Unpublished Work - See page 1 for details. 47 of 52 ### Page 48 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. NOTESQTYREFERENCENAMETASKSTEP Access Panel Number 322CL (left side only) 1AMM 55-30-10Access PanelRemove / Keep1 Access Panel Number 322BL (left side only) 1AMM 55-30-10Access PanelRemove / Keep2 Access Panel Number 324AL (left side only) 1AMM 55-30-10Access PanelRemove / Keep3 Seal Panel Number 322AL (left side) and 322AR (right side) 1AMM 55-30-10Forward Vertical Stabilizer Seal Panel Assembly Remove / Keep4 Seal attaches directly to structure 1-Aft Vertical Stabiliz- er Seal Remove / Keep5 NOTESQTYREFERENCENAMETASKSTEP Seal attaches directly to structure 1-Aft Vertical Stabiliz- er Seal Install / Kept6 Seal Panel Number 322AL (left side) and 322AR (right side) 1AMM 55-30-10Forward Vertical Stabilizer Seal Panel Assembly Install / Kept7 Access Panel Number 324AL (left side only) 1AMM 55-30-10Access PanelInstall / Kept8 Access Panel Number 322BL (left side only) 1AMM 55-30-10Access PanelInstall / Kept9 Access Panel Number 322CL (left side only) 1AMM 55-30-10Access PanelInstall / Kept10 FIGURE 2: ACCESS / RESTORATION (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3 October 17, 2011 48 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 49 (OCR) BOEING SERVICE BULLETIN 747-53A2478 ALERT ALERT STA 2360 STA 2280 (STA 2072 ON 747SF (STA 2340+40 ON 747LCF STA 2628 STA 2521 TYPICAL PASSENGER AIRPLANE SHOWN, SP AND BOEING LCF SIMILAR (LEFT SIDE SHOWN RIGHT SIDE OPPOSITE) V71504 FIGURE 3: FUSELAGE SKIN INSPECTION (SHEET 1 OF 2) Original Issue: February 07, 2002 Revision 3 October 17, 2011 747-53A2478 Copyright © Unpublished Work - See page 1 for details. BOEING PROPRIETARY - 49 of 52 ### Page 50 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. MORE DATAQTYIDENTIFICATIONNAMETASKSTEP Detailed inspection. (a) --Fuselage SkinInspect1 Surface HFEC, in blended areas of skin forward of STA 2360 only. (b) --Fuselage SkinInspect2 (a) Do a detailed inspection of the fuselage skin for cracks and wear at the interface of the vertical stabilizer seal and fuselage skin. (b) In any blended area forward of STA 2360 without external reinforcement, do surface HFEC inspections for cracks in accordance with 747 NDT Part 6, 51-00-00, Figure 4 or 23. Inspect for potential cracks in both the vertical and horizontal directions. Also do surface HFEC inspections for cracks around all fastener heads in any blended area forward of STA 2360 in accordance with 747 NDT Part 6, 51-00-00, Figure 4 or 23. FIGURE 3: FUSELAGE SKIN INSPECTION (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3 October 17, 2011 50 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT ### Page 51 (OCR) BOEING SERVICE BULLETIN 747-53A2478 ALERT ALERT STA 2628 STA 2521 STA STA 1 2416 2360 SIA • 2280 \ (STA 2072 ON 747SP) (STA 2340+40 ON 747LCF) TYPICAL PASSENGER AIRPLANE SHOWN, SP AND BOEING LCF SIMILAR (LEFT SIDE SHOWN RIGHT SIDE OPPOSITE) V71688 FIGURE 4: FUSELAGE SKIN REWORK (SHEET 1 OF 2) Original Issue: February 07, 2002 Revision 3 October 17, 2011 747-53A2478 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 52 ### Page 52 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. More DataQtyIdentificationNameTaskStep (a) (b) (c)--PrimerApply1 (b) (c) (d)--BMS 10-86 Type I or Type II Teflon filled coating Apply2 (a) Use one of the following primers; BMS 10-79 Type III, BMS 10-79 Type II or BMS 10-11 Type I. (b) Apply to an area of the length of each vertical stabilizer seal and a width including approximately two inches on both sides of the seal contact area. (c) Refer to AMM 51-24-04. (d) Apply BMS 10-86 Teflon filled coating with a minimum thickness of 0.005 inch. Refer to SOPM 20-44-01 as an accepted procedure. FIGURE 4: FUSELAGE SKIN REWORK (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478Revision 3 October 17, 2011 52 of 52 BOEING SERVICE BULLETIN 747-53A2478 ALERTALERT --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. 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