### 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. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2002 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 1 of 52 2.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 2 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 33 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 35 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 36 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 FIGURE 1: LOGIC DIAGRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 2: ACCESS / RESTORATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 FIGURE 3: FUSELAGE SKIN INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 FIGURE 4: FUSELAGE SKIN REWORK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 3 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 4 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Revision Transmittal Sheet**  **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 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 747-53A2478 Revision 3: October 17, 2011 5 of 528. 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, 2002 Original Issue: March 27, 2008 Revision 1: July 15, 2010 Revision 2: October 17, 2011 Revision 3:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 6 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **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. **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 747-53A2478 Revision 3: October 17, 2011 7 of 52BMS 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 747-53A2478 Revision 3: October 17, 2011 8 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 Hours**  **Total Task Hours**  **Airplanes**

16.75 33.50 Group 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 747-53A2478 Revision 3: October 17, 2011 9 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 10 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**

### 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.

**DESCRIPTION CONFIGURATION**  **GROUP** 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 **Group Variable Number**  1 RA001 - RA034 1 RA101 - RA115

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 11 of 52**Group Variable Number**  1 RA161 - RA164 1 RA201 - RA203 1 RA216 - RA217 1 RA245 - RA246 1 RA251 - RA266 1 RA301 - RA318 1 RA351 - RA360 1 RA369 - RA373 1 RA401 - RA418 1 RA501 - RA502 1 RA521 - RA528 1 RA532 - RA548 1 RA551 - RA552 1 RA559 - RA561 1 RA581 - RA582 1 RA585 1 RA601 - RA602 1 RA631 - RA635 1 RA651 - RA652 1 RA671 - RA677 1 RA701 - RA702 1 RA721 - RA731 1 RA741 - RA745 1 RA749 - RA750 1 RA761 - RA762 1 RA781 - RA784 1 RA901 - RA916 1 RB001 - RB016 1 RB041 - RB044 1 RB071 - RB075 1 RB101 - RB102 1 RB411 - RB413 1 RB421

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 12 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RB601 - RB607 1 RB681 - RB697 1 RB711 1 RB721 - RB723 1 RB741 - RB748 1 RD001 - RD004 1 RD021 - RD022 1 RD041 - RD059 1 RD071 - RD072 1 RD081 - RD083 1 RD091 - RD092 1 RD101 - RD104 1 RD121 - RD127 1 RD131 - RD144 1 RD166 - RD167 1 RD171 - RD172 1 RD181 - RD183 1 RD201 - RD204 1 RD221 - RD227 1 RD231 - RD235 1 RD241 - RD243 1 RD251 - RD262 1 RD271 - RD272 1 RD291 - RD292 1 RD301 - RD302 1 RD311 1 RD351 - RD358 1 RD361 - RD366 1 RD381 - RD383 1 RD411 - RD414 1 RD421 - RD426 1 RD431 - RD435 1 RD441 - RD442

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 13 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RD451 - RD456 1 RD461 1 RD471 - RD475 1 RD513 - RD519 1 RD531 - RD533 1 RD551 1 RD561 1 RD571 1 RD581 - RD583 1 RD591 - RD593 1 RD601 - RD607 1 RD621 - RD623 1 RD641 - RD649 1 RD651 - RD659 1 RD661 1 RD671 1 RD681 - RD682 1 RD691 - RD692 1 RD701 - RD702 1 RD721 - RD722 1 RD741 - RD742 1 RD751 - RD755 1 RD761 1 RD771 - RD775 1 RD781 - RD783 1 RD791 - RD792 1 RE001 2 RF001 - RF006 1 RG001 - RG009 1 RG091 1 RG095 1 RG101 - RG104 1 RG121 - RG126

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 14 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RG141 - RG142 1 RG161 - RG164 1 RG171 - RG174 1 RG191 - RG193 1 RG211 - RG213 1 RG221 - RG222 1 RH101 - RH102 1 RH111 - RH112 1 RH121 - RH122 1 RJ131 - RJ133 1 RJ151 - RJ152 1 RJ301 - RJ303 1 RJ321 - RJ322 1 RJ331 - RJ333 1 RL401 2 RL402 - RL403 1 RL411 - RL414 2 RL415 - RL436 2 RL451 - RL456 2 RL461 - RL462 2 RL471 - RL481 2 RL491 - RL492 2 RL501 - RL502 2 RL511 - RL516 2 RL521 - RL522 2 RL531 - RL534 2 RL551 2 RL561 - RL568 2 RL571 - RL572 2 RL576 - RL577 2 RL579 2 RL581 - RL586 1 RL651 - RL653

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 15 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 2 RL654 - RL655 2 RL671 - RL675 2 RL681 - RL684 2 RL751 - RL752 1 RM001 - RM005 2 RM006 - RM007 2 RM010 1 RM011 - RM012 2 RM013 1 RM021 - RM024 1 RM026 - RM027 2 RM028 - RM030 1 RM036 - RM039 2 RM040 1 RM041 2 RM042 - RM045 1 RM051 2 RM052 - RM053 1 RM071 1 RM081 - RM084 1 RM091 1 RM096 - RM097 1 RM116 - RM117 1 RM126 - RM131 2 RM132 1 RM136 - RM147 1 RM156 - RM157 2 RM158 1 RM166 - RM177 1 RM191 - RM192 1 RM231 - RM233 1 RM241 - RM244 2 RM245 - RM246

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 16 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RM261 - RM264 1 RM316 - RM318 1 RM331 - RM333 1 RM341 2 RM351 - RM355 2 RM366 - RM367 2 RM401 - RM403 2 RM426 2 RM431 2 RM441 - RM443 2 RM445 1 RM801 - RM802 2 RM803 1 RM811 - RM813 1 RM851 - RM853 2 RM854 - RM855 1 RM856 2 RM857 - RM859 1 RM861 2 RM862 - RM863 1 RM871 - RM873 2 RM874 - RM880 1 RM881 - RM885 2 RM886 - RM890 1 RM891 - RM899 1 RM901 - RM903 2 RM904 - RM906 1 RM911 1 RR001 - RR005 1 RR021 - RR025 1 RR031 1 RR201 - RR206 1 RR221 - RR226

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 17 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RR261 - RR267 1 RR301 - RR310 1 RR331 - RR332 1 RR336 1 RR341 - RR345 1 RR361 - RR362 1 RR421 - RR422 1 RR431 - RR432 1 RR441 - RR442 1 RR451 1 RR501 - RR504 1 RR521 - RR522 1 RR526 1 RR531 1 RR551 - RR556 1 RR561 1 RR566 1 RR701 1 RR721 - RR724 1 RR746 - RR748 1 RR851 - RR856 1 RR861 - RR862 1 RR951 - RR952 1 RS001 - RS002 1 RS201 1 RS211 - RS212 1 RS221 - RS222 1 RS231 - RS241 1 RS251 - RS259 1 RS263 1 RS265 - RS268 1 RS271 - RS276 1 RS291 - RS292

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 18 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RS301 - RS306 1 RS311 - RS320 1 RS331 - RS333 1 RS341 - RS342 1 RS699 1 RS701 - RS703 1 RS711 - RS713 1 RS721 - RS722 1 RS731 - RS732 1 RS741 - RS743 1 RS751 - RS752 1 RS761 - RS762 1 RS771 1 RS781 - RS782 1 RS786 1 RT001 - RT014 1 RT021 - RT022 1 RT031 - RT035 1 RT041 - RT047 1 RT061 1 RT071 - RT075 1 RT101 - RT103 1 RT121 1 RT131 - RT137 1 RT151 - RT152 1 RT161 - RT168 1 RT401 - RT412 1 RT431 - RT447 1 RT451 - RT469 1 RT471 - RT499 1 RT501 - RT535 1 RT551 - RT568 1 RT571 - RT591

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 19 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group**  **Variable Number** 1 RT601 - RT657 1 RT671 - RT673 1 RT681 - RT682 1 RT691 - RT699 1 RT701 - RT704 1 RT711 - RT717 1 RT741 - RT757 1 RT776 - RT777 1 RT781 - RT784 1 RT801 - RT803 1 RT811 - RT814 1 RT831 - RT837 1 RT861 - RT864 1 RT876 - RT880 1 RT931 - RT932 1 RT945 - RT949 1 RT951 - RT955 1 RT966 - RT967 1 RU001 - RU006 1 RU016 - RU017 1 RU031 - RU032 1 RU051 - RU052 1 RU059 - RU062 1 RU081 - RU083 1 RU101 - RU102 1 RU121 - RU132 1 RU801 - RU809 1 RU831 - RU841 2. Spares Affected None. **B. Concurrent Requirements** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 20 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 747-53A2478 Revision 3: October 17, 2011 21 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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 747-53A2478 Revision 3: October 17, 2011 22 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 Zone**  **Model** 311, 312, 313, 314 747-100, 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 747-53A2478 Revision 3: October 17, 2011 23 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Group 2:** 

**Affected Maintenance Zones Zone**  **Model** 311, 312, 313, 314 747-400, 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 Time**  **Action Condition** 

- In accordance with Table 2.Do initial inspection and modify/repair as necessary in accordance with Table 2. (b) (c) All airplanes. (a)

Refer to Table 3 In accordance with Table 3. Do repeat inspections and modify/repair as necessary in accordance with Table 3. (c) Refer to Table 4 In accordance with Table 4.Do inspections and modify/repair in accordance with Table 4. (c) Airplanes with fuselage skinblended without external reinforcement 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 Revision2 of this service bulletin, initial inspections in accordance with Revision 3 of this service bulletin are necessary 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 747-53A2478 Revision 3: October 17, 2011 24 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled**  **coating. Compliance Time**  **Action Condition**  Whichever Occurs Later: Do a detailed inspection of thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary. Airplanes that have not started inspections in accordance with the original issue, Revision 1 orRevision 2 of this service bulletin. (c) Within 6,000 flighthours after the effective date of FAA AD 2009-14-02 or within2,000 flight hours after 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 thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary.Airplanes that have started inspections in accordance with the original issue, Revision 1 orRevision 2 of this service bulletin and, after the last work in accordance with this service bulletin, one of the followingconditions applied in the fuselage skin at the vertical stabilizer seal interface: - there were no blend repairs Within 2,000 flighthours after the Revision 3 date of this service bulletin, or within 3,000 flighthours after the previous inspection in accordance with theoriginal issue, Revision 1 or Revision 2,whichever occurs later. Within 7,500 flighthours after the previous inspection in accordance with theoriginal issue, Revision 1 or Revision 2of this service bulletin. (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 747-53A2478 Revision 3: October 17, 2011 25 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled**  **coating. Compliance Time**  **Action Condition**  Whichever Occurs First: Do a detailed inspection of thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary.Airplanes that have started inspections in accordance with the original issue, Revision 1 orRevision 2 of this service bulletin and, after the last work in accordance with this service bulletin, one of the followingconditions applied in the fuselage skin at the vertical stabilizer seal interface: - the maximum blend repair depth was more than 0.006 inches Within 2,000 flighthours after the Revision 3 date of this service bulletin. Within 7,500 flighthours after the previous inspection in accordance with theoriginal issue, Revision 1 or Revision 2of this service bulletin. (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 10-86Teflon filled coating in accordance with Paragraph 3.B., Work Instructions , PART 1. Wear damage is found that ismore than the rework limit allowed in the SRM. (f) OR Crack is found. (g) (h) AND Within 24 months after finding the condition. Install rub strips at all locationsin accordance with Boeing Service Bulletin 747-53-2721. (e) (h) Before further flight. Apply BMS 10-86 Teflon filled coating in accordance withParagraph 3.B., Work Instructions , 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 747-53A2478 Revision 3: October 17, 2011 26 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Table 2 - Initial inspection for wear damage and cracks, and application of BMS 10-86 Teflon filled**  **coating. Compliance Time**  **Action Condition**  Before further flight. Repair skin and apply BMS 10-86 Teflon filled coating in accordance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is repaired usingblend method and, after the repair, 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 locationsin accordance with Boeing Service 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 747-53A2478 Revision 3: October 17, 2011 27 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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) Action**  **Condition**

3,000 flight hours (h) (i) Within 3,000 flight hoursafter the previous inspection in accordance with this service bulletin. Do a detailed inspection of thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary.Airplanes for which, in the fuselage 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 hoursafter the previous inspection in accordance with this service bulletin. Do a detailed inspection of thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary.Airplanes for which, in the fuselage 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 hoursafter the previous inspection in accordance with this service bulletin. Do a detailed inspection of thefuselage skin at the vertical stabilizer seal interface for wear damage and cracks, and clean the skin, in accordance withParagraph 3.B., Work Instructions, PART 1. Where skin repair doubler is present, inspectthe surface of the repair doubler. Removal of the repair doubler is not necessary.Airplanes for which, in the fuselage 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 locationsin accordance with Boeing Service Bulletin 747-53-2721. (e) (i)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 28 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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) Action**  **Condition**

- 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 10-86Teflon filled coating, in accordance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is found that ismore than the rework limit allowed in the SRM. (f) OR Crack is found. (g) (i) AND

- Within 24 months after finding the condition. Install rub strips at all locationsin accordance with Boeing Service Bulletin 747-53-2721. (e) (i)

- Before further flight. Apply BMS 10-86 Teflon filled coating in accordance withParagraph 3.B., Work Instructions, 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 accordance with Paragraph 3.B., Work Instructions, PART 1. Wear damage is repaired usingblend method and, after the repair, 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 locationsin accordance with Boeing Service 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 747-53A2478 Revision 3: October 17, 2011 29 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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) Action**  **Condition**

(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)**  **Action Condition**  6,000 flight cycles. (d) Within 1,000flight cycles after the effective date of FAA AD 2009-14-02 Before 20,000total flight cycles, or within6,000 flight cycles after the initial blend,whichever occurs 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 ofthe repair doubler is not necessary. (a) (b) (c) (d) Fuselage skin blendedwithout external reinforcement.

- Before further flight. Repair crack and apply BMS 10-86 Teflon filled coating, in accordance with Paragraph 3.B., Work Instructions , PART 1. Crack is found.

(d)

- Before further flight. Apply BMS 10-86 Teflon filled coating, in accordance withParagraph 3.B., Work Instructions , PART 1. No crack is found.

(d)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 30 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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) Action**  **Condition** (a) If there is a knife edge condition at any fastener hole in the blended area (i.e. countersink depth greaterthan 2/3 of the existing skin thickness), repair in accordance with Paragraph 3.B., Accomplishment Instructions, 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 SRM53-39-01 or 747-400LCF SRM 53-00-01. After an SRM repair, if no rub strip was installed, continue inspections 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 747-53A2478 Revision 3: October 17, 2011 31 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**— 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 Hours Task Hours**  **Number of Per- sons**  **Task**

2.50 5.00 2 Open access 1.00 2.00 2 Visually inspect for wear 3.00 6.00 2 Apply BMS 10-86 Teflon filled coating 6.25 12.50 2 Replace seals (b) 0.75 1.50 2 Inspect for soften-ing/blistering of finish (b) 0.75 1.50 2 Clean skin 2.50 5.00 2 Close access 16.75 33.50 TOTAL 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 747-53A2478 Revision 3: October 17, 2011 32 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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:

**Title Drawing Number**  Skin Panel Assembly - STA 2181.10 to 2360, Str 4L to Str 4R 146U3910 Panel Instl - S-1 to S-11, STA 2360 - 2598 65B02706 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-Section Publication**  53-30-01, 53-30-03 747-100/-200/-300 Structural Repair Manual 53-00-01 747-400 Structural Repair Manual 53-31-00, 53-39-01 747 SP Structural Repair Manual 53-00-01 747-400F Structural Repair Manual 53-30-01, 53-30-03 747 E4B Structural Repair Manual 53-00-01 747LCF Structural Repair Manual

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3: October 17, 2011 33 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT Chapter-Section**  **Publication** 53-00-01 747SF 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 747-53A2478 Revision 3: October 17, 2011 34 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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:

**Notes Name**  **QTY Part Number /**  **Specification** (c) Primer 16 oz (a) (c) Teflon Filled Coating 16 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 747-53A2478 Revision 3: October 17, 2011 35 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 747-53A2478 Revision 3: October 17, 2011 36 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:**  KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets are given in 747 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 747-53A2478 Revision 3: October 17, 2011 37 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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 747-53A2478 Revision 3: October 17, 2011 38 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**(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 747-53A2478 Revision 3: October 17, 2011 39 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 747-53A2478 Revision 3: October 17, 2011 40 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**(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 747-53A2478 Revision 3: October 17, 2011 41 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT 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 747-53A2478 Revision 3: October 17, 2011 42 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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 747-53A2478 Revision 3: October 17, 2011 43 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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 747-53A2478 Revision 3: October 17, 2011 44 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**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 747-53A2478 Revision 3: October 17, 2011 45 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT FIGURE 1: LOGIC DIAGRAM**  **(SHEET 1 OF 1)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3 October 17, 2011 46 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT FIGURE 2: ACCESS / RESTORATION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3 October 17, 2011 47 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane.

**NOTES QTY**  **REFERENCE NAME**  **TASK STEP**  Access Panel Number 322CL (left side only) 1 AMM 55-30-10 Access Panel Remove / Keep 1

Access Panel Number 322BL (left side only) 1 AMM 55-30-10 Access Panel Remove / Keep 2

Access Panel Number 324AL (left side only) 1 AMM 55-30-10 Access Panel Remove / Keep 3

Seal Panel Number 322AL (left side) and 322AR (right side) 1 AMM 55-30-10 Forward Vertical Stabilizer Seal Panel Assembly Remove / Keep 4

Seal attaches directly to structure 1

- Aft Vertical Stabiliz- er Seal Remove / Keep 5

**NOTES QTY**  **REFERENCE NAME**  **TASK STEP**  Seal attaches directly to structure 1

- Aft Vertical Stabiliz- er Seal Install / Kept 6

Seal Panel Number 322AL (left side) and 322AR (right side) 1 AMM 55-30-10 Forward Vertical Stabilizer Seal Panel Assembly Install / Kept 7

Access Panel Number 324AL (left side only) 1 AMM 55-30-10 Access Panel Install / Kept 8

Access Panel Number 322BL (left side only) 1 AMM 55-30-10 Access Panel Install / Kept 9

Access Panel Number 322CL (left side only) 1 AMM 55-30-10 Access Panel Install / Kept 10

**FIGURE 2: ACCESS / RESTORATION (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3 October 17, 2011 48 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT FIGURE 3: FUSELAGE SKIN INSPECTION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3 October 17, 2011 49 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Detailed inspection. (a) - - Fuselage Skin Inspect 1 Surface HFEC, in blended areas of skin forward of STA 2360 only. (b) - - Fuselage Skin Inspect 2

(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 747-53A2478 Revision 3 October 17, 2011 50 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT FIGURE 4: FUSELAGE SKIN REWORK**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 07, 2002 747-53A2478 Revision 3 October 17, 2011 51 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane.

**More Data Qty**  **Identification Name**  **Task Step**  (a) (b) (c)

- - Primer Apply 1 (b) (c) (d)

- - BMS 10-86 Type I or Type II Teflon filled coating Apply 2

(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 747-53A2478 Revision 3 October 17, 2011 52 of 52 **BOEING SERVICE BULLETIN 747-53A2478 ALERT**  **ALERT**