### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-53A2876**  Original Issue: October 22, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Section 46 - Crown Skin Under Dorsal Fairing - Inspection, Repair, and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2014 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

Original Issue: October 22, 2014 747-53A2876 1 of 71 4.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 2 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 31 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 32 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 34 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 FIGURE 1: DETAILED INSPECTION FOR WEAR OR CRACKS WITH THE DORSAL FAIRING REMOVED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 FIGURE 2: APPLICATION OF TEFLON COATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 FIGURE 3: RUB STRIP MODIFICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 FIGURE 4: GAP MEASUREMENT AND DETAILED INSPECTION FOR WEAR OR CRACKS WITH THE DORSAL FAIRING INSTALLED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 FIGURE 5: EXTERNAL DOUBLER REPAIR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 FIGURE 6: SURFACE HFEC INSPECTION OF REPAIR DOUBLER. . . . . . . . . . . . . . . . . . 68 APPENDIX A: PART DEMAND INTENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 3 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 4 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **Number: 747-53A2876** Original Issue: October 22, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Section 46 - Crown Skin Under Dorsal Fairing - Inspection, Repair, and Modification
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Accomplishment of this service bulletin will detect skin damage from the dorsal fairing forward of the vertical stabilizer. The fuselage skin is subject to skin damage in the area of the dorsal fairing which can lead to cracking. Undetected cracking in Section 46 could reach sufficient length to cause in-flight depressurization of the airplane. During inspection for skin damage due to wear from the vertical stabilizer seals in accordance with Service Bulletin 747-53A2478, two operators found significant skin damage from the dorsal fairing just forward of the area inspected by Service Bulletin 747-53A2478 at Station (STA) 2280. The two airplanes with damage had 45,707 total flight hours and 71,702 total flight hours. Boeing has determined that the skin damage occurred from inadequate clearance between crown skin and the lower aft corners of the dorsal fairing. Affected airplanes are limited to line numbers that were delivered with or retrofitted with 174U9000 series dorsal fairing assemblies. Airplanes with other dorsal fairing configurations are not expected to develop skin wear. This service bulletin gives instructions for operators of affected airplanes to inspect the skin for wear under the dorsal fairing and repair any damage that may have already occurred. This service bulletin also gives instructions to measure the clearance between the crown skin and lower edge of the dorsal fairing, and trim or adjust the dorsal fairing to provide more clearance, as necessary. Accomplishment of these actions will ensure that skin wear from the dorsal fairing does not lead to cracking and possible depressurization of the airplane. Boeing Service Related Problem (SRP) 747-SRP-53-0442 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 53-13011 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 5 of 71**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No. Spares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval Yes. AD Related Paragraph 1.H., Weight and Balance Changes Yes. Weight and Balance Change Paragraph 1.I., Electrical Load Data No. Electrical Load Changed Paragraph 1.K., Publications Affected Yes. Publications Affected Paragraph 1.K., Publications Affected No. Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts Yes. Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator Yes. Operator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No. Special Tooling Required

**ACTION (PRR 85901-130RS)** Get access and remove the dorsal fairing. Do a detailed inspection of the skin under the dorsal fairing for wear or cracks. If no skin crack or wear is found, apply teflon coating to the skin under the dorsal fairing and repeat the detailed inspection for skin wear or cracks at the interval specified. As an option, install Corrosion Resistant Steel (CRES) rub strips under the dorsal fairing as a preventive modification. If any skin wear is found, do a blend repair or install a repair doubler depending on the depth of the skin wear. If any skin crack is found, install a repair doubler or contact Boeing for repair instructions and do the repair. If a blend repair is done, do initial and repetitive post-repair detailed and high frequency eddy current (HFEC) inspections for cracks in the blended area of the skin, and do detailed inspection for wear or cracks in the unrepaired areas of the skin under the dorsal fairing. If any crack or wear is found in a previously repaired area, contact Boeing for repair instructions and do the repair. If a repair doubler is installed, do initial and repetitive post-repair detailed and HFEC inspections for cracks in the repair doubler, and do detailed inspection for wear or cracks in the unrepaired areas of the skin under the dorsal fairing. If any crack is found in a previously repaired area, contact Boeing for repair instructions and do the repair. Upon re-installation of the fairing, make sure the clearance between the crown skin and the lower edge of the dorsal fairing meets the gap requirements specified in the applicable Aircraft Maintenance Manual (AMM). If necessary, trim the lower edge of the dorsal fairing or adjust the installation shims as specified in the AMM in order to meet the gap requirements. **EFFECTIVITY** 747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, and 747-400F airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 6 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 7 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 8 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-53A2876**  Original Issue: October 22, 2014 ATA System: 5331 **SUBJECT:** FUSELAGE - Skin - Section 46 - Crown Skin Under Dorsal Fairing - Inspection, Repair, and Modification
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is applicable to 747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, and 747-400F airplanes, line numbers 1017-1419, 27, 45, 75, 88, 135, 141, 163, 165, 470, 471, 437, 375, 465, 357, 374, 377, 378, 379, 412, 442, 594, 595, 642, 644, 651, 397, 474, 491, 271, 276, 336, 344, 369, 389, 539, 669, 712, 400, 878, 258, 261, 269, 308, 444, 680, 682, 968, 1002, 1008, 587, 600, 657, 735, 737, 763, 770, 783, 850, 854, 896, 938, 992, 1014, 743, 775, 792, 705, 728, 771, 788, 813, 834, 849, 873, 877, 887, 925, 930, 937, 949, 970, 993, 1007, 831, 852, 859, 860, 921, 923, 953, 955, 962, 981, 1010, 725, 732, 782, 888, 969, 769, 777, 833, 890, 945, 950, 1001, 827, 861, 926, 957 in 2(two) Group(s). The Variable Numbers and Group Information for the applicable airplanes is given below. An equivalent change is on subsequent production airplanes. Refer to PRR 85901-130RS for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** 747-400, 747-400D, and 747-400F airplanes, line numbers 1017-1419. These airplanes were delivered with a 174U9000 series dorsal fairing assembly. - 1

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 9 of 71**DESCRIPTION CONFIGURATION**  **GROUP** 747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, and 747-400F airplanes that have had a 174U9000 series dorsal fairing installed in accordance with one of the following Boeing Master Change service bulletins: 747-55-2037, 747-55-2038, 747-55-2040, 747-55-2041, 747-55-2044, 747-55-2047, 747-55-2049, or 747-55-2064. - 2

Airplane Models: 747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F **Group Variable Number**  2 RA351 2 RA353 2 RA358 2 RA369 - RA373 2 RD056 - RD057 2 RD241 - RD243 2 RD251 - RD262 2 RD381 - RD383 2 RD601 - RD607 1 RF001 - RF006 2 RJ321 - RJ322 1 RL401 - RL403 1 RL411 - RL436 1 RL451 - RL456 1 RL461 - RL462 1 RL471 - RL481 1 RL491 - RL492 1 RL501 - RL502 1 RL511 - RL516 1 RL521 - RL522 1 RL531 - RL534 1 RL551 1 RL561 - RL568 1 RL571 - RL572

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 10 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Group**  **Variable Number** 1 RL576 - RL577 1 RL579 1 RL581 - RL586 1 RL651 - RL655 1 RL671 - RL675 1 RL681 - RL684 1 RL751 - RL752 1 RM001 - RM007 1 RM010 - RM013 1 RM021 - RM024 1 RM026 - RM030 1 RM036 - RM045 1 RM051 - RM053 1 RM071 1 RM081 - RM084 1 RM091 1 RM096 - RM097 1 RM116 - RM117 1 RM126 - RM132 1 RM136 - RM147 1 RM156 - RM158 1 RM166 - RM177 1 RM191 - RM192 1 RM231 - RM233 1 RM241 - RM246 1 RM261 - RM264 1 RM316 - RM318 1 RM331 - RM333 1 RM341 1 RM351 - RM355 1 RM366 - RM367 1 RM401 - RM403 1 RM426

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 11 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Group**  **Variable Number** 1 RM431 1 RM441 - RM443 1 RM445 1 RM801 - RM803 1 RM811 - RM813 1 RM851 - RM859 1 RM861 - RM863 1 RM871 - RM899 1 RM901 - RM906 1 RM911 2 RR005 2 RR310 2 RR341 - RR345 2 RR431 - RR432 2 RR701 2 RR721 - RR722 1 RR723 - RR724 1 RR746 - RR748 1 RR851 - RR856 1 RR861 - RR862 1 RR951 - RR952 2 RS711 - RS713 2 RT001 - RT011 1 RT012 - RT014 2 RT031 - RT033 1 RT034 - RT035 1 RT135 - RT137 1 RT151 - RT152 1 RT165 - RT168 1 RT442 - RT447 2 RT451 - RT467 1 RT468 - RT469 1 RT497 - RT499

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 12 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Group**  **Variable Number** 2 RT508 2 RT510 - RT514 2 RT516 - RT519 2 RT522 1 RT524 - RT530 2 RT531 - RT535 1 RT583 - RT590 1 RT623 - RT630 1 RT636 - RT640 2 RT691 - RT697 1 RT698 - RT699 1 RT748 - RT750 1 RT756 - RT757 2 RT781 - RT782 1 RT801 - RT803 1 RT811 - RT814 1 RT831 - RT837 2 RT877 - RT878 1 RT879 - RT880 1 RT945 - RT949 1 RT955 1 RT966 - RT967 1 RU004 - RU006 1 RU016 - RU017 1 RU032 1 RU059 - RU060 1 RU062 1 RU081 - RU083 1 RU101 - RU102 1 RU121 - RU132 1 RU809 1 RU840 - RU841

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 13 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of this service bulletin will detect skin damage from the dorsal fairing forward of the vertical stabilizer. The fuselage skin is subject to wear damage in the area of the dorsal fairing which can lead to cracking. Undetected cracking in Section 46 could reach sufficient length to cause in-flight depressurization of the airplane. During inspection for skin damage due to wear from the vertical stabilizer seals in accordance with Service Bulletin 747-53A2478, two operators found significant skin damage from the dorsal fairing just forward of the area inspected by Service Bulletin 747-53A2478 at Station (STA) 2280. The two airplanes with damage had 45,707 total flight hours and 71,702 total flight hours. Boeing has determined that the skin damage occurred from inadequate clearance between crown skin and the lower aft corners of the dorsal fairing. Affected airplanes are limited to line numbers that were delivered with or retrofitted with 174U9000 series dorsal fairing assemblies. Airplanes with other dorsal fairing configurations are not expected to develop skin wear. This service bulletin gives instructions for operators of affected airplanes to inspect the skin for wear under the dorsal fairing and repair any damage that may have already occurred. This service bulletin also gives instructions to measure the clearance between the crown skin and lower edge of the dorsal fairing, and trim or adjust the dorsal fairing to provide more clearance, as necessary. Accomplishment of these actions will ensure that skin wear from the dorsal fairing does not lead to cracking and possible depressurization of the airplane. Boeing Service Related Problem (SRP) 747-SRP-53-0442 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 53-13011 is related to this service bulletin. **D. Description** Get access and remove the dorsal fairing. Do a detailed inspection of the skin under the dorsal fairing for wear or cracks. If no skin crack or wear is found, apply teflon coating to the skin under the dorsal fairing and repeat the detailed inspection for skin wear or cracks at the interval specified. As an option, install Corrosion Resistant Steel (CRES) rub strips under the dorsal fairing as a preventive modification. If any skin wear is found, do a blend repair or install a repair doubler depending on the depth of the skin wear. If any skin crack is found, install a repair doubler or contact Boeing for repair instructions and do the repair. If a blend repair is done, do initial and repetitive post-repair detailed and HFEC inspections for cracks in the blended area of the skin, and do detailed inspection for wear or cracks in the unrepaired areas of the skin under the dorsal fairing. If any crack or wear is found in a previously repaired area, contact Boeing for repair instructions and do the repair.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 14 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**If a repair doubler is installed, do initial and repetitive post-repair detailed and HFEC inspections for cracks in the repair doubler, and do detailed inspection for wear or cracks in the unrepaired areas of the skin under the dorsal fairing. If any crack is found in a previously repaired area, contact Boeing for repair instructions and do the repair. Upon re-installation of the fairing, make sure the clearance between the crown skin and the lower edge of the dorsal fairing meets the gap requirements specified in the applicable Aircraft Maintenance Manual (AMM). If necessary, trim the lower edge of the dorsal fairing or adjust the installation shims as specified in the AMM in order to meet the gap requirements. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 273, 274 747-400, 747-400D, 747-400F **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 273, 274 747-100, 747-200B, 747-200C, 747-200F, 747-300, 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. Do the required actions in accordance with Paragraph 3. Accomplishment Instructions. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. The Conditions, Actions and Compliance times shown apply on each side of the dorsal fairing independently.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 15 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 1: Initial Inspection, Repair, and Rub Strip Modification**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 6,000 flight hours afterthe Original Issue date of this service bulletin. Before 20,000 total flight hours.Do PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed. All Group 1 airplanes.

- Within 6,000 flight hours afterthe Original Issue date of this service bulletin. Within 20,000 flight hours aftera 174U9000 series dorsal fairing was installed in accordance with Boeing Master Change.Do PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed. All Group 2 airplanes.

(a)

- Before further flight. OPTION 1 (ACTION 1): Do PART 2: Application of Teflon Coating. CONDITION 1: NO SKIN CRACK OR WEAR FOUND.

- At the times given in compliance Table 2. OPTION 1 (ACTION 2): Do Repetitive Inspection, Repair, or Rub Strip Modification - Locations with No Skin Wear or Cracks.

- Before further flight. OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 3. OPTION 2 (ACTION 2):Do Post-Modification Inspection - Locations with a Rub Strip Installed, but Not Repaired (no blend, no doubler).

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 16 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 1: Initial Inspection, Repair, and Rub Strip Modification**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Before further flight. OPTION 1 (ACTION 1):Do PART 4: Blend Repair. CONDITION 2: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS THAN OREQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH. - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 4. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip. (b)

- Before further flight. OPTION 2 (ACTION 1):Do PART 4: Blend Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 5. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 17 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 1: Initial Inspection, Repair, and Rub Strip Modification**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Before further flight. OPTION 1 (ACTION 1):Do PART 5: Doubler Repair. CONDITION 3: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THANTHE MAXIMUM ALLOWABLE REWORK DEPTH. - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 6. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip. (b)

- Before further flight. OPTION 2 (ACTION 1):Do PART 5: Doubler Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 7. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 4: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260. (a) One of the following Master Change service bulletins for dorsal fairing replacement is applicable to each of the airplanes in Group 2: Service Bulletin 747-55-2037, 747-55-2038, 747-55-2040, 747-55-2041, 747- 55-2044, 747-55-2047, 747-55-2049, or 747-55-2064. (b) The maximum allowable rework depth is 0.015 inch if the damage is less than 10 inches in length and all of the damage is within an area that is less than 20 inches x 20 inches square. Otherwise, the maximum allowable rework depth is 0.012 inch. Refer to 747-100/200/300 SRM 53-30-01 or 747-400 SRM 53-00- 01 or 747-400F SRM 53-00-01 or 747-400SF SRM 53-00-01, as applicable.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 18 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 2: Repetitive Inspection, Repair, or Rub Strip Modification - Locations with No Skin Wear or Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 6,000 flight hours after the initial inspection.Do PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. No crack or wear found during initial inspection in accordance with PART 1.

6,000 flight hours.

- Repeat PART 6: GapMeasurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. CONDITION 5: GAP IS 0.10 INCH OR MORE, AND NO SKIN CRACK OR WEAR FOUND.

- Before further flight. ACTION 1: Do PART 7: Dorsal Fairing Trim or Adjustment. CONDITION 6: GAP IS LESS THAN 0.10 INCH, AND NO SKIN CRACK OR WEAR FOUND. 6,000 flight hours.

- ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed.

- Before further flight. Do PART 1: Detailed In- spection for Wear or Cracks with the Dorsal Fairing Removed. CONDITION 7: SKIN CRACK FOUND OR WEAR FOUND DURING PART 6 INSPECTION. (a)

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 19 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 2: Repetitive Inspection, Repair, or Rub Strip Modification - Locations with No Skin Wear or Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. OPTION 1 (ACTION 1):Do PART 4: Blend Repair. CONDITION 8: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS THAN OREQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH. - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 4. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip. (b)

- Before further flight. OPTION 2 (ACTION 1):Do PART 4: Blend Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 5. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 20 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 2: Repetitive Inspection, Repair, or Rub Strip Modification - Locations with No Skin Wear or Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight. OPTION 1 (ACTION 1):Do PART 5: Doubler Repair. CONDITION 9: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THANTHE MAXIMUM ALLOWABLE REWORK DEPTH. - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 6. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip. (b)

- Before further flight. OPTION 2 (ACTION 1):Do PART 5: Doubler Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 7. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 10: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260. (a) Do this inspection to find the extent and severity of the damage. (b) The maximum allowable rework depth is 0.015 inch if the damage is less than 10 inches in length and all of the damage is within an area that is less than 20 inches x 20 inches square. Otherwise, the maximum allowable rework depth is 0.012 inch. Refer to 747-100/200/300 SRM 53-30-01 or 747-400 SRM 53-00- 01 or 747-400F SRM 53-00-01 or 747-400SF SRM 53-00-01, as applicable.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 21 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 3: Post-Modification Inspection - Locations with Rub Strip Installed, but Not Repaired (No Blend,**  **No Doubler) Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Within 36,000 flight hours after the rub strip was installed. Within 10,000flight cycles after the rub strip was installed.Do PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. No wear or cracks found during initial inspection in accordance with PART 1,and a rub strip was installed in accordance with PART 3. 10,000 flight cycles or 36,000 flight hours, whichever is later. - Repeat PART 6: GapMeasurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. CONDITION 11: GAP IS 0.10 INCH OR MORE, AND NO CRACK OR WEAR FOUND.

- Before further flight. ACTION 1: Do PART 7: Dorsal Fairing Trim or Adjustment. CONDITION 12: GAP IS LESS THAN 0.10 INCH, AND NO CRACK OR WEAR FOUND. 10,000 flight cycles or 36,000 flight hours, whichever is later. - ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed.

- Before further flight. Do PART 1: Detailed In- spection for Wear or Cracks with the Dorsal Fairing Removed. CONDITION 13: ANY CRACK, SKIN WEAR, OR RUB STRIP WEAR FOUND DURING PART 6 INSPECTION. (a) 10,000 flight cycles or 36,000 flight hours, whichever is later. - Repeat PART 6: GapMeasurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. CONDITION 14: NO CRACK OR SKIN WEAR FOUND DURING PART 1 INSPECTION, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH.

- Before further flight. ACTION 1: Replace the rub strip in accordance with PART 3: Rub Strip Modification. CONDITION 15: NO CRACK OR SKIN WEAR FOUND DURING PART 1 INSPECTION, AND RUB STRIP WEAR IS 0.008 INCH OR MORE. 10,000 flight cycles or 36,000 flight hours, whichever is later. - ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 22 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 3: Post-Modification Inspection - Locations with Rub Strip Installed, but Not Repaired (No Blend,**  **No Doubler) Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Before further flight. OPTION 1 (ACTION 1):Do PART 4: Blend Repair. CONDITION 16: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS THAN OREQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 4. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip.

- Before further flight. OPTION 2 (ACTION 1):Do PART 4: Blend Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 5. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 23 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 3: Post-Modification Inspection - Locations with Rub Strip Installed, but Not Repaired (No Blend,**  **No Doubler) Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Before further flight. OPTION 1 (ACTION 1):Do PART 5: Doubler Repair. CONDITION 17: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THANTHE MAXIMUM ALLOWABLE REWORK DEPTH - Before further flight. OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating.

- At the times given in compliance Table 6. OPTION 1 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip.

- Before further flight. OPTION 2 (ACTION 1):Do PART 5: Doubler Repair.

- Before further flight. OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 7. OPTION 2 (ACTION 3):Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 18: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260. (a) Do this inspection to find the extent and severity of the damage. (b) The maximum allowable rework depth is 0.015 inch if the damage is less than 10 inches in length and all of the damage is within an area that is less than 20 inches x 20 inches square. Otherwise, the maximum allowable rework depth is 0.012 inch. Refer to 747-100/200/300 SRM 53-30-01 or 747-400 SRM 53-00- 01 or 747-400F SRM 53-00-01 or 747-400SF SRM 53-00-01, as applicable.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 24 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 4: Post-Repair Inspection - Locations with a Blend Repair, No Rub Strip Installed**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 6,000 flight hours after the blend repair was done. Before 20,000total flight cycles, or within6,000 flight cycles after the blend repair was done, whichever is later. Do PART 8: Detailed andHFEC or LFEC Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas. A blend repair was done between STA 2260 and STA 2280 in accordance with PART 4, and no rub strip is installed.

Before further flight. OPTION 1 (ACTION 1): Do PART 2: Application of Teflon Coating. CONDITION 19: NO SKIN CRACK OR WEAR FOUND. 6,000 flight hours. Within 6,000 flight hours after ini- tial PART 8 inspection. OPTION 1 (ACTION 2):Do Initial and Repeat Inspections in accordancewith PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. 6,000 flight cycles.

- OPTION 1 (ACTION 3): Repeat PART 8: Detailedand HFEC or LFEC Inspection of the BlendedArea and Detailed Inspection of Unrepaired Areas.

- Before further flight. OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 5. OPTION 2 (ACTION 2):Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed.

- Before further flight. Do PART 7: Dorsal Fair- ing Trim or Adjustment. CONDITION 20: GAP IS LESS THAN 0.10 INCH, AND NO SKIN CRACK OR WEAR FOUND.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 21: ANY SKIN CRACK OR WEAR FOUND.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 25 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 5: Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 6,000 flight hours after the blend repair was done. Before 20,000total flight cycles, or within6,000 flight cycles after the blend repair was done, whichever is later. Do PART 8: Detailed andHFEC or LFEC Inspection of the Blended Area, and Detailed Inspection of Unrepaired Areas. A blend repair was done between STA 2260 and STA 2280 in accordance with PART 4, and a rubstrip was installed in accordance with PART 3.

6,000 flight cycles.

- Repeat PART 8: Detailedand HFEC or LFEC Inspection of the BlendedArea and Detailed Inspection of Unrepaired Areas. CONDITION 22: NO SKIN CRACK OR WEAR FOUND, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH.

- Before further flight. ACTION 1: Replace the Rub Strip in accordance with PART 3: Rub Strip Modification. CONDITION 23: NO SKIN CRACK OR WEAR FOUND, AND RUB STRIP WEAR IS 0.008 INCH OR MORE. 6,000 flight cycles.

- ACTION 2: Repeat PART 8: Detailed and HFEC or LFEC Inspection of theBlended Area and Detailed Inspection of Unrepaired Areas.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 24: ANY SKIN CRACK OR WEAR FOUND. **Table 6: Post-Repair Inspection - Locations with a Doubler Repair but No Rub Strip Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Within 20,000 flight hours after the repair was done. Within 10,000flight cycles after the doubler repair was done. Do PART 9: Detailed andHFEC or LFEC Inspection of the Doubler Repair, and Detailed Inspection of Unrepaired Areas. A doubler repair was done between STA 2260 and STA 2280 in accordance PART 5.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 26 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 6: Post-Repair Inspection - Locations with a Doubler Repair but No Rub Strip** **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Before further flight. OPTION 1 (ACTION 1): Do PART 2: Application of Teflon Coating. CONDITION 25: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER. 6,000 flight cycles (HFEC) or 1,500 flight cycles (LFEC). - OPTION 1 (ACTION 2): Repeat PART 9: Detailedand HFEC or LFEC Inspection of the DoublerRepair, and Detailed Inspection of Unrepaired Areas.

- Before further flight. OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification.

- At the times given in compliance Table 7. OPTION 2 (ACTION 2):Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 26: ANY CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER. **Table 7: Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever**  **Occurs Later) Action**  **Condition**

- Within 20,000 flight hours after the repair was done. Within 10,000flight cycles after the doubler repair was done. Do PART 9: Detailed andHFEC or LFEC Inspection of the Doubler Repair, and Detailed Inspection of Unrepaired Areas. A doubler repair was done between STA 2260 and STA 2280 in accordance with PART 5, and rub strip was installed in accordance with PART 3.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 27 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Table 7: Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Before further flight. ACTION 1: Re-install ex- isting rub strip or installan new rub strip in accordance with PART 3: Rub Strip Modification. CONDITION 27: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH. 6,000 flight cycles (HFEC) or 1,500 flight cycles (LFEC). - ACTION 2: Repeat PART 9: Detailed and HFEC or LFEC Inspection of theDoubler Repair, and Detailed Inspection of Unrepaired Areas.

- Before further flight. ACTION 1: Install a new Rub Strip in accordance with PART 3: Rub Strip Modification. CONDITION 28: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER, AND RUB STRIP WEAR IS 0.008 INCH OR MORE. 6,000 flight cycles (HFEC) or 1,500 flight cycles (LFEC). - ACTION 2: Repeat PART 9: Detailed and HFEC or LFEC Inspection of theDoubler Repair, and Detailed Inspection of Unrepaired Areas.

- Before further flight. Contact Boeing for repair instructions and do the repair. CONDITION 29: ANY CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER. **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. **G. Manpower** The table below shows an estimate of the task hours necessary to do this service bulletin 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:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 28 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**• Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Initial Inspection, Application of Teflon Coating, and Optional Rub Strip Modification Elapsed Hours**  **Task Hours Number of Persons**  **Task** 2.15 2.15 1 Access and Dorsal Fairing Removal 1.50 1.50 1 FIGURE 1 - Detailed Inspection for Wear or Cracks 4.00 4.00 1 FIGURE 2 - Applica- tion of Teflon Coating 4.00 8.00 2 FIGURE 3 - Rub Strip Modification (a) 1.40 1.40 1 Install Dorsal Fairing and Close Access 9.05 9.05 TOTAL FOR EACH AIRPLANE (b) (b) (a) Optional to Application of Teflon Coating. Not included in total. (b) More time will be needed if repairs are necessary. **Repetitive Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 0.25 0.25 1 Access 1.00 1.00 1 FIGURE 4 - Gap Measurement and Detailed Inspection for Wear or Crackswith the Dorsal Fairing Installed (a) 0.25 0.25 1 Close Access 1.50 1.50 TOTAL FOR EACH AIRPLANE (b) (b) (a) Different inspections will be required in previously repaired areas. (b) More time will be needed if repairs are necessary.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 29 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT External Doubler Repair**  **Elapsed Hours Task Hours**  **Number of Persons Task**  8.00 16.00 2 FIGURE 5 - External Doubler Repair 8.00 16.00 TOTAL FOR EACH REPAIR **Post-Repair Inspection - External Doubler Repair Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.15 1.15 1 Access and Dorsal Fairing Removal 1.50 1.50 1 FIGURE 6 - SurfaceHFEC or LFEC Inspection of Repair Doubler 1.40 1.40 1 Close Access and Install Dorsal Fairing 4.05 4.05 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes Change in Moment (Pound**  **Inches) Change in Weight (Pounds)**  **Airplane** +2220.0 +1.0 All Groups (a) This change is only applicable if rub strips are installed in accordance with this service bulletin. If other parts are installed, such as a repair doubler, weight and moment changes should be determined by the operator based on the size and configuration of the repair parts that are installed.
**I. Electrical Load Data** Not applicable. **J. References** 1. Existing Data: a. Engineering Change Memo PRR 85901-130RS b. Boeing Service Bulletin 747-53-2721, 747-53A2478 c. Boeing Service Letter 747-SL-51-048 d. Boeing Service Related Problem (SRP) 747-SRP-53-0442 e. Service Bulletin Index D6-30300

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 30 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**f. Standard Overhaul Practices Manual (SOPM) 20-30-02, 20-41-02, 20-43-03, 20-44-01, 20-44-04, 20-50-01, 20-50-19 g. 747 Fleet Team Digest (FTD) 53-13011 h. 747 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Part 6, 51-00-11 i. 747-100/200/300 Aircraft Maintenance Manual (AMM) 51-21, 55-30-03 j. 747-100/200/300 Structural Repair Manual (SRM) 51-30-08, 53-30-01 k. 747-400 Aircraft Maintenance Manual (AMM) 51-21, 51-24-04, 55-30-03 l. 747-400 Structural Repair Manual (SRM) 51-40-08, 53-00-01 m. 747-400F Structural Repair Manual (SRM) 51-40-08, 53-00-01 n. 747-400SF Structural Repair Manual (SRM) 51-40-08, 53-00-01 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  KIT - RUB STRIP INSTL, VERTICAL FIN TO FUSELAGE, SECT 46 675U0008

INSTL - DORSAL FIN 174U9000 The table above lists applicable drawings used to prepare this service bulletin. The drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. The drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  55-30 747 Aircraft Maintenance Manual 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 31 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT L. Interchangeability and Intermixability of Parts**  Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 32 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane . Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The parts are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION** 
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **QTY Date**  **Name Kit Number** 

$2,842.00 139 50 Sept 26, 2014 Kit - Rub Strip Instl, Vertical Fin to Fuselage Sect 46 675U0008-3 45 Nov 7, 2014
Operators are encouraged to complete the survey provided in APPENDIX A of this service bulletin to help Boeing predict the quantity and timing of the Boeing Supplied Kits/Parts. **B. Industry Support Information** Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **NOTE:** One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 33 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT ALL** 
**Kit 675U0008 Notes**  **Existing Part Number**  **Name Qty**  **New Part Number -3**  (a) KIT - RUB STRIP INSTL, VERTICALFIN TO FUSELAGE SECT 46 - 675U0008-3

(b) RUB STRIP 1 675U0008-1 (b) RUB STRIP 1 675U0008-2 (c) BOLT, PROTRUD- ING HD 8 BACB30NX6K2 (c) BOLT, PROTRUD- ING HD 2 BACB30NX6K3Y (c) BOLT, PROTRUD- ING HD 2 BACB30NX6K4Y

- COLLAR 4 BACC30AC6

- COLLAR 8 BACC30BH6 (a) This kit is only required if the operator chooses to install optional rub strips in the dorsal fairing wear areas. (b) This part is not used in production. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. 2. Parts and Materials Supplied by the Operator The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available.
**Notes Name**  **QTY Part Number /**  **Specification** (a) Primer 4 ounces BMS 10-11, Type 1 (a) (b) Primer 4 ounces BMS 10-79, Type 3 (b) (c) Chemical Conversion Coating 2 ounces Alodine: Type 2, Class A

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 34 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Notes**  **Name QTY**  **Part Number / Specification**  (d) Repair Washers as re- quired 66-2955-( ) (a) (b) Sealant 4 ounces BMS 5-95 (f) Stock (Repair Doubler) as re- quired 2024-T3 Clad Sheet (0.071) (g) Stock (Repair Filler) as re- quired 2024-T3 Clad Sheet (0.063) (e) (j) BOLT, PROTRUDING HD 8 BACB30NX6K3 (h) (e) Rivet as re- quired BACR15BB6D( ) (h) (e) Rivet as re- quired BACR15CE6D( ) (i) Shim 2 BACS40R014B016F (i) Shim 2 BACS40R014C016F (i) Shim 4 BACS40R016C019F (i) Shim 2 BACS40R016D016F (i) Shim 2 BACS40R014E016F (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Required only for FIGURE 3 - Rub Strip Modification or FIGURE 5 - External Doubler Repair. (c) Refer to SOPM 20-43-03 or 747 SRM Chapter 51 for material alternatives. (d) No specific part number required. Make repair washers as required for FIGURE 3 - Rub Strip Modification or FIGURE 5 - External Doubler Repair. Refer to 747-100/200/300 SRM 51-30-08, or 747-400 SRM 51-40-08, or 747-400F SRM 51-40-08, or 747-400SF SRM 51-40-08 for accepted procedures. (e) Refer to 747 Structural Repair Manual Chapter 51 for alternate fasteners. (f) 0.071 inch thick stock required only if FIGURE 5 - External Doubler Repair is necessary. (g) 0.063 inch thick stock required only if a filler is necessary during FIGURE 5 - External Doubler Repair. (h) If necessary for FIGURE 5 - External Doubler Repair. (i) These shims could be required during dorsal fairing installation to adjust the fairing to skin gap. The fairing can also be trimmed to adjust the gap. As an option, equivalent shims can be made by the operator. (j) Required only if rub strip is installed over a repair doubler.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 35 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 36 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque Values: — Values for structural fasteners are given in 747 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 747 Airplane Maintenance Manual (AMM). — Values for engine maintenance tasks are included in Chapter 70 of 747 Airplane Maintenance Manual (AMM). — Non-standard torque values for maintenance tasks are included in the applicable installation step.
4. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate full threaded fasteners (screws) needed for installation in this service bulletin. 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 37 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**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. 9. 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. 10. 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. 11. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 12. If shading is used, shaded areas in Figures are to separate the non-critical and non-authoritative information from the critical and authoritative information. 13. Use of colors in Figures is based on guidance from the ATA e-Business Program (ATA) iSpec 2200. 14. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. 15. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. 16. The initial inspection should be done on both the left side and right side of the airplane. However, depending on inspection findings and subsequent repairs, follow-on inspections and compliance times could be different on each side of the airplane. Therefore, the CONDITIONS, ACTIONS and OPTIONS shown can apply to the skin (including any repair doublers) on each side of the dorsal fairing independently. The term "location" as used in the Work Instructions below means the skin (including any repair doubler) on the left side or the right side of the dorsal fairing. 17. Some steps in the Work Instructions are identified as Required for Compliance (RC). If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps identified as RC must be done to comply with the AD. Alternative procedures for steps not identified with RC can be used if the RC steps can still be done as specified, and the airplane can be put back in a serviceable condition. An Alternative Method of Compliance (AMOC) is not necessary for deviations to steps that are not identified as RC.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 38 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**18. The maximum allowable rework depth given in the SRM is 0.015 inch if the damage is less than 10 inches in length and all of the damage is within an area that is less than 20 inches x 20 inches square. Otherwise, the maximum allowable rework depth is 0.012 inch. Refer to 747-100/200/300 SRM 53-30-01 or 747-400 SRM 53-00-01 or 747-400F SRM 53-00-01 or 747-400SF SRM 53-00-01, as applicable. **B. WORK INSTRUCTIONS Initial Inspection, Repair, and Rub Strip Modification (see Compliance Table 1)**  1. Get access to dorsal fairing forward of Station (STA) 2280, and remove the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. 2. Do PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed. **CONDITION 1: NO SKIN CRACK OR WEAR FOUND** a. Do one of the following: (1) OPTION 1: (a) OPTION 1 (ACTION 1): Do PART 2: Application of Teflon Coating. (b) OPTION 1 (ACTION 2): Do Repetitive Inspection, Repair, or Rub Strip Modification - Locations with No Skin Wear or Cracks. (2) OPTION 2: (a) OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification. (b) OPTION 2 (ACTION 2): Do Post-Modification Inspection - Locations with Rub Strip Installed, but Not Repaired. **CONDITION 2: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS THAN OR EQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH**  a. Do one of the following: (1) OPTION 1: (a) OPTION 1 (ACTION 1): Do PART 4: Blend Repair. (b) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. (c) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip. (2) OPTION 2: (a) OPTION 2 (ACTION 1): Do PART 4: Blend Repair. (b) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 39 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**(c) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed. **CONDITION 3: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THAN THE MAXIMUM ALLOWABLE REWORK DEPTH**  a. Do one of the following: (1) OPTION 1: (a) OPTION 1 (ACTION 1): Do PART 5: Doubler Repair. (b) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. (c) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip. (2) OPTION 2: (a) OPTION 2 (ACTION 1): Do PART 5: Doubler Repair. (b) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification. (c) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed. **CONDITION 4: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260** a. Contact Boeing for repair instructions and do the repair. 3. Put the airplane back to a serviceable condition. **Repetitive Inspection, Repair, and Rub Strip Modification - Locations with No Skin Wear or Cracks (see Compliance Table 2)**  1. Do PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 5: GAP IS 0.10 INCH OR MORE, AND NO SKIN CRACK OR WEAR FOUND** a. Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 6: GAP IS LESS THAN 0.10 INCH, AND NO SKIN CRACK OR WEAR FOUND** a. ACTION 1: Do PART 7: Dorsal Fairing Trim or Adjustment. b. ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 7: SKIN CRACK FOUND, OR WEAR FOUND DURING PART 6 INSPECTION** a. Do PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 40 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT CONDITION 8: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS**  **THAN OR EQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH** (1) Do one of the following: (a) OPTION 1: 1) OPTION 1 (ACTION 1): Do PART 4: Blend Repair. 2) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. 3) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip. (b) OPTION 2: 1) OPTION 2 (ACTION 1): Do PART 4: Blend Repair. 2) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification. 3) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed. **CONDITION 9: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THAN THE MAXIMUM ALLOWABLE REWORK DEPTH**  (1) Do one of the following: (a) OPTION 1: 1) OPTION 1 (ACTION 1): Do PART 5: Doubler Repair. 2) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. 3) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip. (b) OPTION 2: 1) OPTION 2 (ACTION 1): Do PART 5: Doubler Repair. 2) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification. 3) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed. **CONDITION 10: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260** (1) Contact Boeing for repair instructions and do the repair. 2. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 41 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Post-Modification Inspection - Locations with Rub Strip Installed, but No Skin Repair (No Skin**  **Blend, No Skin Doubler. See Compliance Table 3)** 1. Do PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 11: GAP IS 0.10 INCH OR MORE, AND NO CRACK OR WEAR FOUND** a. Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 12: GAP IS LESS THAN 0.10 INCH, AND NO CRACK OR WEAR FOUND** a. ACTION 1: Do PART 7: Dorsal Fairing Trim or Adjustment. b. ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 13: CRACK, SKIN WEAR, OR RUB STRIP WEAR FOUND DURING PART 6 INSPECTION**  a. Do PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed. **CONDITION 14: NO CRACK OR SKIN WEAR FOUND DURING PART 1 INSPECTION, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH.**  (1) Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 15: NO CRACK OR SKIN WEAR FOUND DURING PART 1 INSPECTION, AND RUB STRIP WEAR IS 0.008 INCH OR MORE.**  (1) ACTION 1: Remove the existing rub strip and install a new rub strip in accordance with PART 3: Rub Strip Modification. (2) ACTION 2: Repeat PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 16: SKIN WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS LESS THAN OR EQUAL TO THE MAXIMUM ALLOWABLE REWORK DEPTH**  (1) Do one of the following: (a) OPTION 1: 1) OPTION 1 (ACTION 1): Do PART 4: Blend Repair. 2) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. 3) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip. (b) OPTION 2:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 42 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**1) OPTION 2 (ACTION 1): Do PART 4: Blend Repair. 2) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification. 3) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed. **NOTE:** Rub strip would need to be removed to inspect the skin. **CONDITION 17: SKIN CRACK FOUND, OR WEAR FOUND BETWEEN STA 2260 AND STA 2280 THAT IS MORE THAN THE MAXIMUM ALLOWABLE REWORK DEPTH**  (1) Do one of the following: (a) OPTION 1: 1) OPTION 1 (ACTION 1): Do PART 5: Doubler Repair. 2) OPTION 1 (ACTION 2): Do PART 2: Application of Teflon Coating. 3) OPTION 1 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip. (b) OPTION 2: 1) OPTION 2 (ACTION 1): Do PART 5: Doubler Repair. 2) OPTION 2 (ACTION 2): Do PART 3: Rub Strip Modification. 3) OPTION 2 (ACTION 3): Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed. **CONDITION 18: ANY CRACK OR WEAR FOUND FORWARD OF STA 2260** (1) Contact Boeing for repair instructions and do the repair. **Post-Repair Inspection - Locations with a Blend Repair, but No Rub Strip (see Compliance Table 4)**  1. Do PART 8: Detailed and Internal Surface High Frequency Eddy Current (HFEC) or External Surface Low Frequency Eddy Current (LFEC) Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas. **CONDITION 19: NO SKIN CRACK OR WEAR FOUND** a. Do one of the following: (1) OPTION 1: (a) OPTION 1 (ACTION 1): Re-apply teflon coating in accordance with PART 2: Application of Teflon Coating.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 43 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**(b) OPTION 1 (ACTION 2): Do initial and repeat inspections in accordance with PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed. **CONDITION 20: GAP LESS THAN 0.10 INCH, AND NO SKIN CRACK OR WEAR FOUND**  1) Do PART 7: Dorsal Fairing Trim or Adjustment. (c) OPTION 1 (ACTION 3): Repeat PART 8: Detailed and HFEC or LFEC Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas. (2) OPTION 2: (a) OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification. (b) OPTION 2 (ACTION 2): Do Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed. **CONDITION 21: ANY SKIN CRACK OR WEAR FOUND** a. Contact Boeing for repair instructions and do the repair. 2. Put the airplane back to a serviceable condition. **Post-Repair Inspection - Locations with a Blend Repair and a Rub Strip Installed (see Compliance Table 5)**  1. Do PART 8: Detailed and HFEC or LFEC Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas, after removal of rub strip. **CONDITION 22: NO SKIN CRACK OR WEAR FOUND, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH.**  a. Repeat PART 8: Detailed and HFEC or LFEC Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas, after removal of rub strip. **CONDITION 23: NO SKIN CRACK OR WEAR FOUND, AND RUB STRIP WEAR IS 0.008 INCH OR MORE.**  a. ACTION 1: Remove the existing rub strip and install a new rub strip in accordance with PART 3: Rub Strip Modification. b. ACTION 2: Repeat PART 8: Detailed and HFEC or LFEC Inspection of the Blended Area and Detailed Inspection of Unrepaired Areas, while rub strip is removed. **CONDITION 24: ANY SKIN CRACK OR WEAR FOUND** a. Contact Boeing for repair instructions and do the repair. 2. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 44 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT Post-Repair Inspection - Locations with a Doubler Repair, but No Rub Strip (see Compliance**  **Table 6)** 1. Do PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas **CONDITION 25: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER** a. Do one of the following: (1) OPTION 1: (a) OPTION 1 (ACTION 1): Re-apply teflon coating in accordance with PART 2: Application of Teflon Coating. (b) OPTION 1 (ACTION 2): Repeat PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas (2) OPTION 2: (a) OPTION 2 (ACTION 1): Do PART 3: Rub Strip Modification. (b) OPTION 2 (ACTION 2): Do Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed. **CONDITION 26: ANY CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER** a. Contact Boeing for repair instructions and do the repair. 2. Put the airplane back to a serviceable condition. **Post-Repair Inspection - Locations with a Doubler Repair and a Rub Strip Installed (see Compliance Table 7)**  1. Do PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas **CONDITION 27: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER, AND RUB STRIP WEAR IS LESS THAN 0.008 INCH.**  a. ACTION 1: Re-install the existing rub strip or install a new rub strip in accordance with PART 3: Rub Strip Modification. b. ACTION 2: Repeat PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas **CONDITION 28: NO CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER, AND RUB STRIP WEAR IS 0.008 INCH OR MORE.**  a. ACTION 1: Install a new rub strip in accordance with PART 3: Rub Strip Modification. b. ACTION 2: Repeat PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 45 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT CONDITION 29: ANY CRACK OR WEAR FOUND IN THE SKIN OR DOUBLER**  a. Contact Boeing for repair instructions and do the repair. 2. Put the airplane back to a serviceable condition. **PART 1: Detailed Inspection for Wear or Cracks with the Dorsal Fairing Removed** 1. Before removing the dorsal fairing, trace a line on the skin around the entire lower edge of the dorsal fairing. This will help to identify where to inspect, and where to apply teflon coating (if used) after the dorsal fairing is removed. do not use any object that could damage the skin. 2. Remove the dorsal fairing from the airplane. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. 3. RC - Do a detailed inspection for wear or cracks in the skin in accordance with FIGURE 1. **NOTE:**This detailed inspection of the skin includes detailed inspection of any existing doubler or rub strip that has been installed over the skin within the inspection area. 4. After the necessary actions have been completed, do the following: a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures. **PART 2: Application of Teflon Coating** 1. RC - Apply teflon coating to the skin in accordance with FIGURE 2. **NOTE:**Application of teflon coating to the skin should include application of teflon coating to any existing doubler in the application area. 2. After the necessary actions have been completed, do the following: a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 46 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT PART 3: Rub Strip Modification**  1. RC - Install rub strips in accordance with FIGURE 3. 2. After the necessary actions have been completed, do the following: a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures. **PART 4: Blend Repair** 1. RC - Do a blend repair in accordance with 747-100/200/300 SRM 53-30-01 or 747-400 SRM 53-00-01 or 747-400F SRM 53-00-01 or 747-400SF SRM 53-00-01, as applicable. **PART 5: Doubler Repair** 1. RC - Install an external repair doubler in accordance with FIGURE 5. **PART 6: Gap Measurement and Detailed Inspection for Wear or Cracks with the Dorsal Fairing Installed**  1. RC - Measure the gap between the edge of the dorsal fairing and the skin, and do a detailed inspection for wear or cracks in the skin and rub strip, if installed, in accordance with FIGURE 4. 2. After the necessary actions have been completed, do the following: a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures. **PART 7: Dorsal Fairing Trim and/or Shim Adjustment** 1. RC - Trim the dorsal fairing and/or adjust the thickness of the installation shims to obtain a gap of 0.10-0.17 inch. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 47 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT NOTE:** Trimming of the dorsal fairing is likely to be required after the initial gap measurement, or when a new dorsal fairing is installed. However, adjustment of the installation shims to change the gap is optional as long as bulb seal compression is maintained. If the fairing will be trimmed, do the following steps. 2. If no more work is required, install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. **PART 8: Detailed and HFEC or LFEC Inspection of The Blended Area and Detailed Inspection of Unrepaired Areas**  1. Remove the dorsal fairing from the airplane. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. 2. RC - Do an Eddy Current inspection for cracks (remove rub strip if installed) in the skin in any area where a blend repair was previously done. Do the Internal Surface HFEC inspection in accordance with 747 NDT Manual Part 6, 51-00-11, procedure 4 or 23. Do the External Surface LFEC inspection in accordance with 747 NDT Manual 6, 53-30-00, procedure 5. Do the inspection in both the vertical and horizontal directions. 3. RC - Do a detailed inspection for wear or cracks in the skin in accordance with FIGURE 1. 4. After the necessary actions have been completed, do the following: a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures. **PART 9: Detailed and HFEC or LFEC Inspection of Doubler Repair, and Detailed Inspection of Unrepaired Areas**  1. Remove the dorsal fairing from the airplane. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. 2. Remove any existing teflon coating from the HFEC inspection area. 3. If an existing rub strip is installed over the doubler repair, remove the rub strip. 4. RC - Do a detailed inspection for wear on the rub strip. 5. RC - Do Internal Surface HFEC or External Surface LFEC inspections for cracks in the external doubler in accordance with FIGURE 6. 6. RC - Do a detailed inspection for wear or cracks in the skin in accordance with FIGURE 1. 7. After the necessary actions have been completed, do the following:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 48 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**a. Install the dorsal fairing. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 as an accepted procedure. b. RC - Make sure the gap between the edge of the dorsal fairing and the skin is 0.10-0.17 inch. **NOTE:**Adjust the fairing as required. No more than 0.10 - 0,17 trim is allowed per side. c. If the gap is not within limits, trim the edge of the dorsal fairing or change the shim thicknesses at the dorsal fairing attach points in order to meet the gap requirements. Refer to 747-100/200/300 AMM 55-30-03 or 747-400 AMM 55-30-03 for accepted procedures.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 49 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane.
**More Data Qty**  **Identification Name**  **Task Step**  (a) (b) (c) 1 146U3214-( ) OR 65B04155-( ) Skin Inspect 1 (a) Do a detailed inspection for wear or cracks in the skin in the area shown. Inspect a minimum of 3.0 inches on both sides of where the dorsal fairing edge is located when the dorsal fairing is installed. (b) If a doubler is installed in the inspection area, also do a detailed inspection for wear or cracks in the doubler. (c) If a rub strip is installed in the inspection area, also do a detailed inspection for wear or cracks in the rub strip.

**FIGURE 1: DETAILED INSPECTION FOR WEAR OR CRACKS WITH THE DORSAL FAIRING REMOVED (SHEET 1 OF 1)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 50 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane.
**More Data Qty**  **Identification Name**  **Task Step**  (a) 4 Oz BMS 10-11, TYPE 1 Primer Apply 1 (b) 8 Oz BMS 10-86, TYPE 1 OR TYPE 2 Teflon Coating Apply 2 (a) Refer to SOPM 20-41-02 for accepted procedures. If a doubler repair has been done between STA 2260 and STA 2280, apply the primer over the doubler instead of the skin.

**FIGURE 2: APPLICATION OF TEFLON COATING (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 51 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** (b) Refer to SOPM 20-44-01 and/or 747-400 AMM 51-24-04 for accepted procedures. Apply the teflon coating in the area shown. Make sure the teflon coating extends a minimum of 2.0 inches on both sides of where the dorsal fairing edge is located when the dorsal fairing is installed. Apply the teflon coating with a minimum thickness of 0.005 inch. If a doubler repair has been done between STA 2260 and STA 2280, apply the teflon coating over the doubler instead of the skin.

**FIGURE 2: APPLICATION OF TEFLON COATING (SHEET 2 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 52 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 3: RUB STRIP MODIFICATION**  **(SHEET 1 OF 8)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 53 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 3: RUB STRIP MODIFICATION**  **(SHEET 2 OF 8)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 54 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 3: RUB STRIP MODIFICATION**  **(SHEET 3 OF 8)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 55 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 3: RUB STRIP MODIFICATION**  **(SHEET 4 OF 8)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 56 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 3: RUB STRIP MODIFICATION**  **(SHEET 5 OF 8)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 57 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane. **NOTE:**The following procedure gives instructions for installation of a rub strip on both the left side and right side of the dorsal fairing. It is acceptable to install a rub strip on only the left side or the right side. However, inspection requirements and compliance times will be different for areas with a rub strip vs. areas without a rub strip.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- BMS 10-86, TYPE 1 OR TYPE 2 Teflon Coating Remove 1 (b) 4

- Existing Fasteners Remove 2 (c)

- - Existing Finish Remove 3 (d) 2 Oz TYPE 2, CLASS A Chemical Conversion Coating Apply 4 (e) 2 Oz BMS 10-79, TYPE 3 Primer Apply 5 (f) 1 675U0008-1 RUB STRIP Locate 6 (f) 1 675U0008-2 RUB STRIP Locate (g) 2

- Tapered Fillers Locate (h) 4

- Existing Holes Drill / Ream 7 (h) 8

- New Holes Drill / Ream (i) 1 675U0008-1 RUB STRIP Drill / Ream 8 (i) 1 675U0008-2 RUB STRIP Drill / Ream

- - Tapered Fillers Drill / Ream (j) 4

- Repair Washers Install (New) 9 (k) 4 Oz BMS 5-95 Faying Surface Sealant Apply 10 Left side. 1 675U0008-1 RUB STRIP Install (New) 11 Right side. 1 675U0008-2 RUB STRIP Install (New)

- - Tapered Fillers Install (New) (a) Remove any existing teflon coating that was previously applied to the skin or doubler. Refer to SOPM 20- 30-02 for accepted procedures. If there is no existing teflon coating, this step is not necessary. (b) Remove existing fasteners at the locations shown that will be used to attach the forward ends of the rub strips. (c) Remove any loose or damaged finish (primer and/or enamel) in the area that the rub strips will be installed. Blend the edges of the remaining finish to make a smooth surface. Refer to SOPM 20-30-02 for accepted procedures. (d) Apply Type 2, Class A chemical conversion coating (F-17.10) to bare aluminum. Refer to SOPM 20-43- 03 for accepted procedures.

**FIGURE 3: RUB STRIP MODIFICATION (SHEET 6 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 58 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** (e) Apply BMS 10-79, Type 3 primer (F-19.47) to the reworked area plus a minimum of 0.25 inch beyond the edge of where the rub strips will be installed. Refer to SOPM 20-44-04 for accepted procedures. (f) Locate the rub strip as shown along the intersection of the skin and the dorsal fairing edge. If existing rub strips have been installed aft of STA 2280 in accordance with Service Bulletin 747-53-2721, locate the aft ends of the new rub strips with a maximum gap of 0.10 inch from the Service Bulletin 747-53-2721 rub strips. Maintain 1.7D minimum edge margin at new and existing fastener locations common to the rub strip. (g) Make and install tapered fillers for area adjacent to repair doubler as shown. Taper the fillers down to a minimum thickness of 0.020 inch, with a taper ratio of at least 100 to 1. Install the tapered fillers with BMS5-95 sealant. Limit pull-up to all parts to 0.010 maximum. Refer to SOPM 20-50-19 as an accepted procedures. (h) Drill holes through the entire stack up to the size specified in the fastener table. (i) Remove the rub strips and drill holes through the rub strips only to 0.247-0.258 inch diameter at existing fastener locations, and 0.218-0.229 inch diameter at new fastener location. (j) Make and install repair washers in the countersinks of the existing holes where fasteners were removed. Refer to 747-100/200/300 SRM 51-30-08, or 747-400 SRM 51-40-08, or 747-400F SRM 51-40-08, for accepted procedures. After the repair washers are firmly bonded in place, shave the washers flush within +0.005 inch of the skin surface. (k) Apply BMS 5-95 faying surface sealant to the mating surfaces of the rub strips and skin. Refer to SOPM 20-50-19 for accepted procedures. After rub strip installation, form the squeeze out into a small fillet around the edge of the rub strips. The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  Drill 0.247-0.258 inch diameter through rub strips only. 0.216-0.219 2 BACB30NX6K3Y BOLT, PROTRUDING HD A
(a) (b)

- - 2 BACC30AC6 COLLAR Drill 0.247-0.258 inch diameter through rub strips only. 0.216-0.219 2 BACB30NX6K4Y BOLT, PROTRUDING HD B
(a) (b)

- - 2 BACC30AC6 COLLAR 0.218-0.229 inch diameter through rub strips only. 0.187-0.190 8 BACB30NX6K2 BOLT, PROTRUDING HD C (a) (b)

- - 8 BACC30BH6 COLLAR

**FIGURE 3: RUB STRIP MODIFICATION (SHEET 7 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 59 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Hole Dia Qty**  **Identification Name**  **Code** 0.218-0.229 inch diameter through rub strips only. 0.187-0.190 8 BACB30NX6K3 BOLT, PROTRUDING HD D (a) (b) (c)

- - 8 BACC30BH6 COLLAR (a) Maintain 2D minimum edge margin. (b) Install fasteners wet with BMS 5-95 sealant. Refer to SOPM 20-50-19, fastener sealing Method 2 as an accepted procedure. (c) Install this fastener as required at locations where a doubler repair has been accomplished.

**FIGURE 3: RUB STRIP MODIFICATION (SHEET 8 OF 8)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 60 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 4: GAP MEASUREMENT AND DETAILED INSPECTION FOR WEAR OR CRACKS WITH THE**  **DORSAL FAIRING INSTALLED (SHEET 1 OF 2)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 61 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane.
**More Data Qty**  **Identification Name**  **Task Step**  (a) 1

- Skin and Rub Strip (if installed) Inspect 1 (b) (c) 1

- Gap Measure 2 (a) Do a detailed inspection for wear or cracks in the skin and rub strip, if installed, in the area shown. Inspect a minimum of 3.0 inches around the outside perimeter of the dorsal fairing. The left side is shown, but do the inspection of the skin on both sides of the fairing. (b) Measure the gap between the edge of the dorsal fairing and the skin. Do the measurement along the entire edge of the dorsal fairing on both sides of the fairing. The gap should be 0.10-0.17 inch. (c) Adjustment of fairing may be required such that continuous trimming of fairing does not occur.

**FIGURE 4: GAP MEASUREMENT AND DETAILED INSPECTION FOR WEAR OR CRACKS WITH THE DORSAL FAIRING INSTALLED**  **(SHEET 2 OF 2)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 62 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 5: EXTERNAL DOUBLER REPAIR**  **(SHEET 1 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 63 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 5: EXTERNAL DOUBLER REPAIR**  **(SHEET 2 OF 5)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 64 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane. **CAUTION:** COMPLETE DAMAGE REMOVAL IS NECESSARY TO ESTABLISH APPROPRIATE REPAIR ACTIONS AND TO AVOID DEVELOPMENT OF FATIGUE CRACKING. DAMAGE THAT IS NOT COMPLETELY REMOVED CAN REDUCE THE FATIGUE STRENGTH OF THE PART, WHICH CAN RESULT IN CRACKING. IN EXTREME CASES, UNDETECTED FATIGUE CRACKING CAN COMPROMISE STRUCTURAL INTEGRITY.
**More Data Qty**  **Identification Name**  **Task Step**  (a)

- - Existing Fasteners Remove 1 (c) 1 146U3214-( ) OR 65B04155-( ) Skin Repair 2 (g) 1

- Existing Fastener Holes Inspect 3 (h) 1 146U3214-( ) OR 65B04155-( ) Skin Inspect 4 (b) 1 146U3214-( ) OR 65B04155-( ) Skin Cut 5 (i) 1 146U3214-( ) OR 65B04155-( ) Skin Inspect 6 (d) 1

- Repair Doubler Make 7 (e) 1

- Repair Filler Make (f)

- - Repair Washers Make (j) 1

- Repair Doubler Assemble 8 (j) 1

- Repair Filler Assemble (j) 1

- Repair Doubler Drill / Ream 9 (j) 1

- Repair Filler Drill / Ream (k) 1

- Repair Doubler Clean/Deburr 10 (k) 1

- Repair Filler Clean/Deburr (l) 4 Oz TYPE 2, CLASS A Chemical Conversion Coating Apply 11 (m) 4 Oz BMS 10-79, TYPE 3 Primer Apply (n) 4 BMS 5-95 Faying Surface Sealant Apply 12 (o) 1

- Repair Doubler Install (New) 13 (o) 1

- Repair Filler Install (New) (p)

- - Finish Apply 14 (a) Remove existing skin fasteners as necessary.

**FIGURE 5: EXTERNAL DOUBLER REPAIR (SHEET 3 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 65 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** (b) Trim out and remove any damaged skin that is less than 0.050 inch thick after blending. Be careful not to damage underlying support structure including tear straps. Keep a 0.50 inch minimum radius at the corners of the skin cutout. If a rectangular cutout is made, align the edges to be parallel and perpendicularto nearby tear straps and stringers. Maintain 3D minimum edge margin from cutout to any adjacent fastener holes. Maintain 2D minimum edges of parts. Maintain 63 microinches Ra or better surface finish on the trimmed edges. (c) Return all dented skin to the initial contour. Blend the damaged area to remove any nicks, scratches, gouges, burrs, and sharp edges. (d) Make a repair doubler from the same material as the initial skin, but one gage thicker than the initial skin. The repair doubler need to be finished per F-17.10 + F-19.47. The repair shown is an example. Adjust the repair and the size of the doubler as necessary to remove all of the skin damage. (e) Make a repair filler (apply F-17.10 + F-20.02 to filler) of the same material and thickness as the initial skin. A filler is required only if the repair is between tear straps, and between stringers. (f) Make and install repair washers, as necessary, at existing fastener locations. Refer to 747-100/200/300 SRM 51-30-08, or 747-400 SRM 51-40-08, or 747-400F SRM 51-40-08, for accepted procedures. (g) Do an open hole high frequency eddy current (HFEC) inspection at hole locations where fasteners were removed to ensure a crack free condition. Do the inspection in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack indication is found, contact Boeing for repair instructions and do the repair. (h) Do a surface HFEC inspection of the blended area of the skin to ensure a crack free condition. Do the inspection in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. If any crack indication is found, contact Boeing for repair instructions and do the repair, or do additional blending in the area as necessary to remove the crack indication, but do not exceed the limits given in the 747 SRM. (i) Do a surface HFEC inspection of trimmed edges of the cutout to ensure a crack free condition. Do the inspection in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. If any crack indication is found, make the trimmed area larger as necessary to remove the crack indication. (j) Assemble the repair parts and drill the fastener holes with fastener spacing of 1.30 - 1.35 inch, except spacing can be reduced to 4D minimum if limited by existing fastener row, the repair cutout, or if necessary to maintain minimum 2D edge margin on adjacent structure. Use a drill stop to restrict penetration through the skin to 0.06 inch maximum. (k) Disassemble the repair parts and remove any nicks, scratches, gouges, burrs, or sharp edges from the repair parts and initial parts. (l) Apply Type 2, Class A chemical conversion coating (F-17.10) to the repair parts and to bare aluminum surfaces of the initial parts and trimmed skin. Refer to SOPM 20-43-03 as an accepted procedures. (m) Apply BMS 10-79, Type 3 primer (F-19.47) to the repair parts and to bare aluminum surfaces of the initial parts. Refer to SOPM 20-44-04 as an accepted procedures. (n) Apply BMS 5-95 faying surface sealant to the mating surfaces of the repair parts and initial parts. Make sure all voids are filled with sealant. Refer to SOPM 20-50-19 as an accepted procedures.

**FIGURE 5: EXTERNAL DOUBLER REPAIR (SHEET 4 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 66 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** (o) Install the repair parts with fasteners as specified in the illustration. If a rub strip will be installed, do not install the fasteners identified as "rub strip attach location". Fasteners that are not made of aluminum must be installed wet with BMS 5-95 sealant. After installation, form the squeeze out into fillet around the doubler. Apply more sealant as necessary to make a continuous fillet seal around the doubler. Refer to SOPM 20-50-19 as an accepted procedures. For aerodynamic seal refer to SOPM 20-50-11 as an accepted procedures. (p) Apply finish to the repair area. Refer to 747-100/200/300 AMM 51-21 or 747-400 AMM 51-21 for accepted procedures. The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure.
**More Data Hole Dia**  **Qty Identification**  **Name Code**  (a) 0.191-0.202

- BACR15BB6D( ) Rivet A (a) 0.191-0.202

- BACR15CE6D( ) Rivet B (a) Quantity and grip lengths as required depending on the repair.

**FIGURE 5: EXTERNAL DOUBLER REPAIR (SHEET 5 OF 5)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 67 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT FIGURE 6: SURFACE HFEC INSPECTION OF REPAIR DOUBLER**  **(SHEET 1 OF 3)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 68 of 71 **BOEING SERVICE BULLETIN 747-53A2876 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 each airplane.
**More Data Qty**  **Identification Name**  **Task Step**  (a) (b)

- - Skin Inspect 1

**FIGURE 6: SURFACE HFEC INSPECTION OF REPAIR DOUBLER (SHEET 2 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 69 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** (a) Do an internal surface HFEC inspection for cracks in the skin under the repair doubler. Inspect around each fastener in the inspection area. Do the inspection in accordance with 747 NDT Manual Part 6, 51- 00-00, Procedure 4 or 23. As an alternative, do an external surface LFEC inspection for cracks in the skin under the repair doubler. Inspect around each fastener in the inspection area. Do the inspection in accordance with 747 NDT Manual Part 6, 53-30-00, Procedure 6. If an existing rub strip is installed over any part of the inspection area, remove the rub strip to do the inspection. After inspection, re-install the existing rub strip or install a new rub strip in accordance with FIGURE 3. (b) It is not necessary to do the internal HFEC (High Frequency Eddy Current) inspection at locations where the skin is covered by internal structure.

**FIGURE 6: SURFACE HFEC INSPECTION OF REPAIR DOUBLER (SHEET 3 OF 3)** 
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 70 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT APPENDIX A: PART DEMAND INTENT**  **(SHEET 1 OF 1)**
Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 22, 2014 747-53A2876 71 of 71 **BOEING SERVICE BULLETIN 747-53A2876 ALERT**  **ALERT**