### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0035**  Original Issue: October 30, 2014 ATA System: 5451 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Flammable Fluid Drain Path Change 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 Unpublished Work.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Issue: October 30, 2014 777-54-0035 1 of 31 3.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 2 of 31 **BOEING SERVICE BULLETIN 777-54-0035**

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 17 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 19 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 20 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT SIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT SIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 APPENDIX A: GAP BETWEEN LOWER WING PANELS ADJACENT TO STRUT AFT VAPOR BARRIER . 30

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 3 of 31 **BOEING SERVICE BULLETIN 777-54-0035**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 4 of 31 **BOEING SERVICE BULLETIN 777-54-0035**

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### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 777-54-0035** Original Issue: October 30, 2014 ATA System: 5451 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Flammable Fluid Drain Path Change BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Accomplishment of this service bulletin will prevent fire and smoke in the pylon area in the event of a fuel leak. The existing drainage provisions in the wing leading edge flammable fluid leakage zone above the strut may allow leaked flammable fluid (fuel) to come in contact with an ignition source (aft strut heat shield). When the flammable fluid comes in contact with an ignition source, there is a risk of fire in the pylon area, including uncontrolled fire in the upper strut inside the pylon and personal injury during ground operations. Boeing has received two in-service events that reported fire and smoke from the aft pylon area after landing and engine shutdown. Subsequent investigation found that there was a fuel leak caused by a damaged o-ring in the fuel coupling attached to the wing front spar. The fuel was captured by the fuel coupling rubber boot and was discharged into the strut-to-wing cavity flammable fluid leakage zone as intended. The fuel did not follow its intended drain paths into the aft strut and lower wing panel drains, but instead followed an unintended drain path through an unsealed gap between the lower wing panels above the strut aft vapor barrier. The leaking fuel then followed gaps and seams in the aft fairing structure and eventually ignited after contact with the hot engine exhaust heat shield causing the fires. Boeing has done factory testing to analyze and verify the flammable fluid drainage path in the strut-to-wing cavity. The test results showed that the interface between the strut aft vapor barrier and the lower wing panel had an unsealed gap that allowed the fuel to drain down and eventually contact the engine exhaust heat shield, which is an ignition source. Subsequent to the factory testing and analysis, Boeing has developed a sealing method to better control the flammable fluid drain path and prevent fire and smoke in the aft pylon area in the event of a fuel leak. This service bulletin is sent to provide a wing panel gap sealing method to prevent flammable fluids from taking the unintended path and reaching a possible ignition source. Boeing Fleet Team Digest (FTD) 777 FTD 54-13004 is related to this service bulletin. Boeing Service Related Problem (SRP) 777-54-0146 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 30, 2014 777-54-0035 5 of 31**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 No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No 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 No 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 62777-94S)** Get access to the inboard side of the strut-to-wing front spar area by removing fairing and access panels. Apply sealant to fill the gap between the lower wing panels adjacent to the strut aft vapor barrier. Close access. **EFFECTIVITY** 777-200, 777-200LR, 777-300, 777-300ER, and 777F Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s). **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. Boeing recommends that the change given in this service bulletin be done within 1,875 days after the original issue date of this service bulletin. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are available for airplanes in warranty as of February 28, 2013. Please refer to Paragraph 2.B., Industry Support Information. The warranty remedies will expire eight years from the original issue date of this service bulletin. **MANPOWER Elapsed Hours**  **Total Task Hours Airplanes**  2.70 2.70 Group 1

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 6 of 31 **BOEING SERVICE BULLETIN 777-54-0035 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 30, 2014 777-54-0035 7 of 31 **BOEING SERVICE BULLETIN 777-54-0035**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 8 of 31 **BOEING SERVICE BULLETIN 777-54-0035**

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### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-54-0035**  Original Issue: October 30, 2014 ATA System: 5451 **SUBJECT:** NACELLES/PYLONS - Nacelle Strut - Flammable Fluid Drain Path Change BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is applicable to 777-200, 777-200LR, 777-300, 777-300ER, and 777F Airplanes, line numbers 1-1243 in 1 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 62777-94S for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** Airplane line numbers 1 through 1243.

- 1

Airplane Models: 777-200, 777-200LR, 777-300, 777-300ER, 777F **Group Variable Number**  1 WA001 - WA017 1 WA076 - WA080 1 WA086 - WA093 1 WA101 - WA104 1 WA116 - WA119 1 WA131 - WA137 1 WA171 - WA175

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 9 of 31**Group Variable Number**  1 WA196 - WA198 1 WA206 - WA212 1 WA221 - WA223 1 WA231 - WA232 1 WA241 - WA250 1 WA261 - WA266 1 WA281 - WA283 1 WA301 - WA304 1 WB001 - WB021 1 WB031 - WB046 1 WB051 - WB088 1 WB101 - WB106 1 WB121 - WB125 1 WB131 - WB148 1 WB151 - WB155 1 WB161 - WB177 1 WB181 - WB194 1 WB201 - WB215 1 WB231 - WB247 1 WB271 - WB273 1 WB276 - WB286 1 WB291 - WB302 1 WB306 - WB307 1 WB311 - WB337 1 WB341 - WB342 1 WB366 - WB368 1 WB371 - WB388 1 WB406 1 WB411 - WB413 1 WB416 - WB439 1 WB446 - WB453 1 WB476 1 WB481 - WB484

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 10 of 31 **BOEING SERVICE BULLETIN 777-54-0035 Group**  **Variable Number** 1 WB501 - WB512 1 WB531 - WB537 1 WB551 - WB554 1 WB591 - WB597 1 WB601 - WB606 1 WB611 - WB622 1 WB631 - WB638 1 WB646 - WB649 1 WC051 - WC073 1 WC101 - WC104 1 WC111 - WC120 1 WC221 - WC224 1 WC241 - WC243 1 WC281 - WC290 1 WC301 - WC308 1 WC361 - WC364 1 WC371 - WC374 1 WC381 - WC395 1 WC441 1 WC446 - WC449 1 WC456 - WC459 1 WC486 - WC493 1 WC506 - WC508 1 WC521 - WC522 1 WC531 - WC536 1 WC546 - WC548 1 WC556 1 WC566 - WC567 1 WC571 - WC574 1 WC581 1 WC586 - WC587 1 WC591 - WC595 1 WD001 - WD002

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 11 of 31 **BOEING SERVICE BULLETIN 777-54-0035 Group**  **Variable Number** 1 WD011 - WD018 1 WD031 - WD036 1 WD046 - WD055 1 WD066 - WD075 1 WD081 - WD089 1 WD091 1 WD096 1 WD101 - WD106 1 WD111 1 WD116 - WD117 1 WD121 - WD122 1 WD501 - WD513 1 WD521 - WD541 1 WD546 - WD554 1 WD561 - WD573 1 WD581 - WD599 1 WD606 - WD609 1 WD621 - WD632 1 WD651 - WD665 1 WD671 - WD677 1 WD691 - WD709 1 WD741 - WD752 1 WD761 - WD771 1 WD786 - WD788 1 WD796 - WD837 1 WD846 - WD867 1 WD871 - WD897 1 WD911 - WD918 1 WD921 - WD930 1 WD936 - WD957 1 WD966 - WD970 1 WD981 - WD982 1 WD986 - WD987

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 12 of 31 **BOEING SERVICE BULLETIN 777-54-0035 Group**  **Variable Number** 1 WD991 - WD994 1 WD996 1 WE001 - WE004 1 WE011 - WE012 1 WE021 - WE026 1 WE031 - WE034 1 WE051 - WE057 1 WE071 - WE078 1 WE081 - WE084 1 WE091 - WE095 1 WE126 - WE146 1 WE151 - WE170 1 WE176 - WE178 1 WE186 - WE219 1 WE226 - WE231 1 WE236 - WE249 1 WE251 - WE253 1 WE261 - WE267 1 WE271 - WE278 1 WE291 - WE293 1 WE301 - WE315 1 WE331 - WE340 1 WE351 - WE356 1 WE376 - WE377 1 WE381 1 WE386 - WE387 1 WE396 - WE399 1 WE416 - WE420 1 WE426 1 WE436 - WE437 1 WE441 - WE443 1 WE451 1 WE501

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 13 of 31 **BOEING SERVICE BULLETIN 777-54-0035 Group**  **Variable Number** 1 WE556 - WE558 1 WF001 - WF004 1 WF016 - WF023 1 WF031 - WF041 1 WF046 - WF066 1 WF075 - WF077 1 WF081 - WF088 1 WF096 - WF101 1 WF106 - WF109 1 WF111 - WF117 1 WF121 - WF124 1 WF131 - WF133 1 WF136 - WF139 1 WF146 - WF147 1 WF151 - WF152 1 WF156 - WF159 1 WF166 - WF170 1 WF176 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of this service bulletin will prevent fire and smoke in the pylon area in the event of a fuel leak. The existing drainage provisions in the wing leading edge flammable fluid leakage zone above the strut may allow leaked flammable fluid (fuel) to come in contact with an ignition source (aft strut heat shield). When the flammable fluid comes in contact with an ignition source, there is a risk of fire in the pylon area, including uncontrolled fire in the upper strut inside the pylon and personal injury during ground operations.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 14 of 31 **BOEING SERVICE BULLETIN 777-54-0035**Boeing has received two in-service events that reported fire and smoke from the aft pylon area after landing and engine shutdown. Subsequent investigation found that there was a fuel leak caused by a damaged o-ring in the fuel coupling attached to the wing front spar. The fuel was captured by the fuel coupling rubber boot and was discharged into the strut-to-wing cavity flammable fluid leakage zone as intended. The fuel did not follow its intended drain paths into the aft strut and lower wing panel drains, but instead followed an unintended drain path through an unsealed gap between the lower wing panels above the strut aft vapor barrier. The leaking fuel then followed gaps and seams in the aft fairing structure and eventually ignited after contact with the hot engine exhaust heat shield causing the fires. Boeing has done factory testing to analyze and verify the flammable fluid drainage path in the strut-to-wing cavity. The test results showed that the interface between the strut aft vapor barrier and the lower wing panel had an unsealed gap that allowed the fuel to drain down and eventually contact the engine exhaust heat shield, which is an ignition source. Subsequent to the factory testing and analysis, Boeing has developed a sealing method to better control the flammable fluid drain path and prevent fire and smoke in the aft pylon area in the event of a fuel leak. This service bulletin is sent to provide a wing panel gap sealing method to prevent flammable fluids from taking the unintended path and reaching a possible ignition source. Boeing Fleet Team Digest (FTD) 777 FTD 54-13004 is related to this service bulletin. Boeing Service Related Problem (SRP) 777-54-0146 is related to this service bulletin. **D. Description** Get access to the inboard side of the strut-to-wing front spar area by removing fairing and access panels. Apply sealant to fill the gap between the lower wing panels adjacent to the strut aft vapor barrier. Close access. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 431, 441 777-200, 777-200LR, 777-300, 777-300ER, 777F **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. Boeing recommends that the change given in this service bulletin be done within 1,875 days after the original issue date of this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 15 of 31 **BOEING SERVICE BULLETIN 777-54-0035 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 change for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • 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. **Elapsed Hours Task Hours**  **Number of Persons Task**  1.25 1.25 1 Open Access 0.10 0.10 1 FIGURE 1 (Left side) 0.10 0.10 1 FIGURE 2 (Right side) 1.25 1.25 1 Close Access 2.70 2.70 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data: a. Engineering Change Memo PRR 62777-94S

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 16 of 31 **BOEING SERVICE BULLETIN 777-54-0035**b. Boeing Service Related Problem (SRP) 777-54-0146 c. Service Bulletin Index D624W001 d. Standard Overhaul Practices Manual (SOPM) 20-50-11 e. 777 Aircraft Maintenance Manual (AMM) 20-41-00, 27-81-00, 54-52-03, 78-31-00 f. 777 Fleet Team Digest (FTD) 54-13004 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. **K. Publications Affected** 1. Publications: None. 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 does not affect FCS, therefore DTIs are not necessary. **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 30, 2014 777-54-0035 17 of 31 **BOEING SERVICE BULLETIN 777-54-0035**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 18 of 31 **BOEING SERVICE BULLETIN 777-54-0035**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **B. Industry Support Information** Boeing warranty remedies are available for 777 airplanes in warranty as of February 28, 2013. For task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Fleet Support Contracts - Warranty. The kits for airplanes in warranty as of that date will be supplied at no charge. Send a purchase order for the kits to Boeing Material Management. Please refer to this service bulletin number and reference the airplane variable number(s) in your purchase order. The warranty remedies will expire eight years from the original issue date of this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts None. 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) SEALANT 4 OZ BMS 5-142 (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.
3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 19 of 31 **BOEING SERVICE BULLETIN 777-54-0035 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 30, 2014 777-54-0035 20 of 31 **BOEING SERVICE BULLETIN 777-54-0035 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 777 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 777 Airplane Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). — Values for engine maintenance tasks are included in Chapter 70 of 777 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. 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. 6. Refer to APPENDIX A for a clarification of the location of the gap between the lower wing panels.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 21 of 31 **BOEING SERVICE BULLETIN 777-54-0035**7. 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. 8. 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. 9. Use of colors in Figures is based on guidance from the ATA e-Business Program (ATA) iSpec 2200. 10. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. 11. 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. **B. WORK INSTRUCTIONS** 1. Do the following tasks to prepare the strut for the maintenance operations: a. Statically ground the airplane. Refer to 777 AMM 20-41-00 as an accepted procedure. b. Retract the leading edge slats. Refer to 777 AMM 27-81-00 as an accepted procedure. c. Deactivate the leading edge slats. Refer to 777 AMM 27-81-00 as an accepted procedure. d. Deactivate the thrust reversers. Refer to 777 AMM 78-31-00 as an accepted procedure. 2. Remove the underwing inboard fairing panels, 431FR (left nacelle strut) and 441FL (right nacelle strut). Refer to 777 AMM 54-52-03 as an accepted procedure. 3. Remove the underwing inboard access panels, 431GR (left nacelle strut) and 441GL (right nacelle strut). Refer to 777 AMM 54-52-03 as an accepted procedure. 4. RC - Apply sealant to fill the gap between the lower wing panels in accordance with the figures below: **Right Side Left Side**  FIGURE 2 FIGURE 1 5. Install the underwing inboard access panels, 431GR (left nacelle strut) and 441GL (right nacelle strut). Refer to 777 AMM 54-52-03 as an accepted procedure.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 22 of 31 **BOEING SERVICE BULLETIN 777-54-0035**6. Install the underwing inboard fairing panels, 431FR (left nacelle strut) and 441FL (right nacelle strut). Refer to 777 AMM 54-52-03 as an accepted procedure. 7. Activate the thrust reversers. Refer to 777 AMM 78-31-00 as an accepted procedure. 8. Activate the leading edge slats. Refer to 777 AMM 27-81-00 as an accepted procedure. 9. Remove the static ground from the airplane. Refer to 777 AMM 20-41-00 as an accepted procedure. 10. 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 30, 2014 777-54-0035 23 of 31 **BOEING SERVICE BULLETIN 777-54-0035 FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT**  **SIDE (SHEET 1 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 24 of 31 **BOEING SERVICE BULLETIN 777-54-0035 FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT**  **SIDE (SHEET 2 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 25 of 31 **BOEING SERVICE BULLETIN 777-54-0035**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 this figure.
**More Data Qty**  **Identification Name**  **Task Step**  Refer to SOPM 20-50-11 as an accepted procedure.(b) - - GAP Clean 1

(a) (b)

- BMS 5-142 SEALANT Apply (a) Apply sealant to fill the gap between the lower wing panels from the inboard side of the strut. On the forward side of the vapor barrier, apply sealant from the start of the gap at the wing leading edge going aft to where the gap interfaces with the vapor barrier seal, applying as far underneath the seal as is accessible. On the aft side of the vapor barrier, apply sealant from a minimum of 1.0 inch aft along the gap between the wing panels, forward to where the gap interfaces with the vapor barrier seal, applying as far underneath the seal as is accessible. Refer to SOPM 20-50-11 as an accepted procedure. Refer to APPENDIX A for a clarification of the location of the gap between the lower wing panels. (b) Areas underneath the seal that are not accessible do not need to be cleaned and prepared for sealant application. Any sealant underneath the seal that is not accessible does not need to be faired to a smooth finish.

**FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT SIDE**  **(SHEET 3 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 26 of 31 **BOEING SERVICE BULLETIN 777-54-0035 FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT**  **SIDE (SHEET 1 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 27 of 31 **BOEING SERVICE BULLETIN 777-54-0035 FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT**  **SIDE (SHEET 2 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 28 of 31 **BOEING SERVICE BULLETIN 777-54-0035**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 this figure.
**More Data Qty**  **Identification Name**  **Task Step**  Refer to SOPM 20-50-11 as an accepted procedure.(b) - - GAP Clean 1

(a) (b)

- BMS 5-142 SEALANT Apply (a) Apply sealant to fill the gap between the lower wing panels from the inboard side of the strut. On the forward side of the vapor barrier, apply sealant from the start of the gap at the wing leading edge going aft to where the gap interfaces with the vapor barrier seal, applying as far underneath the seal as is accessible. On the aft side of the vapor barrier, apply sealant from a minimum of 1.0 inch aft along the gap between the wing panels, forward to where the gap interfaces with the vapor barrier seal, applying as far underneath the seal as is accessible. Refer to SOPM 20-50-11 as an accepted procedure. Refer to APPENDIX A for a clarification of the location of the gap between the lower wing panels. (b) Areas underneath the seal that are not accessible do not need to be cleaned and prepared for sealant application. Any sealant underneath the seal that is not accessible does not need to be faired to a smooth finish.

**FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT SIDE**  **(SHEET 3 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 29 of 31 **BOEING SERVICE BULLETIN 777-54-0035**The pictures below show the location of the gap between the lower wing panels adjacent to the strut aft vapor barrier from the inboard side of the strut. Refer to this appendix to help locate the gap for the sealant application.

**APPENDIX A: GAP BETWEEN LOWER WING PANELS ADJACENT TO STRUT AFT VAPOR BARRIER (SHEET 1 OF 2)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 30 of 31 **BOEING SERVICE BULLETIN 777-54-0035 APPENDIX A: GAP BETWEEN LOWER WING PANELS ADJACENT TO STRUT AFT VAPOR BARRIER**  **(SHEET 2 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 30, 2014 777-54-0035 31 of 31 **BOEING SERVICE BULLETIN 777-54-0035**