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.

ECCN: 9E991

BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET

Copyright © 2014 Boeing.

Unpublished Work. All Rights Reserved.

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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

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BLANK PAGE
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.

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Planning Data Affected Reference

Spares Affected No Paragraph 1.A.2., Spares Affected

Paragraph 1.E., Compliance and Paragraph

1.F., Approval

AD Related Yes

Weight and Balance Change No Paragraph 1.H., Weight and Balance Changes

Electrical Load Changed No Paragraph 1.I., Electrical Load Data

Publications Affected No Paragraph 1.K., Publications Affected

Airplane Flight Operations Affected (Flight Crew No Paragraph 1.K., Publications Affected

Operations Manual and/or FAA Approved Airplane Flight Manual)

Kits/Parts Required No Paragraph 2.C.1., Kits/Parts

Paragraph 2.C.2., Parts and Materials Supplied

by the Operator

Operator Supplied Parts/Material Yes

Paragraph 2.F., Special Tooling Necessary to

do this Service Bulletin

Special Tooling Required No

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

Airplanes Total Task Hours Elapsed Hours

Group 1 2.70 2.70

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BOEING SERVICE BULLETIN 777-54-0035
MATERIAL INFORMATION

Operator Supplied Parts/Materials.

Refer to Paragraph 2.A., Material - Price and Availability.

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BOEING SERVICE BULLETIN 777-54-0035

BLANK PAGE
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.

GROUP CONFIGURATION DESCRIPTION

1 - Airplane line numbers 1 through 1243.

Airplane Models:

777-200, 777-200LR, 777-300, 777-300ER, 777F

Variable Number Group

WA001 - WA017 1

WA076 - WA080 1

WA086 - WA093 1

WA101 - WA104 1

WA116 - WA119 1

WA131 - WA137 1

WA171 - WA175 1

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Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-54-0035
Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-54-0035
Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-54-0035
Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-54-0035
Variable Number Group

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 1

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.

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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

Model Zone

777-200, 777-200LR, 777-300, 431, 441

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.

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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.

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 1.25 1.25

FIGURE 1 (Left side) 1 0.10 0.10

FIGURE 2 (Right 1 0.10 0.10

side)

Close Access 1 1.25 1.25

TOTAL FOR EACH AIRPLANE 2.70 2.70

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not changed.

J. References

1. Existing Data:

a. Engineering Change Memo PRR 62777-94S

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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.

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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.

Part Number / QTY Name Notes

Specification

BMS 5-142 4 OZ SEALANT (a)

(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.

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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.

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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.

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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:

Left Side Right Side

FIGURE 1 FIGURE 2

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.

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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.

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FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT

SIDE

(SHEET 1 OF 3)

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FIGURE 1: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - LEFT

SIDE

(SHEET 2 OF 3)

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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.

Step Task Name Identification Qty More Data

Refer to SOPM 20-

50-11 as an accepted procedure.(b)

1 Clean GAP - -

Apply SEALANT BMS 5-142 - (a) (b)

(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)

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FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT

SIDE

(SHEET 1 OF 3)

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FIGURE 2: STRUT TO WING FRONT SPAR - LOWER WING PANELS - SEALANT APPLICATION - RIGHT

SIDE

(SHEET 2 OF 3)

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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.

Step Task Name Identification Qty More Data

Refer to SOPM 20-

50-11 as an accepted procedure.(b)

1 Clean GAP - -

Apply SEALANT BMS 5-142 - (a) (b)

(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)

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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)

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APPENDIX A: GAP BETWEEN LOWER WING PANELS ADJACENT TO STRUT AFT VAPOR BARRIER

(SHEET 2 OF 2)

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