Commercial 

Airplanes 777

Service Bulletin

ALERT

Number: 777-57A0090

Original Issue: August 24, 2011

ATA System: 5754

SUBJECT: WINGS - Landing Gear Attach Fittings and Support Beam - Main Landing Gear Forward

Trunnion Lower Housing Fuse Pin - Inspection and Replacement

Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15

CFR 730-774). An export license may be required before it is used for development, production or use by foreign

persons from specific countries. The controller of this data has the individual responsibility to abide by all export

laws.

ECCN: 9E991

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Copyright © 2011 The Boeing Company

Unpublished Work - All Rights Reserved

Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable

subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.

This document includes proprietary information owned by The Boeing Company and/or one or more third parties.

Treatment of the document and the information it contains is governed by contract with Boeing. For more

information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.

Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,

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4.0
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BLANK PAGE
Table of Contents

Summary ...................................................... 5

1. PLANNING INFORMATION ........................................ 9

A. Effectivity ................................................ 9

1. Airplanes ............................................. 9

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 20

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 22

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN

REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

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BLANK PAGE
Commercial 

Airplanes 777

Service Bulletin

ALERT

Summary Number: 777-57A0090

Original Issue: August 24, 2011

ATA System: 5754

SUBJECT: WINGS - Landing Gear Attach Fittings and Support Beam - Main Landing Gear Forward

Trunnion Lower Housing Fuse Pin - Inspection and Replacement

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 make sure the Main Landing Gear (MLG) Forward Trunnion Lower

Housing fuse pins and related cross bolts are correctly installed. An incorrectly installed fuse pin and cross bolt

could result in migration of the fuse pin from the MLG Forward Trunnion Lower Housing. A migrated or missing

fuse pin could lead to faster fatigue rates and possible failure of the adjacent fuse pins in the MLG Forward

Trunnion Upper and Lower Housing. Failure of the fuse pins in the MLG Forward Trunnion Upper and Lower

Housing could result in an incorrect MLG break-away sequence and cause the MLG to puncture the wing box

which could result in fuel leaks. Failure of the fuse pins could also result in possible gear collapse causing a

runway excursion during take-off or landing.

Boeing has received four reports of retaining cross bolt hardware not fully engaged into the MLG Forward

Trunnion Lower Housing fuse pins. Reports indicated the incorrectly installed cross bolt or bolts were found

during a scheduled C-check inspection, a MLG replacement, a 4C inspection, and a hard landing inspection.

All reports found the cross bolt and lock wire intact, but found the bolt not properly engaged in the fuse pin. The

cross bolt and lock wire are used to prevent the fuse pin from migrating out of position. A migrated or missing

fuse pin in the MLG Forward Trunnion Lower Housing can cause the remaining fuse pins in the MLG Forward

Trunnion Upper and Lower Housing to fatigue at a faster rate.

This service bulletin provides instructions to inspect and replace the necessary fuse pins in MLG Forward

Trunnion Upper and Lower Housing. Correct installation of the cross bolt into the fuse pin will make sure all fuse

pins in the MLG Forward Trunnion Upper and Lower Housing will not migrate.

Boeing Service Related Problem (SRP) 777-SRP-57-0246 and Boeing Fleet Team Digest (FTD) 777 FTD

57-10006 are related to this service bulletin.

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ACTION

Do a Detailed Inspection (DET) of the MLG Forward Trunnion Lower Housing fuse pins for correctly installed

cross bolts. If necessary, lift the airplane and replace the MLG Forward Trunnion Upper and Lower Housing

fuse pins making sure cross bolts are correctly installed.

EFFECTIVITY

777-200, -200LR, -300, -300ER and 777F Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected

airplanes.

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 available for airplanes in warranty as of October 28, 2010. Please refer to

Paragraph 2.B., Industry Support Information.

MANPOWER

Airplanes Total Task Hours Elapsed Hours

All 44.00 16.00

MATERIAL INFORMATION

Operator Supplied Parts/Materials.

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

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BLANK PAGE
Commercial 

Airplanes 777

Service Bulletin

ALERT

Number: 777-57A0090

Original Issue: August 24, 2011

ATA System: 5754

SUBJECT: WINGS - Landing Gear Attach Fittings and Support Beam - Main Landing Gear Forward

Trunnion Lower Housing Fuse Pin - Inspection and Replacement

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 D624W001 Part 3 for Airplane Variable Number, Line Number, and

Serial Number data.

This service bulletin is for the airplane(s) shown below.

GROUP CONFIGURATION DESCRIPTION

1 - 777-200 Airplanes line number 1 thru 635

777-200 Airplanes with extended range (ER) option line number 41

thru 868

2 -

3 - 777-300 Airplanes line number 94 thru 567

4 - 777-200LR/-300ER and 777F Airplanes line number 423 thru 915

Airplane Models:

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

Variable Number Group

WA001 - WA017 1

WA076 - WA080 1

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Variable Number Group

WA086 - WA093 1

WA101 - WA104 1

WA116 - WA119 1

WA131 - WA137 1

WA171 - WA175 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 2

WB031 - WB046 2

WB051 - WB088 2

WB101 - WB106 2

WB121 - WB125 2

WB131 - WB148 2

WB151 - WB155 2

WB161 - WB177 2

WB181 - WB194 2

WB201 - WB215 2

WB231 - WB247 2

WB271 - WB273 2

WB276 - WB286 2

WB291 - WB302 2

WB306 - WB307 2

WB311 - WB337 2

WB341 - WB342 2

WB366 - WB368 2

WB371 - WB388 2

WB406 2

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Variable Number Group

WB411 - WB413 2

WB416 - WB439 2

WB446 - WB453 2

WB476 2

WB481 - WB484 2

WB501 - WB512 3

WB531 - WB537 3

WB551 - WB554 3

WB591 - WB597 3

WB601 - WB606 3

WB611 - WB622 3

WB631 - WB638 3

WB646 - WB649 3

WC051 - WC073 2

WC101 - WC104 2

WC111 - WC120 2

WC221 - WC224 2

WC241 - WC243 2

WC281 - WC290 2

WC301 - WC308 2

WC361 - WC364 2

WC371 - WC374 2

WC381 - WC395 2

WC441 2

WC446 - WC449 2

WC456 - WC459 2

WC486 - WC493 2

WC506 - WC508 2

WC521 - WC522 2

WC531 - WC536 2

WC546 - WC548 2

WC556 2

WC566 - WC567 2

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Variable Number Group

WC571 - WC574 2

WC581 2

WD001 - WD002 4

WD011 - WD018 4

WD031 - WD036 4

WD046 - WD055 4

WD066 - WD075 4

WD081 - WD088 4

WD091 4

WD096 4

WD101 - WD103 4

WD501 - WD513 4

WD521 - WD541 4

WD546 - WD554 4

WD561 - WD573 4

WD581 - WD599 4

WD606 - WD609 4

WD621 - WD632 4

WD651 - WD665 4

WD671 - WD676 4

WD691 - WD709 4

WD741 - WD752 4

WD761 - WD771 4

WD786 - WD788 4

WD796 - WD813 4

WD826 - WD837 4

WD846 - WD861 4

WD871 - WD883 4

WD911 - WD915 4

WD921 - WD922 4

WD936 - WD939 4

WD946 - WD951 4

WD966 - WD970 4

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Variable Number Group

WD981 - WD982 4

WD986 - WD987 4

WD996 4

WE001 - WE004 4

WE011 - WE012 4

WE021 - WE024 4

WE031 4

WE051 - WE052 4

WE071 4

WE081 - WE082 4

WE126 - WE131 4

WF001 - WF004 4

WF016 - WF020 4

WF031 - WF032 4

WF046 - WF053 4

WF076 - WF077 4

WF081 - WF088 4

WF096 - WF099 4

WF106 - WF107 4

WF111 - WF112 4

WF121 4

2. Spares Affected

None.

B. Concurrent Requirements

None.

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C. Reason

Accomplishment of this service bulletin will make sure the Main Landing Gear (MLG) Forward Trunnion

Lower Housing fuse pins and related cross bolts are correctly installed. An incorrectly installed fuse

pin and cross bolt could result in migration of the fuse pin from the MLG Forward Trunnion Lower

Housing. A migrated or missing fuse pin could lead to faster fatigue rates and possible failure of the

adjacent fuse pins in the MLG Forward Trunnion Upper and Lower Housing. Failure of the fuse pins

in the MLG Forward Trunnion Upper and Lower Housing could result in an incorrect MLG break-away

sequence and cause the MLG to puncture the wing box which could result in fuel leaks. Failure of the

fuse pins could also result in possible gear collapse causing a runway excursion during take-off or

landing.

Boeing has received four reports of retaining cross bolt hardware not fully engaged into the MLG

Forward Trunnion Lower Housing fuse pins. Reports indicated the incorrectly installed cross bolt or

bolts were found during a scheduled C-check inspection, a MLG replacement, a 4C inspection, and a

hard landing inspection. All reports found the cross bolt and lock wire intact, but found the bolt not

properly engaged in the fuse pin. The cross bolt and lock wire are used to prevent the fuse pin from

migrating out of position. A migrated or missing fuse pin in the MLG Forward Trunnion Lower Housing

can cause the remaining fuse pins in the MLG Forward Trunnion Upper and Lower Housing to fatigue

at a faster rate.

This service bulletin provides instructions to inspect and replace the necessary fuse pins in MLG

Forward Trunnion Upper and Lower Housing. Correct installation of the cross bolt into the fuse pin will

make sure all fuse pins in the MLG Forward Trunnion Upper and Lower Housing will not migrate.

Boeing Service Related Problem (SRP) 777-SRP-57-0246 and 777 Fleet Team Digest (FTD) 777 FTD

57-10006 are related to this service bulletin.

D. Description

Do a Detailed Inspection (DET) of the MLG Forward Trunnion Lower Housing fuse pins for correctly

installed cross bolts. If necessary, lift the airplane and replace the MLG Forward Trunnion Upper and

Lower Housing fuse pins making sure cross bolts are correctly installed.

The work in this service bulletin is done in the maintenance zone(s) given below.

Group 1-2:

Affected Maintenance Zones

Model Zone

777-200 143, 144

Group 3:

Affected Maintenance Zones

Model Zone

777-300 143, 144

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Group 4:

Affected Maintenance Zones

Model Zone

777-200LR, 777-300ER, 777F 143, 144

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.

Accomplish the required actions, based on the applicable conditions, in Table 1, in accordance with

Paragraph 3. Accomplishment Instructions.

Evaluate the conditions and actions for the left and right Main Landing Gear (MLG) Forward Trunnion

Upper and Lower Housing separately.

Table 1: Part 1 - Inspection of the MLG Forward Trunnion Lower Housing Fuse Pin Cross Bolts

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 1125 days -

after the original issue date of this

service bulletin.

Do a Detailed Inspection

(DET) of the left and right

MLG Forward Trunnion

Lower Housing fuse pin

cross bolts to make sure

the cross bolts are correctly installed and all MLG

Forward Trunnion Lower

Housing fuse pins are installed in accordance with

Part 1.

All Airplanes

No further action required - -

(Terminating Action).

Condition 1:

1) All MLG Forward Trunnion Lower Housing cross

bolts are correctly installed.

-AND2) No MLG Forward Trunnion Lower Housing fuse

pins are missing.

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Table 1: Part 1 - Inspection of the MLG Forward Trunnion Lower Housing Fuse Pin Cross Bolts

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before further -

flight.

Replace all fuse pins in

MLG Forward Trunnion

Upper and Lower Housing in accordance with

Part 2 (Terminating Action).

Condition 2:

1) Any MLG Forward Trunnion Lower Housing cross

bolt is not correctly installed.

-OR2) Any MLG Forward Trunnion Lower Housing fuse

pin is missing.

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 inspection and replacement

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

Get Access 1 1.00 1.00

FIGURE 1: Inspect 1 0.50 0.50

FIGURE 2: Inspect 1 0.50 0.50

Lift the Airplane 5 12.50 2.50

Remove Load Straps 2 2.00 1.00

FIGURE 3: Replace 2 6.00 3.00

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Task Number of Persons Task Hours Elapsed Hours

FIGURE 4: Replace 2 6.00 3.00

Install Load Straps 2 2.00 1.00

Lower the Airplane 5 12.50 2.50

Close Access 1 1.00 1.00

TOTAL FOR EACH AIRPLANE 44.00 16.00

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not changed.

J. References

1. Existing Data

a. Boeing Service Related Problem (SRP) 777-SRP-57-0246

b. Service Bulletin Index D624W001

c. 777 Aircraft Maintenance Manual (AMM) 07-11-01, 07-11-03, 32-00-15, 32-00-30, 32-11-01

d. 777 Fleet Team Digest (FTD) 57-10006

2. Data supplied with this Service Bulletin

None.

3. Installation Drawings Used in the Preparation of this Service Bulletin

Drawing Number Title

112W1701 SUPPORT INSTL - FORWARD TRUNNION MLG

This drawing was used to prepare this service bulletin. This drawing is not necessary to make the

specified changes, and is not supplied with this service bulletin. This drawing may not be applicable

to all airplane configurations or operators.

K. Publications Affected

1. Publications:

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Publication Chapter-Section

777 Aircraft Maintenance Manual 32-11

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 but no new DTIs are necessary.

L. Interchangeability and Intermixability of Parts

Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

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ALERT ALERT
2. MATERIAL INFORMATION

A. Material - Price and Availability

Boeing can supply the parts 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

Group 1:

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 Service Bulletin (US

Dollars)

ROLT as of the

original issue

date of this Service Bulletin (Calendar Days)

Part Number Name

112W1712-3 LOWER FUSE PIN 300 $ 1,213.00

112W1712-4 UPPER FUSE PIN 300 $ 1,378.00

Group 2:

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 Service Bulletin (US

Dollars)

ROLT as of the

original issue

date of this Service Bulletin (Calendar Days)

Part Number Name

112W1712-3 LOWER FUSE PIN 300 $ 1,213.00

112W1712-5 UPPER FUSE PIN 300 $ 2,191.00

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ALERT ALERT
Group 3:

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 Service Bulletin (US

Dollars)

ROLT as of the

original issue

date of this Service Bulletin (Calendar Days)

Part Number Name

112W1712-5 UPPER FUSE PIN 300 $ 2,191.00

112W1712-6 LOWER FUSE PIN 300 $ 5,482.00

Group 4:

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 Service Bulletin (US

Dollars)

ROLT as of the

original issue

date of this Service Bulletin (Calendar Days)

Part Number Name

112W1712-7 LOWER FUSE PIN 300 $ 1,751.00

112W1712-8 UPPER FUSE PIN 300 $ 1,751.00

B. Industry Support Information

Boeing warranty remedies are available for 777 airplanes in warranty as of October 28, 2010. For

inspection task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to

Boeing Commercial Airplanes Group - Warranties. If the condition described in this service bulletin is

found during the inspection for airplanes in warranty as of that date and additional task hours and kits,

parts, and/or special tools are required, send a warranty claim to Boeing Commercial Airplanes Group

- Warranties. Please refer to this service bulletin number and reference the airplane variable numbers

in your purchase order.

C. Parts Necessary For Each Airplane

1. Kits/Parts

None.

2. Parts and Materials Supplied by the Operator

Group 1:

Part Number / QTY Name Notes

Specification

112W1712-3 8 LOWER FUSE PIN (a)

112W1712-4 4 UPPER FUSE PIN (a)

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Group 1:

Part Number / QTY Name Notes

Specification

(a) The quantity shown is the total quantity required per airplane if all parts for both the left

and right Main Landing Gear (MLG) Forward Trunnion Upper and Lower Housing require

replacement. Parts are only required if replacement as shown in this service bulletin is

necessary.

Group 2:

Part Number / QTY Name Notes

Specification

112W1712-3 8 LOWER FUSE PIN (a)

112W1712-5 4 UPPER FUSE PIN (a)

(a) The quantity shown is the total quantity required per airplane if all parts for both the left

and right MLG Forward Trunnion Upper and Lower Housing require replacement. Parts

are only required if replacement as shown in this service bulletin is necessary.

Group 3:

Part Number / QTY Name Notes

Specification

112W1712-5 4 UPPER FUSE PIN (a)

112W1712-6 8 LOWER FUSE PIN (a)

(a) The quantity shown is the total quantity required per airplane if all parts for both the left

and right MLG Forward Trunnion Upper and Lower Housing require replacement. Parts

are only required if replacement as shown in this service bulletin is necessary.

Group 4:

Part Number / QTY Name Notes

Specification

112W1712-7 8 LOWER FUSE PIN (a)

112W1712-8 4 UPPER FUSE PIN (a)

(a) The quantity shown is the total quantity required per airplane if all parts for both the left

and right MLG Forward Trunnion Upper and Lower Housing require replacement. Parts

are only required if replacement as shown in this service bulletin is necessary.

3. Parts Modified and Reidentified

None.

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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.

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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 limits to tighten nuts and bolts are in SRM Chapter 51

4. Use the approved fastener and process 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.

6. A Detailed Inspection is defined as: An intensive examination of a specific item,

installation, or assembly to detect damage, failure, or irregularity. Available lighting

is normally supplemented with a direct source of good lighting at an intensity deemed

appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be

necessary. Surface cleaning and elaborate procedures may be required.

7. These work instructions refer to procedures included in other Boeing documents.

When the words "refer to" are used and the operator has an accepted alternative

procedure, the accepted alternative procedure can be used. When the words "in

accordance with" are included in the instruction, the procedure in the Boeing document

must be used.

8. Boeing Service Letter 777-SL-51-013, 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.

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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.

B. WORK INSTRUCTIONS

1. Install Main Landing Gear (MLG) door locks. Refer to 777 AMM 32-00-15 as an accepted procedure.

2. Install MLG down locks. Refer to 777 AMM 32-00-30 as an accepted procedure.

3. Do Part 1: Inspection of the MLG Forward Trunnion Lower Housing Fuse Pin Cross Bolts.

a. Condition 1: 1) All MLG Forward Trunnion Lower Housing cross bolts are correctly installed

and 2) no MLG Forward Trunnion Lower Housing fuse pins are missing.

(1) No further action is required.

b. Condition 2: 1) Any MLG Forward Trunnion Lower Housing fuse pin cross bolt is not correctly

installed or 2) any MLG Forward Trunnion Lower Housing fuse pin is missing.

(1) Do Part 2: Replacement of the MLG Forward Trunnion Upper and Lower Housing Fuse

Pins.

4. Remove MLG down locks. Refer to 777 AMM 32-00-30 as an accepted procedure.

5. Remove MLG door locks. Refer to 777 AMM 32-00-15 as an accepted procedure.

6. Put the airplane back to a serviceable condition.

Part 1: Inspection of the MLG Forward Trunnion Lower Housing Fuse Pin Cross Bolts

1. Do a Detailed Inspection (DET) of the left and right MLG Forward Trunnion Lower Housing fuse

pin cross bolts to make sure the cross bolts are correctly installed and all MLG Forward Trunnion

Lower Housing fuse pins are installed in accordance with the figures below.

Left MLG Right MLG

FIGURE 1 FIGURE 2

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Part 2: Replacement of the MLG Forward Trunnion Upper and Lower Housing Fuse Pins

1. Lift the airplane at the main jack points until the wheels are just off the ground. Refer to 777 AMM

07-11-01 as an accepted procedure.

2. Remove two side load straps from the supports near the MLG Forward Trunnion Upper and Lower

Housing. Refer to 777 AMM 32-11-01 as an accepted procedure.

3. Replace all fuse pins in MLG Forward Trunnion Upper and Lower Housing in accordance with the

figures below. Use Axle Jacks under the forward and aft axle jacking points to relieve the load on

the fuse pins and adjust as needed. The load is approximately 9000 to 10000 lbs. Refer to 777

AMM 07-11-03 as an accepted procedure.

Left MLG Right MLG

FIGURE 3 FIGURE 4

4. Install two side load straps to the supports near the MLG Forward Trunnion Upper and Lower

Housing. Refer to 777 AMM 32-11-01 as an accepted procedure.

5. Lower the airplane. Refer to 777 AMM 07-11-01 as an accepted procedure.

6. Put the airplane back to a serviceable condition.

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FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 1 OF 3)

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FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

in MLG Forward

Trunnion Lower

Housing. Do a Detailed Inspection

(DET) of the cross

bolt to make sure

the cross bolt is correctly installed in the

fuse pin. The cross

bolt should be fully

engaged in the fuse

pin.

1 Inspect CROSS BOLT - 4

FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 3 OF 3)

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FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 1 OF 3)

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FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

in MLG Forward

Trunnion Lower

Housing. Do a Detailed Inspection

(DET) of the cross

bolt to make sure

the cross bolt is correctly installed in the

fuse pin. The cross

bolt should be fully

engaged in the fuse

pin.

1 Inspect CROSS BOLT - 4

FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION

(SHEET 3 OF 3)

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FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 1 OF 3)

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NOTE: Fuse pin replacement is recommended to be done one fuse pin at a time.

FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 2 OF 3)

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STEP TASK NAME IDENTIFICATION QTY MORE DATA

Refer to 777 AMM

32-11-01 as an accepted procedure.

CROSS BOLT (UP- - 2

PER)

1 Remove / Keep

Remove UPPER FUSE PIN - 2

Refer to 777 AMM

32-11-01 as an accepted procedure.

CROSS BOLT (LOW- - 4

ER)

2 Remove / Keep

Remove LOWER FUSE PIN - 4

Refer to 777 AMM

32-11-01 as an accepted procedure.

3 Install (New) LOWER FUSE PIN - 4

CROSS BOLT (LOW- - 4 (a)

ER)

Install (Kept)

Refer to 777 AMM

32-11-01 as an accepted procedure.

4 Install (New) UPPER FUSE PIN - 2

CROSS BOLT (UP- - 2 (a)

PER)

Install (Kept)

(a) Make sure the cross bolt is fully engaged in the fuse pin.

FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 3 OF 3)

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FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 1 OF 3)

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NOTE: Fuse pin replacement is recommended to be done one fuse pin at a time.

FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 2 OF 3)

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STEP TASK NAME IDENTIFICATION QTY MORE DATA

Refer to 777 AMM

32-11-01 as an accepted procedure.

CROSS BOLT (UP- - 2

PER)

1 Remove / Keep

Remove UPPER FUSE PIN - 2

Refer to 777 AMM

32-11-01 as an accepted procedure.

CROSS BOLT (LOW- - 4

ER)

2 Remove / Keep

Remove LOWER FUSE PIN - 4

Refer to 777 AMM

32-11-01 as an accepted procedure.

3 Install (New) LOWER FUSE PIN - 4

CROSS BOLT (LOW- - 4 (a)

ER)

Install (Kept)

Refer to 777 AMM

32-11-01 as an accepted procedure.

4 Install (New) UPPER FUSE PIN - 2

CROSS BOLT (UP- - 2 (a)

PER)

Install (Kept)

(a) Make sure the cross bolt is fully engaged in the fuse pin.

FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT

(SHEET 3 OF 3)

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ALERT ALERT