# Boeing Alert Service Bulletin 777-57A0090: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2011-1320; AD 2012-11-03 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 777-57A0090](https://openairdocs.org/service-documents/boeing/777-57a0090.md)
- Title as filed: U.S. DOT/FAA - Boeing Service Bulletin 777-57A0090
- Pages: 37
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- Page: https://openairdocs.org/service-documents/boeing/777-57a0090/file/3d5449b709eb

## Text

Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

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.
9E991ECCN:
BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET
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Unpublished Work - All Rights Reserved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,
BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the
Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
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Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A. Effectivity ................................................ 9
1. Airplanes ............................................. 9
2. Spares Affected ........................................ 1 3
B. Concurrent Requirements ...................................... 1 3
C. Reason ................................................ 1 4
D. Description .............................................. 1 4
E. Compliance .............................................. 1 5
F. Approval ............................................... 1 6
G. Manpower .............................................. 1 6
H. Weight and Balance Changes .................................... 1 7
I. Electrical Load Data ......................................... 1 7
J. References .............................................. 1 7
1. Existing Data .......................................... 1 7
2. Data supplied with this Service Bulletin ............................ 1 7
3. Installation Drawings Used in the Preparation of this Service Bulletin ............ 1 7
K. Publications Affected ........................................ 1 7
L. Interchangeability and Intermixability of Parts ........................... 1 8
2. MATERIAL INFORMATION ........................................ 1 9
A. Material - Price and Availability ................................... 1 9
B. Industry Support Information .................................... 2 0
C. Parts Necessary For Each Airplane ................................. 2 0
1. Kits/Parts ............................................ 2 0
2. Parts and Materials Supplied by the Operator ........................ 2 0
3. Parts Modified and Reidentified ................................ 2 1
4. Parts Removed and Not Replaced .............................. 2 2
D. Parts Necessary to Change Spares ................................. 2 2
E. Special Tooling - Price and Availability ............................... 2 2
F. Special Tooling Necessary to do this Service Bulletin ....................... 2 2
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 2 3
A. GENERAL INFORMATION ..................................... 2 3
B. WORK INSTRUCTIONS ....................................... 2 4
FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
.................................................. 2 6
FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
.................................................. 2 9
FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT
.................................................. 3 2
FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN
REPLACEMENT ........................................ 3 5
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Commercial 
Airplanes
777
Service Bulletin
ALERT
SummaryNumber: 777-57A0090Original 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
Elapsed HoursTotal Task HoursAirplanes
16.0044.00All
MATERIAL INFORMATION
Operator Supplied Parts/Materials.
Refer to Paragraph 2.A., Material - Price and Availability
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BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
FWD
INBD
LEFT SIDE SHOWN  TRUNNION
RIGHT SIDE OPPOSITE
• MLG FORWARD
TRUNNION
UPPER HOUSING
FUSE PIN
MLG FORWARD
TRUNNION
LOWER HOUSING
FUSE PIN
SIDE LOAD
FWD  STRAPS
DO A DETAILED INSPECTION (DET) OF ALL 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.
2058071
Original Issue: August 24, 2011
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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.
DESCRIPTIONCONFIGURATIONGROUP
777-200 Airplanes line number 1 thru 635-1
777-200 Airplanes with extended range (ER) option line number 41
thru 868
-2
777-300 Airplanes line number 94 thru 567-3
777-200LR/-300ER and 777F Airplanes line number 423 thru 915-4
Airplane Models:
777-200, 777-200LR, 777-300, 777-300ER, 777F
GroupVariable Number
1WA001 - WA017
1WA076 - WA080
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GroupVariable Number
1WA086 - WA093
1WA101 - WA104
1WA116 - WA119
1WA131 - WA137
1WA171 - WA175
1WA196 - WA198
1WA206 - WA212
1WA221 - WA223
1WA231 - WA232
1WA241 - WA250
1WA261 - WA266
1WA281 - WA283
1WA301 - WA304
2WB001 - WB021
2WB031 - WB046
2WB051 - WB088
2WB101 - WB106
2WB121 - WB125
2WB131 - WB148
2WB151 - WB155
2WB161 - WB177
2WB181 - WB194
2WB201 - WB215
2WB231 - WB247
2WB271 - WB273
2WB276 - WB286
2WB291 - WB302
2WB306 - WB307
2WB311 - WB337
2WB341 - WB342
2WB366 - WB368
2WB371 - WB388
2WB406
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GroupVariable Number
2WB411 - WB413
2WB416 - WB439
2WB446 - WB453
2WB476
2WB481 - WB484
3WB501 - WB512
3WB531 - WB537
3WB551 - WB554
3WB591 - WB597
3WB601 - WB606
3WB611 - WB622
3WB631 - WB638
3WB646 - WB649
2WC051 - WC073
2WC101 - WC104
2WC111 - WC120
2WC221 - WC224
2WC241 - WC243
2WC281 - WC290
2WC301 - WC308
2WC361 - WC364
2WC371 - WC374
2WC381 - WC395
2WC441
2WC446 - WC449
2WC456 - WC459
2WC486 - WC493
2WC506 - WC508
2WC521 - WC522
2WC531 - WC536
2WC546 - WC548
2WC556
2WC566 - WC567
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GroupVariable Number
2WC571 - WC574
2WC581
4WD001 - WD002
4WD011 - WD018
4WD031 - WD036
4WD046 - WD055
4WD066 - WD075
4WD081 - WD088
4WD091
4WD096
4WD101 - WD103
4WD501 - WD513
4WD521 - WD541
4WD546 - WD554
4WD561 - WD573
4WD581 - WD599
4WD606 - WD609
4WD621 - WD632
4WD651 - WD665
4WD671 - WD676
4WD691 - WD709
4WD741 - WD752
4WD761 - WD771
4WD786 - WD788
4WD796 - WD813
4WD826 - WD837
4WD846 - WD861
4WD871 - WD883
4WD911 - WD915
4WD921 - WD922
4WD936 - WD939
4WD946 - WD951
4WD966 - WD970
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GroupVariable Number
4WD981 - WD982
4WD986 - WD987
4WD996
4WE001 - WE004
4WE011 - WE012
4WE021 - WE024
4WE031
4WE051 - WE052
4WE071
4WE081 - WE082
4WE126 - WE131
4WF001 - WF004
4WF016 - WF020
4WF031 - WF032
4WF046 - WF053
4WF076 - WF077
4WF081 - WF088
4WF096 - WF099
4WF106 - WF107
4WF111 - WF112
4WF121
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
ZoneModel
143, 144777-200
Group 3:
Affected Maintenance Zones
ZoneModel
143, 144777-300
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Group 4:
Affected Maintenance Zones
ZoneModel
143, 144777-200LR, 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.
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)
Compliance TimeActionCondition
-Within 1125 days
after the original is-
sue 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 correct-
ly installed and all MLG
Forward Trunnion Lower
Housing fuse pins are in-
stalled in accordance with
Part 1.
All Airplanes
--No further action required
(Terminating Action).
Condition 1:
1) All MLG Forward Trun-
nion Lower Housing cross
bolts are correctly installed.
-AND-
2) No MLG Forward Trun-
nion 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)
Compliance TimeActionCondition
-Before further
flight.
Replace all fuse pins in
MLG Forward Trunnion
Upper and Lower Hous-
ing in accordance with
Part 2 (Terminating Ac-
tion).
Condition 2:
1) Any MLG Forward Trun-
nion Lower Housing cross
bolt is not correctly in-
stalled.
-OR-
2) Any MLG Forward Trun-
nion 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.
Elapsed HoursTask HoursNumber of PersonsTask
1.001.001Get Access
0.500.501FIGURE 1: Inspect
0.500.501FIGURE 2: Inspect
2.5012.505Lift the Airplane
1.002.002Remove Load Straps
3.006.002FIGURE 3: Replace
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Elapsed HoursTask HoursNumber of PersonsTask
3.006.002FIGURE 4: Replace
1.002.002Install Load Straps
2.5012.505Lower the Airplane
1.001.001Close Access
16.0044.00TOTAL FOR EACH AIRPLANE
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
TitleDrawing Number
SUPPORT INSTL - FORWARD TRUNNION MLG112W1701
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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Chapter-SectionPublication
32-11777 Aircraft Maintenance Manual
2. Damage Tolerance Based Structural Inspections:
Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue
Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the
Maintenance Program. This service bulletin affects FCS 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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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 Ser-
vice Bulletin (US
Dollars)
ROLT as of the
original issue
date of this Ser-
vice Bulletin (Cal-
endar Days)
NamePart Number
$ 1,213.00300LOWER FUSE PIN112W1712-3
$ 1,378.00300UPPER FUSE PIN112W1712-4
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 Ser-
vice Bulletin (US
Dollars)
ROLT as of the
original issue
date of this Ser-
vice Bulletin (Cal-
endar Days)
NamePart Number
$ 1,213.00300LOWER FUSE PIN112W1712-3
$ 2,191.00300UPPER FUSE PIN112W1712-5
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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 Ser-
vice Bulletin (US
Dollars)
ROLT as of the
original issue
date of this Ser-
vice Bulletin (Cal-
endar Days)
NamePart Number
$ 2,191.00300UPPER FUSE PIN112W1712-5
$ 5,482.00300LOWER FUSE PIN112W1712-6
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 Ser-
vice Bulletin (US
Dollars)
ROLT as of the
original issue
date of this Ser-
vice Bulletin (Cal-
endar Days)
NamePart Number
$ 1,751.00300LOWER FUSE PIN112W1712-7
$ 1,751.00300UPPER FUSE PIN112W1712-8
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:
NotesNameQTYPart Number /
Specification
(a)LOWER FUSE PIN8112W1712-3
(a)UPPER FUSE PIN4112W1712-4
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Group 1:
NotesNameQTYPart Number /
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:
NotesNameQTYPart Number /
Specification
(a)LOWER FUSE PIN8112W1712-3
(a)UPPER FUSE PIN4112W1712-5
(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:
NotesNameQTYPart Number /
Specification
(a)UPPER FUSE PIN4112W1712-5
(a)LOWER FUSE PIN8112W1712-6
(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:
NotesNameQTYPart Number /
Specification
(a)LOWER FUSE PIN8112W1712-7
(a)UPPER FUSE PIN4112W1712-8
(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.
Right MLGLeft MLG
FIGURE 2FIGURE 1
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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.
Right MLGLeft MLG
FIGURE 4FIGURE 3
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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BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
0,08
LEFT SIDE SHOWN
TRUNNION
SIDE LOAD
STRAP
MLG FORWARD
TRUNNION
LOWER HOUSING
SIDE LOAD
STRAP
FWD
2058074
FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLTINSPECTION
(SHEET 1 OF 3)
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### Page 27 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
• SIDE
LOAD
STRAP
MLG FORWARD
TRUNNION
LOWER HOUSING
SIDE
LOAD
STRAP
INBD
B
MLG FORWARD TRUNNION
LOWER HOUSING
FUSE
PIN
INCORRECT  A-A  CORRECT  2058196
FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
(SHEET 2 OF 3)
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### Page 28

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
in MLG Forward
Trunnion Lower
Housing. Do a De-
tailed Inspection
(DET) of the cross
bolt to make sure
the cross bolt is cor-
rectly installed in the
fuse pin. The cross
bolt should be fully
engaged in the fuse
pin.
4-CROSS BOLTInspect1
FIGURE 1: LEFT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
(SHEET 3 OF 3)
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### Page 29 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
FWD  00 0
NBL
RIGHT SIDE SHOWN
TRUNNION
SIDE LOAD
STRAP
B
MLG FORWARD
TRUNNION
LOWER HOUSING
SIDE LOAD
STRAP
2058251
FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
(SHEET 1 OF 3)
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### Page 30 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
SIDE
LOAD
STRAP
MLG FORWARD
TRUNNION
LOWER HOUSING
SIDE
LOAD
STRAP
INBD
MLG FORWARD TRUNNION
LOWER HOUSING
FUSE
PIN
INCORRECT  A-A  CORRECT  2058669
FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
(SHEET 2 OF 3)
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0G000-LLL
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### Page 31

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
in MLG Forward
Trunnion Lower
Housing. Do a De-
tailed Inspection
(DET) of the cross
bolt to make sure
the cross bolt is cor-
rectly installed in the
fuse pin. The cross
bolt should be fully
engaged in the fuse
pin.
4-CROSS BOLTInspect1
FIGURE 2: RIGHT MLG FORWARD TRUNNION LOWER HOUSING FUSE PIN CROSS BOLT INSPECTION
(SHEET 3 OF 3)
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### Page 32 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
0,08
LEFT SIDE SHOWN
TRUNNION
MLG FORWARD
TRUNNION
LOWER HOUSING
FWD
2059992
FIGURE 3: LEFT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT
(SHEET 1 OF 3)
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### Page 33 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
(BOTH SIDES)
₴
(BOTH SIDES)
INBD
2061603
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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### Page 34

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
2-CROSS BOLT (UP-
PER)
Remove / Keep1
2-UPPER FUSE PINRemove
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
4-CROSS BOLT (LOW-
ER)
Remove / Keep2
4-LOWER FUSE PINRemove
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
4-LOWER FUSE PINInstall (New)3
(a)4-CROSS BOLT (LOW-
ER)
Install (Kept)
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
2-UPPER FUSE PINInstall (New)4
(a)2-CROSS BOLT (UP-
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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### Page 35 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
FWD
NBD
RIGHT SIDE SHOWN
TRUNNION
MLG FORWARD
TRUNNION
LOWER HOUSING
2060819
FIGURE 4: RIGHT MLG FORWARD TRUNNION UPPER AND LOWER HOUSING FUSE PIN REPLACEMENT
(SHEET 1 OF 3)
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### Page 36 (OCR)

BOEING SERVICE BULLETIN 777-57A0090
ALERT  ALERT
(2) 3
(BOTH SIDES
(2) 3
(BOTH SIDES)
FWD
INBD
2061605
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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### Page 37

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
2-CROSS BOLT (UP-
PER)
Remove / Keep1
2-UPPER FUSE PINRemove
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
4-CROSS BOLT (LOW-
ER)
Remove / Keep2
4-LOWER FUSE PINRemove
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
4-LOWER FUSE PINInstall (New)3
(a)4-CROSS BOLT (LOW-
ER)
Install (Kept)
Refer to 777 AMM
32-11-01 as an ac-
cepted procedure.
2-UPPER FUSE PINInstall (New)4
(a)2-CROSS BOLT (UP-
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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