# Boeing Alert Service Bulletin 737-57A1277: Revision 3

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2013-0542; AD 2014-05-12 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 737-57A1277](https://openairdocs.org/service-documents/boeing/737-57a1277.md)
- Title as filed: U.S. DOT/FAA - SB-737-57A1277-03
- Pages: 50
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## Text

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### Page 1

Commercial 
Airplanes
737
Service Bulletin
Number: 737-57A1277
Original Issue: July 25, 2002
Revision 3: May 16, 2012
ATA System: 5752
SUBJECT: WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking
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 © 2002 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Unpublished Work - All Rights Reserved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
Revision Transmittal Sheet ............................................ 5
Summary ...................................................... 7
1. PLANNING INFORMATION ........................................ 1 1
A. Effectivity ............................................... 1 1
1. Airplanes ............................................ 1 1
2. Spares Affected ........................................ 2 2
B. Concurrent Requirements ...................................... 2 2
C. Reason ................................................ 2 2
D. Description .............................................. 2 3
E. Compliance .............................................. 2 4
F. Approval ............................................... 2 6
G. Manpower .............................................. 2 6
H. Weight and Balance Changes .................................... 2 7
I. Electrical Load Data ......................................... 2 7
J. References .............................................. 2 7
1. Existing Data: ......................................... 2 7
2. Data supplied with this Service Bulletin: ........................... 2 7
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 2 8
K. Publications Affected ........................................ 2 8
L. Interchangeability and Intermixability of Parts ........................... 2 8
2. MATERIAL INFORMATION ........................................ 2 9
A. Material - Price and Availability ................................... 2 9
B. Industry Support Information .................................... 2 9
C. Parts Necessary For Each Airplane ................................. 2 9
1. Kits/Parts: ........................................... 2 9
2. Parts and Materials Supplied by the Operator: ........................ 2 9
3. Parts Modified and Reidentified: ............................... 2 9
4. Parts Removed and Not Replaced: .............................. 2 9
D. Parts Necessary to Change Spares ................................. 2 9
E. Special Tooling - Price and Availability ............................... 2 9
F. Special Tooling Necessary to do this Service Bulletin ....................... 2 9
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 1
A. GENERAL INFORMATION ..................................... 3 1
B. WORK INSTRUCTIONS ....................................... 3 2
FIGURE 1: CARRIAGE SPINDLE INSPECTION ............................. 3 6
FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD ............. 3 8
FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD ........... 4 0
FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD ...... 4 3
FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD ..... 4 5
FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK ................ 4 8
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Commercial 
Airplanes
737
Service Bulletin
Revision Transmittal SheetNumber: 737-57A1277Original Issue: July 25, 2002
Revision 3: May 16, 2012
ATA System: 5752
SUBJECT: WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking
This revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service bulletin.
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.
No more work is necessary on the airplane(s) changed in accordance with Revision 2 of this service bulletin.
REASON FOR REVISION
This revision is sent to provide information for compliance table 1 that was in revision R1 but was inadvertantly
deleted in revision R2.
These sections were changed:
1. Section 1.E. Compliance, Table 1 - re-inserted "Work Package 1 (NDT): Not Required"
2. Section 1.F. Approval, changed revision 2 to revision 3.
3. Section 3.A. General Information, deleted note 1. "The sequence of steps ... can be changed".
The data given in Information Notice 737-57A1277 IN 03 is included in this revision.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location
of important changes.
Pages with no vertical lines have no important changes.
REVISION HISTORY
July 25, 2002Original Issue:
November 25, 2003Revision 1:
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June 09, 2011Revision 2:
May 16, 2012Revision 3:
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Commercial 
Airplanes
737
Service Bulletin
SummaryNumber: 737-57A1277Original Issue: July 25, 2002
Revision 3: May 16, 2012
ATA System: 5752
SUBJECT: WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking
CONCURRENT REQUIREMENTS
None
BACKGROUND
This service bulletin provides instructions for the inspection of the outboard midflap carriage spindles and will
ensure that the carriage spindles are not fractured.
42 severed outboard midflap carriage spindles (resulting from corrosion, fatigue and/or improper overhaul) have
been reported by 23 operators. The most critical section for a fracture is at the forward end of the spindle through
the large diameter. Of the 42 reported fractures, 24 have been thru the critical "A" location and 18 reported at
the "B" spindle location . The fractures occurred on 737-200/-300/-400/-500 airplanes.
If one carriage spindle fractures in the forward end of the spindle (the critical section), the pilot can compensate
for it with inputs to the aileron and/or rudder. However, if both the inboard and outboard spindles fracture in the
critical section on an outboard flap, continued safe flight and landing of the airplane may be precluded.
Boeing received a recent report about a 737-200 having both inboard and outboard spindles (number 7 & 8
carriage spindles) severed on the right outboard flap during landing. The flight crew reported a loud bang at
approximately 500 feet AGL followed by the airplane rolling off hard to the right. Corrective action was required
to maintain level flight. As a result, a gap check was developed to detect severed spindles only at the critical
"A" location. Whereas, the NDT inspection, in the previous issue of this service bulletin, checks the critical "A"
location thru the "B" location up to the cross bolt for the spherical bearing.
ACTION
Extend the flaps. For the left and right midflaps, do an NDT inspection or Gap Check of the spindle at each
carriage (two carriages per midflap) at the specified time. The NDT inspection or Gap Check will detect a fracture
in the spindle. If the spindle is fractured or severed, remove it from service, discard it, and notify Boeing. Then,
install a new or serviceable carriage spindle. If you notice corrosion at the exposed portion of the spindle, remove
the carriage and overhaul the spindle.
EFFECTIVITY
All 737-100, -200, -200C, -300, -400, and -500 airplanes.
COMPLIANCE
Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service bulletin.
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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.
See Paragraph 1.E., Compliance.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the inspection given in this service bulletin.
MANPOWER
Elapsed HoursTotal Task HoursWork Package
8161
122
MATERIAL INFORMATION
None
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BOEING SERVICE BULLETIN 737-57A1277
SEE  IT IS NOT NECESSARY TO
REMOVE THE COVER PLATE
DO AN NDT INSPECTION
AND GAP CHECK OF THE
CARRIAGE SPINDLE
SPINDLE BEARING
BEARING SUPPORT
SEE  TRAILING
EDGE FLAP
OUTBOARD MIDFLAP
CARRIAGE
V86821
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Commercial 
Airplanes
737
Service Bulletin
Number: 737-57A1277
Original Issue: July 25, 2002
Revision 3: May 16, 2012
ATA System: 5752
SUBJECT: WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking
1.    PLANNING INFORMATION
A. Effectivity
1. Airplanes
Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
This service bulletin is for the airplanes shown below.
DESCRIPTIONCONFIGURATIONGROUP
737-100, -200, -200C, -300, -400 and -500 airplanes-1
Airplane Models:
737-100, 737-200, 737-200C, 737-300, 737-400, 737-500
GroupVariable Number
1PA001 - PA022
1PA099
1PA231 - PA232
1PC001 - PC005
1PG001 - PG075
1PG199
1PG201 - PG230
1PG251 - PG255
1PG271 - PG279
1PG301 - PG314
1PG331 - PG332
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GroupVariable Number
1PG351 - PG356
1PG375
1PG401 - PG403
1PG431 - PG442
1PG471 - PG475
1PG501 - PG505
1PG571 - PG586
1PG621 - PG630
1PG651 - PG652
1PG701 - PG705
1PH001
1PH011 - PH013
1PH021 - PH024
1PH701 - PH715
1PH731 - PH732
1PH741 - PH743
1PJ001 - PJ009
1PJ031 - PJ032
1PJ071 - PJ072
1PJ101 - PJ119
1PJ201 - PJ219
1PJ301 - PJ302
1PJ551 - PJ561
1PJ601 - PJ615
1PJ811
1PJ816 - PJ817
1PK026 - PK029
1PK041 - PK053
1PK061 - PK070
1PK081 - PK082
1PK091 - PK099
1PK101 - PK103
1PK111 - PK120
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GroupVariable Number
1PK141 - PK146
1PK201 - PK204
1PK211 - PK223
1PK231 - PK241
1PK251 - PK258
1PK271 - PK274
1PK281 - PK289
1PK291
1PK301 - PK318
1PK341
1PK351 - PK361
1PK391
1PK431 - PK433
1PK451 - PK452
1PK461 - PK469
1PK495
1PK501 - PK504
1PK511 - PK515
1PK519
1PK521 - PK528
1PK541 - PK565
1PK581
1PK591 - PK599
1PK601 - PK617
1PK621 - PK637
1PK641 - PK642
1PK661 - PK666
1PK671 - PK681
1PK691 - PK697
1PK711 - PK716
1PK731 - PK765
1PK771 - PK779
1PK801 - PK804
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GroupVariable Number
1PK819 - PK827
1PK830
1PK861 - PK863
1PK871 - PK874
1PK881 - PK884
1PK901 - PK938
1PK971 - PK974
1PL001 - PL028
1PL061
1PL081
1PL101 - PL113
1PL151
1PL171 - PL172
1PL201 - PL203
1PL221
1PL401 - PL417
1PL421
1PL441
1PL451 - PL456
1PL471
1PL491
1PL501 - PL506
1PL551 - PL562
1PL581
1PL601 - PL603
1PL611
1PL621 - PL626
1PL631 - PL632
1PL711 - PL712
1PL716 - PL747
1PL756
1PL758
1PL761 - PL770
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GroupVariable Number
1PL781 - PL788
1PL793
1PL801 - PL803
1PM001 - PM006
1PM016 - PM017
1PM021 - PM023
1PM051 - PM066
1PM101 - PM119
1PM141 - PM142
1PM171
1PM181
1PM251 - PM255
1PM281 - PM283
1PM381 - PM399
1PM401 - PM417
1PM541 - PM564
1PN001 - PN002
1PN021 - PN043
1PN081 - PN086
1PN101 - PN117
1PN131 - PN163
1PN401 - PN420
1PN431 - PN433
1PN451 - PN456
1PN471 - PN474
1PN481
1PN491 - PN493
1PN501 - PN502
1PN511 - PN512
1PN521
1PP001 - PP054
1PP101 - PP169
1PP181 - PP199
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GroupVariable Number
1PP201 - PP205
1PP221
1PP231 - PP243
1PP281 - PP286
1PP301 - PP305
1PP351 - PP353
1PP376 - PP384
1PP391 - PP393
1PP401 - PP440
1PP471 - PP475
1PP501 - PP522
1PP631 - PP634
1PP651 - PP652
1PP671 - PP699
1PP701 - PP733
1PP771 - PP779
1PP801 - PP808
1PP821 - PP827
1PP831 - PP848
1PP851 - PP852
1PP861 - PP877
1PP891 - PP899
1PP901 - PP936
1PP946 - PP948
1PP951 - PP952
1PP961 - PP967
1PP981 - PP991
1PP993
1PQ001 - PQ016
1PQ026 - PQ041
1PQ051 - PQ092
1PQ101 - PQ199
1PQ201 - PQ202
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GroupVariable Number
1PQ221 - PQ237
1PQ241 - PQ243
1PQ251 - PQ267
1PQ281 - PQ299
1PQ301 - PQ307
1PQ331 - PQ332
1PQ341 - PQ348
1PQ361 - PQ373
1PQ391 - PQ395
1PQ401 - PQ418
1PQ421
1PQ431 - PQ438
1PQ447 - PQ448
1PQ451
1PQ454
1PQ471 - PQ475
1PQ479 - PQ481
1PQ486 - PQ487
1PQ491 - PQ493
1PQ771 - PQ772
1PQ791 - PQ793
1PQ801 - PQ805
1PQ931 - PQ935
1PQ951
1PQ971 - PQ997
1PR001 - PR017
1PR021 - PR034
1PR041 - PR045
1PR061 - PR072
1PR077 - PR082
1PR091 - PR092
1PR096
1PR101
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GroupVariable Number
1PR121 - PR122
1PR131 - PR132
1PR141 - PR143
1PR161 - PR172
1PR181
1PS601 - PS631
1PS636 - PS638
1PS641 - PS644
1PS651 - PS657
1PS666 - PS669
1PS691 - PS692
1PS701 - PS706
1PS751 - PS799
1PS811
1PS836 - PS837
1PS841 - PS846
1PS851 - PS852
1PS856
1PS861 - PS863
1PS866 - PS868
1PS871 - PS874
1PS896 - PS897
1PS901 - PS941
1PS956 - PS957
1PS961 - PS963
1PS971 - PS978
1PT001 - PT015
1PT021 - PT031
1PT041 - PT064
1PT101 - PT105
1PT121 - PT138
1PT146 - PT148
1PT161 - PT170
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GroupVariable Number
1PT181 - PT188
1PT211 - PT220
1PT295
1PT301 - PT309
1PT331 - PT360
1PT381 - PT399
1PT401 - PT438
1PT501 - PT517
1PT561 - PT565
1PT581 - PT586
1PT611 - PT621
1PT641 - PT644
1PT651 - PT656
1PT671 - PT672
1PT681 - PT685
1PT701 - PT703
1PT716 - PT717
1PT721 - PT725
1PT801 - PT834
1PT851 - PT854
1PT871 - PT886
1PT901 - PT930
1PT971 - PT973
1PT981 - PT985
1PT996
1PU001 - PU025
1PU301
1PU311 - PU313
1PV001 - PV055
1PV201 - PV209
1PV226 - PV229
1PV231 - PV237
1PV271 - PV272
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GroupVariable Number
1PV281 - PV287
1PV296
1PV301 - PV302
1PV351
1PV356 - PV357
1PW001 - PW054
1PW061 - PW068
1PW072
1PW086 - PW088
1PW091 - PW094
1PW101 - PW102
1PW106
1PW111 - PW120
1PW156 - PW157
1PW161 - PW171
1PW201 - PW252
1PW261 - PW268
1PW271 - PW276
1PW278
1PW281 - PW293
1PW296
1PW301 - PW327
1PW401 - PW408
1PW411 - PW418
1PW421 - PW424
1PW431 - PW435
1PW441 - PW450
1PW461 - PW467
1PW501 - PW504
1PW511 - PW522
1PW524 - PW550
1PW556 - PW557
1PW561 - PW564
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GroupVariable Number
1PW571 - PW576
1PW591 - PW596
1PW611 - PW622
1PW631 - PW637
1PW661 - PW662
1PW681 - PW683
1PW701 - PW702
1PW711 - PW717
1PW741 - PW742
1PW761
1PW771
1PW831
1PW851 - PW856
1PX071
1PX701
1PY001 - PY008
1PY021 - PY022
1PY031
1PY036 - PY037
1PY046 - PY048
1PY051 - PY053
1PY056 - PY057
1PY101 - PY103
1PY111 - PY113
1PY131 - PY135
1PY141 - PY143
1PY151 - PY154
1PY156 - PY157
1PY161 - PY162
1PY166
1PY191
1PY201
1PY221 - PY222
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GroupVariable Number
1PY231
1PY241 - PY244
1PY270 - PY275
1PY281
1PY286
1PY301 - PY304
1PY321 - PY323
1PY341 - PY346
1PY361 - PY362
1PY381
1PY401
1PY409 - PY411
1PY421 - PY422
1PY441
1PY451
1PY461 - PY463
1PY591 - PY595
1PY611 - PY612
1PY621
1PY631
1PY651
1PY671 - PY672
1PY721
1PY741
2. Spares Affected
None
B. Concurrent Requirements
None
C. Reason
This service bulletin provides instructions for the inspection of the outboard midflap carriage spindles
and will detect severed carriage spindles.
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42 severed outboard midflap carriage spindles (resulting from corrosion, fatigue and/or improper
overhaul) have been reported by 23 operators. The most critical section for a fracture is at the forward
end of the spindle through the large diameter. Of the 42 reported fractures, 24 have been thru the
critical "A" location and 18 reported at the "B" spindle location . The fractures occurred on
737-200/-300/-400/-500 airplanes.
If one carriage spindle fractures at the forward end of the spindle (the critical section), the pilot can
compensate for it with inputs to the aileron and/or rudder. However, if both the inboard and outboard
spindles fracture in the critical section on a outboard flap, continued safe flight and landing of the
airplane may be precluded.
Boeing received a recent report about a 737-200 having both inboard and outboard spindles (number
7 & 8) severed on the right outboard flap during landing. The flight crew reported a loud bang
approximately 500 feet AGL followed by the airplane rolling off hard to the right. Corrective action was
required to maintain level flight. As a result, a gap check was developed to detect severed spindles
only at the critical "A" location.
Revision 1 is issued to add a gap check to determine if a spindle has been fractured at the critical "A"
location. An additional compliance time is also added for this new check. This gap check is under Work
Package 2. The original NDT inspection is now Work Package 1. The NDT compliance times have also
been revised.
Revision 2 is issued to revise the inspection intervals listed in compliance tables 1 and 2 and add a
new compliance table 3.
The intent of Information Notice 737-57A1277 IN 01 has been incorporated into this revision.
The data given in Information Notice 737-57A1277 IN 02 is included in this revision. One of the 2 AMOC
listed on IN 02 is suspended. The AMOC that referenced the use of ultrasonic inspection method to
confirm a severed spindle after performing the gap check has been incorporated.
Revision 3 is issued to provide information for compliance table 1 that was in revision R1 but was
inadvertantly deleted in revision R2. This information was provided in Information Notice 737-57A1277
IN 03 and has been incorporated.
D. Description
Extend the flaps. For the left and right midflaps, do an NDT inspection of the spindle of each carriage
(two carriages per midflap). The NDT inspection will detect a fractured or severed spindle at the critical
"A" location and thru the "B" location to the bolt hole for the spherical bearing. See compliance paragraph
for threshold and interval.
Expand the flaps. Do a gap check on each outboard flap assembly to detect a severed spindle. See
compliance paragraph for threshold and interval.
If the spindle is fractured or severed, remove it from service, discard it, and notify Boeing; then install
a new or serviceable spindle. If you find corrosion at the exposed portion of the spindle, remove the
carriage and overhaul the spindle.
Revision 1 - More inspections are necessary on airplanes inspected as shown in the initial release of
this service bulletin.
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Revision 2 - More work is necessary on airplanes changed in accordance with the original issue and
Revision 1 of this service bulletin.
Revision 3 - No more work is necessary on the airplane(s) changed in accordance with Revision 2 of
this service bulletin.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1:
Affected Maintenance Zones
ZoneModel
3-7, 4-7737-100, 737-200, 737-200C
Group 1:
Affected Maintenance Zones
ZoneModel
307, 407737-300, 737-400, 737-500
E. Compliance
Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service
bulletin.
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:
Table 1
For 737-100/-200/200C/-300/-400/-500 with NEW (never been overhauled) Carriage Spindles :
INTERVAL Whichever is laterTHRESHOLD
Work Package 1 (NDT): 15 Days or 150 flight cycles> 20,000 flight cycles or 8 Years in-service since
spindle was new, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles*
Work Package 1 (NDT): 45 Days or 450 flight cycles12,000 to 20,000 flight cycles since spindle was
new ** Work Package 2 (Gap Check): 15 Days or 150 flight cycles
*
Work Package 1 (NDT): Not Required< 12,000 flight cycles since spindle was new **
Work Package 2 (Gap Check): Not Required
* The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultra-
sonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection.
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Table 1
For 737-100/-200/200C/-300/-400/-500 with NEW (never been overhauled) Carriage Spindles :
INTERVAL Whichever is laterTHRESHOLD
** If the number of flight cycles or time since new cannot be positively determined by reviewing maintenance
records, the threshold is considered the same as carriage spindles having greater than 20,000 flight cycles.
Table 2
For Overhauled Carriage Spindles with documented life less than 40,000 flight cycles:
INTERVAL -300/-400/-500 Whichever is
later
INTERVAL -100/-200/-200C
Whichever is later
THRESHOLD; flight cycles
since last overhaul
Work Package 1 (NDT): 15 Days or 150 flight cycles> 20,000 flight cycles, or 8
Years in service since spindle
was overhauled, whichever
is less **
Work Package 2 (Gap Check): 3 Days or 30 flight cycles *
Work Package 1 (NDT): 15 Days or 150
flight cycles.
Work Package 1 (NDT): 15 Days or
150 flight cycles.
12,000 to 20,000 flight cy-
cles, or 8 Years in service
since spindle was over-
hauled, whichever is less ** Work Package 2 (Gap Check): 3 Days or30 flight cycles *Work Package 2 (Gap Check): 3Days or 30 flight cycles *
Work Package 1 (NDT): 180 Days or
1,500 flight cycles
Work Package 1 (NDT): 60 Days or
500 flight cycles
3,000 to 12,000 flight cycles**
Work Package 2 (Gap Check): 14 Days
or 140 flight cycles *
Work Package 2 (Gap Check): 7
Days or 70 flight cycles *
Work Package 1 (NDT): Not RequiredWork Package 1 (NDT): 180 Days
or 1,500 flight cycles
< 3,000 flight cycles **
Work Package 2 (Gap Check): Not Re-
quired
Work Package 2 (Gap Check): Not
Required
* The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultra-
sonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection.
** If the number of flight cycles or time since last overhaul cannot be positively determined by reviewing
maintenance records, the threshold is considered the same as carriage spindles having greater than 20,000
flight cycles.
Table 3
For Overhauled Carriage Spindles with 40,000 or more flight cycles since new or if undocumented
life:
INTERVAL -300/-400/-500 Whichever is
later
INTERVAL -100/-200/-200C
Whichever is later
THRESHOLD; flight cycles
since last overhaul
Work Package 1 (NDT): 6 Days or 60 flight cycles> 20,000 flight cycles,or 8
years in service since spindle
was overhauled, whichever
is less **
Work Package 2 (Gap Check): Daily or 20 flight cycles *
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Table 3
For Overhauled Carriage Spindles with 40,000 or more flight cycles since new or if undocumented
life:
INTERVAL -300/-400/-500 Whichever is
later
INTERVAL -100/-200/-200C
Whichever is later
THRESHOLD; flight cycles
since last overhaul
Work Package 1 (NDT): 15 Days or 150
flight cycles
Work Package 1 (NDT): 6 Days or
60 flight cycles
< 20,000 flight cycles, or 8
Years in service since spindle
was overhauled, whichever
is less ** Work Package 2 (Gap Check): 3 Days or30 flight cycles *Work Package 2 (Gap Check):Daily or 20 flight cycles *
* The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultra-
sonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection.
** If the number of flight cycles or time since last overhaul cannot be positively determined by reviewing
maintenance records, the threshold is considered the same as carriage spindles having greater than 20,000
flight cycles.
F. Approval
This service bulletin was inspected by the Federal Aviation Administration (FAA). The changes specified
in this service bulletin comply with the applicable regulations and are FAA approved. This service
bulletin and the FAA approval were based on the airplane in its original Boeing delivery configuration
or as modified by other FAA approved Boeing changes.
The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of
the applicable inspections, investigative, and corrective actions at the corresponding compliance times
specified in Service Bulletin 737-57A1277, Revision 3 as an AMOC to the inspections, investigative
and corrective actions with the corresponding compliance times specified in Service Bulletin 737-57A
1277, Revision 1, required by paragraphs (g), (h), (i), (j), (k), (I), and (n) of AD 2010-15-08. When this
service bulletin specifies contacting Boeing for repair instruction, the repair instructions must be approved
by the FAA in accordance with paragraph (t) of the AD. All provisions of AD 2010-15-08 that are not
specifically referenced in this paragraph remain fully applicable and must be complied with accordingly.
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 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 find the tools.
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Work Package 1 (NDT Ultrasonic and General Visual Inspection)
Elapsed HoursTask-HoursNumber of Per-
sons
Task
1.532Open Access
5.0102Inspect
1.532Close Access
816TOTAL FOR EACH AIRPLANE
Work Package 2 (Gap Check)
Elapsed HoursTask-HoursNumber of Per-
sons
Task
122Inspect
12TOTAL FOR EACH AIRPLANE
H. Weight and Balance Changes
None
I. Electrical Load Data
None
J. References
1. Existing Data:
a. 737 Nondestructive Test (NDT) Manual, Part 4, Subject 57-50-02.
b. 737 Overhaul Manual (OHM), Subject 57-53-35.
c. 737 Component Maintenance Manual (CMM), Subject 57-53-36.
d. 737 Airplane Maintenance Manual (AMM), Subject 27-51-72, 737-100/200 AMM 27-51-81.
e. 737-300/400/500 Airplane Maintenance Manual (AMM), Subject 27-51-34, 737-300/400/500
AMM 27-51-44.
f. Boeing Service Bulletin 737-57A1218, "WINGS - Trailing Edge Flaps - Outboard Flap Carriage
Spindle Repair".
g. Boeing Standard Overhaul Practices Manual (BSOPM) 20-42-09
h. Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08
2. Data supplied with this Service Bulletin:
None.
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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 affects FCS but no new DTIs are necessary.
L. Interchangeability and Intermixability of Parts
None
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2.    MATERIAL INFORMATION
A. Material - Price and Availability
None
B. Industry Support Information
Boeing warranty remedies are not available for the inspection given in this service bulletin.
C. Parts Necessary For Each Airplane
1. Kits/Parts:
None.
2. Parts and Materials Supplied by the Operator:
None.
NotesNameQTYPart Number /
Specification
(a)Clay4 oz.*
* Any type of stable clay is acceptable
(a) An Example is: Permoplast Modeling Clay
AMACO, Phone: 317- 244-6871 or 800-374-1600 4717 W. 16th St. Indianapolis, IN 46222
USA
3. Parts Modified and Reidentified:
None.
4. Parts Removed and Not Replaced:
None.
D. Parts Necessary to Change Spares
None
E. Special Tooling - Price and Availability
None.
F. Special Tooling Necessary to do this Service Bulletin
No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance
and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Inspect
operator tool supply to make sure all necessary tools are available.
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BLANK PAGE

### Page 31

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. The work instructions are divided into work packages. Task Hours and Elapsed Hours
for each package are given in Paragraph 1.G., Manpower. You can do each work
package independently.
4. 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 are in Structural Repair Manual (SRM)
Chapter 51
– Torque limits to tighten nuts and bolts are in SRM Chapter 51
5. Use the approved fastener and process material substitutions in accordance with
SRM Chapter 51. Alternate fasteners are listed in SRM Chapter 51.
6. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures,
and SWPM 20-10-19 for the wire separation requirements, as accepted procedures.
7. 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.
8. 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.
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9. A General Visual Inspection is defined as: A visual examination of an interior or
exterior area, installation or assembly to detect obvious damage, failure or irregularity.
This level of inspection is made from within touching distance unless otherwise
specified. A mirror may be necessary to enhance visual access to all exposed surfaces
in the inspection area. This level of inspection is made under normally available
lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may
require removal or opening of access panels or doors. Stands, ladders or platforms
may be required to gain proximity to the area being checked.
10. 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.
11. 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.
12. 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.
13. 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.
The removed part can be discarded if a new or serviceable part is installed.
14. This service bulletin includes functional test procedures for the systems changed by
this service bulletin. More functional tests can possibly be necessary in accordance
with standard maintenance practices because of interruption to other airplane systems.
15. Some Boeing parts are supplied in a temporary configuration. Those parts are
identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is
permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-'
(dash) part number. Boeing Drawing 005W0900 contains more data.
B. WORK INSTRUCTIONS
WORK PACKAGE 1 - On Wing NDT Ultrasonic & General Visual Inspection
1. Extend outboard flaps to detent 40 by doing the following:
a. For 737-100/-200/-200C airplanes, pressurize hydraulic system A; refer to 737 Airplane
Maintenance Manual (AMM), Subject 27-51-0. For 737-300/-400/-500 airplanes, activate
trailing edge flap system; refer to AMM 27-51-00. Or, you can use you own equivalent
procedure.
b. Extend Flaps to detent 40.
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c. For 737-100/-200/-200C airplanes, depressurize hydraulic system A; refer to AMM 27-51-0.
For 737-300/-400/-500 airplanes, deactivate trailing edge flap system; refer to AMM 27-51-00.
Or, you can use your own equivalent procedure.
2. For each carriage spindle of the left and right outboard midflap (two carriage spindles on each
flap), do an NDT Ultrasonic and General Visual Inspection in accordance with Figure 1.
3. If the Figure 1 NDT Ultrasonic indicates a cracked, or severed spindle - prior to further flight:
a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to
AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Install a new or serviceable spindle,
refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package
1.
b. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap.
Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the
spindle of the carriage. Perform a detailed inspection of the spindle for damage in accordance
with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes) or 737 CMM, Subject
57-53-36 (737-300/-400/-500 airplanes). If inspection indicates a severed spindle, the spindle
cannot be overhauled and must be discarded. Notify Boeing of your findings. Install a new or
serviceable spindle, refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM
27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to
paragraph 6. of Work Package 1. If inspection indicated a crack or corrosion go to 4.d.
4. If General Visual Inspection indicates cracking or corrosion in the exposed portion of the spindle
- prior to further flight - do the following:
a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to
AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44.
b. Install a new or serviceable carriage spindle into the midflap and the midflap on the airplane.
Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6.0 of Work Package
1.
c. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap.
Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the
spindle of the carriage. Perform a Detailed Inspection of the spindle for damage in accordance
with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes) or 737 CMM, Subject
57-53-36 (737-300/-400/-500 airplanes).
d. Overhauled carriage spindles shall be done in accordance with 737 OHM, Subject 57-53-35
(737-100/-200/-200C airplanes) or 737 CMM, Subject 57-53-36 (737-300/-400/-500 airplanes)
and Service Bulletin 737-57A1218, Revision 5.
NOTE: When overhauling the carriage, all finishes and plating must be removed from the
spindle
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e. If the spindle does not pass the inspection requirements, remove the carriage from service
and discard it. Notify Boeing:Send your report to: BOEING COMMERCIAL AIRPLANES
GROUP ATTENTION: MANAGER, AIRLINE SUPPORT
f. Install a new or serviceable carriage spindle, on the midflap and airplane. Refer to AMM
27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package
1.
5. If the NDT Ultrasonic and General Visual Inspection of the spindle shows it is not fractured or
severed, and if no corrosion or cracking is noticed, go to 6.0 below.
6. Put the airplane back to a serviceable condition.
7. Then, repeat Work Package 1 in accordance with compliance intervals provided in Paragraph
1.E., Compliance. Except as spindles gain flight cycles and move from one grouping threshold
row to another, they are subject to repetitive inspection intervals corresponding to the new threshold
grouping.
WORK PACKAGE 2 - Midflap/Spindle Carriage Gap Check
1. Extend outboard flaps to detent 40 by doing the following:
a. For 737-100/-200/-200C airplanes, pressurize hydraulic system A; refer to AMM 27-51-0. For
737-300/-400/-500 airplanes, activate trailing edge flap system; refer to AMM 27-51-00. Or,
you can use you own equivalent procedure.
b. Extend Flaps to detent 40.
c. For 737-100/-200/-200C airplanes, depressurize hydraulic system A; refer to AMM 27-51-0.
For 737-300/-400/-500 airplanes, deactivate trailing edge flap system; refer to AMM 27-51-00.
Or, you can use you own equivalent procedure.
2. For the left wing and right wing outboard midflap, do ONE of the following checks to determine
movement of the midflap with respect to the carriage spindle (be sure to use proper lighting):
a. Gap Check - Clay Method: in accordance with Figure 2 and Figure 3 or:
b. Gap Check - Measurement Method: in accordance with Figure 4 and Figure 5 or:
c. Gap Check - Midflap Leading Edge Relative Movement Check: in accordance with Figure 6.
3. (This lettered work instruction step is no longer used.)
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4. If you find differential movement between the midflap and carriage spindle (from Figure 2 & 3, or
Figure 4 & 5, or Figure 6), this is a positive indication of a severed spindle. Prior to further flight,
do the following steps or first do an ultrasonic inspection in accordance with Work Package 1,
Section 3.B.2 for confirmation of a severed spindle:
a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to
AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Install a new or serviceable carriage
spindle into the midflap and the midflap on the airplane. Refer to AMM 27-51-72
(737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500)
& 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package 2
b. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap.
Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the
spindle of the carriage. Do a Detailed Inspection to determine if there is corrosion, a crack,
or severed spindle. In accordance with 737 OHM 57-53-35 (737-100/-200/-200C), or CMM
57-53-36 (737-300/-400/-500) for inspection criteria of an acceptable spindle.
(1) If spindle is severed, or has non-repairable crack, or non-repairable corrosion, discard it
and notify Boeing and provide service time and cycles of carriage spindle. Prior to further
flight, install a new or serviceable carriage spindle on the midflap. Refer to AMM 27-51-72
(737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34
(737-300/-400/-500) & 737-300/400/500 AMM 27-51-44, or your equivalent procedure.
(2) If spindle has repairable crack, and/or corrosion, prior to further flight, install a new or
serviceable carriage spindle. Overhauled carriage spindles shall be done in accordance
with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes), or 737 CMM, Subject
57-53-36 (737-300/-400/-500 airplanes) and Service Bulletin 737-57A1218, Revision 3,
or later revision.
(3) If carriage spindle is not severed and no corrosion and crack is present, it can be reinstalled
on midflap. However, before reinstalling, investigate to see if there is any damage that
would cause the midflap to move away from the carriage and repair accordingly. Install
the carriage spindle and repeat Work Package 2 to verify disposition of your investigation.
Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM
27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44, or your equivalent
procedure for installing the carriage spindle.
(4) Go to paragraph 6. of Work Package 2.
5. If the midflap does not separate from the clay (from the checks in Figure 2 and Figure 3), or there
is no differential movement between the carriage and midflap, go to 6.0.
6. Put the airplane back to a serviceable condition.
7. Then, repeat Work Package 2 in accordance with compliance intervals provided in Paragraph
1.E., Compliance. Except as spindles gain flight cycles and move from one grouping threshold
row to another, they are subject to repetitive inspection intervals corresponding to the new threshold
grouping.
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BOEING SERVICE BULLETIN 737-57A1277
SEE
SEE
CARRIAGE SPINDLE
COVER PLATE
SPINDLE BEARING
BEARING SUPPORT
TRAILING
EDGE FLAP
OUTBOARD MIDFLAP
CARRIAGE
FIGURE 1: CARRIAGE SPINDLE INSPECTION
(SHEET 1 OF 2)
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### Page 37

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
NOTESQTYPROCESSNAMETASKSTEP
It is not necessary to remove the
cover plate to do the NDT inspec-
tion. Ultrasonic Inspection will find
a severed spindle in the section
shown. The important section
covers the critical "A" location thru
the "B" location to the cross bolt.
-737 NDT Part 4,
Subject 57-50-02
Carriage SpindleInspect1
on exposed areas as shown. Look
for signs of corrosion and cracks.
-General Visual In-
spection
Carriage SpindleInspect2
FIGURE 1: CARRIAGE SPINDLE INSPECTION
(SHEET 2 OF 2)
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### Page 38 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
SEE AB
, F WD
2) CLAY
PARTING  COMPOUND  > FWD
ON FLAP SURFACE  W75118
FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD
(SHEET 1 OF 2)
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### Page 39

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 items necessary for inboard carriage.
NOTESQTYNAMETASKSTEP
to flap surface (for clay), as needed.-Parting CompoundApply1
(approximately 1X1X1 inch) to side/bottom of the
carriage and touching lower surface of midflap as
shown. Use grease as a parting compound between
clay and flap
1ClayApply2
to area indicated - normal to the midflap surface. Use
one or two people. The force applied shall be just
enough to (slightly) lift the carriage off of the dead
weight rollers.
--Apply Force3
between clay and surface of midflap during the ap-
plied force. If spindle is severed, you will see a gap
between the clay and the surface of midflap - hence
movement of the midflap away from the carriage . If
the spindle is not severed, the midflap surface will
stay in contact with the clay.
-GapLook for4
1ClayRemove5
FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD
(SHEET 2 OF 2)
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### Page 40 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
SEE AY
→ FWD
CLAY (2
• FWD
PARTING
COMPOUND  W75117
FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD
(SHEET 1 OF 3)
Original issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  737-57A1277
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### Page 41 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
5) CLAY
→ FWD
W75181
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 items necessary for outboard carriage.
FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD
(SHEET 2 OF 3)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  737-57A1277
Copyright © Unpublished Work - See page 1 for details.  41 of 50

### Page 42

NOTESQTYNAMETASKSTEP
to flap surface (for clay) as needed.-Parting Com-
pound
Apply1
(approximately 1X1X1 inch) to side/bottom of the carriage
and touching lower surface of midflap as shown. Use grease
as a parting compound between clay and flap.
1ClayApply2
at ONE of the two locations indicated - the midflap OR aft
fairing as follows: If you choose the midflap: Apply the force
to area indicated - normal to the midflap surface. Use one
or two people. The force applied shall be just enough to
(slightly) lift the carriage off of the dead weight rollers.
--Apply Force3
If you choose the aft fairing: Apply the force near the end
of fairing in an upward direction. You can use one person
for this. The force applied shall be just enough to (slightly)
lift the carriage off of the dead weight rollers.
between clay and surface of midflap during the applied force.
If spindle is severed, you will see a gap between the clay
and the surface of midflap - hence movement of the midflap
away from the carriage. If the spindle is not severed, the
midflap surface will stay in contact with the clay.
-GapLook for4
1ClayRemove5
FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD
(SHEET 3 OF 3)
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### Page 43 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
SEE AO
@ FWD
W75752
FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD
(SHEET 1 OF 2)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  737-57A1277
Copyright © Unpublished Work - See page 1 for details.  43 of 50

### Page 44

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
NOTESQTYNAMETASKSTEP
on midflap (that is inline with) and a fixed feature on
the carriage with a pen (or equivalent).
-Measurement Loca-
tion
Mark1
between the marked location on the midflap and the
fixed feature on the carriage.
-MeasurementMake a2
to area indicated - normal to the midflap surface. Use
one or two people. The force applied shall be just
enough to (slightly) lift the carriage off of the dead
weight rollers.
--Apply Force3
between the same end points as taken in Step 1 above
during the applied force. If spindle is severed, you will
have a differential measurement between your initial
measurement and this measurement - hence move-
ment of the midflap away from the carriage . If the
spindle is not severed, your second measurement will
be the same as your initial measurement.
-MeasurementMake a4
FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD
(SHEET 2 OF 2)
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### Page 45 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
SEE A B
@FWD
*FWD
W75755
FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD
(SHEET 1 OF 3)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  737-57A1277
Copyright © Unpublished Work - See page 1 for details.  45 of 50

### Page 46 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
W75754
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD
(SHEET 2 OF 3)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  737-57A1277
BOEING PROPRIETARY -
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### Page 47

NOTESQTYNAMETASKSTEP
on midflap (that is inline with) and a fixed feature on
the carriage with a pen (or equivalent).
-Measurement Loca-
tion
Mark1
between the marked location on the midflap and the
fixed feature on the carriage.
-MeasurementMake a2
at ONE of the two locations indicated - the midflap OR
aft fairing as follows: If you choose the midflap: Apply
the force to area indicated - normal to the midflap sur-
face. Use one or two people. The force applied shall
be just enough to (slightly) lift the carriage off of the
dead weight rollers.
--Apply Force3
If you choose the aft fairing: Apply the force near the
end of fairing in an upward direction. You can use one
person for this. The force applied shall be just enough
to (slightly) lift the carriage off of the dead weight
rollers.
between the same end points as taken in Step 1 above
during the applied force. If spindle is severed, you will
have a differential measurement between your initial
measurement and this measurement - hence move-
ment of the midflap away from the carriage. If the
spindle is not severed, your second measurement will
be the same as your initial measurement - hence no
movement.
-MeasurementMake a4
FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD
(SHEET 3 OF 3)
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### Page 48 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
SEE
MIDFLAP
SEE  ' SEE B
LEFT OUTBOARD FLAP SHOWN
MIDFLAP
TRAVEL
DISTANCE /
A-A
INBOARD AND OUTBOARD CARRIAGE SPINDLER SIMILAR  W75756
FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK
(SHEET 1 OF 3)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  ELZILS-LEL
Copyright © Unpublished Work - See page 1 for details.

### Page 49 (OCR)

BOEING SERVICE BULLETIN 737-57A1277
_ FWD
@FWD
W75757
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK
(SHEET 2 OF 3)
Original Issue: July 25, 2002
Revision 3 May 16, 2012  BOEING PROPRIETARY -  737-57A1277
Copyright © Unpublished Work - See page 1 for details.  49 of 50

### Page 50

NOTESQTYNAMETASKSTEP
STEPS 1 THRU 3 ARE FOR THE INBOARD CARRIAGE SPINDLE
position with respect to carriage yoke. Note this rela-
tionship.
-Leading EdgeLook at1
to area indicated - normal to the midflap surface. Use
one or two people. The force applied shall be just
enough to (slightly) lift the carriage off of the dead
weight rollers.
--Apply Force2
of the leading edge of the midflap with respect to the
carriage yoke while the force is applied as described
above. Note the position of the leading edge of the
midflap with respect to carriage yoke. If there is a dif-
ference, then the spindle is severed. If there is no dif-
ference, the the spindle is not severed.
-MovementLook for3
STEPS 4 THRU 6 ARE FOR THE OUTBOARD CARRIAGE SPINDLE
position with respect to carriage yoke. Note this rela-
tionship
-Leading EdgeLook at4
at ONE of the two locations indicated - the midflap OR
aft fairing as follows: If you choose the midflap: Apply
the force to area indicated - normal to the midflap sur-
face. Use one or two people. The force applied shall
be just enough to (slightly) lift the carriage off of the
dead weight rollers.
--Apply Force5
If you choose the aft fairing: Apply the force near the
end of fairing in an upward direction. You can use one
person for this. The force applied shall be just enough
to (slightly) lift the carriage off of the dead weight
rollers.
of the leading edge of the midflap with respect to the
carriage yoke while the force is applied as described
above. Note the position of the leading edge of the
midflap with respect to carriage yoke. If there is a dif-
ference, then the spindle is severed. If there is no dif-
ference, the the spindle is not severed
-MovementLook for6
FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK
(SHEET 3 OF 3)
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BOEING SERVICE BULLETIN 737-57A1277

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