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.

ECCN: 9E991

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Unpublished Work - All Rights Reserved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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4.0
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BOEING SERVICE BULLETIN 737-57A1277

BLANK PAGE
Table of Contents

Revision Transmittal Sheet ............................................ 5

Summary ...................................................... 7

1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 28

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 29

3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 29

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

FIGURE 1: CARRIAGE SPINDLE INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD . . . . . . . . . . . . . 38

FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD . . . . . . . . . . . 40

FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD . . . . . . 43

FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD . . . . . 45

FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK . . . . . . . . . . . . . . . . 48

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BOEING SERVICE BULLETIN 737-57A1277
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BOEING SERVICE BULLETIN 737-57A1277

BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

Revision Transmittal Sheet 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

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

Original Issue: July 25, 2002

Revision 1: November 25, 2003

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Revision 2: June 09, 2011

Revision 3: May 16, 2012

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BOEING SERVICE BULLETIN 737-57A1277
Commercial 

Airplanes 737

Service Bulletin

Summary 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

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

Work Package Total Task Hours Elapsed Hours

1 16 8

2 2 1

MATERIAL INFORMATION

None

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BLANK PAGE
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.

GROUP CONFIGURATION DESCRIPTION

1 - 737-100, -200, -200C, -300, -400 and -500 airplanes

Airplane Models:

737-100, 737-200, 737-200C, 737-300, 737-400, 737-500

Variable Number Group

PA001 - PA022 1

PA099 1

PA231 - PA232 1

PC001 - PC005 1

PG001 - PG075 1

PG199 1

PG201 - PG230 1

PG251 - PG255 1

PG271 - PG279 1

PG301 - PG314 1

PG331 - PG332 1

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Variable Number Group

PG351 - PG356 1

PG375 1

PG401 - PG403 1

PG431 - PG442 1

PG471 - PG475 1

PG501 - PG505 1

PG571 - PG586 1

PG621 - PG630 1

PG651 - PG652 1

PG701 - PG705 1

PH001 1

PH011 - PH013 1

PH021 - PH024 1

PH701 - PH715 1

PH731 - PH732 1

PH741 - PH743 1

PJ001 - PJ009 1

PJ031 - PJ032 1

PJ071 - PJ072 1

PJ101 - PJ119 1

PJ201 - PJ219 1

PJ301 - PJ302 1

PJ551 - PJ561 1

PJ601 - PJ615 1

PJ811 1

PJ816 - PJ817 1

PK026 - PK029 1

PK041 - PK053 1

PK061 - PK070 1

PK081 - PK082 1

PK091 - PK099 1

PK101 - PK103 1

PK111 - PK120 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PK141 - PK146 1

PK201 - PK204 1

PK211 - PK223 1

PK231 - PK241 1

PK251 - PK258 1

PK271 - PK274 1

PK281 - PK289 1

PK291 1

PK301 - PK318 1

PK341 1

PK351 - PK361 1

PK391 1

PK431 - PK433 1

PK451 - PK452 1

PK461 - PK469 1

PK495 1

PK501 - PK504 1

PK511 - PK515 1

PK519 1

PK521 - PK528 1

PK541 - PK565 1

PK581 1

PK591 - PK599 1

PK601 - PK617 1

PK621 - PK637 1

PK641 - PK642 1

PK661 - PK666 1

PK671 - PK681 1

PK691 - PK697 1

PK711 - PK716 1

PK731 - PK765 1

PK771 - PK779 1

PK801 - PK804 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PK819 - PK827 1

PK830 1

PK861 - PK863 1

PK871 - PK874 1

PK881 - PK884 1

PK901 - PK938 1

PK971 - PK974 1

PL001 - PL028 1

PL061 1

PL081 1

PL101 - PL113 1

PL151 1

PL171 - PL172 1

PL201 - PL203 1

PL221 1

PL401 - PL417 1

PL421 1

PL441 1

PL451 - PL456 1

PL471 1

PL491 1

PL501 - PL506 1

PL551 - PL562 1

PL581 1

PL601 - PL603 1

PL611 1

PL621 - PL626 1

PL631 - PL632 1

PL711 - PL712 1

PL716 - PL747 1

PL756 1

PL758 1

PL761 - PL770 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PL781 - PL788 1

PL793 1

PL801 - PL803 1

PM001 - PM006 1

PM016 - PM017 1

PM021 - PM023 1

PM051 - PM066 1

PM101 - PM119 1

PM141 - PM142 1

PM171 1

PM181 1

PM251 - PM255 1

PM281 - PM283 1

PM381 - PM399 1

PM401 - PM417 1

PM541 - PM564 1

PN001 - PN002 1

PN021 - PN043 1

PN081 - PN086 1

PN101 - PN117 1

PN131 - PN163 1

PN401 - PN420 1

PN431 - PN433 1

PN451 - PN456 1

PN471 - PN474 1

PN481 1

PN491 - PN493 1

PN501 - PN502 1

PN511 - PN512 1

PN521 1

PP001 - PP054 1

PP101 - PP169 1

PP181 - PP199 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PP201 - PP205 1

PP221 1

PP231 - PP243 1

PP281 - PP286 1

PP301 - PP305 1

PP351 - PP353 1

PP376 - PP384 1

PP391 - PP393 1

PP401 - PP440 1

PP471 - PP475 1

PP501 - PP522 1

PP631 - PP634 1

PP651 - PP652 1

PP671 - PP699 1

PP701 - PP733 1

PP771 - PP779 1

PP801 - PP808 1

PP821 - PP827 1

PP831 - PP848 1

PP851 - PP852 1

PP861 - PP877 1

PP891 - PP899 1

PP901 - PP936 1

PP946 - PP948 1

PP951 - PP952 1

PP961 - PP967 1

PP981 - PP991 1

PP993 1

PQ001 - PQ016 1

PQ026 - PQ041 1

PQ051 - PQ092 1

PQ101 - PQ199 1

PQ201 - PQ202 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PQ221 - PQ237 1

PQ241 - PQ243 1

PQ251 - PQ267 1

PQ281 - PQ299 1

PQ301 - PQ307 1

PQ331 - PQ332 1

PQ341 - PQ348 1

PQ361 - PQ373 1

PQ391 - PQ395 1

PQ401 - PQ418 1

PQ421 1

PQ431 - PQ438 1

PQ447 - PQ448 1

PQ451 1

PQ454 1

PQ471 - PQ475 1

PQ479 - PQ481 1

PQ486 - PQ487 1

PQ491 - PQ493 1

PQ771 - PQ772 1

PQ791 - PQ793 1

PQ801 - PQ805 1

PQ931 - PQ935 1

PQ951 1

PQ971 - PQ997 1

PR001 - PR017 1

PR021 - PR034 1

PR041 - PR045 1

PR061 - PR072 1

PR077 - PR082 1

PR091 - PR092 1

PR096 1

PR101 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PR121 - PR122 1

PR131 - PR132 1

PR141 - PR143 1

PR161 - PR172 1

PR181 1

PS601 - PS631 1

PS636 - PS638 1

PS641 - PS644 1

PS651 - PS657 1

PS666 - PS669 1

PS691 - PS692 1

PS701 - PS706 1

PS751 - PS799 1

PS811 1

PS836 - PS837 1

PS841 - PS846 1

PS851 - PS852 1

PS856 1

PS861 - PS863 1

PS866 - PS868 1

PS871 - PS874 1

PS896 - PS897 1

PS901 - PS941 1

PS956 - PS957 1

PS961 - PS963 1

PS971 - PS978 1

PT001 - PT015 1

PT021 - PT031 1

PT041 - PT064 1

PT101 - PT105 1

PT121 - PT138 1

PT146 - PT148 1

PT161 - PT170 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PT181 - PT188 1

PT211 - PT220 1

PT295 1

PT301 - PT309 1

PT331 - PT360 1

PT381 - PT399 1

PT401 - PT438 1

PT501 - PT517 1

PT561 - PT565 1

PT581 - PT586 1

PT611 - PT621 1

PT641 - PT644 1

PT651 - PT656 1

PT671 - PT672 1

PT681 - PT685 1

PT701 - PT703 1

PT716 - PT717 1

PT721 - PT725 1

PT801 - PT834 1

PT851 - PT854 1

PT871 - PT886 1

PT901 - PT930 1

PT971 - PT973 1

PT981 - PT985 1

PT996 1

PU001 - PU025 1

PU301 1

PU311 - PU313 1

PV001 - PV055 1

PV201 - PV209 1

PV226 - PV229 1

PV231 - PV237 1

PV271 - PV272 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PV281 - PV287 1

PV296 1

PV301 - PV302 1

PV351 1

PV356 - PV357 1

PW001 - PW054 1

PW061 - PW068 1

PW072 1

PW086 - PW088 1

PW091 - PW094 1

PW101 - PW102 1

PW106 1

PW111 - PW120 1

PW156 - PW157 1

PW161 - PW171 1

PW201 - PW252 1

PW261 - PW268 1

PW271 - PW276 1

PW278 1

PW281 - PW293 1

PW296 1

PW301 - PW327 1

PW401 - PW408 1

PW411 - PW418 1

PW421 - PW424 1

PW431 - PW435 1

PW441 - PW450 1

PW461 - PW467 1

PW501 - PW504 1

PW511 - PW522 1

PW524 - PW550 1

PW556 - PW557 1

PW561 - PW564 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PW571 - PW576 1

PW591 - PW596 1

PW611 - PW622 1

PW631 - PW637 1

PW661 - PW662 1

PW681 - PW683 1

PW701 - PW702 1

PW711 - PW717 1

PW741 - PW742 1

PW761 1

PW771 1

PW831 1

PW851 - PW856 1

PX071 1

PX701 1

PY001 - PY008 1

PY021 - PY022 1

PY031 1

PY036 - PY037 1

PY046 - PY048 1

PY051 - PY053 1

PY056 - PY057 1

PY101 - PY103 1

PY111 - PY113 1

PY131 - PY135 1

PY141 - PY143 1

PY151 - PY154 1

PY156 - PY157 1

PY161 - PY162 1

PY166 1

PY191 1

PY201 1

PY221 - PY222 1

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BOEING SERVICE BULLETIN 737-57A1277
Variable Number Group

PY231 1

PY241 - PY244 1

PY270 - PY275 1

PY281 1

PY286 1

PY301 - PY304 1

PY321 - PY323 1

PY341 - PY346 1

PY361 - PY362 1

PY381 1

PY401 1

PY409 - PY411 1

PY421 - PY422 1

PY441 1

PY451 1

PY461 - PY463 1

PY591 - PY595 1

PY611 - PY612 1

PY621 1

PY631 1

PY651 1

PY671 - PY672 1

PY721 1

PY741 1

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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BOEING SERVICE BULLETIN 737-57A1277
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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BOEING SERVICE BULLETIN 737-57A1277
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

Model Zone

737-100, 737-200, 737-200C 3-7, 4-7

Group 1:

Affected Maintenance Zones

Model Zone

737-300, 737-400, 737-500 307, 407

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 :

THRESHOLD INTERVAL Whichever is later

> 20,000 flight cycles or 8 Years in-service since Work Package 1 (NDT): 15 Days or 150 flight cycles

spindle was new, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles*

12,000 to 20,000 flight cycles since spindle was Work Package 1 (NDT): 45 Days or 450 flight cycles

new ** Work Package 2 (Gap Check): 15 Days or 150 flight cycles

*

< 12,000 flight cycles since spindle was new ** Work Package 1 (NDT): Not Required

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 ultrasonic 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 :

THRESHOLD INTERVAL Whichever is later

** 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

> 20,000 flight cycles, or 8 Work Package 1 (NDT): 15 Days or 150 flight cycles

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 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 2 (Gap Check): 3

Days 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): 180 Days Work Package 1 (NDT): Not Required

or 1,500 flight cycles

< 3,000 flight cycles **

Work Package 2 (Gap Check): Not RequiredWork 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 ultrasonic 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

> 20,000 flight cycles,or 8 Work Package 1 (NDT): 6 Days or 60 flight cycles

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 or

30 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 ultrasonic 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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BOEING SERVICE BULLETIN 737-57A1277
Work Package 1 (NDT Ultrasonic and General Visual Inspection)

Number of Per- Task-Hours Elapsed Hours

sons

Task

Open Access 2 3 1.5

Inspect 2 10 5.0

Close Access 2 3 1.5

TOTAL FOR EACH AIRPLANE 16 8

Work Package 2 (Gap Check)

Number of Per- Task-Hours Elapsed Hours

sons

Task

Inspect 2 2 1

TOTAL FOR EACH AIRPLANE 2 1

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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BOEING SERVICE BULLETIN 737-57A1277
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.

Part Number / QTY Name Notes

Specification

* 4 oz. Clay (a)

* 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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BOEING SERVICE BULLETIN 737-57A1277

BLANK PAGE
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
FIGURE 1: CARRIAGE SPINDLE INSPECTION

(SHEET 1 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

STEP TASK NAME PROCESS QTY NOTES

It is not necessary to remove the

cover plate to do the NDT inspection. 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

1 Inspect Carriage Spindle

on exposed areas as shown. Look

for signs of corrosion and cracks.

General Visual In- -

spection

2 Inspect Carriage Spindle

FIGURE 1: CARRIAGE SPINDLE INSPECTION

(SHEET 2 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD

(SHEET 1 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
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.

STEP TASK NAME QTY NOTES

1 Apply Parting Compound - to flap surface (for clay), as needed.

(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

2 Apply Clay 1

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.

3 Apply Force - -

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.

4 Look for Gap -

5 Remove Clay 1

FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD

(SHEET 2 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD

(SHEET 1 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277
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)

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BOEING SERVICE BULLETIN 737-57A1277
STEP TASK NAME QTY NOTES

Parting Com- - to flap surface (for clay) as needed.

pound

1 Apply

(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.

2 Apply Clay 1

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.

3 Apply Force - -

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.

4 Look for Gap -

5 Remove Clay 1

FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD

(SHEET 3 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277
FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD

(SHEET 1 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

STEP TASK NAME QTY NOTES

on midflap (that is inline with) and a fixed feature on

the carriage with a pen (or equivalent).

Measurement Loca- -

tion

1 Mark

between the marked location on the midflap and the

fixed feature on the carriage.

2 Make a Measurement -

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.

3 Apply Force - -

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 movement of the midflap away from the carriage . If the

spindle is not severed, your second measurement will

be the same as your initial measurement.

4 Make a Measurement -

FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD

(SHEET 2 OF 2)

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BOEING SERVICE BULLETIN 737-57A1277
FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD

(SHEET 1 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277
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)

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BOEING SERVICE BULLETIN 737-57A1277
STEP TASK NAME QTY NOTES

on midflap (that is inline with) and a fixed feature on

the carriage with a pen (or equivalent).

Measurement Loca- -

tion

1 Mark

between the marked location on the midflap and the

fixed feature on the carriage.

2 Make a Measurement -

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.

3 Apply Force - -

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 movement 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.

4 Make a Measurement -

FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD

(SHEET 3 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277
FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK

(SHEET 1 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277
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)

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BOEING SERVICE BULLETIN 737-57A1277
STEP TASK NAME QTY NOTES

STEPS 1 THRU 3 ARE FOR THE INBOARD CARRIAGE SPINDLE

position with respect to carriage yoke. Note this relationship.1 Look at Leading Edge -

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.

2 Apply Force - -

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 difference, then the spindle is severed. If there is no difference, the the spindle is not severed.

3 Look for Movement -

STEPS 4 THRU 6 ARE FOR THE OUTBOARD CARRIAGE SPINDLE

position with respect to carriage yoke. Note this relationship4 Look at Leading Edge -

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.

5 Apply Force - -

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 difference, then the spindle is severed. If there is no difference, the the spindle is not severed

6 Look for Movement -

FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK

(SHEET 3 OF 3)

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BOEING SERVICE BULLETIN 737-57A1277