Commercial 

Airplanes 737

Service Bulletin

Number: 737-57A1302

Original Issue: December 15, 2008

Revision 1: October 18, 2010

ATA System: 5754

SUBJECT: WINGS - Leading Edge Slats- Main Track Down Stop Modification and Detailed

Inspection

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

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ECCN: 9E991

BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET

Copyright © 2008 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Unpublished Work - All Rights Reserved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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7.0
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BOEING SERVICE BULLETIN 737-57A1302

BLANK PAGE
Table of Contents

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

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

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

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

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

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2. Data supplied with this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3. Installation Drawings Used in the Preparation of this Service Bulletin . . . . . . . . . . . . 24

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 28

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

FIGURE 1: SHRINK-FIT BUSHING INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

FIGURE 2: SHRINK-FIT BUSHING REAMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION . . . . . . . 37

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BOEING SERVICE BULLETIN 737-57A1302
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BOEING SERVICE BULLETIN 737-57A1302

BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

Revision Transmittal Sheet Number: 737-57A1302

Original Issue: December 15, 2008

Revision 1: October 18, 2010

ATA System: 5754

SUBJECT: WINGS - Leading Edge Slats- Main Track Down Stop Modification and Detailed

Inspection

This revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

No more work is necessary on airplanes changed in accordance with the original issue of this service bulletin.

Federal Aviation Administration (FAA) Airworthiness Directive FAA AD 2007-18-52 is related to this service

bulletin.

REASON FOR REVISION

This revision is sent to add clarification to this service bulletin.

Changes to this service bulletin include:

– Added borescope inspection option for the slat main track and in the slat can.

– Updated Industry Support Information with the applicable Boeing Program Letter.

– Added Damage Tolerance Information to Publications Affected.

– Added optional stainless steel lockwire to Operator Supplied Parts table and Figure 3.

– Updated Special Tooling - Price and Availability section, with Boeing's offer of two free optional toolkits to

all operators, and removed toolkit rental option.

– Added HAND reaming recommendation in the event interference occurs between the new down stop

assembly bolt and the hole in the slat main track, in the Accomplishment Instructions.

– Added the option to remove the wing anti-icing duct elbows near the down stop assembly in the right wing

near the fuel metering manifold in order to gain easier access, in the Accomplishment Instructions. If the

duct is disassembled a leak test is required.

– Added reference to Aircraft Maintenance Manual 737-600/700/800/900 AMM 57-41-02 when reinstalling

lower leading edge wing panels at the end of the Accomplishment Instructions.

– Changed lower hole tolerance limit to 0.4375 inches in the event a bushing repair becomes necessary for

the slat main track, in Figure 2.

– Added step to apply corrosion preventive compound, MIL-C-11796, Class 3, to new aft side guide bolts

upon installation, in Figure 3.

The data given in Information Notice 737-57A1302 IN 01 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.

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REVISION HISTORY

Original Issue: December 15, 2008

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BOEING SERVICE BULLETIN 737-57A1302
Commercial 

Airplanes 737

Service Bulletin

Summary Number: 737-57A1302

Original Issue: December 15, 2008

Revision 1: October 18, 2010

ATA System: 5754

SUBJECT: WINGS - Leading Edge Slats- Main Track Down Stop Modification and Detailed

Inspection

CONCURRENT REQUIREMENTS

None.

BACKGROUND

Recently, a fuel leak and a subsequent fire resulted from loose down stop assembly hardware being pushed

through the slat can while the slats were being retracted. FAA Airworthiness Directive FAA AD 2007-18-52 was

initiated to inspect the 737NG fleet and re-torque the down stop assemblies as a result of this fire. Several issues

were found including missing hardware, low torque, and improper assembly. This service bulletin requires 1)

removal of the existing down stop assemblies and installation of a new down stop assembly on all 16 slat main

tracks, and 2) removal of the existing aft side guide attach bolts at all 64 locations and replacement with identical

bolts with drilled heads that are lock wired together on the ribs of the leading edge of the wing. Failure to

incorporate this service bulletin could lead to conditions that allow the down stop assembly to fall off, or the aft

side guides to become loose, and fall into the slat can. If the down stop assembly comes apart inside the slat

can or the aft side guide falls into the slat can, then the slat main track may trap a down stop assembly component

between the slat can and slat main track causing a puncture of the fuel tank creating a fuel leak and the risk of

fire.

As a part of a service bulletin validation program, this change was completed on airplane YC578 by Service

Bulletin 737-57A1302 Original Issue before the release of Revision 1 of this service bulletin. The change

completed on airplane YC578 by Service Bulletin 737-57A1302 Original Issue is equivalent to the release of

Revision 1 of this service bulletin. Airplane YC578 has the configuration of a Group 1 airplane.

Boeing Service Related Problem (SRP) 737-SRP-57-0209 is related to this service bulletin.

ACTION (PRR 38275-136S)

Remove the existing down stop assembly hardware from the slat main tracks of slats one through eight. Install

the new down stop assembly hardware in the correct order and torque the nut. Install the cotter pin after all other

hardware has been installed and bend the legs of the cotter pin. Remove the bolts which secure the aft side

guides to the leading edge slat track ribs and replace them with the new drilled head bolts. Install the lock wire

on the aft side guide boltheads. After the changes are done, do a detailed inspection or borescope inspection

for debris on the slat main track and in the slat can.

Special tooling is available from Boeing to assist with the installation of the down stop assembly hardware.

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EFFECTIVITY

737-600, 700, 700C, 800, 900, 900ER airplanes. See Paragraph 1.A.1., Airplanes, for effectivity.

COMPLIANCE

Refer to Paragraph 1.E., Compliance.

Federal Aviation Administration (FAA) Airworthiness Directive FAA AD 2007-18-52 is related to this service

bulletin.

INDUSTRY SUPPORT INFORMATION

Boeing Industry Support information is provided in Program Letter BPL 6-1151-737-PGM-190, dated March 9,

2009 . Additional copies of program letters are available from Boeing Warranty and Product Assurance Contracts.

MANPOWER

Refer to Paragraph 1.G., Manpower.

MATERIAL INFORMATION

Boeing Supplied Kits/Parts.

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

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BOEING SERVICE BULLETIN 737-57A1302

BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

Number: 737-57A1302

Original Issue: December 15, 2008

Revision 1: October 18, 2010

ATA System: 5754

SUBJECT: WINGS - Leading Edge Slats- Main Track Down Stop Modification and Detailed

Inspection

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. An equivalent change is on subsequent

production airplanes. Refer to PRR 38275-136S for data about this change.

GROUP CONFIGURATION DESCRIPTION

737-600/700/700C/800/900/900ER airplanes line numbers 1 through

2699

1 -

Airplane Models:

737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER

Variable Number Group

YA001 - YA099 1

YA101 - YA199 1

YA201 - YA211 1

YA221 1

YA231 - YA242 1

YA251 - YA256 1

YA271 - YA272 1

YA291 1

YA301 - YA302 1

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Variable Number Group

YA311 - YA314 1

YA321 - YA323 1

YA336 - YA345 1

YA351 1

YA356 - YA357 1

YA366 - YA367 1

YA371 - YA377 1

YA501 - YA536 1

YA541 - YA552 1

YA571 - YA578 1

YA601 - YA615 1

YA621 - YA622 1

YA626 - YA631 1

YA635 - YA636 1

YA641 - YA642 1

YA645 - YA650 1

YA656 - YA659 1

YA666 - YA667 1

YA671 - YA672 1

YA681 - YA691 1

YA701 - YA710 1

YA721 - YA722 1

YA731 - YA734 1

YA751 - YA756 1

YA801 - YA803 1

YA809 1

YA811 - YA814 1

YA831 - YA835 1

YA841 - YA862 1

YA881 - YA882 1

YA891 - YA892 1

YA961 - YA978 1

YB001 - YB006 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YB101 - YB132 1

YB151 - YB153 1

YB156 - YB158 1

YB161 - YB164 1

YB171 - YB172 1

YB181 - YB184 1

YB201 - YB208 1

YB271 1

YB276 1

YB301 - YB310 1

YB371 - YB392 1

YB501 - YB502 1

YB521 - YB526 1

YB541 - YB544 1

YB551 1

YB561 - YB598 1

YB601 - YB632 1

YB651 1

YB656 1

YB671 - YB672 1

YB851 - YB863 1

YB871 - YB874 1

YB881 - YB893 1

YB901 - YB903 1

YB911 1

YB961 - YB974 1

YB986 - YB987 1

YC001 - YC030 1

YC051 - YC084 1

YC091 - YC094 1

YC101 - YC104 1

YC111 - YC113 1

YC121 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YC126 - YC127 1

YC136 - YC141 1

YC146 - YC147 1

YC151 - YC156 1

YC166 - YC171 1

YC176 - YC179 1

YC186 - YC190 1

YC201 - YC203 1

YC206 - YC207 1

YC301 - YC305 1

YC321 - YC387 1

YC391 - YC394 1

YC396 1

YC401 - YC417 1

YC421 - YC422 1

YC426 - YC428 1

YC436 - YC439 1

YC441 - YC448 1

YC451 - YC455 1

YC459 1

YC461 - YC467 1

YC471 - YC499 1

YC501 - YC526 1

YC571 - YC583 1

YC587 - YC589 1

YC591 - YC593 1

YC601 - YC655 1

YC681 - YC696 1

YC701 - YC715 1

YC720 - YC725 1

YC727 - YC752 1

YC761 - YC770 1

YC781 - YC793 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YC801 - YC892 1

YC901 - YC907 1

YC921 - YC922 1

YC931 - YC932 1

YC941 - YC951 1

YC971 - YC978 1

YC981 - YC983 1

YD001 - YD007 1

YD021 - YD025 1

YD041 - YD057 1

YD081 - YD084 1

YD101 - YD110 1

YD121 - YD126 1

YD151 - YD159 1

YD171 - YD172 1

YD201 - YD203 1

YD206 - YD209 1

YD216 - YD219 1

YD251 - YD254 1

YD256 - YD257 1

YD261 1

YD301 - YD334 1

YD391 1

YD401 - YD410 1

YD412 - YD415 1

YD481 - YD485 1

YD491 - YD499 1

YD501 - YD512 1

YD531 - YD535 1

YD541 - YD547 1

YD561 - YD564 1

YD571 - YD572 1

YD591 - YD595 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YD601 - YD612 1

YD651 - YD655 1

YE001 - YE020 1

YE051 1

YE101 - YE109 1

YE151 - YE157 1

YE171 - YE172 1

YE201 - YE206 1

YE301 - YE305 1

YE321 - YE326 1

YE371 - YE383 1

YF001 1

YF021 - YF026 1

YF051 - YF052 1

YF086 1

YF106 - YF107 1

YF111 1

YF176 - YF178 1

YG001 - YG044 1

YG061 - YG064 1

YG066 - YG089 1

YG091 - YG099 1

YG101 - YG103 1

YG111 - YG114 1

YG116 - YG120 1

YG201 - YG205 1

YG211 - YG214 1

YG251 - YG252 1

YG501 - YG509 1

YG601 - YG602 1

YG701 1

YG711 1

YH001 - YH012 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YH051 - YH054 1

YH101 - YH114 1

YH201 - YH202 1

YH206 - YH207 1

YH301 1

YJ001 - YJ013 1

YJ021 1

YJ471 - YJ480 1

YJ501 - YJ517 1

YJ531 - YJ566 1

YJ591 - YJ597 1

YJ631 - YJ632 1

YJ671 - YJ694 1

YJ801 - YJ867 1

YJ871 - YJ875 1

YJ901 - YJ904 1

YJ908 1

YJ911 - YJ929 1

YJ931 - YJ937 1

YJ941 - YJ956 1

YJ976 - YJ977 1

YK001 - YK007 1

YK101 - YK104 1

YK111 - YK112 1

YK121 - YK122 1

YK131 - YK133 1

YK136 - YK139 1

YK141 - YK142 1

YK146 - YK148 1

YK151 - YK154 1

YK161 - YK167 1

YK171 1

YK176 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YK301 - YK309 1

YK321 - YK338 1

YK361 - YK375 1

YK401 - YK406 1

YK426 - YK427 1

YK431 - YK450 1

YK456 - YK460 1

YK476 1

YK480 - YK485 1

YK495 1

YK511 - YK516 1

YK521 - YK523 1

YK551 - YK569 1

YK571 1

YK576 - YK577 1

YK580 - YK585 1

YK601 - YK602 1

YK606 - YK607 1

YK611 - YK616 1

YK621 - YK627 1

YK631 - YK634 1

YK641 - YK644 1

YK651 - YK661 1

YK671 1

YK701 - YK712 1

YK716 - YK719 1

YK721 - YK741 1

YK751 - YK759 1

YK791 - YK792 1

YK796 - YK797 1

YK801 - YK887 1

YK901 - YK911 1

YK918 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YK921 - YK927 1

YK941 - YK952 1

YK961 - YK971 1

YK981 - YK985 1

YL001 - YL005 1

YL011 - YL016 1

YL021 - YL024 1

YL051 - YL052 1

YL056 - YL057 1

YL061 1

YL066 - YL069 1

YL076 - YL077 1

YL101 - YL116 1

YL201 - YL208 1

YL271 - YL272 1

YL281 - YL282 1

YL301 - YL303 1

YL311 - YL312 1

YL316 - YL319 1

YL371 - YL373 1

YL421 - YL426 1

YL431 - YL437 1

YL461 - YL473 1

YL501 - YL505 1

YL531 - YL533 1

YL561 - YL565 1

YL591 - YL592 1

YL601 - YL606 1

YL611 1

YL661 - YL663 1

YL901 - YL906 1

YL931 - YL932 1

YL951 - YL952 1

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BOEING SERVICE BULLETIN 737-57A1302
Variable Number Group

YM101 - YM103 1

YM201 - YM238 1

YM251 - YM299 1

YM301 - YM374 1

YM471 1

YM481 - YM484 1

YM501 - YM515 1

YM521 - YM522 1

YM541 1

YM551 - YM553 1

YM571 - YM572 1

YM581 - YM582 1

YM591 - YM593 1

YM631 - YM634 1

YM641 - YM651 1

YM671 - YM672 1

YM691 1

YM701 - YM702 1

YN001 - YN016 1

YN021 - YN024 1

YN061 1

YN071 - YN079 1

YN091 - YN092 1

YN101 - YN112 1

YN121 1

YN201 1

YN211 - YN216 1

YN231 - YN232 1

2. Spares Affected

None.

B. Concurrent Requirements

None.

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BOEING SERVICE BULLETIN 737-57A1302
C. Reason

Recently, a fuel leak and a subsequent fire resulted from loose down stop assembly hardware being

pushed through the slat can while the slats were being retracted. FAA Airworthiness Directive FAA AD

2007-18-52 was initiated to inspect the 737NG fleet and re-torque the down stop assemblies as a result

of this fire. Several issues were found including missing hardware, low torque, and improper assembly.

This service bulletin requires 1) removal of the existing down stop assemblies and installation of a new

down stop assembly on all 16 slat main tracks, and 2) removal of the existing aft side guide attach bolts

at all 64 locations and replacement with identical bolts with drilled heads that are lock wired together

on the ribs of the leading edge of the wing. Failure to incorporate this service bulletin could lead to

conditions that allow the down stop assembly to fall off, or the aft side guides to become loose, and

fall into the slat can. If the down stop assembly comes apart inside the slat can or the aft side guide

falls into the slat can, then the slat main track may trap a down stop assembly component between the

slat can and slat main track causing a puncture of the fuel tank creating a fuel leak and the risk of fire.

As a part of a service bulletin validation program, this change was completed on airplane YC578 by

Service Bulletin 737-57A1302 Original Issue before the release of Revision 1 of this service bulletin.

The change completed on airplane YC578 by Service Bulletin 737-57A1302 Original Issue is equivalent

to the release of Revision 1 of this service bulletin. Airplane YC578 has the configuration of a Group

1 airplane.

Revision 1: This revision is sent to add clarification to this service bulletin.

Changes to this service bulletin include:

– Added borescope inspection option for the slat main track and in the slat can.

– Updated Industry Support Information with the applicable Boeing Program Letter.

– Updated the Compliance Time in the Compliance Table.

– Updated Reference Listing.

– Added Damage Tolerance Information to Publications Affected.

– Added optional stainless steel lockwire to Operator Supplied Parts table and Figure 3.

– Updated Special Tooling - Price and Availability section, with Boeing's offer of two free optional

toolkits to all operators, and removed toolkit rental option.

– Added HAND reaming recommendation in the event interference occurs between the new down

stop assembly bolt and the hole in the slat main track, in the Accomplishment Instructions.

– Added the option to remove the wing anti-icing duct elbows near the down stop assembly in the

right wing near the fuel metering manifold in order to gain easier access, in the Accomplishment

Instructions. If the duct is disassembled a leak test is required.

– Added reference to Aircraft Maintenance Manual 737-600/700/800/900 AMM 57-41-02 when

reinstalling lower leading edge wing panels at the end of the Accomplishment Instructions.

– Changed lower hole tolerance limit to 0.4375 inches in the event a bushing repair becomes

necessary for the slat main track, in Figure 2.

– Added step to apply corrosion preventive compound, MIL-C-11796, Class 3, to new aft side guide

bolts upon installation, in Figure 3.

Boeing Service Related Problem (SRP) 737-SRP-57-0209 is related to this service bulletin.

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D. Description

Remove the existing down stop assembly hardware from the slat main tracks of slats one through eight.

Install the new down stop assembly hardware in the correct order and torque the nut. Install the cotter

pin after all other hardware has been installed and bend the legs of the cotter pin. Remove the bolts

which secure the aft side guides to the leading edge slat track ribs and replace them with the new

drilled head bolts. Install the lock wire on the aft side guide boltheads. After the changes are done, do

a detailed inspection or borescope inspection for debris on the slat main track and in the slat can.

Special tooling is available from Boeing to assist with the installation of the down stop assembly

hardware.

Revision 1 - No more work is necessary on airplanes changed in accordance with the original issue of

this service bulletin.

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

Affected Maintenance Zones

Model Zone

737-600, 737-700, 737-700C, 522, 523, 524, 525, 622, 623, 624, 625

737-800, 737-900, 737-900ER

E. Compliance

Federal Aviation Administration (FAA) Airworthiness Directive FAA AD 2007-18-52 is related to this

service bulletin.

Table 1: Slats 1 through 8 Main Track Down Stop Assembly- Modification

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 3 years after -

the original issue

date of this service

bulletin

Replace down stop assembly hardware with

new down stop assembly

hardware and do a detailed inspection of the

slat cans and slat main

tracks for debris in accordance with Paragraph

3.B., Work Instructions,

Step 2, at all 16 slat main

track locations.(a)

All Airplanes

Within 3 years after -

the original issue

date of this service

bulletin

Replace aft side guide

bolts with new aft side

guide bolts in accordance

with Paragraph 3.B.,

Work Instructions, Step

2, at all 16 slat main track

locations.(a)

All Airplanes

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BOEING SERVICE BULLETIN 737-57A1302
Table 1: Slats 1 through 8 Main Track Down Stop Assembly- Modification

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before Further -

Flight

Remove debris in accordance with Paragraph

3.B., Work Instructions,

Step 2.b.

Debris found in slat can

(a) Replacement of down stop assembly hardware and detailed inspection for debris on slat

main track and in slat can, in accordance with this service bulletin, terminates the repeat

inspections in FAA AD 2007-18-52.

F. Approval

This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified

in this service bulletin comply with the applicable regulations and are FAA approved, as well as European

Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved

airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on

the airplane in its original Boeing delivery configuration or as modified by other approved Boeing

changes.

If an airplane has a non-Boeing modification or repair that affects a component or system also affected

by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval

before incorporating this service bulletin.

This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft

Certification Office approves the inspections and installation of the modification defined in this service

bulletin as an alternative method of compliance to the inspections and torquing required by paragraphs

(f) and (g) of AD 2007-18-52. All provisions of AD 2007-18-52 that are not specifically referenced in

this paragraph remain fully applicable and must be complied with.

G. Manpower

The table below shows an estimate of the task hours necessary to do this change for each airplane.

This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator

task hour data if necessary. The estimate does not include lost time. These are some examples of lost

time:

• Time to adjust to the workplace

• Time to schedule the work

• Time to inspect the work

• Time to cure the materials

• Time to make the parts

• Time to find the tools.

Number of Per- Task Hours Elapsed Hours

sons

Task

Open Access 4 11.00 2.75

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BOEING SERVICE BULLETIN 737-57A1302
Number of Per- Task Hours Elapsed Hours

sons

Task

Figure 3 (16 loca- 4 18.00 4.50

tions)

Close Access 2 6.00 3.00

TOTAL FOR EACH AIRPLANE 35.00 10.25

H. Weight and Balance Changes

Change in Moment

(Pound-Inches)

Change in Weight

Airplane (Pounds)

-0.4 Pounds -270 Pound-Inches

I. Electrical Load Data

Not applicable.

J. References

1. Existing Data

a. Engineering Change Memo PRR 38275-136S

b. Boeing Program Letter 6-1151-737-PGM-190, dated March 9, 2009

c. Boeing Service Bulletin 737-57-1293, 737-57A1301

d. Federal Aviation Administration (FAA) Airworthiness Directive 2007-18-52

e. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-44-04, 20-50-02, 20-50-03

f. 737-600/700/800/900 Aircraft Maintenance Manual (AMM) 12-22, 27-81, 27-81-21, 30-11-00,

57-41-02

g. 737-600/700/800/900 Illustrated Parts Catalog (IPC) 57-54

2. Data supplied with this Service Bulletin

None.

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

Drawing Number Title

114A4001 SLAT RIGGING INSTL-OUTBD LE

114A4002 SLAT INSTL-OUTBD LEADING EDGE, WING

116A8300 SIDE GUIDE AND ROLLER INSTL-OUTBD FIXED LE

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BOEING SERVICE BULLETIN 737-57A1302
These drawings were used to prepare this service bulletin. These drawings are not necessary to

make the specified changes, and are not supplied with this service bulletin. These drawings may

not be applicable to all airplane configurations or operators.

K. Publications Affected

1. Publications:

Publication Chapter-Section

737-600/700/800/900 AMM 27-81,

737-600/700/800/900 AMM 12-22

737 Maintenance Manual

737 Illustrated Parts Catalog 737-600/700/800/900 IPC 57-54

2. Damage Tolerance Based Structural Inspections:

Boeing has evaluated this service bulletin for effects on Fatigue Critical Structure (FCS) and for

changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This

service bulletin does not affect FCS, therefore DTIs are not necessary.

L. Interchangeability and Intermixability of Parts

Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability

information.

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BOEING SERVICE BULLETIN 737-57A1302

BLANK PAGE
2. MATERIAL INFORMATION

A. Material - Price and Availability

Boeing can supply the kit shown in Paragraph 2.C., Parts Necessary for Each Airplane as shown below.

If there is a limit in the quantity (QTY) of kits, a supply sequence is given by Spares.

Unit Price thru

12/31/2008

Number Name Date QTY

TOP KIT, RETROFIT - 10/31/08 1 $5,388.00

DOWNSTOP REPLACEMENT

002A0001-90

1/09/09 200

1/16/09 300

1/23/09 300

1/30/09 500

3/12/09 500

3/20/09 500

B. Industry Support Information

Boeing Industry Support information is provided in Program Letter BPL 6-1151-737-PGM-190, dated

March 9, 2009 . Additional copies of program letters are available from Boeing Warranty and Product

Assurance Contracts.

C. Parts Necessary For Each Airplane

1. Kits/Parts

To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability.

Figure Kit

Top Kit 3

002A0001-90 1

ALL

KIT 002A0001-90

NOTES

Existing Part

Name Number

Figure

New Part Number

3

QTY

DOWN STOP FITTING - SLAT MAIN

TRACK

114A4103-5 32

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BOEING SERVICE BULLETIN 737-57A1302
ALL

KIT 002A0001-90

NOTES

Existing Part

Name Number

Figure

New Part Number

3

QTY

BACB30NM4HK13 64 BOLT, HEX HEAD

BACB30NR7DK12 16 BOLT

SELF-LOCKING

NUT

BACN10YR7CM 16

BACP18BC03A06P 16 PIN

BACW10P22CC 32 WASHER

2. Parts and Materials Supplied by the Operator

Part Number/ Specification QTY Name Notes

BMS 5-95, TYPE I, CLASS B 4 Oz Sealant

BACB28AW06A017C - Bushing

BMS 10-79, TYPE III 1 Oz Primer

BMS 10-60, TYPE II 1 Oz Paint

BMS 3-38 4 Oz Corrosion Inhibiting Material

Corrosion Preventive CompoundMIL-C-11796, CLASS 3 4 Oz

MS20995NC32 (MS20995C32 32 ft Lockwire

optional)

3. Parts Modified and Reidentified

None.

4. Parts Removed and Not Replaced

None.

D. Parts Necessary to Change Spares

None.

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BOEING SERVICE BULLETIN 737-57A1302
E. Special Tooling - Price and Availability

No special tooling is necessary to do this service bulletin. However, special tooling is available to help

with the installation of the down stop assembly hardware. Boeing will supply two optional toolkits free

of charge to all operators. Refer to BPL 6-1151-737-PGM-190, dated March 9, 2009 . Send a Purchase

Order to the Director of Spares. Give this service bulletin number and the date the tools will be used.

NOTE: Customers with a fleet consisting of 737NG and Classic airplanes will receive only (2) toolkits,

one toolkit for their 737NG fleet and one for their 737 Classic fleet (refer to Boeing Service

Bulletin 737-57A1301). Additional toolkits are available for purchase.

Purchase Data:

Unit Price thru

12/31/2008

Tool Kit Number Name

Miscellaneous Tool Main Slat $2,678.00

Downstop Installation Collector

MIT002A0001-90

The kits are subject to the terms and conditions of the Boeing standard purchase order

acknowledgement. After the Price date, new price data is applicable. Prices are in United States dollars.

Terms: Net 30 days.

Reference this service bulletin number and submit purchase order by one of the methods that follow:

1. Order on-line via ATA Spec 2000 or Boeing Part Page

2. Fax to (206) 662-7145

3. Spares Customer Support - MC 36-65

Boeing Spares Department

P.O. Box 3707

Seattle, Washington 98124-2207 USA

(Service Bulletin 737-57A1302)

F. Special Tooling Necessary to do this Service Bulletin

No special tooling is necessary to do this service bulletin. However, special tooling is available to help

with the installation of the down stop assembly hardware. Refer to Paragraph 2.E., Special Tooling -

Price and Availability. Maintenance and overhaul tools in the manuals shown in Paragraph 1.J.,

References, can also be necessary. Examine operator tool supply to make sure all necessary tools

are available.

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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. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s)

give the recommended sequence of steps. The sequence of steps to do this service

bulletin can be changed.

2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for

definition of the acronyms.

3. Obey all of the warnings and cautions given in the specified manual sections.

4. Unless shown differently, these dimensions and tolerances are used:

– Linear dimensions are in inches

5. 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.

6. 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.

B. WORK INSTRUCTIONS

1. PART 1 - Access

a. Do the following steps for each slat main track for slats one through eight:

(1) Remove the applicable panels from the lower leading edge surface of the wing in order

to gain access to the slat main track. Refer to 737-600/700/800/900 AMM 27-81-21 as

an accepted procedure.

(2) Align the down stop assembly with the access holes in the ribs to get access to the down

stop assembly. The slats may be positioned using the hydraulic system as given in the

following procedure.

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(a) Pressurize hydraulic system B by toggling the Hydraulic System B electric motor

pump switch, located on the P5-8 panel, to ON.

(b) Place the flap handle to detent 40.

(c) Allow the leading edge slats to fully extend.

(d) Toggle the hydraulic system B electric motor pump switch to OFF.

(e) Place the flap handle to detent 5.

(f) Turn ON, and then immediately turn OFF (Pulse), the hydraulic system B electric

motor pump switch.

(g) If the down stop assembly has not moved far enough to line up with the access holes

in the ribs, then pulse the hydraulic system B electric motor pump switch again.

Repeat this step until the down stop assembly lines up with the access holes.

NOTE: Successive start up cycles (pulses) of the hydraulic system B electric motor

pump can overheat the pump and damage it. Do not let the pump get too

hot to touch. If the pump gets hot and/or the overheat light on the P5-8

panel is illuminated, wait until the pump is cool enough to touch and the

warning light goes off before pulsing or turning on the pump.

(h) Once the down stop assembly lines up with the access holes, place the flap handle

to detent 40.

(i) After using the hydraulic system to align the down stop assembly with the access

holes, install DO-NOT-OPERATE Tags on the hydraulic switch and flap lever in the

cockpit.

WARNING: Failure to do this may result in the slats being retracted which could

cause serious bodily injury and damage to the slats.

(3) As an option to the above procedure, you can deactivate the slats, disconnect the actuator

from the slat, and move the slat manually to line up the down stop assembly with the

access holes in the ribs. Refer to 737-600/700/800/900 AMM 27-81-21 as an accepted

procedure to disconnect the actuator.

b. It is optional to remove the wing anti-icing duct elbows near the aft side of the fuel metering

manifold in the right wing in order to gain access to the down stop assembly near that location.

2. PART 2 - Preventive Modification

a. Do the following steps for each slat main track for slats one through eight:

(1) Remove the existing down stop assembly hardware (bolt, washer, down stop fitting,

sleeve, stop locator, down stop fitting, washer and nut) from the slat main track. Refer to

737-600/700/800/900 AMM 27-81-21 as an accepted procedure.

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NOTE: Be careful in handling the small parts. Do not drop them. Dropping a part into

the slat can can result in unscheduled downtime. A part left in the slat can also

create a risk of puncturing the slat can, which in turn could allow fuel to leak and

pose a risk of fire.

(2) Check the fit of the new down stop assembly bolt in the hole in the slat main track (the

new down stop bolt is identified in Figure 3):

(a) If the hole diameter is less than the bolt's shank diameter, then ream the hole up to

a max of 0.4375 inches. It is recommended that you hand ream the hole. Clean in

accordance with Boeing SOPM 20-30-03. Apply BMS 3-38, corrosion inhibiting

material, to reamed hole. If slat removal is necessary, refer to 737-600/700/800/900

AMM 27-81-21 as an accepted procedure.

(b) If the bolt has side-to-side play in the hole, then measure the hole. If the hole diameter

is less than 0.4421 no further modification is needed for the slat track. If the hole

diameter is 0.4421 to 0.5005 inches, then install a bushing in accordance with Figures

1 and 2. If slat removal is necessary, refer to 737-600/700/800/900 AMM 27-81-21

as an accepted procedure for removal and installation of the slat.

(c) If the hole diameter is greater than 0.5005 inches, then contact Boeing for further

repair instructions, or replace the slat main track.

(3) Install the new down stop assembly hardware and aft side guide bolts in accordance with

Figure 3. Optional tooling is available from Boeing to assist in installing the new down

stop assembly hardware. Refer to Paragraph 2.E., Special Tooling - Price and Availability.

NOTE: Be careful in handling the small parts. Do not drop them. Dropping a part into

the slat can can result in unscheduled downtime. A part left in the slat can also

create a risk of puncturing the slat can, which in turn could allow fuel to leak and

pose a risk of fire.

b. After all the down stop assemblies and aft side guide bolts have been modified, do a detailed

inspection or a borescope inspection for debris in the slat cans of each wing. Also look for

debris that may have fallen onto the lower rail of the slat main track. If debris is found, remove

the debris.

c. If an actuator was disconnected, then reconnect it. Refer to 737-600/700/800/900 AMM

27-81-21 as an accepted procedure. Remove the DO-NOT-OPERATE tags from the hydraulic

switch and flap lever in the cockpit if they were installed earlier.

d. If the wing anti-icing duct was disassembled, then reassemble it, and perform a leak test on

the wing anti-icing duct. Refer to 737-600/700/800/900 AMM 30-11-00 as an accepted

procedure.

3. PART III - Close Access

a. Reinstall the panels that were removed from the lower leading edge of the wing. Refer to

737-600/700/800/900 AMM 57-41-02 as an accepted procedure.

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BOEING SERVICE BULLETIN 737-57A1302
NOTE: Before reinstalling the panels that were removed from the lower leading edge of the

wing, you may want to do the changes in Service Bulletin 737-57-1293.

b. Return the airplane to a serviceable condition.

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BOEING SERVICE BULLETIN 737-57A1302
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Ream the hole in

main slat track to

0.5000 - 0.5005

inches diameter.

1 Drill / Ream Slat Main Track - -

Clean hole in slat

main track. Refer to

Boeing SOPM 20-

30-03 as an accepted procedure.

2 Clean Slat Main Track - -

Apply to the hole in

the slat main track.

BMS 5-95, TYPE I, -

CLASS B

3 Apply Sealant

Install Bushing, wet

with BMS 5-95

sealant, using the

shrink-fit method.

Refer to Boeing

SOPM 20-50-03 as

an accepted procedure. Wipe off any

excess sealant.

Install (New) Bushing BACB28AW06A017C -

FIGURE 1: SHRINK-FIT BUSHING INSTALLATION

(SHEET 1 OF 1)

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BOEING SERVICE BULLETIN 737-57A1302
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Ream bushing inner

diameter to 0.4375 -

0.4420 inches.

1 Drill / Ream Bushing BACB28AW06A017C -

Clean bushing. Refer to Boeing SOPM

20-30-03 as an accepted procedure.

2 Clean Bushing BACB28AW06A017C -

Apply 1 layer of

primer to bushing

face. Refer to Boeing SOPM 20-44-04

as an accepted procedure.

3 Apply Primer BMS 10-79, TYPE III -

Apply 1 layer of

gloss enamel to

bushing face. Refer

to Boeing SOPM 20-

44-04 as an accepted procedure.

4 Apply Paint BMS 10-60, TYPE II -

FIGURE 2: SHRINK-FIT BUSHING REAMING

(SHEET 1 OF 1)

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BOEING SERVICE BULLETIN 737-57A1302
FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 1 OF 6)

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BOEING SERVICE BULLETIN 737-57A1302
FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 2 OF 6)

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BOEING SERVICE BULLETIN 737-57A1302
FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 3 OF 6)

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BOEING SERVICE BULLETIN 737-57A1302
STEP TASK NAME IDENTIFICATION QTY MORE DATA

One bolt for each

slat main track, 16

per airplane. Mark

reference line on

threaded end of bolt

to show cotter pin

hole using felt-tip

pen. Install bolt with

BMS 3-38 corrosion

inhibiting material.(a)

(b)

1 Install (New) BOLT BACB30NR7DK12 16

One washer under

the bolt head for

each slat main track,

16 per airplane(b)

Install (New) WASHER BACW10P22CC 16

One down stop fitting on each side of

slat main track, 2 per

slat main track, 32

per airplane. Install

down stop fitting with

BMS 3-38 corrosion

inhibiting material.(b)

DOWN STOP FITTING 114A4103-5 32

- SLAT MAIN TRACK

Install (New)

Apply corrosion inhibiting material to

bolt shank and inner

faces of both down

stop fittings.

Corrosion Inhibiting BMS 3-38 -

Material

Apply

One washer under

the nut for each slat

main track, 16 per

airplane(b)

Install (New) WASHER BACW10P22CC 16

Torque the nut to

180-200 inch

pounds. One nut per

slat main track, 16

per airplane(b)

Install (New) SELF-LOCKING NUT BACN10YR7CM 16

Install (New) PIN BACP18BC03A06P 16

FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 4 OF 6)

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BOEING SERVICE BULLETIN 737-57A1302
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Using marked line

as reference, rotate

bolt so that cotter pin

can be installed. Install cotter pin approximately as

shown in the illustration. Be careful not

to damage the bolt

threads when installing the cotter

pin. One cotter pin

for each slat main

track, 16 per airplane.(b)

Remove/Install one

bolt at a time per aft

side guide. If you remove both of the existing bolts from an

aft side guide, then

it is possible you

may have to remove/reinstall the

slat main track to reinstall the aft side

guide. Keep existing

washers.

2 Remove BOLT BACB30() 32

32 per airplane, 2 at

each slat main track

location. Install bolt

with MIL-C-11796,

Class 3, corrosion

preventive compound. Re-Install

existing washers.

Install (New) BOLT, HEX HEAD BACB30NM4HK13 32

Apply to new bolts

before installation.

MIL-C-11796, CLASS -

3

Corrosion Preventive

Compound

Apply

Torque bolts to 78-

82 inch pounds. 32

per airplane, 2 at

each slat main track

location.

Torque BOLT, HEX HEAD BACB30NM4HK13 32

FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 5 OF 6)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 15, 2008

Revision 1 October 18, 2010 737-57A1302

41 of 42

BOEING SERVICE BULLETIN 737-57A1302
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Remove/Install one

bolt at a time per aft

side guide. If you remove both of the existing bolts from an

aft side guide, then

it is possible you

may have to remove/reinstall the

slat main track to reinstall the aft side

guide. Keep existing

washers.

3 Remove BOLT BACB30() 32

32 per airplane, 2 at

each slat main track

location. Install bolt

with MIL-C-11796,

Class 3, corrosion

preventive compound. Re-Install

existing washers.

Install (New) BOLT, HEX HEAD BACB30NM4HK13 32

Apply to new bolts

before installation.

MIL-C-11796, CLASS -

3

Corrosion Preventive

Compound

Apply

Torque bolts to 78-

82 inch pounds. 32

per airplane, 2 at

each slat main track

location.

Torque BOLT, HEX HEAD BACB30NM4HK13 32

Refer to Boeing

SOPM 20-50-02 as

an accepted procedure.

MS20995NC32 -

(MS20995C32 optional)

4 Install (New) Lockwire

(a) The down stop assembly can be installed with the bolt head on either the inboard side or the outboard

side of the slat main track

(b) Optional Tool MIT002A0001-90 will ease installation of the down stop assembly and cotter pin.

FIGURE 3: SLAT MAIN TRACK DOWN STOP AND AFT SIDE GUIDE MODIFICATION

(SHEET 6 OF 6)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 15, 2008

Revision 1 October 18, 2010 737-57A1302

42 of 42

BOEING SERVICE BULLETIN 737-57A1302