Commercial 

Airplanes 737

Service Bulletin

ALERT

Number: 737-26A1137

Original Issue: May 22, 2014

ATA System: 2616 2127

SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke

Clearance Mode Operational Test for Cargo Smoke Protection

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

CFR 300-774). 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 © 2014 Boeing.

Unpublished Work. All Rights Reserved.

Treatment of this document and its content is governed by contract with Boeing. Rights to use this document

are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The

Boeing Company.

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

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BLANK PAGE
Table of Contents

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

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

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

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

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 31

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 33

3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 33

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

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BOEING SERVICE BULLETIN 737-26A1137

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

ALERT

Summary Number: 737-26A1137

Original Issue: May 22, 2014

ATA System: 2616 2127

SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke

Clearance Mode Operational Test for Cargo Smoke Protection

THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH

1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO

THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO

THE NEW OWNER.

CONCURRENT REQUIREMENTS

Refer to Paragraph 1.B., Concurrent Requirements.

BACKGROUND

This service bulletin gives instructions to do the Smoke Clearance Mode - Operational Test at the repeat intervals

on airplanes equipped with the reconfigured low pressure air distribution system during a cargo fire event. The

repeat operational testing of the Equipment Cooling System and Low Pressure Environmental Control System

(ECS) will reduce the probability of a latent failure which could result in smoke and/or fire in the airplane.

A subsequent review by Boeing found that there was no maintenance procedure available to inspect the

components used to reconfigure the air distribution system. Without the maintenance procedure, failures of

components could possibly be latent for periods greater than required to meet certification requirements. A cargo

fire event in conjunction with a latent failure of the air distribution system can possibly result in smoke penetration

to occupied areas. The amount of smoke and toxicity of the smoke that could reach the occupied areas is

unknown.

Boeing Service Bulletins 737-26-1121 and either 737-21-1135 or 737-21-1163 are related to 737-26-1122.

Accomplishment of the changes in the Boeing Service Bulletins 737-26-1121, 737-21-1135 or 737-21-1163 will

not cause a failure of the test in this service bulletin. Boeing Service Bulletin 737-26A1083 is related to

737-21-1135.

Boeing Service Related Problem (SRP) 737-SRP-26-0079 is related to this service bulletin.

This table is provided to operators for planning purposes only. Refer to the applicable sections for more

information.

Planning Data Affected Reference

Spares Affected No Paragraph 1.A.2., Spares Affected

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Planning Data Affected Reference

Paragraph 1.E., Compliance and Paragraph

1.F., Approval

AD Related Yes

Weight and Balance Change No Paragraph 1.H., Weight and Balance Changes

Electrical Load Changed No Paragraph 1.I., Electrical Load Data

Publications Affected Yes Paragraph 1.K., Publications Affected

Airplane Flight Operations Affected (Flight Crew Yes Paragraph 1.K., Publications Affected

Operations Manual and/or FAA Approved Airplane Flight Manual)

Kits/Parts Required No Paragraph 2.C.1., Kits/Parts

Paragraph 2.C.2., Parts and Materials Supplied

by the Operator

Operator Supplied Parts/Material No

Paragraph 2.F., Special Tooling Necessary to

do this Service Bulletin

Special Tooling Required No

ACTION

Get access into the flight compartment and main electronics equipment compartment. As an alternate location

to the flight compartment to make sure of the Recirculation Fan's operation, between the left and right air

conditioning (AC) pack compartments, open the access panel to the ground conditioned air connection duct.

Do the Smoke Clearance Mode - Operational Test to make sure the cargo smoke system operates correctly. If

the Smoke Clearance Mode - Operational Test result is not satisfactory, do the troubleshooting procedure on

the Equipment Cooling and Low Pressure ECS systems to find and replace faulty component.

EFFECTIVITY

All 737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER Airplanes. Refer to Paragraph 1.A., Effectivity,

for the list of affected airplanes.

COMPLIANCE

The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service

bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin

mandatory.

Refer to Paragraph 1.E., Compliance.

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the Operational Test given in this service bulletin.

MANPOWER

Airplanes Total Task Hours Elapsed Hours

Each 737 Airplane 4.00 2.50

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ALERT ALERT
MATERIAL INFORMATION

None.

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BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

ALERT

Number: 737-26A1137

Original Issue: May 22, 2014

ATA System: 2616 2127

SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke

Clearance Mode Operational Test for Cargo Smoke Protection

THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH

1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO

THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO

THE NEW OWNER.

1. PLANNING INFORMATION

A. Effectivity

1. Airplanes

This service bulletin is applicable to 737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER,

line numbers 1 through 9999 in three Groups. The Variable Numbers and Group Information for

the applicable airplanes is given below.

Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line

Number, and Serial Number data.

NOTE: Variable numbers for airplanes scheduled to be delivered more than a year after the

Original Issue date of this service bulletin are not listed in the table below. MyBoeingFleet

(MBF) will show current listing of the affected airplanes.

NOTE: The Variable Number table below includes all affected airplanes up to Line Number 5263.

Affected airplanes after Line Number 5263 will be added to the service bulletin's

MyBoeingFleet.com (MBF) "get effectivity" result when they are added to the MBF Fleet

Profile Page.

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GROUP CONFIGURATION DESCRIPTION

737-600/-700/-800 Line Numbers 1 Through 1700 Included in Boeing

Service Bulletin 737-26-1122

1 -

737-600/-700/-800 Line Numbers 1 Through 1700 Included in Boeing

Service Bulletin 737-26-1122 and Had Not Accomplished Boeing

Service Bulletin 737-26-1122

1

737-600/-700/-800 Line Numbers 1 Through 1700 Included in Boeing

Service Bulletin 737-26-1122 and Had Accomplished Boeing Service

Bulletin 737-26-1122

2

737-700/-700C/-900 Line Numbers 1 Through 1700 Not Included in

Boeing Service Bulletin 737-26-1122

2 -

737-600/-700/-700C/-800/-900/-900ER Line Numbers 1701 and All

Line Numbers After 1701

3 -

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

YA311 - YA314 1

YA321 - YA323 1

YA336 - YA345 1

YA351 1

YA356 - YA357 1

YA366 - YA367 1

YA371 - YA377 1

YA501 - YA536 1

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Variable Number Group

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 - YA976 1

YA977 - YA978 3

YB001 - YB006 1

YB101 - YB132 1

YB151 - YB153 1

YB156 - YB157 1

YB158 3

YB161 - YB164 1

YB171 - YB172 1

YB181 - YB184 1

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ALERT ALERT
Variable Number Group

YB201 - YB208 1

YB271 1

YB276 1

YB301 - YB310 1

YB371 - YB380 1

YB381 - YB392 3

YB501 - YB502 1

YB521 - YB525 1

YB526 3

YB541 - YB544 1

YB551 1

YB561 - YB573 1

YB574 - YB580 3

YB581 - YB586 1

YB587 - YB598 3

YB601 - YB629 1

YB630 3

YB631 - YB632 1

YB633 - YB636 3

YB651 1

YB656 1

YB671 - YB672 3

YB851 - YB859 1

YB860 3

YB861 - YB863 1

YB871 - YB873 1

YB874 3

YB881 - YB888 1

YB889 - YB893 3

YB901 - YB903 1

YB911 1

YB961 - YB975 3

YB981 3

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ALERT ALERT
Variable Number Group

YB986 - YB998 3

YC001 - YC030 1

YC051 - YC083 1

YC084 3

YC091 - YC094 1

YC095 3

YC101 - YC104 1

YC111 - YC113 1

YC121 1

YC126 - YC127 1

YC136 - YC141 1

YC146 - YC147 1

YC151 - YC156 1

YC166 - YC171 1

YC176 - YC178 1

YC179 3

YC186 - YC189 1

YC190 3

YC201 - YC203 1

YC206 - YC207 1

YC301 - YC305 1

YC321 - YC385 1

YC386 - YC387 3

YC391 - YC394 1

YC396 1

YC401 - YC417 1

YC421 - YC422 1

YC426 - YC428 1

YC436 - YC437 1

YC438 - YC439 3

YC441 - YC448 1

YC451 - YC455 1

YC459 1

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ALERT ALERT
Variable Number Group

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 - YC741 1

YC742 - YC750 3

YC751 - YC752 1

YC761 - YC770 1

YC781 - YC793 1

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 - YD107 1

YD108 - YD117 3

YD121 - YD126 1

YD151 - YD159 1

YD171 - YD172 1

YD201 - YD203 1

YD206 - YD209 1

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ALERT ALERT
Variable Number Group

YD216 - YD219 1

YD251 - YD254 1

YD256 - YD257 1

YD261 1

YD301 - YD334 1

YD391 1

YD401 - YD410 1

YD412 1

YD413 - YD422 3

YD481 - YD485 1

YD491 - YD499 3

YD501 - YD512 2

YD531 - YD535 2

YD541 - YD547 2

YD561 - YD564 2

YD571 - YD572 2

YD591 - YD594 2

YD595 3

YD601 - YD612 2

YD651 - YD655 3

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 3

YF001 - YF011 3

YF021 - YF049 3

YF051 - YF080 3

YF086 - YF087 3

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ALERT ALERT
Variable Number Group

YF106 - YF107 3

YF111 - YF114 3

YF116 - YF119 3

YF121 - YF132 3

YF176 - YF178 3

YF191 - YF192 3

YF201 - YF276 3

YF401 - YF402 3

YF431 - YF432 3

YF436 - YF437 3

YF441 - YF442 3

YF451 - YF460 3

YF501 - YF599 3

YF601 - YF666 3

YF701 - YF707 3

YF801 - YF805 3

YF831 - YF832 3

YF836 - YF838 3

YF871 - YF872 3

YF901 - YF905 3

YF921 - YF928 3

YF951 - YF954 3

YG001 - YG043 1

YG044 2

YG061 - YG064 1

YG066 1

YG067 2

YG068 1

YG069 2

YG070 - YG073 1

YG074 2

YG075 - YG080 1

YG081 2

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ALERT ALERT
Variable Number Group

YG082 - YG083 1

YG084 2

YG085 - YG087 1

YG088 2

YG089 1

YG091 - YG099 3

YG101 - YG104 3

YG111 - YG114 3

YG116 - YG142 3

YG201 1

YG202 - YG205 3

YG211 1

YG212 - YG214 3

YG221 - YG224 3

YG251 - YG252 3

YG501 - YG508 2

YG509 - YG514 3

YG601 - YG602 2

YG701 3

YG711 3

YH001 - YH012 3

YH031 - YH055 3

YH071 - YH080 3

YH101 - YH132 3

YH201 - YH202 3

YH206 - YH207 3

YH301 - YH306 3

YH321 - YH322 3

YH501 - YH542 3

YH551 - YH594 3

YH601 - YH606 3

YH611 - YH620 3

YH631 - YH632 3

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ALERT ALERT
Variable Number Group

YH636 - YH637 3

YH641 3

YH681 3

YH701 - YH723 3

YH751 3

YH801 - YH831 3

YH901 - YH904 3

YH911 3

YH951 3

YJ001 - YJ004 1

YJ005 - YJ010 3

YJ011 - YJ013 1

YJ021 1

YJ471 - YJ480 1

YJ501 - YJ517 1

YJ531 - YJ545 1

YJ546 - YJ579 3

YJ591 - YJ593 1

YJ594 - YJ599 3

YJ631 - YJ632 1

YJ671 - YJ682 1

YJ683 - YJ694 3

YJ801 - YJ853 1

YJ854 - YJ860 3

YJ861 - YJ867 1

YJ871 1

YJ872 - YJ880 3

YJ901 - YJ902 1

YJ903 - YJ904 3

YJ908 - YJ910 3

YJ911 - YJ919 1

YJ920 - YJ929 3

YJ931 - YJ936 1

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ALERT ALERT
Variable Number Group

YJ937 3

YJ941 - YJ943 1

YJ944 - YJ956 3

YJ961 3

YJ976 - YJ977 3

YK001 - YK007 1

YK101 - YK104 1

YK111 - YK112 1

YK121 - YK122 1

YK131 - YK132 1

YK133 3

YK136 1

YK137 - YK139 3

YK141 - YK142 3

YK146 - YK148 3

YK151 - YK154 3

YK161 - YK167 3

YK171 3

YK176 - YK177 3

YK186 3

YK191 3

YK196 3

YK201 - YK202 3

YK301 - YK304 1

YK305 - YK314 3

YK321 - YK330 1

YK331 - YK340 3

YK361 - YK364 1

YK365 - YK378 3

YK401 - YK405 1

YK406 3

YK426 1

YK427 3

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Variable Number Group

YK431 1

YK432 - YK450 3

YK456 - YK458 1

YK459 - YK467 3

YK471 - YK473 3

YK476 3

YK480 1

YK481 - YK487 3

YK491 - YK493 3

YK495 - YK499 3

YK511 - YK516 3

YK521 - YK530 3

YK551 - YK571 3

YK576 - YK577 3

YK580 - YK585 3

YK601 - YK602 3

YK606 - YK607 3

YK611 - YK616 3

YK621 - YK634 3

YK641 - YK644 3

YK651 - YK665 3

YK671 - YK672 3

YK676 - YK677 3

YK681 - YK686 3

YK691 3

YK695 - YK699 3

YK701 - YK713 3

YK716 - YK719 3

YK721 - YK741 3

YK751 - YK770 3

YK776 - YK778 3

YK781 - YK785 3

YK791 - YK792 3

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Variable Number Group

YK796 - YK797 3

YK801 - YK899 3

YK901 - YK912 3

YK918 - YK919 3

YK921 - YK929 3

YK941 - YK999 3

YL001 - YL005 3

YL011 - YL016 3

YL021 - YL024 3

YL051 - YL052 3

YL056 - YL057 3

YL061 3

YL066 - YL069 3

YL076 - YL077 3

YL101 - YL137 3

YL201 - YL237 3

YL241 - YL242 3

YL271 - YL272 3

YL281 - YL284 3

YL301 - YL303 3

YL311 - YL314 3

YL316 - YL321 3

YL351 - YL353 3

YL371 - YL374 3

YL401 3

YL421 - YL429 3

YL431 - YL444 3

YL461 - YL478 3

YL501 - YL509 3

YL531 - YL534 3

YL541 - YL551 3

YL561 - YL579 3

YL591 - YL598 3

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Variable Number Group

YL601 - YL606 3

YL611 - YL612 3

YL616 - YL617 3

YL621 3

YL626 3

YL631 - YL634 3

YL636 - YL637 3

YL661 - YL664 3

YL676 - YL691 3

YL696 - YL697 3

YL701 - YL707 3

YL731 3

YL751 - YL752 3

YL756 - YL757 3

YL761 - YL780 3

YL796 - YL797 3

YL801 - YL815 3

YL901 - YL910 3

YL921 - YL940 3

YL951 - YL968 3

YM101 1

YM102 - YM103 3

YM201 - YM202 1

YM203 - YM244 3

YM251 - YM259 1

YM260 - YM299 3

YM301 - YM399 3

YM401 - YM415 3

YM471 3

YM481 - YM484 3

YM501 - YM515 3

YM521 - YM522 3

YM541 3

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Variable Number Group

YM551 - YM553 3

YM571 - YM572 3

YM581 - YM582 3

YM591 - YM599 3

YM631 - YM634 3

YM641 - YM652 3

YM671 - YM674 3

YM691 - YM699 3

YM701 - YM710 3

YM761 - YM765 3

YM771 - YM779 3

YN001 - YN016 3

YN021 - YN024 3

YN061 3

YN071 - YN082 3

YN091 - YN092 3

YN101 - YN112 3

YN121 3

YN126 3

YN201 - YN202 3

YN211 - YN219 3

YN231 - YN236 3

YN261 3

YN501 3

YN531 - YN534 3

YN551 - YN562 3

YN581 - YN583 3

YN591 3

YN601 - YN606 3

YN651 - YN653 3

YN701 - YN702 3

YN741 - YN746 3

YN756 3

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Variable Number Group

YQ001 - YQ003 3

YQ011 - YQ021 3

YQ026 - YQ029 3

YQ036 - YQ045 3

YQ201 - YQ207 3

YQ231 3

YQ241 - YQ251 3

YQ281 - YQ284 3

YQ291 - YQ296 3

YQ301 - YQ302 3

YQ321 - YQ324 3

YQ331 - YQ334 3

YQ346 - YQ347 3

YQ401 - YQ403 3

YQ451 - YQ454 3

YQ456 3

YQ461 3

YQ471 3

YQ501 - YQ514 3

YR001 - YR037 3

YR051 - YR087 3

YR091 - YR098 3

YR101 - YR105 3

YR111 - YR119 3

YR126 - YR144 3

YR166 - YR182 3

YR186 - YR198 3

YR201 - YR204 3

YR231 - YR294 3

YR296 - YR297 3

YR301 - YR334 3

YR338 - YR339 3

YR361 - YR366 3

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Variable Number Group

YR371 - YR373 3

YR376 3

YR381 - YR382 3

YR386 - YR387 3

YR391 3

YR396 - YR398 3

YR401 - YR405 3

YR411 - YR413 3

YR416 - YR418 3

YR421 - YR424 3

YR426 - YR438 3

YR441 - YR449 3

YR451 - YR455 3

YR457 - YR499 3

YR501 - YR506 3

YR511 - YR520 3

YR526 - YR544 3

YR546 - YR551 3

YR556 - YR562 3

YR571 - YR580 3

YR591 - YR592 3

YR601 - YR605 3

YR616 - YR648 3

YR651 - YR658 3

YR661 - YR663 3

YR671 - YR672 3

YR676 - YR677 3

YR701 - YR769 3

YR771 - YR796 3

YR801 - YR816 3

YR831 - YR838 3

YR841 - YR849 3

YR851 - YR883 3

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Variable Number Group

YR901 - YR903 3

YR931 - YR934 3

YR938 - YR944 3

YR951 - YR970 3

YR981 - YR994 3

YS001 - YS002 3

YS006 - YS009 3

YS031 - YS032 3

YS051 - YS073 3

YS101 - YS120 3

YS126 - YS130 3

YS151 - YS160 3

YS166 - YS189 3

YS191 - YS194 3

YS196 - YS197 3

YS201 - YS209 3

YS221 - YS225 3

YS231 - YS236 3

YS271 - YS282 3

YS301 - YS333 3

YS351 - YS362 3

YS371 - YS374 3

YS381 - YS383 3

YS401 3

YS451 3

YS456 - YS457 3

YS462 3

YS501 - YS502 3

YS506 3

YS511 3

YS551 - YS553 3

YS561 - YS575 3

YS581 - YS589 3

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Variable Number Group

YS591 - YS595 3

YS601 - YS680 3

YS686 - YS690 3

YS701 - YS708 3

YS721 - YS750 3

YS761 - YS762 3

YS771 - YS780 3

YS806 - YS810 3

YS816 - YS818 3

YS823 - YS825 3

YS851 - YS856 3

YS876 3

YS881 - YS882 3

YS901 - YS909 3

YS911 - YS917 3

YS961 - YS965 3

YS991 - YS993 3

YT001 - YT004 3

YT006 3

YT031 - YT032 3

YT036 - YT037 3

YT061 - YT068 3

YT101 - YT106 3

YT126 - YT127 3

YT136 - YT138 3

YT176 - YT179 3

YT201 3

YT251 - YT267 3

YT301 3

YT306 - YT307 3

YT311 - YT312 3

YT401 - YT403 3

YT411 - YT414 3

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Variable Number Group

YT461 - YT468 3

YT601 - YT606 3

YT761 - YT769 3

YT891 - YT894 3

YU001 - YU029 3

YU201 - YU207 3

2. Spares Affected

None.

B. Concurrent Requirements

The service bulletins listed below must be done before or at the same time as this service bulletin:

Group 1:

Company Service Bulletin Description

FIRE PROTECTION - Lower Cargo Compartment Smoke Detection - Forward Cargo

Compartment Smoke Penetration Electrical

Changes

Boeing 737-26-1122, Revision 1 (a)

(a) Incorporation of this service bulletin is necessary to make sure the Smoke Clearance

Mode - Operational Test result is satisfactory.

C. Reason

This service bulletin gives instructions to do the Smoke Clearance Mode - Operational Test at the

repeat intervals on airplanes equipped with the reconfigured low pressure air distribution system during

a cargo fire event. The repeat operational testing of the Equipment Cooling System and Low Pressure

Environmental Control System (ECS) will reduce the probability of a latent failure which could result in

smoke and/or fire in the airplane.

A subsequent review by Boeing found that there was no maintenance procedure available to inspect

the components used to reconfigure the air distribution system. Without the maintenance procedure,

failures of components could possibly be latent for periods greater than required to meet certification

requirements. A cargo fire event in conjunction with a latent failure of the air distribution system can

possibly result in smoke penetration to occupied areas. The amount of smoke and toxicity of the smoke

that could reach the occupied areas is unknown.

Boeing Service Bulletins 737-26-1121 and either 737-21-1135 or 737-21-1163 are related to

737-26-1122. Accomplishment of the changes in the Boeing Service Bulletins 737-26-1121, 737-21-1135

or 737-21-1163 will not cause a failure of the test in this service bulletin. Boeing Service Bulletin

737-26A1083 is related to 737-21-1135.

Boeing Service Related Problem (SRP) 737-SRP-26-0079 is related to this service bulletin.

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D. Description

Get access into the flight compartment and main electronics equipment compartment. As an alternate

location to the flight compartment to make sure of the Recirculation Fan's operation, between the left

and right air conditioning (AC) pack compartments, open the access panel to the ground conditioned

air connection duct. Do the Smoke Clearance Mode - Operational Test to make sure the cargo smoke

system operates correctly. If the Smoke Clearance Mode - Operational Test result is not satisfactory,

do the troubleshooting procedure on the Equipment Cooling and Low Pressure ECS systems to find

and replace faulty component.

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

Group 1:

Affected Maintenance Zones

Model Zone

737-600, 737-700, 737-800 112, 113, 114, 117, 118, 125, 126

Group 2:

Affected Maintenance Zones

Model Zone

737-700, 737-700C, 737-900 112, 113, 114, 117, 118, 125, 126

Group 3:

Affected Maintenance Zones

Model Zone

737-600, 737-700, 737-700C, 112, 113, 114, 117, 118, 125, 126

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

E. Compliance

The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to

this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this

service bulletin mandatory.

Table: Smoke Clearance Mode - Operational Test

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 51 months 9000 flight hours.

after the original issue date of this

service bulletin.

Do a Smoke Clearance

Mode - Operational Test

in accordance with Paragraph 3.B., Work Instructions.

Group 1, Configuration 1

Airplanes.

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Table: Smoke Clearance Mode - Operational Test

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 10 months 9000 flight hours.

after the original issue date of this

service bulletin.

Do a Smoke Clearance

Mode - Operational Test

in accordance with Paragraph 3.B., Work Instructions.

Group 1, Configuration 2,

Group 2 and Group 3 Airplanes.

Before further -

flight.

Do a system fault isolation in accordance with

Paragraph 3.B., Work Instructions.

If the Smoke Clearance

Mode - Operational Test

result is not satisfactory.

F. Approval

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

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

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

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

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

changes.

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

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

before incorporating this service bulletin.

G. Manpower

The table below shows an estimate of the task hours necessary to do this 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 find the tools.

Number of Per- Task-Hours Elapsed Hours

sons

Task

Open Access 1 0.50 0.50

Test (a) 2 3.00 1.50

Close Access 1 0.50 0.50

TOTAL FOR EACH AIRPLANE 4.00 2.50

(a) The task hour does not include time that is possibly needed to troubleshoot

wiring and components if test result is not satisfactory.

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This estimate does not include the task hour data given in the service bulletins in Paragraph 1.B.,

Concurrent Requirements.

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not changed.

J. References

1. Existing Data:

a. Boeing Service Bulletin 737-21-1135, 737-21-1163, 737-26-1121, 737-26-1122, 737-26A1083

b. Boeing Service Related Problem (SRP) 737-SRP-26-0079

c. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19

d. 737-600/700/800/900 Aircraft Maintenance Manual (AMM) 06-41-00, 21-27-00, 21-31-01,

24-22-00, 52-51-00

e. 737-600/700/800/900 Fault Isolation Manual (FIM) 21-25-801, 21-25-802, 21-27-805,

21-27-806, 21-27-807, 21-27-808, 21-27-809, 21-27-810, 21-27-811

2. Data Supplied with this Service Bulletin:

None.

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

None.

K. Publications Affected

1. Publications:

Publication Chapter-Section

737 Flight Crew Operations Manual 8-20

737 Aircraft Maintenance Manual 21-27

737 Fault Isolation Manual 21-25, 21-27

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 does not affect FCS, therefore DTIs are not necessary.

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L. Interchangeability and Intermixability of Parts

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

M. Software Accomplishment Summary

Not affected.

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2. MATERIAL INFORMATION

A. Material - Price and Availability

None.

B. Industry Support Information

Boeing warranty remedies are not available for the Operational Test given in this service bulletin.

C. Parts Necessary for Each Airplane

1. Kits/Parts:

None.

2. Parts and Materials Supplied by the Operator:

None.

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. Examine

operator tool supply to make sure all necessary tools are available.

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ALERT ALERT

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

– Linear dimensions are in inches

– Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus

or minus 0.03 inch

– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch

– Angular tolerance is plus or minus 2 degrees

– Hole dimensions for standard solid rivets and fasteners are in Structural Repair

Manual (SRM) Chapter 51

– Torque Values:

— Values for structural fasteners are given in 737 Structural Repair Manual,

Chapter 51.

— Values for airframe maintenance tasks are included in Chapter 20 of 737

Airplane Maintenance Manual (AMM).

— Values for electrical maintenance tasks are included in Chapter 20 of

Standard Wiring Practices Manual (SWPM).

— Values for engine maintenance tasks are included in Chapter 70 of 737

Airplane Maintenance Manual (AMM).

— Non-standard torque values for maintenance tasks are included in the

applicable installation step.

4. 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.

5. 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.

6. 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.

7. 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.

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8. If shading is used, shaded areas in Figures are to separate the non-critical and

non-authoritative information from the critical and authoritative information.

9. Use of colors in Figures is based on guidance from the ATA e-Business Program

(ATA) iSpec 2200.

10. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS

are in Paragraph 1.E., Compliance.

11. Some steps in the Work Instructions are identified as Required for Compliance (RC).

If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps

identified as RC must be done to comply with the AD. Alternative procedures for

steps not identified with RC can be used if the RC steps can still be done as specified,

and the airplane can be put back in a serviceable condition. An Alternative Method

of Compliance (AMOC) is not necessary for deviations to steps that are not identified

as RC.

B. WORK INSTRUCTIONS

1. Do these steps to get access.

a. Below the main electronics equipment compartment, open the Access Door 117A. Refer to

737-600/700/800/900 AMM 06-41-00 as an accepted procedure.

b. In the main electronics equipment compartment, get access to the Cabin Pressure Controller.

For the Cabin Pressure Controller location, refer to 737-600/700/800/900 AMM 21-31-01 as

an accepted procedure.

c. Below the AC mix air compartment, open the ECS Panel 191E to get access to the Ground

Conditioned Air Connection Duct. Refer to 737-600/700/800/900 AMM 06-41-00 as an accepted

procedure.

NOTE: This is an alternate location to the flight compartment to make sure of the Recirculation

Fan's operation.

d. Get access into the flight compartment. Refer to 737-600/700/800/900 AMM 52-51-00 as an

accepted procedure.

2. Do these steps to make sure the Cargo Fire Protection system operates correctly:

a. In the flight compartment, apply electrical power to the airplane. Refer to 737-600/700/800/900

AMM 24-22-00 as an accepted procedure.

b. RC - In the flight compartment and main electronics equipment compartment, do the AMM

task 21-27-00-700-807, Smoke Clearance Mode - Operational Test. Refer to

737-600/700/800/900 AMM 21-27-00 as an accepted procedure.

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c. If the Smoke Clearance Mode - Operational Test result is not satisfactory, do a system fault

isolation to find and replace faulty component. Refer to 737-600/700/800/900 FIM 21-25-801,

737-600/700/800/900 FIM 21-25-802, 737-600/700/800/900 FIM 21-27-805,

737-600/700/800/900 FIM 21-27-806, 737-600/700/800/900 FIM 21-27-807,

737-600/700/800/900 FIM 21-27-808 , 737-600/700/800/900 FIM 21-27-809,

737-600/700/800/900 FIM 21-27-810 and 737-600/700/800/900 FIM 21-27-811 as accepted

procedures.

d. Remove electrical power from the airplane if electrical power is not necessary. Refer to

737-600/700/800/900 AMM 24-22-00 as an accepted procedure.

3. Do these steps to close access.

a. Below the main electronics equipment compartment, close the Access Door 117A. Refer to

737-600/700/800/900 AMM 06-41-00 as an accepted procedure.

b. Below the AC mix air compartment, close the Low Pressure ECS Panel 191E if it was opened.

Refer to 737-600/700/800/900 AMM 06-41-00 as an accepted procedure.

4. Put the airplane back to a serviceable condition.

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