Commercial 

Airplanes 737

Service Bulletin

Number: 737-21-1186

Original Issue: April 17, 2012

ATA System: 2100

SUBJECT: AIR CONDITIONING - Control Cabin Conditioned Air Distribution System - Inspection

of the Metal Clamp Installed on Hoses to the Air Conditioning Temperature Sensor,

Gasper Air Outlet and Diffuser

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 © 2012 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Unpublished Work.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, DreamlinerTM,

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 Boeing

liveries 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. BOEING is a trademark of Boeing Management

Company.

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Table of Contents

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

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

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

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

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 29

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 31

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 31

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

FIGURE 1: INSPECT OF THE METAL CLAMP INSTALLATION [Group 1] . . . . . . . . . . . . . . . 35

FIGURE 2: INSPECT OF THE METAL CLAMP INSTALLATION [Group 2] . . . . . . . . . . . . . . . 38

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Commercial 

Airplanes 737

Service Bulletin

Summary Number: 737-21-1186

Original Issue: April 17, 2012

ATA System: 2100

SUBJECT: AIR CONDITIONING - Control Cabin Conditioned Air Distribution System - Inspection

of the Metal Clamp Installed on Hoses to the Air Conditioning Temperature Sensor,

Gasper Air Outlet and Diffuser

CONCURRENT REQUIREMENTS

None.

BACKGROUND

This service bulletin gives instructions to do a General Visual inspection of the installation of metal clamps

installed on the hoses of the Air Conditioning Temperature Sensor, Gasper Air Outlet and the Diffuser on the

left side of the Control Cabin at STA 259.5. If the metal clamps are not the correct part number or not correctly

positioned on the hose, the adjacent wire bundles can become damaged. Also, if the metal clamps are not the

correct part number or not installed in the correct position, do a General Visual inspection of the wire bundles

and repair if necessary. If this inspection is not done, any damaged wires could cause an electrical short circuit

that can cause a fire or smoke in the Control Cabin.

Operators have informed Boeing of chafed wire bundles caused by metal clamps installed on hoses to the Air

Conditioning Temperature Sensor, Gasper Air Outlet and the Diffuser on the left side of the Control Cabin at

STA 259.5. A metal clamp can cause chafed wire bundles if it is the incorrect part number or incorrectly installed.

Accomplishment of this service bulletin will check the part number and position of the metal clamps and adjacent

wire bundles for chafing.

Boeing Service Related Problem (SRP) 737-SRP-21-0186 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

AD Related No Paragraph 1.E., Compliance

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 No Paragraph 1.K., Publications Affected

Operations Manual and/or FAA Approved Airplane Flight Manual)

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Planning Data Affected Reference

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

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

by the Operator

Operator Supplied Material Yes

Paragraph 2.F., Special Tooling Necessary to

do this Service Bulletin

Special Tooling Required No

ACTION

Group 1-2:

Get access to the hoses of the Air Conditioning Temperature Sensor, Gasper Air Outlets and the Diffuser at

STA 259.5. Do a General Visual Inspection of the metal clamp installation.

– If the metal clamp is not the correct part number, install the correct part number metal clamp or as an option

install a plastic tie strap. Do a General Visual Inspection of the adjacent wire bundles and repair if necessary.

– If the metal clamp is the correct part number but not in the correct position, rotate the clamp to the correct

position. Do a General Visual Inspection of the adjacent wire bundles and repair if necessary.

– If the metal clamp part number and position is correct, no more work is necessary. As an option the metal

clamp can be replaced with a plastic tie strap.

Group 3:

Contact Boeing to get instructions for the change for this service bulletin, 737-21-1186 original issue, and do

the work instructed by Boeing.

EFFECTIVITY

737-100/-200/-200C/-300/-400/-500 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected

airplane(s).

COMPLIANCE

No compliance time is given.

Boeing recommends this service bulletin be done to prevent possible operational disruptions.

On Group 3 airplanes, contact Boeing to get instructions for the change for this service bulletin, 737-21-1186

original issue, and do the work instructed by Boeing

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the inspection and repair procedure given in this service bulletin.

MANPOWER

Airplanes Total Task Hours Elapsed Hours

Group 1 1.25 1.25

Group 2 1.25 1.25

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BOEING SERVICE BULLETIN 737-21-1186
MATERIAL INFORMATION

Operator Supplied Parts/Materials.

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

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BOEING SERVICE BULLETIN 737-21-1186

BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

Number: 737-21-1186

Original Issue: April 17, 2012

ATA System: 2100

SUBJECT: AIR CONDITIONING - Control Cabin Conditioned Air Distribution System - Inspection

of the Metal Clamp Installed on Hoses to the Air Conditioning Temperature Sensor,

Gasper Air Outlet and Diffuser

1. PLANNING INFORMATION

A. Effectivity

1. Airplanes

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

Serial Number data.

This service bulletin is for the airplane(s) shown below.

GROUP CONFIGURATION DESCRIPTION

737 Airplanes with an Air Conditioning Temperature Sensor, 1 Gasper

Air Outlet and Diffuser.

1 -

737 Airplanes with an Air Conditioning Temperature Sensor, 2 Gasper

Air Outlets and a Diffuser.

2 -

3 - 737 Airplanes line numbers 1 - 291

Airplane Models:

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

Variable Number Group

PA001 - PA022 3

PA099 3

PA231 - PA232 3

PC001 - PC005 3

PG001 - PG075 3

PG199 3

PG201 - PG230 3

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Variable Number Group

PG251 - PG255 3

PG271 - PG279 3

PG301 - PG314 3

PG331 - PG332 3

PG351 - PG356 3

PG375 3

PG401 - PG403 3

PG431 - PG442 3

PG471 - PG475 3

PG501 - PG505 3

PG571 - PG583 3

PG584 - PG585 1

PG586 2

PG621 - PG630 3

PG651 - PG652 3

PG701 - PG705 3

PH001 2

PH011 2

PH012 1

PH013 2

PH021 2

PH022 - PH023 1

PH024 2

PH701 - PH715 3

PH731 - PH732 3

PH741 - PH742 3

PH743 2

PJ001 - PJ002 3

PJ003 - PJ006 1

PJ007 - PJ009 2

PJ031 - PJ032 3

PJ071 - PJ072 3

PJ101 - PJ104 3

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PJ105 - PJ112 1

PJ113 - PJ114 2

PJ115 - PJ118 1

PJ119 2

PJ201 2

PJ202 - PJ218 1

PJ219 2

PJ301 - PJ302 1

PJ551 - PJ561 1

PJ601 - PJ615 1

PJ811 1

PJ816 - PJ817 1

PK026 2

PK027 - PK028 1

PK029 2

PK041 2

PK042 - PK052 1

PK053 2

PK061 2

PK062 - PK069 1

PK070 2

PK081 - PK082 2

PK091 2

PK092 - PK098 1

PK099 2

PK101 2

PK102 1

PK103 2

PK111 2

PK112 - PK119 1

PK120 2

PK141 2

PK142 - PK145 1

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PK146 2

PK201 2

PK202 1

PK203 - PK204 2

PK211 2

PK212 1

PK213 - PK214 2

PK215 - PK219 1

PK220 - PK223 2

PK231 2

PK232 - PK234 1

PK235 - PK236 2

PK237 - PK239 1

PK240 - PK241 2

PK251 2

PK252 - PK257 1

PK258 2

PK271 2

PK272 1

PK273 - PK274 2

PK281 - PK285 2

PK286 1

PK287 - PK289 2

PK291 2

PK301 2

PK302 - PK305 1

PK306 - PK307 2

PK308 - PK309 1

PK310 - PK311 2

PK312 - PK316 1

PK317 - PK318 2

PK341 2

PK351 2

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Variable Number Group

PK352 - PK354 1

PK355 - PK356 2

PK357 - PK360 1

PK361 2

PK391 2

PK431 - PK433 2

PK451 - PK452 2

PK461 2

PK462 - PK468 1

PK469 2

PK495 2

PK501 - PK502 2

PK503 1

PK504 2

PK511 - PK512 2

PK513 - PK514 1

PK515 2

PK519 2

PK521 - PK523 2

PK524 - PK527 1

PK528 2

PK541 2

PK542 - PK545 1

PK546 - PK547 2

PK548 - PK559 1

PK560 - PK563 2

PK564 1

PK565 2

PK581 2

PK591 2

PK592 1

PK593 - PK594 2

PK595 - PK598 1

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PK599 2

PK601 2

PK602 - PK609 1

PK610 - PK611 2

PK612 1

PK613 - PK614 2

PK615 - PK616 1

PK617 2

PK621 2

PK622 - PK636 1

PK637 2

PK641 - PK642 2

PK661 - PK662 2

PK663 - PK665 1

PK666 2

PK671 2

PK672 - PK680 1

PK681 2

PK691 - PK693 2

PK694 - PK696 1

PK697 2

PK711 2

PK712 - PK714 1

PK715 - PK716 2

PK731 2

PK732 - PK764 1

PK765 2

PK771 2

PK772 - PK778 1

PK779 2

PK801 2

PK802 - PK803 1

PK804 2

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PK819 2

PK820 - PK826 1

PK827 2

PK830 2

PK861 2

PK862 1

PK863 2

PK871 2

PK872 - PK873 1

PK874 2

PK881 2

PK882 - PK883 1

PK884 2

PK901 2

PK902 - PK937 1

PK938 2

PK971 2

PK972 - PK973 1

PK974 2

PL001 2

PL002 - PL013 1

PL014 - PL015 2

PL016 - PL027 1

PL028 2

PL061 2

PL081 2

PL101 2

PL102 - PL112 1

PL113 2

PL151 2

PL171 - PL172 2

PL201 2

PL202 1

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PL203 2

PL221 2

PL401 2

PL402 1

PL403 - PL404 2

PL405 - PL416 1

PL417 2

PL421 2

PL441 2

PL451 2

PL452 - PL455 1

PL456 2

PL471 2

PL491 2

PL501 2

PL502 - PL505 1

PL506 2

PL551 2

PL552 - PL561 1

PL562 2

PL581 2

PL601 2

PL602 1

PL603 2

PL611 2

PL621 2

PL622 - PL625 1

PL626 2

PL631 - PL632 2

PL711 - PL712 3

PL716 3

PL717 - PL743 1

PL744 - PL745 2

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PL746 1

PL747 2

PL756 2

PL758 2

PL761 2

PL762 - PL768 1

PL769 - PL770 2

PL781 - PL783 2

PL784 - PL787 1

PL788 2

PL793 2

PL801 - PL803 3

PM001 2

PM002 - PM005 1

PM006 2

PM016 - PM017 2

PM021 2

PM022 1

PM023 2

PM051 2

PM052 - PM065 1

PM066 2

PM101 2

PM102 - PM118 1

PM119 2

PM141 - PM142 2

PM171 2

PM181 2

PM251 2

PM252 - PM254 1

PM255 2

PM281 2

PM282 1

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PM283 2

PM381 - PM399 1

PM401 - PM417 1

PM541 - PM564 1

PN001 - PN002 2

PN021 2

PN022 - PN042 1

PN043 2

PN081 2

PN082 - PN085 1

PN086 2

PN101 2

PN102 - PN116 1

PN117 2

PN131 2

PN132 - PN162 1

PN163 2

PN401 2

PN402 - PN419 1

PN420 2

PN431 2

PN432 1

PN433 2

PN451 2

PN452 - PN455 1

PN456 2

PN471 2

PN472 - PN473 1

PN474 2

PN481 2

PN491 2

PN492 1

PN493 2

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Variable Number Group

PN501 - PN502 2

PN511 - PN512 2

PN521 2

PP001 - PP054 1

PP101 - PP169 1

PP181 - PP199 1

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

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PP993 1

PQ001 - PQ016 1

PQ026 - PQ041 1

PQ051 - PQ092 1

PQ101 - PQ199 1

PQ201 - PQ202 1

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

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PR041 - PR045 1

PR061 - PR072 1

PR077 - PR082 1

PR091 - PR092 1

PR096 1

PR101 1

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

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BOEING SERVICE BULLETIN 737-21-1186
Variable Number Group

PT021 - PT031 1

PT041 - PT064 1

PT101 - PT105 1

PT121 - PT138 1

PT146 - PT148 1

PT161 - PT170 1

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

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Variable Number Group

PU311 - PU313 1

PV001 - PV055 1

PV201 - PV209 1

PV226 - PV229 1

PV231 - PV237 1

PV271 - PV272 1

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

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Variable Number Group

PW461 - PW467 1

PW501 - PW504 1

PW511 - PW522 1

PW524 - PW550 1

PW556 - PW557 1

PW561 - PW564 1

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 3

PX701 3

PY001 - PY008 3

PY021 3

PY022 2

PY031 3

PY036 - PY037 2

PY046 2

PY047 1

PY048 2

PY051 2

PY052 1

PY053 2

PY056 - PY057 2

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Variable Number Group

PY101 2

PY102 1

PY103 2

PY111 2

PY112 1

PY113 2

PY131 2

PY132 1

PY133 - PY135 2

PY141 2

PY142 1

PY143 2

PY151 - PY154 2

PY156 - PY157 2

PY161 - PY162 2

PY166 2

PY191 2

PY201 2

PY221 - PY222 2

PY231 2

PY241 2

PY242 - PY243 1

PY244 2

PY270 - PY271 2

PY272 - PY274 1

PY275 2

PY281 2

PY286 2

PY301 - PY304 3

PY321 - PY323 3

PY341 - PY346 3

PY361 - PY362 3

PY381 3

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Variable Number Group

PY401 2

PY409 - PY411 2

PY421 - PY422 2

PY441 2

PY451 2

PY461 2

PY462 1

PY463 2

PY591 2

PY592 - PY594 1

PY595 2

PY611 - PY612 2

PY621 2

PY631 2

PY651 2

PY671 - PY672 2

PY721 2

PY741 2

2. Spares Affected

None.

B. Concurrent Requirements

None.

C. Reason

This service bulletin gives instructions to do a General Visual inspection of the installation of metal

clamps installed on the hoses of the Air Conditioning Temperature Sensor, Gasper Air Outlet and the

Diffuser on the left side of the Control Cabin at STA 259.5. If the metal clamps are not the correct part

number or not correctly positioned on the hose, the adjacent wire bundles can become damaged. Also,

if the metal clamps are not the correct part number or not installed in the correct position, do a General

Visual inspection of the wire bundles and repair if necessary. If this inspection is not done, any damaged

wires could cause an electrical short circuit that can cause a fire or smoke in the Control Cabin.

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BOEING SERVICE BULLETIN 737-21-1186
Operators have informed Boeing of chafed wire bundles caused by metal clamps installed on hoses

to the Air Conditioning Temperature Sensor, Gasper Air Outlet and the Diffuser on the left side of the

Control Cabin at STA 259.5. A metal clamp can cause chafed wire bundles if it is the incorrect part

number or incorrectly installed. Accomplishment of this service bulletin will check the part number and

position of the metal clamps and adjacent wire bundles for chafing.

Boeing Service Related Problem (SRP) 737-SRP-21-0186 is related to this service bulletin.

D. Description

Group 1-2:

Get access to the hoses of the Air Conditioning Temperature Sensor, Gasper Air Outlets and the

Diffuser at STA 259.5. Do a General Visual Inspection of the metal clamp installation.

– If the metal clamp is not the correct part number, install the correct part number metal clamp or

as an option install a plastic tie strap. Do a General Visual Inspection of the adjacent wire bundles

and repair if necessary.

– If the metal clamp is the correct part number but not in the correct position, rotate the clamp to the

correct position. Do a General Visual Inspection of the adjacent wire bundles and repair if necessary.

– If the metal clamp part number and position is correct, no more work is necessary. As an option

the metal clamp can be replaced with a plastic tie strap.

Group 3:

Contact Boeing to get instructions for the change for this service bulletin, 737-21-1186 original issue,

and do the work instructed by Boeing.

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

Group 1:

Affected Maintenance Zones

Model Zone

737-300, 737-400, 737-500 101

Group 1-2:

Affected Maintenance Zones

Model Zone

737-200, 737-200C 1-11

Group 3:

Affected Maintenance Zones

Model Zone

737-100, 737-200, 737-200C 1-11

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BOEING SERVICE BULLETIN 737-21-1186
E. Compliance

No compliance time is given.

Boeing recommends this service bulletin be done to prevent possible operational disruptions.

F. Approval

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

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

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

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

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

changes.

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

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

before incorporating this service bulletin.

G. Manpower

The table below shows an estimate of the task hours necessary to do this inspection and 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.

Group 1:

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.50 0.50

FIGURE 1 1 0.25 0.25

Close Access 1 0.50 0.50

TOTAL FOR EACH AIRPLANE 1.25 1.25

Group 2:

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.50 0.50

FIGURE 2 1 0.25 0.25

Close Access 1 0.50 0.50

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BOEING SERVICE BULLETIN 737-21-1186
Group 2:

Task Number of Persons Task Hours Elapsed Hours

TOTAL FOR EACH AIRPLANE 1.25 1.25

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not changed.

J. References

1. Existing Data:

a. Boeing Service Related Problem (SRP) 737-SRP-21-0186

b. Service Bulletin Index D6-19567

c. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-13, 20-10-19

d. 737-100/200 Aircraft Maintenance Manual (AMM) 21-22-09, 25-11-21

e. 737-300/400/500 Aircraft Maintenance Manual (AMM) 21-22-09, 25-11-21

2. Data Supplied with this Service Bulletin:

None.

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

Drawing Number Title

65-52958 TEMP SENSOR INSTL - CONTROL CABIN, AIR CONDITIONING

65-55402 TEMP SENSOR INSTL - CONTROL CABIN, AIR CONDITIONING

65-54415 DIFFUSER INSTL - OVERHEAD DISTRIB, CONTROL CABIN

69-42753 DUCT INSTL - INDIVIDUAL AIR CONTROL CABIN

The table above lists applicable drawings used to prepare this service bulletin. The drawings are

not necessary to make the specified changes, and are not supplied with this service bulletin. The

drawings may not be applicable to all airplane configurations or operators.

K. Publications Affected

1. Publications:

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BOEING SERVICE BULLETIN 737-21-1186
Publication Chapter-Section

737 Illustrated Parts Catalog 21-00, 21-20, 21-60

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.

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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BOEING SERVICE BULLETIN 737-21-1186
2. MATERIAL INFORMATION

A. Material - Price and Availability

The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each

Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin

does not show the Boeing price and supply data.

B. Industry Support Information

Boeing warranty remedies are not available for the inspection and repair procedure given in this service

bulletin.

C. Parts Necessary for Each Airplane

1. Kits/Parts

None.

2. Parts and Materials Supplied by the Operator

Part Number / QTY Name Existing Part Number Notes

Specification

STRAP, PLASTIC, ADJUSTABLE, - (a)

SELF-LOCKING

BACS38K7 1

(a) Quantity required for each metal clamp replaced.

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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BOEING SERVICE BULLETIN 737-21-1186

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. 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.

4. 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.

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.

B. WORK INSTRUCTIONS

1. Group 1-2:

At the left side of the Control Cabin, get access to the hoses that attach to the Air Conditioning

Temperature Sensor, Gasper Air Outlet and Diffuser at STA 259.5. Refer to 737-100/200 AMM

25-11-21 or 737-300/400/500 AMM 25-11-21 as an accepted procedure.

2. Group 1:

Do a General Visual Inspection of the metal clamp installation in accordance with FIGURE 1.

a. If metal clamp is the incorrect part number, install the correct part number metal clamp or as

an option install a plastic tie strap. Refer to the Illustrated Parts Catalog for the correct metal

clamp part number. Do a General Visual Inspection of the adjacent wire bundles. If any wire

bundles are damaged, repair the wire bundle. Refer to SWPM 20-10-13 as an accepted

procedure.

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BOEING SERVICE BULLETIN 737-21-1186
NOTE: If an optional plastic tie strap is installed, install so that the head of the plastic tie

strap is next to the panel. Use plastic tie strap tool to tighten the strap. Use a tension

setting of 1 or a tension between 18-22 inch-lbs. Refer to SWPM 20-10-11 as an

accepted procedure.

b. If the metal clamp is the correct part number but is not in the correct position, rotate the metal

clamp to the correct position so that the head of the clamp is next to the panel. Refer to

737-100/200 AMM 21-22-09 or 737-300/400/500 AMM 21-22-09 as an accepted procedure.

Do a General Visual Inspection of the adjacent wire bundles. If any wire bundles are damaged,

repair the wire bundle. Refer to SWPM 20-10-13 as an accepted procedure.

c. If the metal clamp is the correct part number and in the correct position, no more work is

necessary. As an option a plastic tie strap can be installed.

NOTE: If an optional plastic tie strap is installed, install so that the head of the plastic tie

strap is next to the panel. Use plastic tie strap tool to tighten the strap. Use a tension

setting of 1 or a tension between 18-22 inch-lbs. Refer to SWPM 20-10-11 as an

accepted procedure.

3. Group 2:

Do a General Visual Inspection of the metal clamp installation in accordance with FIGURE 2.

a. If metal clamp is the incorrect part number, install the correct part number metal clamp or as

an option install a plastic tie strap. Refer to the Illustrated Parts Catalog for the correct metal

clamp part number. Do a General Visual Inspection of the adjacent wire bundles. If any wire

bundles are damaged, repair the wire bundle. Refer to SWPM 20-10-13 as an accepted

procedure.

NOTE: If an optional plastic tie strap is installed, install so that the head of the plastic tie

strap is next to the panel. Use plastic tie strap tool to tighten the strap. Use a tension

setting of 1 or a tension between 18-22 inch-lbs. Refer to SWPM 20-10-11 as an

accepted procedure.

b. If the metal clamp is the correct part number but is not in the correct position, rotate the metal

clamp to the correct position so that the head of the clamp is next to the panel. Refer to

737-100/200 AMM 21-22-09 or 737-300/400/500 AMM 21-22-09 as an accepted procedure.

Do a General Visual Inspection of the adjacent wire bundles. If any wire bundles are damaged,

repair the wire bundle. Refer to SWPM 20-10-13 as an accepted procedure.

c. If the metal clamp is the correct part number and in the correct position, no more work is

necessary. As an option a plastic tie strap can be installed.

NOTE: If an optional plastic tie strap is installed, install so that the head of the plastic tie

strap is next to the panel. Use plastic tie strap tool to tighten the strap. Use a tension

setting of 1 or a tension between 18-22 inch-lbs. Refer to SWPM 20-10-11 as an

accepted procedure.

4. Group 1-2:

Put the airplane back to a serviceable condition.

5. Group 3:

Contact Boeing to get instructions for the change for this service bulletin, 737-21-1186 original

issue, and do the work instructed by Boeing.

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BOEING SERVICE BULLETIN 737-21-1186
This Figure applies only to: Group 1.

FIGURE 1: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 1 OF 3)

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BOEING SERVICE BULLETIN 737-21-1186
FIGURE 1: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 2 OF 3)

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BOEING SERVICE BULLETIN 737-21-1186
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

Step Task Name Identification Qty More Data

1 Inspect Clamp - - (a)

(a) Do a General Visual Inspection for metal clamp part number and position.

FIGURE 1: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 3 OF 3)

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This Figure applies only to: Group 2.

FIGURE 2: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 1 OF 3)

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BOEING SERVICE BULLETIN 737-21-1186
FIGURE 2: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 2 OF 3)

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BOEING SERVICE BULLETIN 737-21-1186
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

Step Task Name Identification Qty More Data

1 Inspect Clamp - - (a)

(a) Do a General Visual Inspection for metal clamp part number and position.

FIGURE 2: INSPECT OF THE METAL CLAMP INSTALLATION

(SHEET 3 OF 3)

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