### 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.9E991 ECCN: 

## 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 Unpublished Work.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, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, 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.

Original Issue: May 22, 2014 737-26A1137 1 of 37 2.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 2 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**

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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 3 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 4 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**

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### 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.

**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 5 of 37**Reference Affected**  **Planning Data** Paragraph 1.E., Compliance and Paragraph 1.F., Approval Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected Yes Publications Affected Paragraph 1.K., Publications Affected Yes Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts No Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator No Operator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

**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 Elapsed Hours**  **Total Task Hours Airplanes**  2.50 4.00 Each 737 Airplane

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 6 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT MATERIAL INFORMATION**  None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 7 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 8 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**

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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 9 of 37**DESCRIPTION CONFIGURATION**  **GROUP** 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 **Group Variable Number** 1 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 10 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**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 - YA976 3 YA977 - YA978 1 YB001 - YB006 1 YB101 - YB132 1 YB151 - YB153 1 YB156 - YB157 3 YB158 1 YB161 - YB164 1 YB171 - YB172 1 YB181 - YB184

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 11 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**1 YB201 - YB208 1 YB271 1 YB276 1 YB301 - YB310 1 YB371 - YB380 3 YB381 - YB392 1 YB501 - YB502 1 YB521 - YB525 3 YB526 1 YB541 - YB544 1 YB551 1 YB561 - YB573 3 YB574 - YB580 1 YB581 - YB586 3 YB587 - YB598 1 YB601 - YB629 3 YB630 1 YB631 - YB632 3 YB633 - YB636 1 YB651 1 YB656 3 YB671 - YB672 1 YB851 - YB859 3 YB860 1 YB861 - YB863 1 YB871 - YB873 3 YB874 1 YB881 - YB888 3 YB889 - YB893 1 YB901 - YB903 1 YB911 3 YB961 - YB975 3 YB981

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 12 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 YB986 - YB998 1 YC001 - YC030 1 YC051 - YC083 3 YC084 1 YC091 - YC094 3 YC095 1 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 3 YC179 1 YC186 - YC189 3 YC190 1 YC201 - YC203 1 YC206 - YC207 1 YC301 - YC305 1 YC321 - YC385 3 YC386 - YC387 1 YC391 - YC394 1 YC396 1 YC401 - YC417 1 YC421 - YC422 1 YC426 - YC428 1 YC436 - YC437 3 YC438 - YC439 1 YC441 - YC448 1 YC451 - YC455 1 YC459

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 13 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**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 - YC741 3 YC742 - YC750 1 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 3 YD108 - YD117 1 YD121 - YD126 1 YD151 - YD159 1 YD171 - YD172 1 YD201 - YD203 1 YD206 - YD209

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 14 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**1 YD216 - YD219 1 YD251 - YD254 1 YD256 - YD257 1 YD261 1 YD301 - YD334 1 YD391 1 YD401 - YD410 1 YD412 3 YD413 - YD422 1 YD481 - YD485 3 YD491 - YD499 2 YD501 - YD512 2 YD531 - YD535 2 YD541 - YD547 2 YD561 - YD564 2 YD571 - YD572 2 YD591 - YD594 3 YD595 2 YD601 - YD612 3 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 3 YE371 - YE383 3 YF001 - YF011 3 YF021 - YF049 3 YF051 - YF080 3 YF086 - YF087

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 15 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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 1 YG001 - YG043 2 YG044 1 YG061 - YG064 1 YG066 2 YG067 1 YG068 2 YG069 1 YG070 - YG073 2 YG074 1 YG075 - YG080 2 YG081

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 16 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**1 YG082 - YG083 2 YG084 1 YG085 - YG087 2 YG088 1 YG089 3 YG091 - YG099 3 YG101 - YG104 3 YG111 - YG114 3 YG116 - YG142 1 YG201 3 YG202 - YG205 1 YG211 3 YG212 - YG214 3 YG221 - YG224 3 YG251 - YG252 2 YG501 - YG508 3 YG509 - YG514 2 YG601 - YG602 3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 17 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 YH636 - YH637 3 YH641 3 YH681 3 YH701 - YH723 3 YH751 3 YH801 - YH831 3 YH901 - YH904 3 YH911 3 YH951 1 YJ001 - YJ004 3 YJ005 - YJ010 1 YJ011 - YJ013 1 YJ021 1 YJ471 - YJ480 1 YJ501 - YJ517 1 YJ531 - YJ545 3 YJ546 - YJ579 1 YJ591 - YJ593 3 YJ594 - YJ599 1 YJ631 - YJ632 1 YJ671 - YJ682 3 YJ683 - YJ694 1 YJ801 - YJ853 3 YJ854 - YJ860 1 YJ861 - YJ867 1 YJ871 3 YJ872 - YJ880 1 YJ901 - YJ902 3 YJ903 - YJ904 3 YJ908 - YJ910 1 YJ911 - YJ919 3 YJ920 - YJ929 1 YJ931 - YJ936

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 18 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 YJ937 1 YJ941 - YJ943 3 YJ944 - YJ956 3 YJ961 3 YJ976 - YJ977 1 YK001 - YK007 1 YK101 - YK104 1 YK111 - YK112 1 YK121 - YK122 1 YK131 - YK132 3 YK133 1 YK136 3 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 1 YK301 - YK304 3 YK305 - YK314 1 YK321 - YK330 3 YK331 - YK340 1 YK361 - YK364 3 YK365 - YK378 1 YK401 - YK405 3 YK406 1 YK426 3 YK427

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 19 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**1 YK431 3 YK432 - YK450 1 YK456 - YK458 3 YK459 - YK467 3 YK471 - YK473 3 YK476 1 YK480 3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 20 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 21 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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 1 YM101 3 YM102 - YM103 1 YM201 - YM202 3 YM203 - YM244 1 YM251 - YM2593 YM260 - YM2993 YM301 - YM3993 YM401 - YM4153 YM471 3 YM481 - YM4843 YM501 - YM5153 YM521 - YM522 3 YM541

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 22 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 YM551 - YM5533 YM571 - YM572 3 YM581 - YM582 3 YM591 - YM5993 YM631 - YM6343 YM641 - YM652 3 YM671 - YM6743 YM691 - YM6993 YM701 - YM7103 YM761 - YM7653 YM771 - YM7793 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 23 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 24 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 25 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 26 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 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

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 27 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Group**  **Variable Number**3 YT461 - YT468 3 YT601 - YT606 3 YT761 - YT769 3 YT891 - YT894 3 YU001 - YU029 3 YU201 - YU207 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: Description**  **Service Bulletin Company**  FIRE PROTECTION - Lower Cargo Compartment Smoke Detection - Forward Cargo Compartment Smoke Penetration Electrical Changes 737-26-1122, Revision 1 (a) Boeing

(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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 28 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT 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 Zone**  **Model** 112, 113, 114, 117, 118, 125, 126 737-600, 737-700, 737-800 **Group 2:**

**Affected Maintenance Zones Zone**  **Model** 112, 113, 114, 117, 118, 125, 126 737-700, 737-700C, 737-900 **Group 3:**

**Affected Maintenance Zones Zone**  **Model** 112, 113, 114, 117, 118, 125, 126 737-600, 737-700, 737-700C, 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) Compliance Time**  **Action Condition**  9000 flight hours. Within 51 monthsafter the original issue date of this service bulletin. Do a Smoke Clearance Mode - Operational Testin accordance with Paragraph 3.B., Work Instructions. Group 1, Configuration 1 Airplanes.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 29 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT Table: Smoke Clearance Mode - Operational Test**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** 9000 flight hours. Within 10 monthsafter the original issue date of this service bulletin. Do a Smoke Clearance Mode - Operational Testin 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 withParagraph 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. **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**

0.50 0.50 1 Open Access 1.50 3.00 2 Test (a) 0.50 0.50 1 Close Access 2.50 4.00 TOTAL FOR EACH AIRPLANE (a) The task hour does not include time that is possibly needed to troubleshoot wiring and components if test result is not satisfactory.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 30 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**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: **Chapter-Section Publication**  8-20 737 Flight Crew Operations Manual 21-27 737 Aircraft Maintenance Manual 21-25, 21-27 737 Fault Isolation Manual 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 31 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 32 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 33 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 34 of 37 **BOEING SERVICE BULLETIN 737-26A1137 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 35 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 36 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 22, 2014 737-26A1137 37 of 37 **BOEING SERVICE BULLETIN 737-26A1137 ALERT**  **ALERT**