# Boeing Alert Service Bulletin 737-26A1137: Revision 2

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2020-1109; AD 2021-01-07 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 737-26A1137](https://openairdocs.org/service-documents/boeing/737-26a1137.md)
- Title as filed: SB-737-26A1137-02--
- Pages: 31
- PDF: https://openairdocs.org/files/sha256/49/9a/499a43edb0cf14e42189dd0577a56ac8e53a3202b9ed1b9ac803ea9849709fd2
- Page: https://openairdocs.org/service-documents/boeing/737-26a1137/file/499a43edb0cf

## Text

Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-26A1137
Original Issue: May 22, 2014
Revision 2: January 27, 2020
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.
9E991ECCN:
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Unpublished Work.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
737-26A1137Revision 2: January 27, 2020
1 of 31
4.0

### Page 2

Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
2 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT
BLANK PAGE

### Page 3

Table of Contents
Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 26
K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 27
3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 27
3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
3 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 4

Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
4 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT
BLANK PAGE

### Page 5

Commercial 
Airplanes
737
Service Bulletin
ALERT
Revision Transmittal SheetNumber: 737-26A1137Original Issue: May 22, 2014
Revision 2: January 27, 2020
ATA System: 2616 2127
SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke
Clearance Mode Operational Test for Cargo Smoke Protection
This revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2016-04-06 is related to this service bulletin.
Effects of this Revision on airplanes on which Original Issue or Revision 1 was previously done:
None.
Airplanes YG044, YG067, YG069, YG074, YG081, YG084 and YG088 were added to new Group 5 of this
service bulletin.
REASON FOR REVISION
This revision is sent to add airplanes YG044, YG067, YG069, YG074, YG081, YG084 and YG088 to new Group
5 of this service bulletin. Also, an FAA AD is added to this service bulletin, and the Maintenance Planning Data
(MPD) information is changed.
At the revision of this service bulletin, related Boeing Service Bulletin 737-26-1122 has been elevated to an Alert
status. Anywhere in this bulletin where 737-26-1122 is used, 737-26A1122 may be used.
These sections were changed:
1. In Summary:
a. Background, added Service Related Problem (SRP) number.
b. Compliance, added FAA AD statements.
2. In Paragraph 1.A.1., Airplanes:
a. Changed airplane applicability statement.
b. Removed a note.
c. Added Group 5 airplanes.
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
5 of 31

### Page 6

3. In Paragraph 1.B., Concurrent Requirements, added service bulletin revision levels and Group 5
information.
4. In Paragraph 1.C., Reason, added SRP number, revision statement and Information Notice (IN).
5. In Paragraph 1.D., Description, added revision statement.
6. In Paragraph 1.E., Compliance:
a. Added FAA AD statements.
b. Table 1, Compliance Time, changed compliance time to effective date of AD.
c. Added Table 2 for Group 5 compliance time.
7. In Paragraph 1.F., Approval, added Alternative Method of Compliance (AMOC) statement and approval
statement for non-EASA models.
8. In Paragraph 1.J.1., Existing Data, changed NPRM to FAA AD and added SRP number.
9. In Paragraph 1.K., Publications Affected, changed the number of the Maintenance Planning Data (MPD)
reference.
The data given in Information Notice 737-26A1137 IN 01 is included in this revision.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity and format changes,
to show the location of all content changes.
Pages with no vertical lines have no changes.
REVISION HISTORY
May 22, 2014Original Issue:
August 28, 2015Revision 1:
January 27, 2020Revision 2:
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
6 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 7

Commercial 
Airplanes
737
Service Bulletin
ALERT
SummaryNumber: 737-26A1137Original Issue: May 22, 2014
Revision 2: January 27, 2020
ATA System: 2616 2127
SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke
Clearance Mode Operational Test for Cargo Smoke Protection
THIS DOCUMENT 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 DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT 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 repeat intervals
on airplanes equipped with the reconfigurable 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 will
reduce the probability of a latent failure which, in conjunction with a cargo fire event, could result in smoke in
the flight deck and possible loss of aircraft control.
A review by Boeing found that there was no maintenance procedure available to inspect the components used
to reconfigure the air distribution system to the cargo fire mode. 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, 737NG-SRP-26-0088 are related to this service
bulletin.
This table is provided to operators for planning purposes only. Refer to the applicable sections for more
information.
ReferenceAffectedPlanning Data
Paragraph 1.A.2., Spares AffectedNoSpares Affected
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
7 of 31

### Page 8

ReferenceAffectedPlanning Data
Paragraph 1.E., Compliance and Paragraph
1.F., Approval
YesAD Related
Paragraph 1.H., Weight and Balance ChangesNoWeight and Balance Change
Paragraph 1.I., Electrical Load DataNoElectrical Load Changed
Paragraph 1.K., Publications AffectedYesPublications Affected
Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew
Operations Manual and/or FAA Approved Air-
plane Flight Manual)
Paragraph 2.C.1., Kits/PartsNoKits/Parts Required
Paragraph 2.C.2., Parts and Materials Supplied
by the Operator
NoOperator Supplied Parts/Material
Paragraph 2.F., Special Tooling Necessary to
do this Service Bulletin
NoSpecial 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 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 Fire Protection system operates correctly.
If the Smoke Clearance Mode - Operational Test result is not satisfactory, do the troubleshooting procedure on
the equipment cooling system and low pressure environmental control system to find and replace faulty
components.
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
Federal Aviation Administration (FAA) Airworthiness Directive AD 2016-04-06 is related to this service bulletin.
The effective date of AD 2016-04-06 is April 1, 2016.
The Federal Aviation Administration (FAA) will possibly release an additional 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.
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
8 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 9

MANPOWER
Elapsed HoursTotal Task HoursAirplanes
2.504.00Each 737 Airplane
MATERIAL INFORMATION
None.
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
9 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 10 (OCR)

ALERT
Original Issue: May 22, 2014
Revision 2: January 27, 2020
BOEING SERVICE BULLETIN 737-26A1137
ALERT
IN FLIGHT COMPARTMENT AND MAIN
ELECTRONICS EQUIPMENT COMPARTMENT:
-DO SMOKE CLEARANCE MODE
OPERATIONAL TEST
-IF TEST RESULTS NOT SATISFACTORY
TROUBLESHOOT SYSTEM COMPONENTS
BELOW AC MIX AIR COMPARTMENT:
-AS AN ALTERNATE LOCATION TO FLIGHT
COMPARTMENT TO MAKE SURE OF RECIRCULATION
FAN'S OPERATION, OPEN ACCESS PANEL 191E
-MAKE SURE THERE IS AIR FLOW DURING SMOKE
CLEARANCE MODE TEST
2302407
Export Controlled ECCN: 9E991 - BOEING  737-26A1137
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.  10 of 31

### Page 11

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-26A1137
Original Issue: May 22, 2014
Revision 2: January 27, 2020
ATA System: 2616 2127
SUBJECT: FIRE PROTECTION - Cargo Bay Smoke Detection - Equipment Cooling System Smoke
Clearance Mode Operational Test for Cargo Smoke Protection
THIS DOCUMENT 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 DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE
NEW OWNER.
1.    PLANNING INFORMATION
A. Effectivity
1. Airplanes
This bulletin is applicable to 737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER
Airplane(s), line number(s) 1-2598, 2600-2721, 2723-2813, 2815-2930, 2932-3068, 3070-3323,
3325-3425, 3427-3521, 3523-3611, 3613-3701, 3703-3791, 3793-3878, 3880-3915, 3917-3968,
3970-4013, 4015-4054, 4056-4098, 4100-4140, 4142-4180, 4182-4218, 4220-4255, 4257-4293,
4295-4330, 4332-4365, 4367-4398, 4400-4444, 4446-4480, 4482-4546, 4548-4608, 4610-4672,
4674-4727, 4729-4767, 4769-4812, 4814-4858, 4860-4897, 4899-4937, 4939-4977, 4979-5019,
5021-5057, 5059-5097, 5099-5137, 5139-5177, 5179-5217, 5219-5261, 5263-5297, 5299-5337,
5339-5367, 5369-5397, 5399-5427, 5429-5457, 5459-5477, 5479-5509, 5511-5541, 5543-5566,
5568-5586, 5588-5601, 5603-5622, 5624-5655, 5657-5667, 5669-5679, 5681-5711, 5713-5727,
5729-5739, 5741-5764, 5766-5787, 5789-5795, 5797-5822, 5824-5850, 5853-5879, 5881-5901,
5904-5935, 5937-5947, 5949-5962, 5964-5991, 5994-6019, 6021-6033, 6035-6047, 6049-6073,
6075, 6077-6103, 6105-6113, 6115-6131, 6133-6153, 6155-6159, 6161-6187, 6190-6215,
6217-6221, 6223-6243, 6245-6249, 6251-6271, 6274-6289, 6291-6299, 6301-6307, 6309-6325,
6327, 6329-6343, 6345-6355, 6357-6359, 6361-6371, 6373-6383, 6386-6395, 6397-6407,
6409-6411, 6413-6419, 6421-6429, 6431-6439, 6442-6447, 6449-6455, 6457-6463, 6465-6467,
6469-6471, 6473-6480, 6482-6489, 6491, 6493-6498, 6500-6507, 6509-6514, 6516-6520,
6522-6527, 6529-6531, 6533-6534, 6536-6541, 6543-6547, 6549-6554, 6556-6559, 6561,
6563-6568, 6570-6574, 6576-6581, 6583-6588, 6590-6593, 6596-6597, 6599-6602, 6604-6606,
6608-6611, 6613-6615, 6617-6620, 6622, 6624, 6626-6629, 6631-6633, 6635-6638, 6640-6642,
6644-6647, 6649-6651, 6653-6656, 6659-6660, 6662-6665, 6667-6671, 6673-6676, 6678-6680,
6682-6685, 6688-6689, 6691-6694, 6696-6698, 6700-6703, 6705-6707, 6709-6712, 6714-6716,
6718-6719, 6721, 6723-6725, 6727-6730, 6732-6734, 6736-6739, 6741-6743, 6745-6748,
6751-6752, 6754-6757, 6759-6761, 6763-6766, 6768-6770, 6772-6775, 6777-6779, 6781-6782,
6786-6788, 6790-6791, 6793, 6795, 6797, 6799-6802, 6804, 6806, 6808-6809, 6811, 6813, 6815,
6817-6818, 6820, 6822-6824, 6826-6827, 6829, 6831-6833, 6835-6836, 6838, 6840, 6842,
6844-6845, 6847, 6849, 6851, 6853-6854, 6856-6858, 6860, 6862-6863, 6865, 6867, 6869-6871,
6873-6874, 6878-6880, 6882-6883, 6885, 6887-6889, 6891-6892, 6894, 6896, 6898, 6900-6903,
Export Controlled ECCN: 9E991 - BOEING
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### Page 12

6905, 6907, 6910, 6912-6914, 6916, 6918-6919, 6921, 6923-6925, 6927-6928, 6930, 6932-6934,
6936-6937, 6939, 6943, 6945-6948, 6950, 6952, 6954-6955, 6957-6959, 6961-6962, 6964,
6966-6967, 6969, 6971-6972, 6977, 6979, 6981-6982, 6984, 6986-6987, 6989, 6992, 6994,
6996-6997, 6999, 7001-7002, 7007, 7009, 7011-7012, 7014, 7016-7017, 7019, 7021-7022, 7024,
7026, 7029, 7031-7032, 7034, 7036-7037, 7039, 7041, 7046-7047, 7049, 7051-7052, 7054,
7056-7057, 7059, 7061, 7063, 7066-7067, 7069, 7071-7072, 7076, 7078, 7081-7082, 7084,
7086-7087, 7089, 7091-7092, 7094, 7097, 7099, 7101-7102, 7104, 7106-7107, 7109, 7112,
7116-7117, 7119, 7121-7122, 7124, 7126-7127, 7129, 7131, 7134, 7136-7137, 7139, 7141-7142,
7146, 7149, 7151-7152, 7154, 7156-7157, 7159, 7161-7162, 7164, 7167, 7169, 7171-7172, 7174,
7176-7177, 7179, 7182, 7187, 7189, 7191, 7194, 7197, 7199, 7202, 7204, 7206, 7209, 7212,
7214, 7217, 7221, 7224, 7227, 7229, 7232, 7234-7235, 7239, 7242, 7244, 7247, 7249, 7251,
7257, 7259, 7262, 7264, 7266, 7269, 7272, 7274, 7277, 7279-7280, 7284, 7287, 7292, 7294,
7297, 7299, 7302, 7304, 7307, 7309, 7312, 7314, 7317, 7319, 7322, 7327, 7329, 7332, 7334,
7337, 7339, 7342, 7344, 7347, 7349, 7352, 7354, 7357, 7362, 7364, 7367, 7369, 7372, 7374,
7377, 7379, 7382, 7387, 7397, 7402, 7407, 7412, 7417, 7422, 7432, 7437, 7442, 7447, 7452,
7457, 7467, 7472, 7477, 7482, 7487, 7492, 7502, 7507, 7512, 7517, 7522, 7527, 7537, 7542,
7547, 7552, 7557, 7562, 7572, 7577, 7582, 7587, 7592, 7597, 8592, 9103 in 5 Group(s). Where
the effectivity is presented with hyphens between line numbers, the airplane applicability means
"through" and "inclusive", e.g. line numbers 1-9 means line numbers 1 through 9 inclusive.
Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
The Variable Numbers and Group Information for the applicable airplanes is given below.
NOTE: The Variable Number table below includes all affected airplanes up to Line Number 9103.
Affected airplanes after Line Number 9103 will be added to the service bulletin's
MyBoeingFleet.com (MBF) "get effectivity" result when they are added to the MBF Fleet
Profile Page.
DESCRIPTIONCONFIGURATIONGROUP
737-600/-700/-800 Line Numbers 1 Through 1700 Included in Boeing
Service Bulletin 737-26-1122, except for 737-700 Line Numbers 481,
545, 684, 979, 1089, 1211, and 1223.
-1
Airplane Line Numbers 1 Through 1700 Included in Boeing Service
Bulletin 737-26-1122 and Had Not Accomplished Boeing Service
Bulletin 737-26-1122, except for 737-700 Line Numbers 481, 545,
684, 979, 1089, 1211, and 1223.
1
Airplane Line Numbers 1 Through 1700 Included in Boeing Service
Bulletin 737-26-1122 and Had Accomplished Boeing Service Bulletin
737-26-1122, except for 737-700 Line Numbers 481, 545, 684, 979,
1089, 1211, and 1223.
2
737-700/-700C/-900 Line Numbers 1 Through 1700 Not Included in
Boeing Service Bulletin 737-26-1122, except for 737-700 Line
Numbers 481, 545, 684, 979, 1089, 1211, and 1223.
-2
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
12 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 13

DESCRIPTIONCONFIGURATIONGROUP
737-600/-700/-700C/-800/-900/-900ER Line Numbers 1701 through
4922 and 4925 delivered on or before the original issue date of the
service bulletin.
-3
737-600/-700/-700C/-800/-900/-900ER Line Numbers 4923, 4924,
and 4926 and on delivered after the original issue date of the service
bulletin.
-4
737-700 Line Numbers 481, 545, 684, 979, 1089, 1211 and 1223.-5
Airplane Models:
737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER
GroupVariable Number
1YA001 - YA099
1YA101 - YA199
1YA201 - YA211
1YA221
1YA231 - YA242
1YA251 - YA256
1YA271 - YA272
1YA291
1YA301 - YA302
1YA311 - YA314
1YA321 - YA323
1YA336 - YA345
1YA351
1YA356 - YA357
1YA366 - YA367
1YA371 - YA377
1YA501 - YA536
1YA541 - YA552
1YA571 - YA578
1YA601 - YA615
1YA621 - YA622
1YA626 - YA631
GroupVariable Number
1YA635 - YA636
1YA641 - YA642
1YA645 - YA650
1YA656 - YA659
1YA666 - YA667
1YA671 - YA672
1YA681 - YA691
1YA701 - YA710
1YA721 - YA722
1YA731 - YA734
1YA751 - YA756
1YA801 - YA803
1YA809
1YA811 - YA814
1YA831 - YA835
1YA841 - YA862
1YA881 - YA882
1YA891 - YA892
1YA961 - YA976
3YA977 - YA978
1YB001 - YB006
1YB101 - YB132
GroupVariable Number
1YB151 - YB153
1YB156 - YB157
3YB158
1YB161 - YB164
1YB171 - YB172
1YB181 - YB184
1YB201 - YB208
1YB271
1YB276
1YB301 - YB310
1YB371 - YB380
3YB381 - YB392
1YB501 - YB502
1YB521 - YB525
3YB526
1YB541 - YB544
1YB551
1YB561 - YB573
3YB574 - YB580
1YB581 - YB586
3YB587 - YB598
1YB601 - YB629
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
13 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 14

GroupVariable Number
3YB630
1YB631 - YB632
3YB633 - YB636
1YB651
1YB656
3YB671 - YB672
1YB851 - YB859
3YB860
1YB861 - YB863
1YB871 - YB873
3YB874
1YB881 - YB888
3YB889 - YB893
1YB901 - YB903
1YB911
3YB961 - YB975
3YB981
3YB986 - YB998
1YC001 - YC030
1YC051 - YC083
3YC084
1YC091 - YC094
3YC095
1YC101 - YC104
1YC111 - YC113
1YC121
1YC126 - YC127
1YC136 - YC141
1YC146 - YC147
1YC151 - YC156
1YC166 - YC171
1YC176 - YC178
3YC179
GroupVariable Number
1YC186 - YC189
3YC190
1YC201 - YC203
1YC206 - YC207
1YC301 - YC305
1YC321 - YC385
3YC386 - YC387
1YC391 - YC394
1YC396
1YC401 - YC417
1YC421 - YC422
1YC426 - YC428
1YC436 - YC437
3YC438 - YC439
1YC441 - YC448
1YC451 - YC455
1YC459
1YC461 - YC467
1YC471 - YC499
1YC501 - YC526
1YC571 - YC583
1YC587 - YC589
1YC591 - YC593
1YC601 - YC655
1YC681 - YC696
1YC701 - YC715
1YC720 - YC725
1YC727 - YC741
3YC742 - YC750
1YC751 - YC752
1YC761 - YC770
1YC781 - YC793
1YC801 - YC892
GroupVariable Number
1YC901 - YC907
1YC921 - YC922
1YC931 - YC932
1YC941 - YC951
1YC971 - YC978
1YC981 - YC983
1YD001 - YD007
1YD021 - YD025
1YD041 - YD057
1YD081 - YD084
1YD101 - YD107
3YD108 - YD117
1YD121 - YD126
1YD151 - YD159
1YD171 - YD172
1YD201 - YD203
1YD206 - YD209
1YD216 - YD219
1YD251 - YD254
1YD256 - YD257
1YD261
1YD301 - YD334
1YD391
1YD401 - YD410
1YD412
3YD413 - YD420
4YD421 - YD424
1YD481 - YD485
3YD491 - YD499
2YD501 - YD512
2YD531 - YD535
2YD541 - YD547
2YD561 - YD564
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
14 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 15

GroupVariable Number
2YD571 - YD572
2YD591 - YD594
3YD595
2YD601 - YD612
3YD651 - YD655
1YE001 - YE020
1YE051
1YE101 - YE109
1YE151 - YE157
1YE171 - YE172
1YE201 - YE206
1YE301 - YE305
1YE321 - YE326
3YE371 - YE383
3YF001 - YF011
3YF021 - YF049
3YF051 - YF076
4YF077 - YF080
3YF086 - YF087
3YF106 - YF107
3YF111 - YF114
3YF116 - YF119
3YF121 - YF132
3YF176 - YF178
3YF191 - YF192
3YF201 - YF276
3YF401 - YF402
3YF431 - YF432
3YF436 - YF437
3YF441 - YF442
3YF451 - YF460
3YF501 - YF599
3YF601 - YF661
GroupVariable Number
4YF662 - YF685
4YF691 - YF695
3YF701 - YF707
3YF801 - YF805
3YF831 - YF832
3YF836 - YF838
3YF871 - YF872
3YF901 - YF905
3YF921 - YF928
3YF951 - YF954
1YG001 - YG043
5YG044
1YG061 - YG064
1YG066
5YG067
1YG068
5YG069
1YG070 - YG073
5YG074
1YG075 - YG080
5YG081
1YG082 - YG083
5YG084
1YG085 - YG087
5YG088
1YG089
3YG091 - YG099
3YG101 - YG104
3YG111 - YG114
3YG116 - YG141
4YG142 - YG149
1YG201
3YG202 - YG205
GroupVariable Number
1YG211
3YG212 - YG214
3YG221 - YG224
3YG251 - YG252
2YG501 - YG508
3YG509 - YG512
4YG513 - YG517
2YG601 - YG602
3YG701
3YG711
4YG721 - YG722
3YH001 - YH012
3YH031 - YH055
3YH071 - YH080
3YH101 - YH132
3YH201 - YH202
3YH206 - YH207
3YH301 - YH306
4YH307
3YH321 - YH322
3YH501 - YH542
3YH551 - YH594
3YH601 - YH606
3YH611 - YH620
3YH631 - YH632
3YH636 - YH637
3YH641
4YH681 - YH686
3YH701 - YH720
4YH721 - YH755
3YH801 - YH821
4YH822 - YH899
3YH901 - YH903
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
15 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 16

GroupVariable Number
4YH904 - YH908
4YH911 - YH915
4YH951 - YH952
1YJ001 - YJ004
3YJ005 - YJ010
1YJ011 - YJ013
1YJ021
1YJ471 - YJ480
1YJ501 - YJ517
1YJ531 - YJ545
3YJ546 - YJ579
1YJ591 - YJ593
3YJ594 - YJ599
1YJ631 - YJ632
1YJ671 - YJ682
3YJ683 - YJ694
1YJ801 - YJ853
3YJ854 - YJ860
1YJ861 - YJ867
1YJ871
3YJ872 - YJ880
1YJ901 - YJ902
3YJ903 - YJ904
3YJ908 - YJ910
1YJ911 - YJ919
3YJ920 - YJ929
1YJ931 - YJ936
3YJ937
1YJ941 - YJ943
3YJ944 - YJ956
3YJ961
3YJ976 - YJ977
1YK001 - YK007
GroupVariable Number
1YK101 - YK104
1YK111 - YK112
1YK121 - YK122
1YK131 - YK132
3YK133
1YK136
3YK137 - YK139
3YK141 - YK142
3YK146 - YK148
3YK151 - YK154
3YK161 - YK167
3YK171
3YK176 - YK177
3YK186
3YK191
3YK196
3YK201 - YK202
1YK301 - YK304
3YK305 - YK314
1YK321 - YK330
3YK331 - YK340
1YK361 - YK364
3YK365 - YK378
1YK401 - YK405
3YK406
1YK426
3YK427
1YK431
3YK432 - YK450
1YK456 - YK458
3YK459 - YK467
3YK471 - YK473
3YK476
GroupVariable Number
4YK478
1YK480
3YK481 - YK487
3YK491 - YK493
3YK495 - YK499
3YK511 - YK516
3YK521 - YK530
3YK551 - YK571
3YK576 - YK577
3YK580 - YK585
3YK601 - YK602
3YK606 - YK607
3YK611 - YK616
3YK621 - YK634
3YK641 - YK644
3YK651 - YK665
3YK671 - YK672
3YK676 - YK677
3YK681 - YK686
3YK691
3YK695 - YK699
3YK701 - YK713
3YK716 - YK719
3YK721 - YK741
3YK751 - YK770
3YK776 - YK778
3YK781 - YK785
3YK791 - YK792
3YK796 - YK797
3YK801 - YK899
3YK901 - YK912
3YK918 - YK919
3YK921 - YK929
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
16 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 17

GroupVariable Number
3YK941 - YK999
3YL001 - YL005
3YL011 - YL016
3YL021 - YL024
3YL051 - YL052
3YL056 - YL057
3YL061
3YL066 - YL069
3YL076 - YL077
3YL101 - YL137
3YL201 - YL237
3YL241 - YL242
3YL271 - YL272
3YL281 - YL284
3YL301 - YL303
3YL311 - YL314
3YL316 - YL321
3YL351 - YL353
3YL371 - YL374
3YL401
3YL421 - YL429
3YL431 - YL444
3YL461 - YL478
3YL501 - YL509
3YL531 - YL534
3YL541 - YL551
3YL561 - YL579
3YL591 - YL598
3YL601 - YL606
3YL611 - YL612
3YL616 - YL617
3YL621
3YL626
GroupVariable Number
3YL631 - YL634
3YL636 - YL637
3YL661 - YL664
3YL676 - YL691
3YL696 - YL697
3YL701 - YL707
3YL731
3YL751 - YL752
3YL756 - YL757
3YL761 - YL780
3YL796 - YL797
3YL801 - YL815
3YL901 - YL910
3YL921 - YL940
3YL951 - YL968
1YM101
3YM102 - YM103
1YM201 - YM202
3YM203 - YM244
1YM251 - YM259
3YM260 - YM299
3YM301 - YM399
3YM401 - YM415
3YM471
3YM481 - YM484
3YM501 - YM515
3YM521 - YM522
3YM541
3YM551 - YM553
3YM571 - YM572
3YM581 - YM582
3YM591 - YM599
3YM631 - YM634
GroupVariable Number
3YM641 - YM652
3YM671 - YM674
3YM691 - YM699
3YM701 - YM710
3YM761 - YM765
3YM771 - YM779
3YN001 - YN016
3YN021 - YN024
3YN061
3YN071 - YN082
3YN091 - YN092
3YN101 - YN112
3YN121
3YN126
3YN201 - YN202
3YN211 - YN219
3YN231 - YN236
3YN261
3YN501
3YN531 - YN534
3YN551 - YN559
4YN560 - YN566
3YN581 - YN582
4YN583 - YN585
4YN591 - YN593
3YN601 - YN606
3YN651 - YN653
4YN661 - YN663
4YN666 - YN667
4YN671 - YN674
3YN701 - YN702
3YN741 - YN746
4YN756 - YN758
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
17 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 18

GroupVariable Number
3YQ001 - YQ003
3YQ011 - YQ021
3YQ026 - YQ029
3YQ036 - YQ045
3YQ201 - YQ207
3YQ231
3YQ241 - YQ251
3YQ281 - YQ284
3YQ291 - YQ296
3YQ301 - YQ302
3YQ321 - YQ324
3YQ331 - YQ334
3YQ346 - YQ347
4YQ351 - YQ367
4YQ371
3YQ401 - YQ403
3YQ451 - YQ454
3YQ456
3YQ461
3YQ471
3YQ501 - YQ507
4YQ508 - YQ520
4YQ601 - YQ606
4YQ610 - YQ614
3YR001 - YR029
4YR030 - YR050
3YR051 - YR082
4YR083 - YR090
3YR091 - YR098
3YR101 - YR105
3YR111 - YR119
4YR120 - YR124
3YR126 - YR144
GroupVariable Number
3YR166 - YR182
3YR186 - YR196
4YR197 - YR198
3YR201 - YR204
4YR205 - YR215
3YR231 - YR294
3YR296 - YR297
3YR301 - YR334
4YR338 - YR341
3YR361 - YR366
3YR371 - YR373
3YR376
4YR377
3YR381 - YR382
3YR386 - YR387
4YR388
3YR391
3YR396 - YR398
4YR399
3YR401 - YR405
3YR411 - YR413
3YR416 - YR418
3YR421 - YR424
3YR426 - YR436
4YR437 - YR440
3YR441 - YR449
4YR450
3YR451 - YR455
3YR457 - YR499
3YR501 - YR506
3YR511 - YR520
3YR526 - YR544
3YR546 - YR548
GroupVariable Number
4YR549 - YR551
3YR556 - YR559
4YR560
3YR561 - YR562
3YR571 - YR574
4YR575 - YR582
4YR591 - YR592
3YR601 - YR605
3YR616 - YR646
4YR647 - YR650
3YR651 - YR658
3YR661 - YR663
4YR671 - YR673
4YR676 - YR678
4YR681 - YR682
3YR701 - YR769
3YR771 - YR782
4YR783 - YR799
3YR801 - YR816
4YR817 - YR827
3YR831 - YR838
3YR841 - YR847
4YR848 - YR850
3YR851 - YR874
4YR875 - YR899
3YR901 - YR903
3YR931 - YR934
3YR938 - YR944
3YR951 - YR968
4YR969 - YR980
3YR981 - YR994
4YR995 - YR998
3YS001 - YS002
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
18 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 19

GroupVariable Number
3YS006 - YS007
4YS008 - YS009
3YS031 - YS032
3YS051 - YS068
4YS069 - YS073
3YS101 - YS120
4YS126 - YS142
4YS146 - YS150
3YS151 - YS160
3YS166 - YS181
4YS182 - YS190
3YS191 - YS194
3YS196 - YS197
3YS201 - YS209
3YS221 - YS225
3YS231 - YS233
4YS234 - YS236
3YS271 - YS276
4YS277 - YS288
4YS295 - YS296
3YS301 - YS328
4YS329 - YS348
3YS351 - YS356
4YS357 - YS370
3YS371 - YS374
4YS375 - YS378
3YS381 - YS383
4YS384 - YS386
4YS393 - YS395
4YS401
3YS451
4YS456 - YS457
4YS462 - YS465
GroupVariable Number
4YS467
3YS501 - YS502
3YS506
4YS511 - YS518
4YS531
4YS536 - YS538
4YS541 - YS542
4YS546
3YS551 - YS553
4YS554 - YS556
3YS561 - YS569
4YS570
3YS571 - YS573
4YS574 - YS578
3YS581
4YS582 - YS590
3YS591 - YS595
3YS601 - YS654
4YS655 - YS685
3YS686 - YS690
3YS701 - YS708
4YS709 - YS716
3YS721 - YS743
4YS744 - YS760
3YS761
4YS762
3YS771 - YS779
4YS780
3YS806 - YS810
3YS816
4YS817 - YS818
3YS823 - YS825
3YS851 - YS854
GroupVariable Number
4YS855 - YS863
3YS876
3YS881
4YS882 - YS884
4YS891 - YS894
4YS896 - YS897
3YS901 - YS905
4YS906 - YS909
3YS911 - YS912
4YS913 - YS957
3YS961 - YS962
4YS963 - YS974
4YS976 - YS977
4YS981 - YS987
3YS991 - YS992
4YS993 - YS998
3YT001 - YT003
4YT004
3YT006
4YT026 - YT027
3YT031 - YT032
4YT036 - YT038
3YT061 - YT063
4YT064 - YT068
3YT101 - YT105
4YT106 - YT138
4YT176 - YT185
4YT191
4YT196 - YT199
3YT201
4YT206 - YT207
4YT211 - YT213
3YT251 - YT259
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
19 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 20

GroupVariable Number
4YT260 - YT299
4YT301 - YT305
3YT306 - YT307
3YT311 - YT312
4YT321 - YT355
4YT371 - YT372
4YT381
4YT391 - YT396
3YT401 - YT402
4YT403
3YT411
4YT412 - YT417
4YT427
3YT461 - YT463
4YT464 - YT477
4YT491 - YT492
4YT501 - YT521
4YT551 - YT552
4YT556 - YT563
4YT565
4YT571 - YT578
4YT601 - YT606
4YT701 - YT708
4YT723 - YT726
4YT761 - YT781
4YT791 - YT794
4YT796 - YT797
4YT801 - YT804
4YT811 - YT813
4YT826 - YT827
4YT831 - YT832
4YT841 - YT852
4YT856 - YT863
GroupVariable Number
4YT885 - YT887
4YT891 - YT895
4YT901 - YT998
3YU001 - YU015
4YU016 - YU060
4YU201 - YU218
4YU301 - YU329
4YU901 - YU931
4YV001 - YV012
4YV021 - YV023
4YV030 - YV034
4YV037 - YV042
4YV045 - YV047
4YV051 - YV059
4YV081
4YV083 - YV084
4YV097 - YV099
4YV101 - YV154
4YV201 - YV203
4YV251 - YV252
4YV256 - YV257
4YV301 - YV312
4YV351 - YV368
4YV381 - YV388
4YV391 - YV394
4YV401
4YV411 - YV413
4YV431 - YV433
4YV441 - YV454
4YV461 - YV464
4YV467 - YV470
4YV501 - YV512
4YV521
GroupVariable Number
4YV571 - YV586
4YV596
4YV601 - YV605
4YV651 - YV676
4YV695 - YV696
4YV701 - YV702
4YV711
4YV722 - YV731
4YV741 - YV794
4YV801 - YV820
4YV831 - YV848
4YV881 - YV883
4YV901 - YV915
4YV923 - YV926
4YV971 - YV983
4YW001
4YW011 - YW099
4YW101 - YW164
4YW201 - YW212
4YW226 - YW240
4YW245 - YW261
4YW263
4YW267 - YW281
4YW283 - YW285
4YW292 - YW299
4YW351
4YW356 - YW358
4YW361 - YW366
4YW371 - YW399
4YW401 - YW430
4YW441 - YW445
4YW451 - YW452
4YW471 - YW472
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: May 22, 2014
737-26A1137Revision 2: January 27, 2020
20 of 31
BOEING SERVICE BULLETIN 737-26A1137
ALERTALERT

### Page 21

GroupVariable Number
4YW491 - YW498
4YW531 - YW536
4YW541 - YW545
4YW551 - YW580
4YW585 - YW591
4YW595 - YW596
4YW601
4YW610 - YW613
GroupVariable Number
4YW616 - YW623
4YW666
4YW696 - YW699
4YW701 - YW715
4YW726 - YW731
4YW766 - YW775
4YW801 - YW803
4YW811 - YW813
GroupVariable Number
4YW821
4YW831
4YW881
4YW891 - YW893
4YW906 - YW910
4YW916 - YW918
4YW921 - YW925
4YW971 - YW976
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, Configuration 1:
DescriptionService BulletinCompany
FIRE PROTECTION - Lower Cargo Compartment
Smoke Detection - Forward Cargo Compartment
Smoke Penetration Electrical Changes
737-26-1122 Original Issue,
Revision 1, Revision 2, or 737-
26A1122 Revision 3
Boeing
Group 1, Configuration 2; Group 2-4:
None.
Group 5:
DescriptionService BulletinCompany
FIRE PROTECTION - Lower Cargo Compartment
Smoke Detection - Forward Cargo Compartment
Smoke Penetration Electrical Changes
737-26A1122 Revision 3Boeing
C. Reason
This service bulletin gives instructions to do the Smoke Clearance Mode - Operational Test at repeat
intervals on airplanes equipped with the reconfigurable 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 will reduce the probability of a latent failure which, in conjunction with a
cargo fire event, could result in smoke in the flight deck and possible loss of aircraft control.
A review by Boeing found that there was no maintenance procedure available to inspect the components
used to reconfigure the air distribution system to the cargo fire mode. 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.
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### Page 22

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, 737NG-SRP-26-0088 are related to this
service bulletin.
Revision 1: Sent to clearly identify the compliance time and inspection interval for airplane line numbers
1701 and on, delivered after the original issue date of this service bulletin. These airplanes have been
moved from Group 3 to new Group 4.
Revision 2: Sent to add airplanes YG044, YG067, YG069, YG074, YG081, YG084 and YG088 to new
Group 5 of this service bulletin. Also, an FAA AD is added to this service bulletin, and the Maintenance
Planning Data (MPD) information is changed.
The data given in Information Notice 737-26A1137 IN 01 is included in this revision.
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 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 Fire
Protection system operates correctly. If the Smoke Clearance Mode - Operational Test result is not
satisfactory, do the troubleshooting procedure on the equipment cooling system and low pressure
environmental control system to find and replace faulty components.
Effects of this Revision on airplanes on which Original Issue or Revision 1 was previously done:
None, except as stated below.
Airplanes YG044, YG067, YG069, YG074, YG081, YG084 and YG088 were moved to new Group 5
of this service bulletin.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1:
Affected Maintenance Zones
ZoneModel
112, 113, 114, 117, 118, 125, 126737-600, 737-700, 737-800
Group 2:
Affected Maintenance Zones
ZoneModel
112, 113, 114, 117, 118, 125, 126737-700C, 737-900
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Group 3:
Affected Maintenance Zones
ZoneModel
112, 113, 114, 117, 118, 125, 126737-600, 737-700, 737-700C,
737-800, 737-900, 737-900ER
Group 4:
Affected Maintenance Zones
ZoneModel
112, 113, 114, 117, 118, 125, 126737-700, 737-700C, 737-800,
737-900ER
Group 5:
Affected Maintenance Zones
ZoneModel
112, 113, 114, 117, 118, 125, 126737-700
E. Compliance
Federal Aviation Administration (FAA) Airworthiness Directive AD 2016-04-06 is related to this service
bulletin. The effective date of AD 2016-04-06 is April 1, 2016.
The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive
related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times
given in this service bulletin mandatory.
Group 1-4:
Table 1: Equipment Cooling System - Smoke Clearance Mode - Operational Test
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
9000 flight hours.Within 51 months
after the effective
date of AD 2016-
04-06.
Do a Smoke Clearance
Mode - Operational Test
in accordance with Para-
graph 3.B., Work Instruc-
tions.
Group 1, Configuration 1
Airplanes.
9000 flight hours.Within 10 months
after the effective
date of AD 2016-
04-06.
Do a Smoke Clearance
Mode - Operational Test
in accordance with Para-
graph 3.B., Work Instruc-
tions.
Group 1, Configuration 2,
Group 2 and Group 3 Air-
planes.
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Group 1-4:
Table 1: Equipment Cooling System - Smoke Clearance Mode - Operational Test
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
9000 flight hours.Before 9000 total
flight hours.
Do a Smoke Clearance
Mode - Operational Test
in accordance with Para-
graph 3.B., Work Instruc-
tions
Group 4 Airplanes
-Before further
flight.
Do a system fault isola-
tion in accordance with
Paragraph 3.B., Work In-
structions.
If the Smoke Clearance
Mode - Operational Test
fails.
Group 5:
Table 2: Equipment Cooling System - Smoke Clearance Mode - Operational Test
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
9000 flight hours.Within 51 months
after the R02 issue
date of SB 737-
26A1137.
Do a Smoke Clearance
Mode - Operational Test
in accordance with Para-
graph 3.B., Work Instruc-
tions.
All Airplanes.
-Before further
flight.
Do a system fault isola-
tion in accordance with
Paragraph 3.B., Work In-
structions.
If the Smoke Clearance
Mode - Operational Test
fails.
F. Approval
NOTE: The approval statement that follows is valid for all affected airplanes, except 737-700C.
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.
In addition, the Manager of the FAA Seattle ACO Branch approves accomplishment of the change
defined in this service bulletin revision as an alternative method of compliance to the requirements of
paragraph (g) of AD 2016-04-06. All provisions of AD 2016-04-06 that are not specifically referenced
in the above statement remain fully applicable and must be complied with accordingly.
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### Page 25

NOTE: The approval statement that follows is valid for all 737-700C.
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 for the 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.
In addition, the Manager of the FAA Seattle ACO Branch approves accomplishment of the change
defined in this service bulletin revision as an alternative method of compliance to the requirements of
paragraph (g) of AD 2016-04-06. All provisions of AD 2016-04-06 that are not specifically referenced
in the above statement remain fully applicable and must be complied with accordingly.
G. Manpower
The table below shows an estimate of the task hours necessary to do this change for each airplane.
This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator
task hour data if necessary. The estimate does not include lost time. These are some examples of lost
time:
• Time to adjust to the workplace.
• Time to schedule the work.
• Time to inspect the work.
• Time to cure the materials.
• Time to make the parts.
• Time to find the tools.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
0.500.501Open Access
1.503.002Test (a)
0.500.501Close Access
2.504.00TOTAL 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.
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.
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### Page 26

J. References
1. Existing Data:
a. Boeing Service Bulletin 737-21-1135, 737-21-1163, 737-26-1121, 737-26-1122, 737-26A1083,
737-26A1122
b. Boeing Service Related Problem (SRP) 737-SRP-26-0079, 737NG-SRP-26-0088
c. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2016-04-06
d. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19
e. 737-600/700/800/900 Aircraft Maintenance Manual (AMM) 06-41-00, 21-27-00, 21-31-01,
24-22-00, 52-51-00
f. 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-SectionPublication
21-27737 Aircraft Maintenance Manual
21-050-00737 Maintenance Planning Data
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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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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### Page 29

3.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
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.
CAUTION
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
Aircraft 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
Aircraft 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.
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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.
8. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS
are in Paragraph 1.E., Compliance.
9. Some steps in the Work Instructions are labeled as Required for Compliance (RC).
If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps
labeled as RC, including sub-steps under an RC step and any figures identified in
an RC step, must be done to comply with the AD. An Alternative Method of
Compliance (AMOC) is required for any deviations to RC steps, including sub-steps
and identified figures. Steps not labeled as RC may be deviated from using accepted
methods in accordance with the operator's maintenance or inspection program without
obtaining approval of an AMOC. This is provided that the RC steps, including
sub-steps and identified figures, can still be done as specified, and the airplane can
be put back in an airworthy condition.
B. WORK INSTRUCTIONS
1. Do these steps to get access.
a. Below the main electronics equipment compartment, open 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 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 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. RC - If the Smoke Clearance Mode - Operational Test fails, do a system fault isolation and
corrective actions. Repeat the Smoke Clearance Mode - Operational Test, fault isolation and
corrective actions until the test is passed. 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.
NOTE: Fault Isolation Manual (FIM) reference 21-25-801 is only applicable to 737-600 and
737-700 airplanes.
NOTE: Operators should reference their airplane effectivity when using FIM references
21-27-810 and 21-27-811.
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 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 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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