# Boeing Alert Service Bulletin 737-31A1398: No revision named

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- Document: [Boeing Alert Service Bulletin 737-31A1398](https://openairdocs.org/service-documents/boeing/737-31a1398.md)
- Title as filed: U.S. DOT/FAA - Service Bulletin
- Pages: 20
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## Text

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### Page 1

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-31A1398
Original Issue: January 07, 2010
ATA System: 3126
SUBJECT: INDICATING/RECORDING SYSTEMS - Aural Warning System - Installation Of The
Cabin Altitude Warning System And Takeoff Configuration Warning System Lights
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 730-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET
Copyright © 2010 The Boeing Company
Unpublished Work - All Rights Reserved
Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable
subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.
This document includes proprietary information owned by The Boeing Company and/or one or more third parties.
Treatment of the document and the information it contains is governed by contract with Boeing. For more
information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the
Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
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Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 7
A. Effectivity ................................................ 7
1. Airplanes ............................................. 7
2. Spares Affected ......................................... 7
B. Concurrent Requirements ....................................... 8
C. Reason ................................................. 8
D. Description ............................................... 8
E. Compliance .............................................. 8
F. Approval ................................................ 8
G. Manpower ............................................... 9
H. Weight and Balance Changes .................................... 9
I. Electrical Load Data .......................................... 9
J. References .............................................. 9
1. Existing Data .......................................... 9
2. Data supplied with this Service Bulletin ............................ 9
3. Installation Drawings Used in the Preparation of this Service Bulletin ............ 9
K. Publications Affected ........................................ 1 0
L. Interchangeability and Intermixability of Parts ........................... 1 0
2. MATERIAL INFORMATION ........................................ 1 1
A. Material - Price and Availability ................................... 1 1
B. Industry Support Information .................................... 1 1
C. Parts Necessary For Each Airplane ................................. 1 1
1. Kits/Parts ............................................ 1 1
2. Parts and Materials Supplied by the Operator ........................ 1 1
3. Parts Modified and Reidentified ................................ 1 1
4. Parts Removed and Not Replaced .............................. 1 1
D. Parts Necessary to Change Spares ................................. 1 1
E. Special Tooling - Price and Availability ............................... 1 1
F. Special Tooling Necessary to do this Service Bulletin ....................... 1 1
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 3
A. GENERAL INFORMATION ..................................... 1 3
B. WORK INSTRUCTIONS ....................................... 1 3
FIGURE 1: WIRE BUNDLE W066 WIRE ROUTING ........................... 1 6
FIGURE 2: ACTIVATION OF THE CABIN ALTITUDE WARNING AND TAKEOFF CONFIGURATION
WARNING LIGHTS ....................................... 1 7
FIGURE 3: REMOVE THE INOP MARKERS AT THE L1304 AND L1316 LIGHT ASSEMBLIES . . . 18
FIGURE 4: L1304 AND L1316 LIGHT ASSEMBLY REFERENCE .................... 2 0
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Commercial 
Airplanes
737
Service Bulletin
ALERT
SummaryNumber: 737-31A1398Original Issue: January 07, 2010
ATA System: 3126
SUBJECT: INDICATING/RECORDING SYSTEMS - Aural Warning System - Installation Of The
Cabin Altitude Warning System And Takeoff Configuration Warning System Lights
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
None.
BACKGROUND
This service bulletin gives the instructions to activate the cabin altitude warning system and takeoff configuration
warning lights. Incorporation of this service bulletin will allow the operator to activate the cabin altitude warning
system and takeoff configuration warning lights. Activation of these lights will provide a visual indication to the
flight crew to be used in conjunction with the existing aural warning horn for cabin altitude and takeoff configuration
alerts. The visual warning lights are intended to provide additional notice to crews to prepare a correct takeoff
configuration, respond to excessive cabin altitude and avoid confusion between the takeoff configuration and
cabin altitude alerts. An unrecognized incorrect takeoff configuration or excessive cabin altitude could prevent
a continued safe flight and landing.
ACTION
Get access to the flight compartment. Remove the P2-2 panel to get access to the W066 wire bundle located
behind the panel. Change the wiring in the W066 wire bundle. Remove the INOP markers from the cabin altitude
warning system and takeoff configuration warning lights. Do an operational test of the cabin altitude warning
system and takeoff configuration warning lights.
EFFECTIVITY
737-400 Airplanes. Refer to Paragraph 1.A.1., Airplanes 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.
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Boeing recommends that the change given in this service bulletin be done within 36 months after the date of
this service bulletin.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the configuration changes given in this service bulletin.
MANPOWER
Elapsed HoursTotal Task HoursAirplanes
1.751.75PW234
MATERIAL INFORMATION
None.
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Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-31A1398
Original Issue: January 07, 2010
ATA System: 3126
SUBJECT: INDICATING/RECORDING SYSTEMS - Aural Warning System - Installation Of The
Cabin Altitude Warning System And Takeoff Configuration Warning System Lights
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 for the airplanes shown below.
Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
DESCRIPTIONCONFIGURATIONGROUP
Airplanes with Cabin Altitude Warning System and Takeoff
Configuration Warning System Lights installed and deactivated.
Accomplishment of Boeing Service Bulletin 737-31-1377 deactivated
the lights.
-1
Airplane Models:
737-400
GroupVariable Number
1PW234
2. Spares Affected
None.
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B. Concurrent Requirements
None.
C. Reason
This service bulletin gives the instructions to activate the cabin altitude warning system and takeoff
configuration warning lights. Incorporation of this service bulletin will allow the operator to activate the
cabin altitude warning system and takeoff configuration warning lights. Activation of these lights will
provide a visual indication to the flight crew to be used in conjunction with the existing aural warning
horn for cabin altitude and takeoff configuration alerts. The visual warning lights are intended to provide
additional notice to crews to prepare a correct takeoff configuration, respond to excessive cabin altitude
and avoid confusion between the takeoff configuration and cabin altitude alerts. An unrecognized
incorrect takeoff configuration or excessive cabin altitude could prevent a continued safe flight and
landing
D. Description
Get access to the flight compartment. Remove the P2-2 panel to get access to the W066 wire bundle
located behind the panel. Change the wiring in the W066 wire bundle. Remove the INOP markers from
the cabin altitude warning system and takeoff configuration warning lights. Do an operational test of
the cabin altitude warning system and takeoff configuration warning lights.
The work in this service bulletin is done in the maintenance zone(s) given below.
Affected Maintenance Zones
ZoneModel
101, 102737-400
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.
Boeing recommends that the change given in this service bulletin be done within 36 months after the
date on this service bulletin.
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.
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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
0.250.251Open Access
0.500.501Change
0.250.251Close Access
0.750.751Test
1.751.75TOTAL FOR EACH AIRPLANE
H. Weight and Balance Changes
None.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data
a. Standard Overhaul Practices Manual (SOPM) 20-50-05
b. Standard Wiring Practices Manual (SWPM) 20-00-11, 20-10-11, 20-10-12, 20-10-19
c. 737-300/400/500 Wiring Diagram Manual (WDM) 21-33-01, 27-43-01
2. Data supplied with this Service Bulletin
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin
None.
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K. Publications Affected
1. Publications:
Chapter-SectionPublication
Section 2737 FAA Approved Airplane Flight Manual
1-20, 15-10, 15-20737 Flight Crew Operations Manual
31-51737 Maintenance Manual
21-33, 27-43737 Wiring Diagram Manual
31-11737 Illustrated Parts Catalog
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.
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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 configuration changes 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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3.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL
PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL,
METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE
DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR
OTHER ELECTRICAL DAMAGE.
NOTE: 1. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s)
give the recommended sequence of steps. The sequence of steps to do this service
bulletin can be changed.
2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for
definition of the acronyms.
3. Obey all of the warnings and cautions given in the specified manual sections.
4. 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.
B. WORK INSTRUCTIONS
1. Get access to the flight compartment.
2. Open the following circuit breakers and install DO-NOT-CLOSE tags:
Circuit Breaker Num-
ber
NameLocation (Panel/Posi-
tion)
C451AURAL WARNP6-3 / C16
C129LAND LATCH &
PRESS WARN
P6-3 / C17
3. Change the W066 wire bundle in accordance with Figure 1, Figure 2, and Figure 4.
4. Remove the INOP markers on the P2-2 panel in accordance with Figure 3.
5. Close the circuit breakers opened in Step 2 above.
6. Do a test for activation of the TAKEOFF CONFIG and CABIN ALTITUDE warning lights:
a. Make sure the following circuit breakers are closed:
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Circuit Breaker Num-
ber
NameLocation (Panel/Posi-
tion)
C451AURAL WARNP6-3 / C16
C129LAND LATCH &
PRESS WARN
P6-3 / C17
b. Test the TAKEOFF CONFIG light activation:
(1) Make sure the parking brake is set.
(2) Move the thrust levers to the takeoff position (engines are not running).
(3) Make sure you hear the warning horn.
(4) Make sure the "Red" TAKEOFF CONFIG light on the P2-2 panel is ON.
(5) Move the thrust levers to the idle position.
(6) Make sure the warning horn stops.
(7) Make sure the "Red" TAKEOFF CONFIG light on the P2-2 panel is OFF
c. Test the CABIN ALTITUDE light activation:
(1) Open the forward access door and get access to the Cabin Altitude pressure switch S128.
(2) Remove the vent port screen from the cabin altitude pressure switch S128.
(3) Connect the pitot static system tester (No. 4 Union and O-ring) to the vent port in the
cabin altitude warning switch S128 (737-300/400/500 AMM 34-11-00).
(4) Operate the system by slowly increasing the vacuum and monitor the altimeter.
(5) Make a record of the altitude at which you hear the warning horn.
(6) Make sure you hear the intermittent warning horn at an altitude between 9,000 and 11,000
feet and make sure the "Red" CABIN ALTITUDE light on the P2-2 panel is ON.
(7) Push the switch for the ALTITUDE HORN CUTOUT on the P5-16 cabin pressure control
panel.
(8) Make sure the aural warning horn stops.
(9) Make sure the "Red" CABIN ALTITUDE light on the P2-2 panels stays ON.
(10) Slowly lower the altitude shown to approximately 1,700 feet below the altitude at which
you heard the horn.
(11) Make sure the "Red" CABIN ALTITUDE light on the P2-2 panel goes OFF.
(12) Increase the altitude.
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(13) Make sure the horn is again heard between 9,000 and 11,000 feet.
(14) Make sure the "Red" CABIN ALTITUDE light on the P2-2 panel comes ON.
(15) Decrease the altitude to the ground level.
(16) Make sure the "Red" CABIN ALTITUDE light on the P2-2 panel goes off and the aural
warning horn stops.
(17) Disconnect the pitot static system test equipment.
(18) Install the vent port screen.
(19) Close the forward access door.
7. Return the airplane to a serviceable condition
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### Page 16 (OCR)

BOEING SERVICE BULLETIN 737-31A1398
ALERT  ALERT
L1316
L1304
W066
1744383
FIGURE 1: WIRE BUNDLE W066 WIRE ROUTING
(SHEET 1 OF 1)
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### Page 17 (OCR)

BOEING SERVICE BULLETIN 737-31A1398
ALERT  ALERT
W066
- 8033-20-1
L1316 TAKEOFF WARNING LIGHT
- 8032-20-→
L1304 CABIN ALTITUDE LIGHT
P2-2 PANEL
P2 CENTER INSTRUMENT PANEL
• ADDED WIRE OR NEW ROUTING
+ DELETED WIRE OR FORMER ROUTING
• EXISTING WIRE  1744385
REFERENCES: 737-300/400/500 WDM 21-33-01, 737-300/400/500 WDM 27-43-01.
FIGURE 2: ACTIVATION OF THE CABIN ALTITUDE WARNING AND TAKEOFF CONFIGURATION WARNING
LIGHTS
(SHEET 1 OF 1)
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### Page 18 (OCR)

BOEING SERVICE BULLETIN 737-31A1398
ALERT  ALERT
FLIGHT COMPARTMENT
MARKER
í@;
P2-2 CENTER INSTRUMENT PANEL
EIS CONFIGURATION
1744386
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
FIGURE 3: REMOVE THE INOP MARKERS AT THE L1304 AND L1316 LIGHT ASSEMBLIES
(SHEET 1 OF 2)
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### Page 19

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
Refer to SOPM 20-
50-05 as an accept-
ed procedure.
2BAC27DCC2769MARKERRemove1
FIGURE 3: REMOVE THE INOP MARKERS AT THE L1304 AND L1316 LIGHT ASSEMBLIES
(SHEET 2 OF 2)
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FIGURE 4: L1304 AND L1316 LIGHT ASSEMBLY REFERENCE
(SHEET 1 OF 1)
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