### 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. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 1 of 20 4.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 2 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**

BLANK PAGE**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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 11 3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 11 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 FIGURE 1: WIRE BUNDLE W066 WIRE ROUTING . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 FIGURE 2: ACTIVATION OF THE CABIN ALTITUDE WARNING AND TAKEOFF CONFIGURATION WARNING LIGHTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 FIGURE 3: REMOVE THE INOP MARKERS AT THE L1304 AND L1316 LIGHT ASSEMBLIES . . . 18 FIGURE 4: L1304 AND L1316 LIGHT ASSEMBLY REFERENCE . . . . . . . . . . . . . . . . . . . . 20

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 3 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 4 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **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. **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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 5 of 20Boeing 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 Hours**  **Total Task Hours Airplanes**  1.75 1.75 PW234
**MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 6 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**

### 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.
**DESCRIPTION CONFIGURATION**  **GROUP** 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 **Group Variable Number**  1 PW234 2. Spares Affected None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 7 of 20**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 Zone**  **Model** 101, 102 737-400 **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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 8 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT 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 Hours Task Hours**  **Number of Per- sons**  **Task**

0.25 0.25 1 Open Access 0.50 0.50 1 Change 0.25 0.25 1 Close Access 0.75 0.75 1 Test 1.75 1.75 TOTAL 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 9 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT K. Publications Affected**  1. Publications: **Chapter-Section Publication**  Section 2 737 FAA Approved Airplane Flight Manual 1-20, 15-10, 15-20 737 Flight Crew Operations Manual 31-51 737 Maintenance Manual 21-33, 27-43 737 Wiring Diagram Manual 31-11 737 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 10 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 11 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 12 of 20 **BOEING SERVICE BULLETIN 737-31A1398 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. 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**  **Name Location (Panel/Posi-**  **tion)** C451 AURAL WARN P6-3 / C16 C129 LAND 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:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 13 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT Circuit Breaker Num**  **ber Name**  **Location (Panel/Posi- tion)**  C451 AURAL WARN P6-3 / C16 C129 LAND 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 14 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**(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

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 15 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT FIGURE 1: WIRE BUNDLE W066 WIRE ROUTING**  **(SHEET 1 OF 1)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 16 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**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)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 17 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**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)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 18 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Refer to SOPM 20-50-05 as an accepted procedure. 2 BAC27DCC2769 MARKER Remove 1

**FIGURE 3: REMOVE THE INOP MARKERS AT THE L1304 AND L1316 LIGHT ASSEMBLIES (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 19 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT FIGURE 4: L1304 AND L1316 LIGHT ASSEMBLY REFERENCE**  **(SHEET 1 OF 1)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: January 07, 2010 737-31A1398 20 of 20 **BOEING SERVICE BULLETIN 737-31A1398 ALERT**  **ALERT**