### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Number: 757-28-0121**  Original Issue: August 18, 2010 ATA System: 2841 **SUBJECT:** FUEL-Fuel Quantity Indicating System (FQIS)- Fuel Quantity Processor Unit, Low Fuel Quantity Indication Test 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 1 of 20 4.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 2 of 20 **BOEING SERVICE BULLETIN 757-28-0121**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 15 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 17 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 17 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 3 of 20 **BOEING SERVICE BULLETIN 757-28-0121**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 4 of 20 **BOEING SERVICE BULLETIN 757-28-0121**

BLANK PAGE

### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 757-28-0121** Original Issue: August 18, 2010 ATA System: 2841 **SUBJECT:** FUEL-Fuel Quantity Indicating System (FQIS)- Fuel Quantity Processor Unit, Low Fuel Quantity Indication Test BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **CONCURRENT REQUIREMENTS** None.

**BACKGROUND** This service bulletin provides test procedures to make sure that the Engine Indication and Crew Alerting System (EICAS) receives both, the LOW FUEL and the FUEL CONFIG discrete signals from the Fuel Quantity Processor Unit (FQPU), and the Fuel Quantity Indicating System (FQIS), is functioning correctly. If this service bulletin is not incorporated flight crews may be unaware of low fuel situations that can lead to fuel exhaustion and extreme emergency measures. A 757-200 operator reported that the Low Fuel Indicating System failed to alert the flight crew that the fuel in Left Hand (LH) and Right Hand (RH) main tanks were depleted below the minimum 2,200 lbs in either tank. The Low Fuel Threshold is 2,200 lbs of fuel for either Main Fuel Tank. When the fuel in either LH or RH main tank is below 2,200 lbs, the EICAS should receive both the LOW FUEL and FUEL CONFIG discrete signals from the FQPU in order for EICAS to display the LOW FUEL caution message. The Operator reported to Boeing that the airplane arrived at it’s destination with main tank fuel levels below the Low Fuel Threshold. The next flight crew reported 8,000 lbs of fuel in the Center Wing Tank (CWT), 1,800 lbs of fuel in the Right Hand Main Fuel Tank and 1,400 lbs of fuel in the Left Hand Main Fuel tank. Boeing determined this to be a safety issue. Operators can expect to eliminate similar safety incidents by doing the interval tests in accordance with this service bulletin. 757/767-SRP-28-0124 is related to this service bulletin. **ACTION** Test the Low Fuel Quantity Indicating System to make sure that the, Low Fuel Indication, and the Fuel Configuration indication are functioning correctly. Make sure the EICAS displays the "LOW FUEL" caution message and the "FUEL CONFIG" light on the Pilots Overhead Panel (P5 Panel) comes "ON".

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 5 of 20If the test fails troubleshoot for wiring faults, bent connector pins, or damaged equipment. Repair or replace damaged wires or equipment.

**EFFECTIVITY** 757-200/-200CB/-200PF/-300 Airplanes line numbers 1 through 1050. 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 recommends that the Inspection/Interval Test given in this service bulletin be done every 100 flight hours. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the Inspection/Interval Test given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 6 of 20 **BOEING SERVICE BULLETIN 757-28-0121**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 7 of 20 **BOEING SERVICE BULLETIN 757-28-0121**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 8 of 20 **BOEING SERVICE BULLETIN 757-28-0121**

BLANK PAGE

### Commercial **Airplanes** 

# 757 Service Bulletin **SPECIAL ATTENTION Number: 757-28-0121**  Original Issue: August 18, 2010 ATA System: 2841 **SUBJECT:** FUEL-Fuel Quantity Indicating System (FQIS)- Fuel Quantity Processor Unit, Low Fuel Quantity Indication Test BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes This service bulletin is for the airplanes shown below. Refer to Service Bulletin Index Document D624N001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.

**DESCRIPTION CONFIGURATION**  **GROUP** 757-200/-200CB/-200PF/-300 Airplanes line numbers 1 to 1050.

- 1

Airplane Models: 757-200, 757-200CB, 757-200PF, 757-300 **Group Variable Number**  1 NA001 - NA028 1 NA191 - NA199 1 NA201 - NA239 1 NA301 - NA305 1 NA341 - NA352 1 NA391 - NA399 1 NA401 - NA408 1 NA441 - NA447

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 9 of 20**Group Variable Number**  1 NA501 - NA586 1 NB001 - NB004 1 NB021 - NB023 1 NB036 - NB041 1 NB051 - NB053 1 NB061 - NB073 1 NB079 1 NB131 - NB148 1 NB161 - NB162 1 NB166 - NB168 1 NB201 - NB204 1 NB221 - NB228 1 NB230 1 NB236 1 NB239 1 NB261 - NB267 1 NB291 - NB299 1 NB301 - NB302 1 NB311 - NB312 1 NB321 - NB331 1 NB421 - NB438 1 NB446 1 NB451 - NB454 1 NB501 - NB523 1 NB561 1 NB571 1 NB581 - NB583 1 NC001 - NC033 1 NC041 - NC042 1 NC051 - NC052 1 NC056 - NC062 1 NC066 - NC084 1 NC091 - NC094

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 10 of 20 **BOEING SERVICE BULLETIN 757-28-0121 Group**  **Variable Number** 1 NC151 1 NC161 1 NC901 - NC951 1 NC971 - NC974 1 ND001 - ND007 1 ND011 - ND059 1 ND111 - ND113 1 ND161 - ND199 1 ND201 - ND203 1 ND221 - ND225 1 ND241 - ND248 1 ND301 - ND322 1 ND401 1 ND891 1 ND895 1 NE001 - NE008 1 NE011 - NE088 1 NE091 - NE094 1 NE141 - NE150 1 NE161 - NE177 1 NE201 - NE204 1 NE301 - NE302 1 NE311 - NE325 1 NJ001 - NJ004 1 NJ031 - NJ032 1 NJ551 - NJ555 1 NL001 - NL002 1 NL006 - NL017 1 NL101 - NL109 1 NL141 1 NL601 - NL616 1 NN001 - NN002 1 NN051 - NN052

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 11 of 20 **BOEING SERVICE BULLETIN 757-28-0121 Group**  **Variable Number** 1 NP901 - NP904 1 NS601 - NS616 1 NT001 - NT009 1 NT201 - NT202 1 NT231 - NT234 1 NT237 - NT240 1 NT242 1 NT245 - NT248 1 NT281 - NT289 1 NT341 - NT347 1 NT351 - NT360 1 NT371 - NT373 1 NT375 - NT379 1 NT381 - NT386 1 NT401 - NT409 1 NT411 - NT412 1 NT426 - NT427 1 NT431 - NT432 1 NT436 - NT438 1 NT441 - NT442 1 NT446 1 NT701 - NT769 1 NT791 - NT796 1 NT861 - NT862 1 NT881 - NT885 1 NT901 - NT916 1 NT971 - NT985 1 NU031 - NU038 1 NU701 - NU705 1 NU721 - NU728 1 NU731 - NU732

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 12 of 20 **BOEING SERVICE BULLETIN 757-28-0121**2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** This service bulletin provides test procedures to make sure that the Engine Indication and Crew Alerting System (EICAS) receives both, the LOW FUEL and the FUEL CONFIG discrete signals from the Fuel Quantity Processor Unit (FQPU), and the Fuel Quantity Indicating System (FQIS), is functioning correctly. If this service bulletin is not incorporated flight crews may be unaware of low fuel situations that can lead to fuel exhaustion and extreme emergency measures. A 757-200 operator reported that the Low Fuel Indicating System failed to alert the flight crew that the fuel in Left Hand (LH) and Right Hand (RH) main tanks were depleted below the minimum 2,200 lbs in either tank. The Low Fuel Threshold is 2,200 lbs of fuel for either Main Fuel Tank. When the fuel in either LH or RH main tank is below 2,200 lbs, the EICAS should receive both the LOW FUEL and FUEL CONFIG discrete signals from the FQPU in order for EICAS to display the LOW FUEL caution message. The Operator reported to Boeing that the airplane arrived at it’s destination with main tank fuel levels below the Low Fuel Threshold. The next flight crew reported 8,000 lbs of fuel in the Center Wing Tank (CWT), 1,800 lbs of fuel in the Right Hand Main Fuel Tank and 1,400 lbs of fuel in the Left Hand Main Fuel tank. Boeing determined this to be a safety issue. Operators can expect to eliminate similar safety incidents by doing the interval tests in accordance with this service bulletin. 757/767-SRP-28-0124 is related to this service bulletin. **D. Description** Test the Low Fuel Quantity Indicating System to make sure that the, Low Fuel Indication, and the Fuel Configuration indication are functioning correctly. Make sure the EICAS displays the "LOW FUEL" caution message and the "FUEL CONFIG" light on the Pilots Overhead Panel (P5 Panel) comes "ON". If the test fails troubleshoot for wiring faults, bent connector pins, or damaged equipment. Repair or replace damaged wires or equipment. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 119, 121, 122, 211, 212, 221, 222 757-200, 757-200CB, 757- 200PF, 757-300

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 13 of 20 **BOEING SERVICE BULLETIN 757-28-0121 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 inspection/Interval Test given in this service bulletin be done every 100 flight hours. **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task hours necessary to do this for each . 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 Persons Task**  0.25 0.25 1 Open Access 0.50 0.50 1 Test 0.25 0.25 1 Close Access 1.00 1.00 TOTAL FOR EACH AIRPLANE

**H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 14 of 20 **BOEING SERVICE BULLETIN 757-28-0121 J. References**  1. Existing Data a. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19 b. 757 Aircraft Maintenance Manual (AMM) 24-22-00 c. 757 Fault Isolation Manual (FIM) 28-41-00 d. 757 Wiring Diagram Manual (WDM) 28-41-13 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin

**K. Publications Affected** 1. Publications: None. 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: August 18, 2010 757-28-0121 15 of 20 **BOEING SERVICE BULLETIN 757-28-0121**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 16 of 20 **BOEING SERVICE BULLETIN 757-28-0121**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** Boeing warranty remedies are not available for the Inspection/Interval 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 17 of 20 **BOEING SERVICE BULLETIN 757-28-0121**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 18 of 20 **BOEING SERVICE BULLETIN 757-28-0121**

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. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 6. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 7. 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. Supply electrical power. Refer to 757 AMM 24-22-00 as an accepted procedure. 2. Make sure the following six EICAS circuit breakers are closed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 19 of 20 **BOEING SERVICE BULLETIN 757-28-0121 EICAS CIRCUIT BREAKERS, P11 PANEL** 
**LOCATION PANEL**  **NAME CIRCUIT**  **BREAKER** J2 P11-3 EICAS CMPTR L C4078 J29 P11-4 EICAS CMPTR R C4079 J32 P11-4 EICAS PILOTS DSP C4094 J31 P11-4 EICAS DISPLAY SW C4189 J30 P11-4 EICAS LOWER IND C4082 J3 P11-3 EICAS UPPER IND C4081 3. Push the MASTER CAUTION Cancel button on the P1-3, Captain Instrument Panel, Center to reset warnings. 4. Push and release the FUEL QTY test switch on the Miscellaneous Test Panel (M10398), P61 Panel, to the FUEL QTY position. a. Make sure the FUEL CONFIG light on the P5, Pilot's Overhead Panel, comes on. b. Make sure the EICAS caution message, LOW FUEL, shows on the upper (EICAS) display, P1 Panel. **NOTE:** If the test fails, trouble shoot for wire faults, bent connector pins, or damaged equipment. Repair and or replace damaged wires and or equipment. Refer to Fault Isolation Manual 757 FIM 28-41-00 as an accepted procedure and to Wire Diagram Manual 757 WDM 28-41-13 for related wires. 5. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 18, 2010 757-28-0121 20 of 20 **BOEING SERVICE BULLETIN 757-28-0121**