### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-24-0112**  Original Issue: February 19, 2009 Revision 2: December 14, 2011 ATA System: 2409 **SUBJECT:** ELECTRICAL POWER - Electrical Load Management (ELM) System - P200 and P300 Power Panels - Contactor Replacement 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2009 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 1 of 23 2.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 2 of 23 **BOEING SERVICE BULLETIN 777-24-0112**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 17 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 19 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 19 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 FIGURE 1: LOCATION OF THE ELMS POWER PANELS. . . . . . . . . . . . . . . . . . . . . . . . 22

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 3 of 23 **BOEING SERVICE BULLETIN 777-24-0112**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 4 of 23 **BOEING SERVICE BULLETIN 777-24-0112**

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### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Revision Transmittal Sheet**  **Number: 777-24-0112** Original Issue: February 19, 2009 Revision 2: December 14, 2011 ATA System: 2409 **SUBJECT:** ELECTRICAL POWER - Electrical Load Management (ELM) System - P200 and P300 Power Panels - Contactor Replacement This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on the airplanes changed in accordance with the original issue or Revision 1 of this service bulletin. **REASON FOR REVISION** This revision is sent to correct the Concurrent Requirements data given in this service bulletin. In Paragraph 1.B., Concurrent Requirements, the Concurrent Requirements table is changed to add a reference to GE Aviation SB 2000ELM-24-697 Revision 1 and GE Aviation SB 3000ELM-24-698 Revision 1. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** February 19, 2009 Original Issue: June 30, 2011 Revision 1: December 14, 2011 Revision 2:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 5 of 23BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 6 of 23 **BOEING SERVICE BULLETIN 777-24-0112**

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### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Summary**  **Number: 777-24-0112** Original Issue: February 19, 2009 Revision 2: December 14, 2011 ATA System: 2409 **SUBJECT:** ELECTRICAL POWER - Electrical Load Management (ELM) System - P200 and P300 Power Panels - Contactor Replacement BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **CONCURRENT REQUIREMENTS** Refer to Paragraph 1.B., Concurrent Requirements. **BACKGROUND** This service bulletin gives instructions to replace certain contactors (also known as breakers) in the Electrical Load Management System (ELMS) P200 and P300 power panels with contactors of a new design. The design changes are intended to make the contactor more reliable and less susceptible to high energy arcing events. The replacement of these contactors is intended to reduce the frequency of failures due to arcing events. If a high energy event causes a failure of a contactor, the airplane will have reduced capability to switch power sources. The failure of a contactor can also result in arcing, which could result in smoke and fire and could result in an emergency evacuation. In-service events related to electrical power system malfunctions resulted in findings of damage to P200 and P300 panels. In some incidents, operators experienced severe contactor and ELMS panel damage. No contactor failures have been reported as occurring in flight. The analysis of contactors returned from the fleet identified opportunities to improve the contactor design. Extended operation of contactor at current close to maximum can lead to thermal degradation of materials in the contactor which further reduces contactor protection and can lead to loose parts which increases the probability of arcing. In addition, there was evidence of material buildup from normal operation of the contactor and potential for Foreign Object Debris (FOD) that could lead to short circuits within the contactor. Design improvements have been incorporated on contactors to address a number of issues that were identified in the above analysis. Improvements have been made to increase the contactors resistance to the effects of thermal cycling, and addition of insulation to provide better phase to phase and phase to ground isolation. The major improvements include: – Additional hardware on the stationary contact assembly to reduce the plastic compression and the possibility that the hardware will loosen under abnormal temperatures – Arc Chute material and dimensional changes to improve thermal stability, with additional inter-phase and cover protection – Additional insulation on contactor plunger nuts within the contactor. This provides a barrier to other conductive components in the event of a failure in the main contact area.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 7 of 23The failure of a contactor could cause significant schedule delays and or economic impact to the operator such as unplanned downtime, labor and material costs. The replacement of certain contactors with the improved design could prevent a failure of the contactor and possible damage or failure of the power panel. **ACTION (PRR 62240)** Get access to the main equipment center. Replace the applicable contactors in the P200 panel in accordance with the GE Aviation service bulletin. Replace the applicable contactor in the P300 panel in accordance with the GE Aviation service bulletin. Do an installation test of applicable contactors in the P200 panel. Do an installation test of the applicable contactor in the P300 panel. Close access to the main equipment center. Return airplane to a serviceable condition. **EFFECTIVITY** 777-200/-200LR/-300/-300ER 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 recommends that the change given in this service bulletin be done within 60 months after the Revision 1 date of this service bulletin. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspections given in this service bulletin. **MANPOWER Elapsed Hours**  **Total Task Hours Airplanes**  2.50 4.50 Group 1
**MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 8 of 23 **BOEING SERVICE BULLETIN 777-24-0112**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 9 of 23 **BOEING SERVICE BULLETIN 777-24-0112**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 10 of 23 **BOEING SERVICE BULLETIN 777-24-0112**

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### Commercial **Airplanes** 

# 777 Service Bulletin **SPECIAL ATTENTION Number: 777-24-0112**  Original Issue: February 19, 2009 Revision 2: December 14, 2011 ATA System: 2409 **SUBJECT:** ELECTRICAL POWER - Electrical Load Management (ELM) System - P200 and P300 Power Panels - Contactor Replacement BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS SERVICE BULLETIN IMMEDIATELY. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 62440 for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** 777-200/-200LR/-300/-300ER Airplanes

- 1

Airplane Models: 777-200, 777-200LR, 777-300, 777-300ER **Group Variable Number**  1 WA001 - WA017 1 WA076 - WA080 1 WA086 - WA093 1 WA101 - WA104 1 WA116 - WA119 1 WA131 - WA137 1 WA171 - WA175

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 11 of 23**Group Variable Number**  1 WA196 - WA198 1 WA206 - WA212 1 WA221 - WA223 1 WA231 - WA232 1 WA241 - WA250 1 WA261 - WA266 1 WA281 - WA283 1 WA301 - WA304 1 WB001 - WB021 1 WB031 - WB046 1 WB051 - WB088 1 WB101 - WB106 1 WB121 - WB125 1 WB131 - WB148 1 WB151 - WB155 1 WB161 - WB177 1 WB181 - WB194 1 WB201 - WB215 1 WB231 - WB247 1 WB271 - WB273 1 WB276 - WB286 1 WB291 - WB302 1 WB306 - WB307 1 WB311 - WB337 1 WB341 - WB342 1 WB366 - WB368 1 WB371 - WB388 1 WB406 1 WB411 - WB413 1 WB416 - WB439 1 WB446 - WB453 1 WB476 1 WB481 - WB484

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 12 of 23 **BOEING SERVICE BULLETIN 777-24-0112 Group**  **Variable Number** 1 WB501 - WB512 1 WB531 - WB537 1 WB551 - WB554 1 WB591 - WB597 1 WB601 - WB606 1 WB611 - WB622 1 WB631 - WB638 1 WB646 - WB649 1 WC051 - WC073 1 WC101 - WC104 1 WC111 - WC120 1 WC221 - WC222 1 WC241 - WC243 1 WC281 - WC290 1 WC301 - WC308 1 WC361 - WC364 1 WC371 - WC374 1 WC381 - WC395 1 WC441 1 WC446 - WC449 1 WC456 - WC459 1 WC486 - WC493 1 WC506 - WC508 1 WC521 - WC522 1 WC531 - WC536 1 WC546 - WC548 1 WC556 1 WC566 - WC567 1 WD001 - WD002 1 WD011 - WD015 1 WD031 - WD036 1 WD046 - WD054 1 WD066 - WD067

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 13 of 23 **BOEING SERVICE BULLETIN 777-24-0112 Group**  **Variable Number** 1 WD081 1 WD501 - WD510 1 WD521 - WD539 1 WD546 - WD552 1 WD561 - WD573 1 WD581 - WD596 1 WD606 - WD609 1 WD621 - WD632 1 WD651 - WD662 1 WD671 - WD675 1 WD691 - WD709 1 WD741 - WD750 1 WD761 - WD770 1 WD786 - WD788 1 WD796 - WD805 1 WD826 - WD830 1 WD846 - WD852 1 WD871 - WD875 1 WD911 - WD912 1 WD936 - WD939 1 WD966 - WD967 2. Spares Affected None. **B. Concurrent Requirements** The service bulletins listed below must be done at the same time as this service bulletin: **Description Service Bulletin**  **Company** This service bulletin gives instructions to replace contactors in the ELMS P200 panel. 2000ELM-24-697 Original Issue, Revision 1, Revision 2 GE Aviation This service bulletin gives instructions to replace a contactor in the ELMS P300 panel. 3000ELM-24-698 Original Issue, Revision 1, Revision 2 GE Aviation

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 14 of 23 **BOEING SERVICE BULLETIN 777-24-0112 C. Reason**  This service bulletin gives instructions to replace certain contactors (also known as breakers) in the Electrical Load Management System (ELMS) P200 and P300 power panels with contactors of a new design. The design changes are intended to make the contactor more reliable and less susceptible to high energy arcing events. The replacement of these contactors is intended to reduce the frequency of failures due to arcing events. If a high energy event causes a failure of a contactor, the airplane will have reduced capability to switch power sources. The failure of a contactor can also result in arcing, which could result in smoke and fire and could result in an emergency evacuation. In-service events related to electrical power system malfunctions resulted in findings of damage to P200 and P300 panels. In some incidents, operators experienced severe contactor and ELMS panel damage. No contactor failures have been reported as occurring in flight. The analysis of contactors returned from the fleet identified opportunities to improve the contactor design. Extended operation of contactor at current close to maximum can lead to thermal degradation of materials in the contactor which further reduces contactor protection and can lead to loose parts which increases the probability of arcing. In addition, there was evidence of material buildup from normal operation of the contactor and potential for Foreign Object Debris (FOD) that could lead to short circuits within the contactor. Design improvements have been incorporated on contactors to address a number of issues that were identified in the above analysis. Improvements have been made to increase the contactors resistance to the effects of thermal cycling, and addition of insulation to provide better phase to phase and phase to ground isolation. The major improvements include: – Additional hardware on the stationary contact assembly to reduce the plastic compression and the possibility that the hardware will loosen under abnormal temperatures. – Arc Chute material and dimensional changes to improve thermal stability, with additional inter-phase and cover protection. – Additional insulation on contactor plunger nuts within the contactor. This provides a barrier to other conductive components in the event of a failure in the main contact area. The failure of a contactor could cause significant schedule delays and or economic impact to the operator such as unplanned downtime, labor and material costs. The replacement of certain breakers with the improved design could prevent a failure of the breaker and possible damage or failure of the power panel. Revision 1 was sent to add compliance details and change the service bulletin type to Unusually Significant (USG). Revision 2 is sent to correct the Concurrent Requirements data given in this service bulletin. In Paragraph 1.B., Concurrent Requirements, the Concurrent Requirements table is changed to add a reference to GE Aviation SB 2000ELM-24-697 Revision 1 and GE Aviation SB 3000ELM-24-698 Revision 1. **D. Description** Get access to the main equipment center. Replace the applicable contactors in the P200 panel in accordance with the GE Aviation service bulletin. Replace the applicable contactor in the P300 panel in accordance with the GE Aviation service bulletin. Do an installation test of applicable contactors in the P200 panel. Do an installation test of the applicable contactor in the P300 panel. Close access to the main equipment center. Return airplane to a serviceable condition. Revision 1 - No more work is necessary on airplanes changed in accordance with the original issue of this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 15 of 23 **BOEING SERVICE BULLETIN 777-24-0112**Revision 2 - No more work is necessary on the airplanes changed in accordance with the original issue or Revision 1 of this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 118 777-200, 777-200LR, 777-300, 777-300ER **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 60 months after the Revision 1 date of 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. **G. Manpower** The table below shows an estimate of the task hours necessary to do this inspection 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 Persons Task**  0.75 0.75 1 Open Access 1.00 3.00 3 Test

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 16 of 23 **BOEING SERVICE BULLETIN 777-24-0112 Elapsed Hours**  **Task Hours Number of Persons**  **Task** 0.75 0.75 1 Close Access 2.50 4.50 TOTAL FOR EACH AIRPLANE The time it takes to do the changes to the P200 and P300 power panels as given in GE Aviation SB 2000ELM-24-697 Revision 2 and GE Aviation SB 3000ELM-24-698 Revision 2 Service Bulletins are not included. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data a. Engineering Change Memo PRR 62240 b. Service Bulletin Index D624W001 c. 777 Aircraft Maintenance Manual (AMM) 24-22-00, 24-22-03 d. GE Aviation Service Bulletin 2000ELM-24-697, 3000ELM-24-698 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin None. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  24-09 777 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 17 of 23 **BOEING SERVICE BULLETIN 777-24-0112 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: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 18 of 23 **BOEING SERVICE BULLETIN 777-24-0112 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** None. **B. Industry Support Information** Boeing warranty remedies are not available for the inspection given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator Refer to the Supplier service bulletins for the parts required for this change. 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: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 19 of 23 **BOEING SERVICE BULLETIN 777-24-0112**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 20 of 23 **BOEING SERVICE BULLETIN 777-24-0112**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. 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 WARNING:**  IF THE ELECTRICAL POWER IS NOT REMOVED FROM THE AIRPLANE, THE POWER PANEL WILL CONTAIN HIGH VOLTAGES AND CURRENTS THAT CAN CAUSE AND INJURY TO PERSONS AND DAMAGE EQUIPMENT. 1. Remove electrical power from the airplane. Refer to 777 AMM 24-22-00 as an accepted procedure. 2. Get access to the main equipment center. 3. Replace the specified contactors (also known as breakers) in the Electrical Load Management System (ELMS) P200 panel in accordance with GE Aviation SB 2000ELM-24-697 Revision 2. Refer to FIGURE 1 for the location of the power panel. **NOTE:** Contactors removed by the GE Aviation service bulletin are discarded. 4. Replace the specified contactors in the ELMS P300 panel in accordance with GE Aviation SB 3000ELM-24-698 Revision 2. Refer to FIGURE 1 for the location of the power panel. **NOTE:** Contactors removed by the GE Aviation service bulletin are discarded. 5. Do an installation test of the applicable contactors in the P200 panel. Refer to 777 AMM 24-22-03 as an accepted procedure. 6. Do an installation test of the applicable contactors in the P300 panel. Refer to 777 AMM 24-22-03 as an accepted procedure. 7. Close access to the main equipment center. 8. Restore electrical power to the airplane. Refer to 777 AMM 24-22-00 as an accepted procedure. 9. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2: December 14, 2011 21 of 23 **BOEING SERVICE BULLETIN 777-24-0112**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**FIGURE 1: LOCATION OF THE ELMS POWER PANELS (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2 December 14, 2011 22 of 23 **BOEING SERVICE BULLETIN 777-24-0112 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** 1

- ELMS P200 Panel Locate 1 1

- ELMS P300 Panel Locate 2

**FIGURE 1: LOCATION OF THE ELMS POWER PANELS (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: February 19, 2009 777-24-0112 Revision 2 December 14, 2011 23 of 23 **BOEING SERVICE BULLETIN 777-24-0112**