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

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laws.

ECCN: 9E991

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2.0
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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

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BLANK PAGE
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

Original Issue: February 19, 2009

Revision 1: June 30, 2011

Revision 2: December 14, 2011

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BOEING SERVICE BULLETIN 777-24-0112

BLANK PAGE
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.

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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 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

Airplanes Total Task Hours Elapsed Hours

Group 1 4.50 2.50

MATERIAL INFORMATION

None.

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BLANK PAGE
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.

GROUP CONFIGURATION DESCRIPTION

1 - 777-200/-200LR/-300/-300ER Airplanes

Airplane Models:

777-200, 777-200LR, 777-300, 777-300ER

Variable Number Group

WA001 - WA017 1

WA076 - WA080 1

WA086 - WA093 1

WA101 - WA104 1

WA116 - WA119 1

WA131 - WA137 1

WA171 - WA175 1

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Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-24-0112
Variable Number Group

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 1

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BOEING SERVICE BULLETIN 777-24-0112
Variable Number Group

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 1

2. Spares Affected

None.

B. Concurrent Requirements

The service bulletins listed below must be done at the same time as this service bulletin:

Company Service Bulletin Description

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

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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.

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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

Model Zone

777-200, 777-200LR, 777-300, 118

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

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.75 0.75

Test 3 3.00 1.00

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BOEING SERVICE BULLETIN 777-24-0112
Task Number of Persons Task Hours Elapsed Hours

Close Access 1 0.75 0.75

TOTAL FOR EACH AIRPLANE 4.50 2.50

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:

Publication Chapter-Section

777 Illustrated Parts Catalog 24-09

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.

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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.

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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.

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BOEING SERVICE BULLETIN 777-24-0112
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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

Revision 2: December 14, 2011 777-24-0112

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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

Revision 2 December 14, 2011 777-24-0112

22 of 23

BOEING SERVICE BULLETIN 777-24-0112
STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Locate ELMS P200 Panel - 1

2 Locate ELMS P300 Panel - 1

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

Revision 2 December 14, 2011 777-24-0112

23 of 23

BOEING SERVICE BULLETIN 777-24-0112