Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-78A2184

Original Issue: January 12, 2010

Revision 1: December 23, 2010

ATA System: 7834

SUBJECT: EXHAUST (PW4000 Series Engines) - Thrust Reverser Control System - Automatic

Leading Edge Flap Retraction System Wiring Change

Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15

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persons from specific countries. The controller of this data has the individual responsibility to abide by all export

laws.

ECCN: 9E991

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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Unpublished Work - All Rights Reserved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

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4.0
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ALERT ALERT

BLANK PAGE
Table of Contents

Revision Transmittal Sheet ............................................ 5

Summary ...................................................... 7

1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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 . . . . . . . . . . . . 16

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 18

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

FIGURE 1: NO.1 AND NO.2 ENGINE THRUST REVERSER CONTROL WIRING - P252 PANEL ROUTING

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

FIGURE 2: NO.1 AND NO.2 ENGINE THRUST REVERSER CONTROL WIRING, P252 PANEL - CHANGE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

FIGURE 3: NO.3 AND NO.4 ENGINE THRUST REVERSER CONTROL WIRING - P253 PANEL ROUTING

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

FIGURE 4: NO.3 AND NO.4 ENGINE THRUST REVERSER CONTROL WIRING, P253 PANEL - CHANGE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

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ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Revision Transmittal Sheet Number: 747-78A2184

Original Issue: January 12, 2010

Revision 1: December 23, 2010

ATA System: 7834

SUBJECT: EXHAUST (PW4000 Series Engines) - Thrust Reverser Control System - Automatic

Leading Edge Flap Retraction System Wiring Change

This revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

Federal Aviation Administration (FAA) Notice of Proposed Rule Making NPRM 2010-NM-064-AD is related to

this service bulletin.

No more work is necessary on airplanes changed in accordance with the original issue of this service bulletin.

REASON FOR REVISION

This revision is sent to change the functional test in the work instructions to give a better sequence and to better

describe the use of pneumatic and electrical power during its accomplishment.

These sections are changed:

– Summary Manpower and Paragraph 1.G., Manpower; Changed to show adjusted functional test hours.

– Summary Compliance and Paragraph 1.E., Compliance; Changed to add FAA NPRM.

– Paragraph 2.C.2., Part and Material Supplied by the Operator; Changed to add supplier information for a

part.

– Paragraph 1.J.1., Existing Data; SWPM, AMM and FAA NPRM references added.

– Paragraph 3.B., Work Instructions; Tasks added and sequence changed.

– Figure 2 and 4; SWPM references added for the disassembly of equipment related to this change.

The data given in Information Notice 747-78A2184 IN 01 is included in this revision.

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: January 12, 2010

Revision 1: December 23, 2010

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Summary Number: 747-78A2184

Original Issue: January 12, 2010

Revision 1: December 23, 2010

ATA System: 7834

SUBJECT: EXHAUST (PW4000 Series Engines) - Thrust Reverser Control System - Automatic

Leading Edge Flap Retraction System Wiring Change

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 is sent to prevent the Group A Leading Edge (LE) flaps from automatically retracting if the

Flap Control Unit (FCU) receives dual cowl unstowed indications from the thrust reversers. If this service bulletin

is not done, the Group A LE flaps can automatically retract if the FCU gets dual cowl unstowed indications from

the thrust reverser which could result in decreased climb performance of the airplane during takeoff.

During takeoff roll, an operator of a Rolls-Royce RB211 powered 747-400 airplane had a REV Amber indication

occurrence on the No.3 engine thrust reverser. This was followed thirteen seconds later by a REV Amber

indication on the No.2 engine thrust reverser. At the time of the second REV amber, the aircraft was beyond

V1. To prevent impingement from the thrust reversers, the FCU of the 747-400 is designed to automatically

retract the Group A LE flaps when a REV Amber signal is transmitted from the two inboard or the two outboard

thrust reversers and the aircraft is on the ground. The FCU performed as designed, and retracted the Group A

leading edge flaps. After takeoff, the air/ground logic took over and the Group A LE flaps re-deployed. During

the event, the flight crew reported buffeting and momentary stick shaker activation. The aircraft jettisoned fuel

and returned to the airport with a usual landing. All four thrust reversers deployed and stowed normally after

landing.

The automatic LE flap retraction logic for PW4000 engines automatically retracts the Group A LE flaps during

reverse thrust operation. This is to prevent thrust reverser efflux air from impinging onto the Group A LE flaps

to improve the Group A LE flap panel’s structural life. This function is armed when the airplane is on the ground.

The Group A LE flaps retract when the FCU gets a signal from the LE Flap relay in the reverser circuitry on the

two inboard engines or the two outboard engines. The LE Flap relay is energized by the microswitch of the

reverse thrust lever or the unstow proximity sensor on the thrust reverser cowl.

The initial signal to the FCU comes from the microswitch in the aisle stand when thrust reverser deployment is

commanded. The signal to the FCU is kept after stow is commanded by the proximity switches. This signal is

removed 5 seconds after the thrust reverser is stowed.

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The Group A LE flaps retract (or extend) in ten seconds. Once auto-retracted, there is a five second time delay

after the thrust reverser signal is removed from the FCU before the Group A LE flaps return to the commanded

position. The thrust reverser extends in two seconds and stows in three seconds. This time can slightly increase

during cold weather operation.

Accomplishment of this service bulletin will remove the thrust reverser unstow signal from the FCU. The timing

of the thrust reverser stow versus the time delay in the FCU accomplishes the original intent of the design. The

thrust reversers are fully stowed prior to the FCU time delay lapsing and Group A LE flap movement starting.

The signal from the thrust reverser lever will not be affected by this change, but the CMC message, "ENG X

AUTO RESTOW EVENT" will be permanently inhibited. Instead, if there is an auto restow event on an airplane

the "ENG X PRESSURE SWITCH FAIL" message will be set.

Boeing Service Related Problem (SRP) 747-SRP-78-0069 is related to this service bulletin.

Boeing Fleet Team Digest (FTD) 747 FTD 78-09002 is related to this service bulletin.

ACTION (PRR 85665-R)

Get access to the P252 and P253 Thrust Reverser Relay panels in the Electrical and Electronics Compartment.

Make wiring changes in the panels to wires related to the thrust reverser control system of the No.1 thru No.4

engines. Do tests of the thrust reverser control and the Group A Leading Edge (LE) flap systems.

EFFECTIVITY

747-400/400F Airplanes powered by PW4000 engines. Refer to Paragraph 1.A., Effectivity for the list of affected

airplanes.

COMPLIANCE

Federal Aviation Administration (FAA) Notice of Proposed Rule Making NPRM 2010-NM-064-AD is related to

this service bulletin.

Boeing recommends that the change given in this service bulletin be done within 36 months after the original

issue date of this service bulletin.

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the configuration changes given in this service bulletin.

MANPOWER

Airplanes Total Task Hours Elapsed Hours

Group 1 11.30 6.80

MATERIAL INFORMATION

Operator Supplied Parts/Materials.

Refer to Paragraph 2.A., Material - Price and Availability.

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ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-78A2184

Original Issue: January 12, 2010

Revision 1: December 23, 2010

ATA System: 7834

SUBJECT: EXHAUST (PW4000 Series Engines) - Thrust Reverser Control System - Automatic

Leading Edge Flap Retraction System Wiring Change

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

Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line

Number, and Serial Number data.

This service bulletin is for the airplanes shown below. Refer to PRR 85665-R for data about this

change.

GROUP CONFIGURATION DESCRIPTION

747-400/400F airplanes with Pratt & Whitney (PW) 4000 series

engines.

1 -

Airplane Models:

747-400, 747-400F

Variable Number Group

RL431 - RL436 1

RL451 - RL456 1

RL491 - RL492 1

RL501 - RL502 1

RL581 - RL586 1

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Variable Number Group

RL751 - RL752 1

RM011 - RM013 1

RM021 - RM024 1

RM036 - RM045 1

RM091 1

RM166 - RM177 1

RM241 - RM246 1

RM341 1

RM366 - RM367 1

RM811 - RM813 1

RM851 - RM855 1

RM871 - RM880 1

RR851 - RR856 1

RR861 - RR862 1

RT031 - RT035 1

RT061 1

RT101 - RT103 1

RT401 - RT412 1

RT501 - RT530 1

RT571 - RT590 1

RT601 - RT640 1

RT743 - RT750 1

RT811 - RT814 1

RT831 - RT837 1

RT876 - RT880 1

RU001 - RU006 1

RU016 - RU017 1

RU081 - RU083 1

2. Spares Affected

None.

B. Concurrent Requirements

None.

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT
C. Reason

This service bulletin is sent to prevent the Group A Leading Edge (LE) flaps from automatically retracting

if the Flap Control Unit (FCU) receives dual cowl unstowed indications from the thrust reversers. If this

service bulletin is not done, the Group A LE flaps can automatically retract if the FCU gets dual cowl

unstowed indications from the thrust reverser which could result in decreased climb performance of

the airplane during takeoff.

During takeoff roll, an operator of a Rolls-Royce RB211 powered 747-400 airplane had a REV Amber

indication occurrence on the No.3 engine thrust reverser. This was followed thirteen seconds later by

a REV Amber indication on the No.2 engine thrust reverser. At the time of the second REV amber, the

aircraft was beyond V1. To prevent impingement from the thrust reversers, the FCU of the 747-400 is

designed to automatically retract the Group A LE flaps when a REV Amber signal is transmitted from

the two inboard or the two outboard thrust reversers and the aircraft is on the ground. The FCU performed

as designed, and retracted the Group A leading edge flaps. After takeoff, the air/ground logic took over

and the Group A LE flaps re-deployed. During the event, the flight crew reported buffeting and momentary

stick shaker activation. The aircraft jettisoned fuel and returned to the airport with a usual landing. All

four thrust reversers deployed and stowed normally after landing.

The automatic LE flap retraction logic for PW4000 engines automatically retracts the Group A LE flaps

during reverse thrust operation. This is to prevent thrust reverser efflux air from impinging onto the

Group A LE flaps to improve the Group A LE flap panel’s structural life. This function is armed when

the airplane is on the ground. The Group A LE flaps retract when the FCU gets a signal from the LE

Flap relay in the reverser circuitry on the two inboard engines or the two outboard engines. The LE

Flap relay is energized by the microswitch of the reverse thrust lever or the unstow proximity sensor

on the thrust reverser cowl.

The initial signal to the FCU comes from the microswitch in the aisle stand when thrust reverser

deployment is commanded. The signal to the FCU is kept after stow is commanded by the proximity

switches. This signal is removed 5 seconds after the thrust reverser is stowed.

The Group A LE flaps retract (or extend) in ten seconds. Once auto-retracted, there is a five second

time delay after the thrust reverser signal is removed from the FCU before the Group A LE flaps return

to the commanded position. The thrust reverser extends in two seconds and stows in three seconds.

This time can slightly increase during cold weather operation.

Accomplishment of this service bulletin will remove the thrust reverser unstow signal from the FCU.

The timing of the thrust reverser stow versus the time delay in the FCU accomplishes the original intent

of the design. The thrust reversers are fully stowed prior to the FCU time delay lapsing and Group A

LE flap movement starting. The signal from the thrust reverser lever will not be affected by this change,

but the CMC message, "ENG X AUTO RESTOW EVENT" will be permanently inhibited. Instead, if

there is an auto restow event on an airplane the "ENG X PRESSURE SWITCH FAIL" message will be

set.

Boeing Service Related Problem (SRP) 747-SRP-78-0069 is related to this service bulletin.

Boeing Fleet Team Digest (FTD) 747 FTD 78-09002 is related to this service bulletin.

Revision 1 is sent to change the functional test in the work instructions to give a better sequence and

to better describe the use of pneumatic and electrical power during its accomplishment.

The data given in Information Notice 747-78A2184 IN 01 is included in Revision 1.

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT
D. Description

Get access to the P252 and P253 Thrust Reverser Relay panels in the Electrical and Electronics

Compartment. Make wiring changes in the panels to wires related to the thrust reverser control system

of the No.1 thru No.4 engines. Do tests of the thrust reverser control and the Group A Leading Edge

(LE) flap systems.

Revision 1 - No more work is necessary on airplanes changed in accordance with the original issue of

this service bulletin.

The work in this service bulletin is done in the maintenance zone(s) given below.

Affected Maintenance Zones

Model Zone

747-400, 747-400F 117, 118

E. Compliance

Federal Aviation Administration (FAA) Notice of Proposed Rule Making NPRM 2010-NM-064-AD is

related to this service bulletin.

Boeing recommends that the change given in this service bulletin be done within 36 months after the

original issue 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 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.

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT
Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.75 0.75

FIGURE 1 (Wire -

Routing Only)

FIGURE 2 1 0.40 0.40

FIGURE 3 (Wire -

Routing Only)

FIGURE 4 1 0.40 0.40

Close Access 1 0.75 0.75

Test 2 9.00 4.50

TOTAL FOR EACH AIRPLANE 11.30 6.80

H. Weight and Balance Changes

None.

I. Electrical Load Data

None.

J. References

1. Existing Data

a. Engineering Change Memo PRR 85665-R.

b. Boeing Service Related Problem (SRP) 747-SRP-78-0069.

c. Boeing Standard Wiring Practices Manual (SWPM) 20-00-11, 20-10-11, 20-10-12, 20-10-14,

20-10-19, 20-30-16, 20-81-12, 20-90-11.

d. Federal Aviation Administration (FAA) Notice of Proposed Rule Making (NPRM)

2010-NM-064-AD.

e. 747 Fleet Team Digest (FTD) 747 FTD 78-09002.

f. 747-400 Aircraft Maintenance Manual (AMM) 06-09-09, 24-22-00, 27-62-00, 27-81-00,

36-00-00, 54-62-00, 71-11-04, 78-31-00, 78-34-05, 78-34-13, 78-36-07.

g. 747-400 Wiring Diagram Manual (WDM) 78-34-12, 78-34-22, 78-34-32, 78-34-42.

2. Data supplied with this Service Bulletin

None.

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT
3. Installation Drawings Used in the Preparation of this Service Bulletin

Drawing Number Title

284U4255 PANEL INSTL P252 AND P253

This drawing was used to prepare this service bulletin. This drawing is not necessary to make the

specified changes, and is not supplied with this service bulletin. This drawing may not be applicable

to all airplane configurations or operators.

K. Publications Affected

1. Publications:

Publication Chapter-Section

747 Wiring Diagram Manual 78-34

747 Fault Isolation Manual 71-00

2. Damage Tolerance Based Structural Inspections:

Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue

Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the

Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary.

L. Interchangeability and Intermixability of Parts

Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

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BOEING SERVICE BULLETIN 747-78A2184

ALERT ALERT
2. MATERIAL INFORMATION

A. Material - Price and Availability

The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each

Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin

does not show the Boeing price and supply data.

The parts are subject to the terms and conditions of the Boeing standard purchase order

acknowledgment. Prices are in United States dollars. Terms: Net 30 days.

Reference this service bulletin and submit your purchase order by one of the methods that follow:

1. Order on-line via ATA Spec 2000 or Boeing Part Page

2. Fax to (206) 662-7145

3. Mail to:

Spares Customer Support - MC 36-65

Boeing Spares Department

P.O. Box 3707

Seattle, Washington 98124-2207 USA

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

Part Number / QTY Name Notes

Specification

Insulation Tubing, Heat Shrinkable, (a)

Flexible, Adhesive Lined (3/16 Inch

Dia., 0.75 Inch Length)

DWP-125-3/16-0 4

BACT63D2 8 End Cap (b)

(a) Refer to Boeing Standard Wiring Practices Manual SWPM 20-00-11 for material and

supplier information.

(b) Refer to Paragraph 2.A., Material - Price and Availability for procurement information.

3. Parts Modified and Reidentified

None.

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ALERT ALERT
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

None.

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ALERT ALERT
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.

6. The instructions in Paragraph 3.B., Work Instructions and the figures can include

operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated

Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing

Index contain data on versions of the tools or test equipment that you can use. It is

permitted to use replaced tools. It is not permitted to use superseded tools.

7. If it is necessary to remove more parts for access, you can remove those parts. If

you can get access without removing identified parts, it is not necessary to remove

all of the identified parts. Jacking and shoring limitations must be observed.

8. This service bulletin includes functional test procedures for the systems changed by

this service bulletin. More functional tests can possibly be necessary in accordance

with standard maintenance practices because of interruption to other airplane systems.

B. WORK INSTRUCTIONS

1. In the Flight Compartment, open the circuit breakers specified in the table below and attach

DO-NOT-CLOSE tags:

MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 F11 T/R LOCK CONT ENG 1 C10934

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MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 F12 T/R IND ENG 1 C00405

P6 F13 T/R CONT ENG 1 C01703

P6 E11 T/R LOCK CONT ENG 2 C10935

P6 E12 T/R IND ENG 2 C00402

P6 E13 T/R CONT ENG 2 or ENG 2, T/R CONT C01704

P6 D11 T/R LOCK CONT ENG 3 C10936

P6 D12 T/R IND ENG 3 C00403

P6 D13 T/R CONT ENG 3 C01442

P6 C11 T/R LOCK CONT ENG 4 C10937

P6 C12 T/R IND ENG 4 C00404

P6 C13 T/R CONT ENG 4 or ENG 4, T/R CONT C01441

2. Get access to the P252 and P253 thrust reverser relay panels in the Electrical and Electronics

Compartment. Refer to 747-400 AMM 78-36-07 for the location of the relay panels.

3. Change the thrust reverser control wiring in the P252 and P253 thrust reverser relay panels for

each engine in accordance with:

Engine Figure

No.1 and No.2 FIGURE 1 and FIGURE 2

No.3 and No.4 FIGURE 3 and FIGURE 4

4. In the Flight Compartment, remove the DO-NOT-CLOSE tags and close the circuit breakers

specified in the table below:

MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 F11 T/R LOCK CONT ENG 1 C10934

P6 F12 T/R IND ENG 1 C00405

P6 F13 T/R CONT ENG 1 C01703

P6 E11 T/R LOCK CONT ENG 2 C10935

P6 E12 T/R IND ENG 2 C00402

P6 E13 T/R CONT ENG 2 or ENG 2, T/R CONT C01704

P6 D11 T/R LOCK CONT ENG 3 C10936

P6 D12 T/R IND ENG 3 C00403

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MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 D13 T/R CONT ENG 3 C01442

P6 C11 T/R LOCK CONT ENG 4 C10937

P6 C12 T/R IND ENG 4 C00404

P6 C13 T/R CONT ENG 4 or ENG 4, T/R CONT C01441

5. Close access to the P252 and P253 relay panels.

WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE LEADING

EDGE (LE), TRAILING EDGE (TE) FLAPS AND FLAP DRIVE MECHANISMS BEFORE

THE FLAP CONTROL LEVER IS MOVED. WITH HYDRAULIC POWER REMOVED,

THE FLAPS WILL MOVE AUTOMATICALLY BY ELECTRICAL POWER WHEN THE

FLAP CONTROL LEVER IS MOVED. THIS CAN CAUSE INJURY TO PERSONS OR

DAMAGE TO EQUIPMENT.

6. Supply electrical power to the airplane. Refer to 747-400 AMM 24-22-00 as an accepted procedure.

7. Do the functional test as follows:

a. In the Flight Compartment, make sure the applicable engine START and ENGINE BLEED

switches, on the overhead panel, are in the OFF position.

b. In the Flight Compartment, make sure the reverse thrust lever is in the forward thrust position.

c. Do the 'Automatic Speed Brake System Deactivation'. Refer to 747-400 AMM 27-62-00 as

an accepted procedure.

WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE LE FLAPS

AND CONTROL SURFACES BEFORE PNEUMATIC POWER IS SUPPLIED. THIS

CAN CAUSE INJURY TO PERSONS AND DAMAGE EQUIPMENT.

d. Make sure the Leading Edge (LE) flaps are retracted. Refer to 747-400 AMM 27-81-00 as an

accepted procedure.

NOTE: If this task is accomplished by pneumatic power, it is not necessary to remove

pneumatics from the airplane at the end of the procedure.

e. In the Flight Compartment, open the circuit breakers specified in the table below and attach

DO-NOT-CLOSE tags:

MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 F11 T/R LOCK CONT ENG 1 C10934

P6 F13 T/R CONT ENG 1 C01703

P6 E11 T/R LOCK CONT ENG 2 C10935

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ALERT ALERT
MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 E13 T/R CONT ENG 2 or ENG 2, T/R CONT C01704

P6 D11 T/R LOCK CONT ENG 3 C10936

P6 D13 T/R CONT ENG 3 C01442

P6 C11 T/R LOCK CONT ENG 4 C10937

P6 C13 T/R CONT ENG 4 or ENG 4, T/R CONT C01441

f. Make sure pneumatic power is supplied to the airplane. Refer to 747-400 AMM 36-00-00 as

an acceptable procedure.

g. Remove the access doors on the No.1 thru No.4 engine nacelle struts. Refer to 747-400 AMM

54-62-00 as an accepted procedure.

h. Open the access panels specified in the table below. Refer to 747-400 AMM 06-09-09.

Access Panel / Door Name/Location

No.

ACCESS DOOR - THRUST REVERSER ISOLATION

VALVE

451BL

THRUST REVERSER ISOLATION VALVE, UPPER

MIDSPAR, SPRING BEAM GREASE FITTING,

PRESSURE RELIEF (AFT)

462EL

THRUST REVERSER ISOLATION VALVE, UPPER

MIDSPAR, SPRING BEAM GREASE FITTING,

PRESSURE RELIEF (AFT)

472EL

481BL ACCESS DOOR - CORE COWL TO STRUT (AFT)

i. Deactivate the isolation valves for the No.1 thru No.4 engines as follows. Refer to 747-400

AMM 78-34-05 for the location of the isolation valves.

(1) Push the deactivation slide into the isolation valve housing.

(2) Install a streamered pin in the deactivation slide.

(3) Install a hitch pin the streamered pin.

NOTE: Use a ground lock, SPL-5635, where necessary.

j. Open the bypass valve (of the isolation valve) for the No.1 thru No.4 engines as follows. Refer

to 747-400 AMM 78-34-05 for the location of the bypass valves.

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NOTE: The bypass valve must be open before you manually extend or retract the thrust

reverser. This will prevent a hydraulic lock, which can prevent the movement of the

thrust reverser. But the bypass valve must be closed again if thrust reverser

components or hydraulic tubes are removed (after you extend or retract the thrust

reverser). If the bypass valve is not closed again, hydraulic fluid leakage will occur

when the components or tubing are removed.

(1) Remove the lockwire, if applicable, on the bypass valve lever.

NOTE: There are two types of bypass valves, one that has a spring that controls the

position of the lever, and one that does not have a spring. Lockwire is not installed

on bypass valve levers that have a spring.

(2) Push in the bypass valve lever to open the bypass valve of the isolation valve.

(3) Install a streamered pin to hold the bypass valve lever in the open position.

(4) Install a hitch pin in the streamered pin.

NOTE: Use a ground lock, SPL-5635, where necessary.

k. After the deactivation procedure is completed, make sure the REMOVE-BEFORE-FLIGHT

streamers can be seen outside of the No.1 thru No.4 engine nacelle struts.

l. Open the left or right fan cowl panels on the No.1 thru No.4 engines. Refer to 747-400 AMM

71-11-04 as an accepted procedure.

NOTE: Open and unlock the applicable sleeve. It is only necessary to manually deploy one

sleeve for each engine to complete this functional test.

CAUTION: DO NOT USE A SCREWDRIVER BETWEEN THE LOCK PROXIMITY SENSOR

AND THE TARGET TO MOVE THE LOCK LEVER TO THE UNLOCKED POSITION.

IF A SCREWDRIVER OR OTHER TOOL IS USED TO SUPPLY A SEPARATION

FORCE, DAMAGE CAN BE CAUSED TO THE LOCK PROXIMITY SENSOR OR

THE TARGET.

m. On the No.1 thru No.4 engines, move the lock lever on the left or right locking actuator away

from the sensor. Refer to 747-400 AMM 78-31-00 for the location of the locking actuators.

NOTE: If the lock lever does not move easily, turn the manual crank counter-clockwise to

relieve pressure on the actuator locks.

n. In the Flight Compartment, remove the DO-NOT-CLOSE tags and close the circuit breakers

specified in the tables below:

MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 F11 T/R LOCK CONT ENG 1 C10934

P6 F13 T/R CONT ENG 1 C01703

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ALERT ALERT
MAIN POWER DISTRIBUTION PANEL

Panel Number Location Name Number

P6 E11 T/R LOCK CONT ENG 2 C10935

P6 E13 T/R CONT ENG 2 or ENG 2, T/R CONT C01704

P6 D11 T/R LOCK CONT ENG 3 C10936

P6 D13 T/R CONT ENG 3 C01442

P6 C11 T/R LOCK CONT ENG 4 C10937

P6 C13 T/R CONT ENG 4 or ENG 4, T/R CONT C01441

OVERHEAD CIRCUIT BREAKER PANEL

Panel Number Location Name Number

P7 C10 FLT CONT ELEC 2L-AC C10263

P7 C11 FLT CONT ELEC 2L-DC C10264

P7 C12 FLT CONT ELEC 1L-AC C08782

P7 C13 FLT CONT ELEC 1L-DC C08783

P7 C14 FLT CONT ELEC 1R-AC C08784

P7 C15 FLT CONT ELEC 1R-DC C08785

P7 C16 FLT CONT ELEC 2R-AC C10265

P7 C17 FLT CONT ELEC 2R-DC C10266

CAUTION: ONLY EXTEND OR RETRACT THE FLAPS ELECTRICALLY ONCE IN A FIVE

MINUTE PERIOD TO PREVENT OVERHEATING OF THE MOTOR.

o. In the Flight Compartment, move the flap control lever to the 1-unit detent to extend the LE

flaps.

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ALERT ALERT
WARNING: MAKE SURE PERSONS AND EQUIPMENT ARE CLEAR OF THE LE FLAPS

BEFORE THE THRUST REVERSER SLEEVES ARE MOVED MANUALLY.

CAUTION: DO NOT MOVE THE THRUST REVERSER WHILE THE THRUST REVERSER OR

THE CORE COWL PANELS ARE OPEN. DAMAGE TO THE THRUST REVERSER

AND THE CORE COWL PANELS CAN OCCUR.

CAUTION: DO NOT EXTEND THE THRUST REVERSER SLEEVE WHEN THE THRUST

REVERSER IS OPEN MORE THAN 23 DEGREES. DAMAGE TO THE SLEEVE

AND THE STRUT CAN OCCUR.

CAUTION: THE EXTENSION OF THE SLEEVE WITH THE THRUST REVERSER OPEN IS

PERMITTED IN THE 23 DEGREE POSITION ONLY. THE CORE COWL PANELS

MUST BE REMOVED TO EXTEND THE SLEEVE WITH THE THRUST REVERSER

OPEN.

CAUTION: MAKE SURE THERE IS NO EQUIPMENT IN THE AREA BEHIND THE THRUST

REVERSER. DAMAGE CAN OCCUR IF THE THRUST REVERSER HITS THE

EQUIPMENT.

CAUTION: MAKE SURE THE MANUAL DRIVE IS FULLY ENGAGED WITH THE SYNC LOCK

DRIVE SHAFT BEFORE IT IS TURNED. DO NOT USE FORCE TO ENGAGE THE

MANUAL DRIVE. ALSO, MAKE SURE THE MANUAL DRIVE STAYS FULLY

ENGAGED WHILE THE SQUARE DRIVE IS OPERATED. IF THE MANUAL DRIVE

IS NOT FULLY ENGAGED OR IF FORCE IS USED TO ENGAGE IT, DAMAGE TO

THE SYNC LOCK CAN OCCUR.

p. Do the test as follows for the position of the Group A LE flaps during the reverse thrust operation

of the inboard engines:

(1) Manually extend the left or right sleeve on the No.2 and No.3 engine thrust reversers as

follows. Refer to 747-400 AMM 78-34-13 for the location of the sync lock.

(a) Put a 3/8 inch square drive into the end of the manual drive mechanism on the sync

lock:

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ALERT ALERT
1) The square drive must be pushed in until it stops and held in that position to

manually disengage the synch lock and engage the manual drive shaft.

2) Make small position adjustments of the manual drive as necessary to align it

with the sync lock drive shaft.

3) If a 3/8 inch square drive cannot be inserted, use a 5/8 inch hex drive on the

outer hex nut and turn counter-clockwise and clockwise a very small amount

until a 3/8 inch square drive can be put in.

CAUTION: MAKE SURE ALL THE ACTUATORS OPERATE CORRECTLY WHEN

THE THRUST REVERSER IS EXTENDED. IF THE FLEXSHAFT BETWEEN

THE ACTUATORS IS BROKEN, OR IS NOT INSTALLED, ONLY THE

BOTTOM ACTUATOR WILL OPERATE. IF THRUST REVERSER

OPERATION CONTINUES WITH THIS CONDITION, DAMAGE TO THE

THRUST REVERSER CAN OCCUR.

(b) At the same time as the sync lock is kept disengaged, turn the square drive to extend

the applicable thrust reverser sleeve to between 0.5 and 2.0 inches:

1) Make sure the square drive is turned in the direction that extends the thrust

reverser sleeve:

a) For the left sleeve, turn the manual drive counter-clockwise.

b) For the right sleeve, turn the manual drive clockwise.

(2) Make sure the LE flaps do not retract.

(3) Manually return the No.2 and No.3 engine thrust reversers to the stowed position.

(a) Make sure the square drive is turned in the direction that retracts the thrust reverser

sleeve.

1) For the left sleeve, turn the manual drive clockwise.

2) For the right sleeve, turn the manual drive counter-clockwise.

q. Do the test as follows for the position of the Group A LE flaps during the reverse thrust operation

of the outboard engines:

(1) Manually extend the left or right sleeve on the No.1 and No.4 engine thrust reversers as

follows. Refer to 747-400 AMM 78-34-13 for the location of the sync lock.

(a) Put a 3/8 inch square drive into the end of the manual drive mechanism on the sync

lock:

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ALERT ALERT
1) The square drive must be pushed in until it stops and held in that position to

manually disengage the synch lock and engage the manual drive shaft.

2) Make small position adjustments of the manual drive as necessary to align it

with the sync lock drive shaft.

3) If a 3/8 inch square drive cannot be inserted, use a 5/8 inch hex drive on the

outer hex nut and turn counter-clockwise and clockwise a very small amount

until a 3/8 inch square drive can be put in.

CAUTION: MAKE SURE ALL THE ACTUATORS OPERATE CORRECTLY WHEN

THE THRUST REVERSER IS EXTENDED. IF THE FLEXSHAFT BETWEEN

THE ACTUATORS IS BROKEN, OR IS NOT INSTALLED, ONLY THE

BOTTOM ACTUATOR WILL OPERATE. IF THRUST REVERSER

OPERATION CONTINUES WITH THIS CONDITION, DAMAGE TO THE

THRUST REVERSER CAN OCCUR.

(b) At the same time as the sync lock is kept disengaged, turn the square drive to extend

the applicable thrust reverser sleeve to between 0.5 and 2.0 inches:

1) Make sure the square drive is turned in the direction that extends the thrust

reverser sleeve:

a) For the left sleeve, turn the manual drive counter-clockwise.

b) For the right sleeve, turn the manual drive clockwise.

(2) Make sure the LE flaps do not retract.

(3) Manually return the No.1 and No.4 engine thrust reversers to the stowed position:

(a) Make sure the square drive is turned in the direction that retracts the thrust reverser

sleeve:

1) For the left sleeve, turn the manual drive clockwise.

2) For the right sleeve, turn the manual drive counter-clockwise.

r. Put the LE flaps back to the normal stowed position.

s. Do the 'Thrust Reverser Activation After Ground Maintenance' for the No.1 thru No.4 engines.

Refer to 747-400 AMM 78-31-00 as an accepted procedure.

t. Do the 'Automatic Speed Brake System Reactivation'. Refer to 747-400 AMM 27-62-00 as

an accepted procedure.

u. Do the 'Group A Leading Edge Flaps during Reverse Thrust Operation - Operational Test'.

Refer to 747-400 AMM 27-81-00 as an accepted procedure.

v. Do the 'Thrust Reverser Operational Test'. Refer to 747-400 AMM 78-31-00 as an accepted

procedure.

8. Put the airplane back to a serviceable condition.

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ALERT ALERT
FIGURE 1: NO.1 AND NO.2 ENGINE THRUST REVERSER CONTROL WIRING - P252 PANEL ROUTING

(SHEET 1 OF 2)

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ALERT ALERT
FIGURE 1: NO.1 AND NO.2 ENGINE THRUST REVERSER CONTROL WIRING - P252 PANEL ROUTING

(SHEET 2 OF 2)

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ALERT ALERT
REFERENCE: 747-400 WDM 78-34-12, 747-400 WDM 78-34-22.

The flag note numbers shown below agree with the numbers shown in the flag symbols in the figure.

NAME IDENTIFICATION QTY MORE DATA

FLAG

NOTE

Refer to SWPM 20-30-16 as an

accepted procedure. (a)

1 END CAP BACT63D2 4

Refer to SWPM 20-10-14 as an

accepted procedure.

INSULATION TUBING, DWP-125-3/16-0 2

HEAT SHRINKABLE,

FLEXIBLE, ADHESIVE

LINED (3/16 INCH DIA.,

0.75 INCH LENGTH)

2

(a) Refer to SWPM 20-81-12 as an accepted procedure for the disassembly of the DR7311 and DR7312 relay

sockets. Refer to SWPM 20-90-11 as an accepted procedure for the disassembly of the TD17 and TD18

terminal blocks.

FIGURE 2: NO.1 AND NO.2 ENGINE THRUST REVERSER CONTROL WIRING, P252 PANEL - CHANGE

(SHEET 1 OF 1)

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ALERT ALERT
FIGURE 3: NO.3 AND NO.4 ENGINE THRUST REVERSER CONTROL WIRING - P253 PANEL ROUTING

(SHEET 1 OF 2)

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ALERT ALERT
FIGURE 3: NO.3 AND NO.4 ENGINE THRUST REVERSER CONTROL WIRING - P253 PANEL ROUTING

(SHEET 2 OF 2)

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ALERT ALERT
REFERENCE: 747-400 WDM 78-34-32, 747-400 WDM 78-34-42.

The flag note numbers shown below agree with the numbers shown in the flag symbols in the figure.

NAME IDENTIFICATION QTY MORE DATA

FLAG

NOTE

Refer to SWPM 20-30-16 as an

accepted procedure. (a)

1 END CAP BACT63D2 4

Refer to SWPM 20-10-14 as an

accepted procedure.

INSULATION TUBING, DWP-125-3/16-0 2

HEAT SHRINKABLE,

FLEXIBLE, ADHESIVE

LINED (3/16 INCH DIA.,

0.75 INCH LENGTH)

2

(a) Refer to SWPM 20-81-12 as an accepted procedure for the disassembly of the DR7313 and DR7314 relay

sockets. Refer to SWPM 20-90-11 as an accepted procedure for the disassembly of the TD19 and TD20

terminal blocks.

FIGURE 4: NO.3 AND NO.4 ENGINE THRUST REVERSER CONTROL WIRING, P253 PANEL - CHANGE

(SHEET 1 OF 1)

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ALERT ALERT