Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-78A2185

Original Issue: October 26, 2010

ATA System: 7831 7834

SUBJECT: EXHAUST (GE CF6-80 Series Engines) - Thrust Reverser Control System - Short

Flexible Drive Shaft 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.

ECCN: 9E991

BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET

Copyright © 2010 The Boeing Company

Unpublished Work - All Rights Reserved

Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable

subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.

This document includes proprietary information owned by The Boeing Company and/or one or more third parties.

Treatment of the document and the information it contains is governed by contract with Boeing. For more

information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.

Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,

BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the

Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in

connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

1 of 26

2.0
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

2 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT

BLANK PAGE
Table of Contents

Summary ...................................................... 5

1. PLANNING INFORMATION ........................................ 9

A. Effectivity ................................................ 9

1. Airplanes ............................................. 9

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

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

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2. Data supplied with this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3. Installation Drawings Used in the Preparation of this Service Bulletin . . . . . . . . . . . . 15

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 17

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 17

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

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

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

FIGURE 1: THRUST REVERSER LEFT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

FIGURE 2: THRUST REVERSER RIGHT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

3 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

4 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Summary Number: 747-78A2185

Original Issue: October 26, 2010

ATA System: 7831 7834

SUBJECT: EXHAUST (GE CF6-80 Series Engines) - Thrust Reverser Control System - Short

Flexible Drive Shaft Replacement

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

Accomplishment of this service bulletin will prevent damage and the possible breakage of the short flexshafts

related to the electro-mechanical brake of General Electric (GE) CF6-80C2 engines. Flexshaft breakage removes

the primary level of protection against an uncommanded thrust reverser deployment occurrence. Uncommanded

T/R deployment could result in a loss of control of the airplane.

In 1998 operators first told Boeing of unserviceable short flexible drive shafts (also referred to as 'flexshafts')

related to the electro-mechanical brake of the Thrust Reverser Actuation System (TRAS) on GE CF6-80C2

engines. Boeing released service bulletin 747-78A2179 to replace these short flexshafts individually when

necessary. But since the release of that service bulletin, flexshaft damage and breakage has continued to occur.

The performance of the short flexshaft installed by service bulletin 747-78A2179 did not have the necessary

reliability for the system. Since its installation on GE CF6-80C2 engines, short flexshaft part number 3278500-7

has had a number of unserviceable occurrences reported by operators. Similar to the reports described in Boeing

service bulletin 747-78A2179, the unserviceable flexshafts were found to have cores that had become sheared

and unbraided. The manufacturer of the engines, General Electric (GE), and Middle River Aircraft Systems

(MRAS), the supplier of the T/R, have changed the design and supplier of the flexshafts. The flexshaft design

change incorporates a better end fitting attachment, a larger core diameter with the core wound specifically for

use on a left and right T/R half to increase its resistance to damage. The incorporation of this service bulletin is

the recommended alternative to Boeing service bulletin 747-78A2179.

This service bulletin, together with MRAS service bulletin CF6-80C2 S/B 78-1168, gives instructions to replace

the short flexible drive shaft of each T/R half of each engine. Left and right halves of each T/R will have a new

flexshaft installed that is specific to each half.

Boeing Service Related Problem 747-SRP-78-0061 is related to this service bulletin.

Boeing Fleet Team Digest 747 FTD 78-07001 is related to this service bulletin.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

5 of 26
ACTION (PRR 85901-106RS)

Work Package 1 - Prepare the thrust reverser (T/R) and get access the short flexshaft between the

electro-mechanical brake and the upper angle gearbox of each T/R left half. Replace the short flexshaft.

Work Package 2 - Prepare the thrust reverser (T/R) and get access the short flexshaft between the

electro-mechanical brake and the upper angle gearbox of each T/R right half. Replace the short flexshaft.

EFFECTIVITY

747-200B/300/400/400D/400F airplanes powered by General Electric CF6-80C2 engines. Refer to Paragraph

1.A., Effectivity 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 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

Refer to Paragraph 1.G., Manpower.

MATERIAL INFORMATION

Operator Supplied Parts/Materials.

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

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

6 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

7 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

8 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-78A2185

Original Issue: October 26, 2010

ATA System: 7831 7834

SUBJECT: EXHAUST (GE CF6-80 Series Engines) - Thrust Reverser Control System - Short

Flexible Drive Shaft Replacement

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 85901-106RS for data about

this change.

GROUP CONFIGURATION DESCRIPTION

747-200B/300/400/400D/400F airplanes powered by General Electric

(GE) CF6-80C2 engines

1 -

Airplane Models:

747-200B, 747-300, 747-400, 747-400D, 747-400F

Variable Number Group

RD166 - RD167 1

RF001 - RF006 1

RL401 - RL403 1

RL411 - RL430 1

RL461 - RL462 1

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

9 of 26
Variable Number Group

RL471 - RL481 1

RL511 - RL516 1

RL521 - RL522 1

RL531 - RL534 1

RL561 - RL568 1

RL571 - RL572 1

RL576 - RL577 1

RL579 1

RL651 - RL655 1

RL671 - RL675 1

RL681 - RL684 1

RM001 - RM007 1

RM010 1

RM026 - RM030 1

RM051 - RM053 1

RM071 1

RM081 - RM084 1

RM116 - RM117 1

RM126 - RM132 1

RM156 - RM158 1

RM191 - RM192 1

RM231 - RM233 1

RM316 - RM318 1

RM351 - RM355 1

RM401 - RM403 1

RM426 1

RM431 1

RM441 - RM443 1

RM445 1

RM801 - RM803 1

RM861 - RM863 1

RM891 - RM899 1

RM901 - RM906 1

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

10 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
Variable Number Group

RM911 1

RR701 1

RR721 - RR724 1

RR746 - RR748 1

RS331 - RS333 1

RS341 - RS342 1

RS781 - RS782 1

RT001 - RT014 1

RT021 - RT022 1

RT041 - RT047 1

RT071 - RT075 1

RT121 1

RT131 - RT137 1

RT151 - RT152 1

RT161 - RT168 1

RT431 - RT447 1

RT531 - RT535 1

RT591 1

RT641 - RT657 1

RT681 - RT682 1

RT691 - RT699 1

RT701 - RT704 1

RT711 - RT717 1

RT741 - RT742 1

RT751 - RT757 1

RT776 - RT777 1

RT801 - RT803 1

RT861 - RT864 1

RT931 - RT932 1

RT945 - RT949 1

RT951 - RT955 1

RT966 - RT967 1

RU031 - RU032 1

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

11 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
Variable Number Group

RU051 - RU052 1

RU059 - RU062 1

RU101 - RU102 1

RU801 - RU809 1

RU831 - RU841 1

2. Spares Affected

Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts

Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for

the recommended use.

B. Concurrent Requirements

None.

C. Reason

Accomplishment of this service bulletin will prevent damage and the possible breakage of the short

flexshafts related to the electro-mechanical brake of General Electric (GE) CF6-80C2 engines. Flexshaft

breakage removes the primary level of protection against an uncommanded thrust reverser deployment

occurrence. Uncommanded T/R deployment could result in a loss of control of the airplane.

In 1998 operators first told Boeing of unserviceable short flexible drive shafts (also referred to as

'flexshafts') related to the electro-mechanical brake of the Thrust Reverser Actuation System (TRAS)

on GE CF6-80C2 engines. Boeing released service bulletin 747-78A2179 to replace these short

flexshafts individually when necessary. But since the release of that service bulletin, flexshaft damage

and breakage has continued to occur. The performance of the short flexshaft installed by service bulletin

747-78A2179 did not have the necessary reliability for the system. Since its installation on GE CF6-80C2

engines, short flexshaft part number 3278500-7 has had a number of unserviceable occurrences

reported by operators. Similar to the reports described in Boeing service bulletin 747-78A2179, the

unserviceable flexshafts were found to have cores that had become sheared and unbraided. The

manufacturer of the engines, General Electric (GE), and Middle River Aircraft Systems (MRAS), the

supplier of the T/R, have changed the design and supplier of the flexshafts. The flexshaft design change

incorporates a better end fitting attachment, a larger core diameter with the core wound specifically for

use on a left and right T/R half to increase its resistance to damage. The incorporation of this service

bulletin is the recommended alternative to Boeing service bulletin 747-78A2179.

This service bulletin, together with MRAS service bulletin CF6-80C2 S/B 78-1168, gives instructions

to replace the short flexible drive shaft of each T/R half of each engine. Left and right halves of each

T/R will have a new flexshaft installed that is specific to each half.

Boeing Service Related Problem 747-SRP-78-0061 is related to this service bulletin.

Boeing Fleet Team Digest 747 FTD 78-07001 is related to this service bulletin.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

12 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
D. Description

Work Package 1 - Prepare the thrust reverser (T/R) and get access the short flexshaft between the

electro-mechanical brake and the upper angle gearbox of each T/R left half. Replace the short flexshaft.

Work Package 2 - Prepare the thrust reverser (T/R) and get access the short flexshaft between the

electro-mechanical brake and the upper angle gearbox of each T/R right half. Replace the short flexshaft.

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

Affected Maintenance Zones

Model Zone

747-200B, 747-300, 747-400, 415, 416, 425, 426, 435, 436, 445, 446

747-400D, 747-400F

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

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.

In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the action (i.e. inspection

or modification) defined in this service bulletin as an alternative method of compliance to the requirements

of paragraph (d) of AD 2003-16-16 and paragraph (f)(1) of AD 2000-15-04. All provisions of AD

2003-16-16 and AD 2000-15-04 that are not specifically referenced in the above statement remain fully

applicable and must be complied with.

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 service bulletin for each

engine. 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:

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

13 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
• 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.

WORK PACKAGE 1

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.50 0.50

FIGURE 1 (a)

Close Access 1 0.50 0.50

TOTAL FOR EACH T/R LEFT HALF 1.00 1.00

(a) Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

WORK PACKAGE 2

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.50 0.50

FIGURE 2 (a)

Close Access 1 0.50 0.50

TOTAL FOR EACH T/R RIGHT HALF 1.00 1.00

(a) Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

The time to make the change in accordance with MRAS service bulletin CF6-80C2 S/B 78-1168 is not

included.

Work Package 1 and 2 can be done independently, but preparation and restoration time will be less if

the work packages are done at the same time. Work Package 1 and 2 are necessary for each engine.

H. Weight and Balance Changes

Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

I. Electrical Load Data

Not applicable.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

14 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
J. References

1. Existing Data

a. Engineering Change Memo PRR 85901-106RS.

b. Boeing Fleet Team Digest 747 FTD 78-07001.

c. Boeing Service Bulletin 747-78A2179.

d. Boeing Service Related Problem (SRP) 747-SRP-78-0061.

e. Federal Aviation Administration (FAA) Airworthiness Directive 2000-15-04, 2003-16-16.

f. Middle River Aircraft Systems (MRAS) Service Bulletin CF6-80C2 S/B 78-1168.

NOTE: The supplier was told to send a copy of the service bulletin to each operator.

g. 747-100/200/300 Aircraft Maintenance Manual (AMM) 78-31-00, 78-31-18, 78-34-07.

h. 747-400 Aircraft Maintenance Manual (AMM) 78-31-00, 78-31-18, 78-34-07.

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

747 Illustrated Parts Catalog 78-34

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

Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability

information.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

15 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

16 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT

BLANK PAGE
2. MATERIAL INFORMATION

A. Material - Price and Availability

Refer to Middle River Aircraft Systems (MRAS) service bulletin CF6-80C2 S/B 78-1168.

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

Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

2. Parts and Materials Supplied by the Operator

Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

3. Parts Modified and Reidentified

None.

4. Parts Removed and Not Replaced

None.

D. Parts Necessary to Change Spares

Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.

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: October 26, 2010

747-78A2185

17 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

18 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT

BLANK PAGE
3. ACCOMPLISHMENT INSTRUCTIONS

A. GENERAL INFORMATION

CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL

PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL,

METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE

DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR

OTHER ELECTRICAL DAMAGE.

NOTE: 1. The instructions identified in Paragraph 3.B., Work Instructions, and the Figure(s)

give the recommended sequence of steps. The sequence of steps to do this service

bulletin can be changed.

2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for

definition of the acronyms.

3. Obey all of the warnings and cautions given in the specified manual sections.

4. The work instructions are divided into work packages. Task Hours and Elapsed Hours

for each package are given in Paragraph 1.G., Manpower. You can do each work

package independently. Work Package 1 and 2 are necessary for each engine.

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.

B. WORK INSTRUCTIONS

WORK PACKAGE 1 - THRUST REVERSER LEFT HALF

1. Deactivate the thrust reverser (T/R) for ground maintenance. Refer to 747-100/200/300 AMM

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

2. Replace the short flexshaft in accordance with FIGURE 1.

3. Activate the T/R after ground maintenance. Refer to 747-100/200/300 AMM 78-31-00 or 747-400

AMM 78-31-00 as an accepted procedure.

4. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

19 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
WORK PACKAGE 2 - THRUST REVERSER RIGHT HALF

1. Deactivate the thrust reverser (T/R) for ground maintenance. Refer to 747-100/200/300 AMM

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

2. Replace the short flexshaft in accordance with FIGURE 2.

3. Activate the T/R after ground maintenance. Refer to 747-100/200/300 AMM 78-31-00 or 747-400

AMM 78-31-00 as an accepted procedure.

4. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

20 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
FIGURE 1: THRUST REVERSER LEFT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 1 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

21 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
FIGURE 1: THRUST REVERSER LEFT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 2 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

22 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY

numbers shown below are the number of parts necessary for each thrust reverser left half.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

CABLE-FLEXIBLE 3278500-( ) 1 (a)

DRIVE

1 Remove

CABLE-FLEXIBLE 491B1200036-001 1 (a)

DRIVE

2 Install (New)

(a) in accordance with Middle River Aircraft Systems (MRAS) service bulletin CF6-80C2 S/B 78-1168. Also

refer to 747-100/200/300 AMM 78-31-18 and 747-100/200/300 AMM 78-34-07 or 747-400 AMM 78-31-

18 and 747-400 AMM 78-34-07 for additional information.

FIGURE 1: THRUST REVERSER LEFT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 3 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

23 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
FIGURE 2: THRUST REVERSER RIGHT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 1 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

24 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY

numbers shown below are the number of parts necessary for each thrust reverser right half.

FIGURE 2: THRUST REVERSER RIGHT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 2 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

25 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

CABLE-FLEXIBLE 3278500-( ) 1 (a)

DRIVE

1 Remove

CABLE-FLEXIBLE 491B1200036-002 1 (a)

DRIVE

2 Install (New)

(a) in accordance with Middle River Aircraft Systems (MRAS) service bulletin CF6-80C2 S/B 78-1168. Also

refer to 747-100/200/300 AMM 78-31-18 and 747-100/200/300 AMM 78-34-07 or 747-400 AMM 78-31-

18 and 747-400 AMM 78-34-07 for additional information.

FIGURE 2: THRUST REVERSER RIGHT HALF ELECTRO-MECHANICAL BRAKE - SHORT FLEXSHAFT

REPLACEMENT

(SHEET 3 OF 3)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: October 26, 2010

747-78A2185

26 of 26

BOEING SERVICE BULLETIN 747-78A2185

ALERT ALERT