### 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. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 26, 2010 747-78A2185 1 of 26 2.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details.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.
**DESCRIPTION CONFIGURATION**  **GROUP** 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 **Group Variable Number**  1 RD166 - RD167 1 RF001 - RF006 1 RL401 - RL403 1 RL411 - RL430 1 RL461 - RL462

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: October 26, 2010 747-78A2185 9 of 26**Group Variable Number**  1 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

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 Group**  **Variable Number** 1 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

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 Group**  **Variable Number** 1 RU051 - RU052 1 RU059 - RU062 1 RU101 - RU102 1 RU801 - RU809 1 RU831 - RU841 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 Zone**  **Model** 415, 416, 425, 426, 435, 436, 445, 446 747-200B, 747-300, 747-400, 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 Elapsed Hours**  **Task Hours Number of Persons**  **Task** 0.50 0.50 1 Open Access (a) FIGURE 1 0.50 0.50 1 Close Access 1.00 1.00 TOTAL FOR EACH T/R LEFT HALF (a) Refer to MRAS service bulletin CF6-80C2 S/B 78-1168.
**WORK PACKAGE 2 Elapsed Hours**  **Task Hours Number of Persons**  **Task** 0.50 0.50 1 Open Access (a) FIGURE 2 0.50 0.50 1 Close Access 1.00 1.00 TOTAL FOR EACH T/R RIGHT HALF (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: **Chapter-Section Publication**  78-34 747 Illustrated Parts Catalog 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary. **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.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) 1 3278500-( ) CABLE-FLEXIBLE DRIVE Remove 1 (a) 1 491B1200036-001 CABLE-FLEXIBLE DRIVE Install (New) 2 (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 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) 1 3278500-( ) CABLE-FLEXIBLE DRIVE Remove 1 (a) 1 491B1200036-002 CABLE-FLEXIBLE DRIVE Install (New) 2 (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**