Middle River Aircraft Systems

CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 1 of 17 

MRAS PROPRIETARY INFORMATION 

The information contained in this document is Middle River Aircraft Systems proprietary information and 

is disclosed in confidence. It is the property of Middle River Aircraft Systems and shall not be used, 

disclosed to others or reproduced without the express written consent of Middle River Aircraft Systems, 

including, but without limitation, it is not to be used in the creation, manufacture, development, or 

derivation of any repairs, modifications, spare parts, designs, or configuration changes or to obtain FAA 

or any other government or regulatory approval to do so. If consent is given for reproduction in whole or 

in part, this notice and the notice set forth on each page of this document shall appear in any such 

reproduction in whole or in part. 

This technical data is considered EAR controlled pursuant to 15 CFR Parts 730-774 respectively. 

Transfer of this data by any means to a Non-US Person, whether in the United States or abroad, without 

the proper U.S. Government authorization (e.g., License, exemption, NLR, etc.), is strictly prohibited. 

All technical documentation and information contained herein, with respect to assembly and disassembly, 

cleaning, inspection methods and limits, repair methods and limits, operational limits, life limits and the 

like, have been developed and approved for use with fan reversers and parts that have been 

manufactured and/or approved by Middle River Aircraft Systems and that have been maintained in 

accordance with Middle River Aircraft Systems technical documentation and recommendations. Middle 

River Aircraft Systems has no contractual or legal obligation for, nor knowledge of, non-MRAS-approved 

parts and repairs. Accordingly, this document is not intended to apply to non-MRAS-approved parts and 

repairs. 

MRAS authorizes the Federal Aviation Administration to incorporate this document by reference in an 

Airworthiness Directive. 

Copyright (2011) Middle River Aircraft Systems, MRA Systems Inc. – A Subsidiary of GE 

TRANSMITTAL INFORMATION 

REVISION 2 - SERVICE BULLETIN 78-1168 

Revision 2 of Service Bulletin (SB) 78-1168 incorporates operator comments and adds optional 

Installation Record & Operator Torque Checks Feedback Forms. MRAS requests operators who 

have incorporated Revision 1 of SB 78-1168 to complete the Installation Record & Operator 

Torque Checks Feedback Forms in this Revision 2 (refer to Figures 2 and 3 herein) and to return 

the Installation Record & Operator Torque Checks Feedback Forms to MRAS (refer to the fax 

number and the e-mail address at the bottom of Figures 2 and 3). 

1.A., Effectivity, is revised to add TRAS Lock Flexible Drive Cables Part Numbers (PNs) 1806M47P01 

and 1806M47P02. 

1.C., Description, is revised to add TRAS Lock Flexible Drive Cables PNs 1806M47P01 and 

1806M47P02 and to request completion of optional flex drive cables installation 

records/operator torque checks feedback forms. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 2 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

TRANSMITTAL INFORMATION 

REVISION 2 – SERVICE BULLETIN 78-1168 

(Continued) 

1.D., Compliance, is revised to agree with the compliance statements in Boeing cover Service Bulletins 

747-78A2185 and 767-78A0100. 

1.I., References, is revised to add six references. 

1.K., Interchangeability, is revised to add TRAS Lock Flexible Drive Cables PNs 1806M47P01 and 

1806M47P02 and to correct a part number. 

2.A., Material – Price and Availability, is updated. 

2.B., Industry Support Information, is revised to incorporate Addendum No. 1 for CF6-80C2 SB 78-1168 

Revision 1. 

2.D., Parts Disposition, is revised to give operators the option to quarantine, to scrap or to retain removed 

flexible drive cables and to provide a reference to the flexible drive cable component 

maintenance manual. 

3.A.(1), ACCOMPLISHMENT INSTRUCTIONS, is revised to add “fan reverser” prior to “PRSOV.” 

3.B.(5), ACCOMPLISHMENT INSTRUCTIONS, is revised to remove the instruction to inspect and to 

retain the removed flexible drive cable. 

3.C., ACCOMPLISHMENT INSTRUCTIONS, is revised to arrange steps to match the sequence in the 

Boeing Aircraft Maintenance Manual (AMM). 

3.E., ACCOMPLISHMENT INSTRUCTIONS, is revised to allow use of an equivalent approved TRAS lock 

holding torque check procedure. 

3.F., ACCOMPLISHMENT INSTRUCTIONS, is added to request completion of the optional Installation 

Record & Operator Torque Checks Feedback Form and return of the Installation Record & 

Operator Torque Checks Feedback Form to MRAS. 

4., DOCUMENT PERIODIC POST-SB 78-1168 TRAS LOCK HOLDING TORQUE CHECK RESULTS 

(OPTIONAL) is added. 

Legend for Figure 1 is revised to add TRAS Lock Flexible Drive Cables PNs 1806M47P01 and 

1806M47P02. 

Figures 2 and 3, Installation Record & Operator Torque Checks Feedback Form, are added. 

Revision 1 was issued 26 August 2010. The original was issued 17 August 2010. The original was not 

distributed because Boeing cover service bulletins were pending. 

Revision bars in the left margin identify Revision 2 changes. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 3 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

1. PLANNING INFORMATION 

 A. Effectivity 

 CF6-80C2B1/B2/B4/B6/B1F/B2F/B4F/B5F/B6F/B6FA/B7F/B8F 

 (1) TRAS Lock Flexible Drive Cable Part Numbers (PNs) 1806M47P01, 1806M47P02 and 

1806M47P05 (Vendor Item Numbers (VINs) 3278500-1/-4, 3278500-2/-5 and 3278500-7, 

respectively) installed on CF6-80C2B fan reversers are affected. 

 (2) Left-Hand (LH) TRAS Lock Flexible Drive Cable PN 491B1200036-001 and Right-Hand 

(RH) TRAS Lock Flexible Drive Cable PN 491B1200036-002 will be introduced in 

production on the fan reversers listed below. 

 (Boeing) R647/648-2022 and up, R649/650-457 and up, R651/652-064 and up 

 (Boeing B6FA) R563/564-011 and up 

 (3) These serial numbers are the best available numbers. 

 B. Concurrent Requirements 

 None 

 C. Description 

 This service bulletin provides instructions for replacing TRAS Lock Flexible Drive Cable PN 

 1806M47P02 or 1806M47P05 with TRAS Lock Flexible Drive Cable PN 491B1200036-001 on 

the left-hand fan reverser half. This service bulletin provides instructions for replacing TRAS 

Lock Flexible Drive Cable PN 1806M47P01, 1806M47P02 or 1806M47P05 with TRAS Lock 

 Flexible Drive Cable PN 491B1200036-002 on the right-hand fan reverser half. 

 Following installation of TRAS Lock Flexible Drive Cables PN 491B1200036-001 and PN 

491B1200036-002 on a fan reverser, the operator is requested to complete the optional 

Installation Record & Operator Torque Checks Feedback Form (refer to Figures 2 and 3) and to 

return the Installation Record & Operator Torque Checks Feedback Form to MRAS. 

 D. Compliance 

 Category 2 

 Do as soon as possible without effect on revenue service but no later than 26 October 2015. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 4 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

1. E. Reason 

 Objective: 

 Install improved TRAS lock flexible drive cables on CF6-80C2B fan reversers. 

 Condition: 

 The current TRAS lock flexible drive cables can fail prematurely on CF6-80C2B fan 

reversers. 

 Cause: 

 Engineering analysis and testing has determined that the torsional strength and stiffness of 

the current flexible shaft is not optimal for the operating environment. 

 Improvement: 

 TRAS Lock Flexible Drive Cables PN 491B1200036-001 and PN 491B1200036-002 have 

improved durability, improved ultimate torsional strength, and improved fatigue life. Reduced 

core stiffness results in lower torque at the end-of-travel impact. The improved design 

reduces stress concentrations on the flexible drive cable core and end fittings. 

 Substantiation: 

 Substantiation is by analysis and testing. 

 F. Approval 

 The FAA has approved the technical content of this Service Bulletin. 

 G. Manpower 

 With access to the upper torque box of each fan reverser half, the estimate to replace two 

TRAS lock flexible drive cables is 1.0 man-hour. 

 H. Weight and Balance 

 Weight and balance are not changed. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 5 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

1. I. References 

 Boeing 747 Aircraft Maintenance Manual (AMM) 

 Boeing 747-400 Aircraft Maintenance Manual (AMM) 

 Boeing 767 Aircraft Maintenance Manual (AMM) 

 Boeing Service Bulletin 747-78A2185 entitled “EXHAUST (GE CF6-80 Series Engines) – 

Thrust Reverser Control System – Short Flexible Drive Shaft Replacement” 

 Boeing Service Bulletin 767-78A0100 entitled “EXHAUST (GE CF6-80 Series Engines) – 

Thrust Reverser Control System – Short Flexible Drive Shaft Replacement” 

 GE Commercial Engine Standard Practices Manual, GEK 9250 (CD GEK 108792) 

 Component Maintenance Manual (CMM) GEK 103024 (ATA 78-32-57), Flexible Shaft 

Assembly 

 CF6-80C2 Service Bulletin 78-1133 entitled “EXHAUST - Fan Reverser – Identification Plate 

for Recording Service Bulletin Accomplishment” 

 FAA AD 2000-09-04 

 FAA AD 2000-15-04 

 FAA AD 2003-16-16 

 For MRAS internal use: ECS 10-00709 

 J. Publications Affected 

 CF6-80C2 Fan Reverser Illustrated Parts Catalog (IPC), MR 92464 

 K. Interchangeability 

 TRAS Lock Flexible Drive Cable PN 1806M47P02 or PN 1806M47P05 and TRAS Lock 

Flexible Drive Cable PN 491B1200036-001 (LH) are one-way interchangeable. TRAS Lock 

Flexible Drive Cable PN 1806M47P01, 1806M47P02 or 1806M47P05 and TRAS Lock Flexible 

Drive Cable PN 491B1200036-002 (RH) are one-way interchangeable. (1806M47P01/P02/P05 

may be used as a replacement only where 1806M47P01/P02/P05 is installed. On the LH fan 

reverser half, 491B1200036-001 is an acceptable replacement for 1806M47P02, 1806M47P05 

or 491B1200036-001. On the RH fan reverser half, 491B1200036-002 is an acceptable 

replacement for 1806M47P01, 1806M47P02, 1806M47P05 or 491B1200036-002.) 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 6 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

2. MATERIAL INFORMATION 

 A. Material – Price and Availability 

 (1) Parts necessary to do this service bulletin: 

 

Part Number 

Quantity 

per Fan 

Reverser Part Name 

2011 

Unit Price 

($) 

Pkg 

Qty 

Lead Time 

(Days) 

 

 491B1200036-001 1 Flexible Drive Cable (LH) 3,811.20 * 1 30 

 491B1200036-002 1 Flexible Drive Cable (RH) 3,811.20 * 1 30 

 NOTE: Price and lead time are subject to change. 

 * Discount is available until 15 November 2012. See Section 2.B., Industry Support 

Information. 

 (2) Consumables: 

 NOTE: Middle River Aircraft Systems does not supply consumables. Refer to GE Aircraft 

Engines Commercial Standard Practices Manual (SPM), GEK 9250, for sources 

of supply. 

 Code Number Description 

 C02-032 Loctite C5-A® or equivalent anti-seize thread compound 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 7 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

2. B. Industry Support Information 

 Middle River Aircraft Systems (MRAS) will supply Flexible Drive Cables PN 491B1200036-001 

and PN 491B1200036-002. Refer to Paragraph 2.A., Material – Price and Availability, for 

quantities and prices. Send a Charge Purchase Order (the Purchase Order must include the 

flexible drive cables part numbers and the number of this Service Bulletin) to: 

 Middle River Aircraft Systems 

 ATTN: Commercial Spares Support 

 Mail Point 46 

 103 Chesapeake Park Plaza 

 Baltimore, MD 21220 U.S.A. 

 Fax: 410.682.0090 

 SITA: BWIMS7X 

 E-mail: spares_support@mras-usa.com 

 MRAS will provide a 50% up-front price discount for Flexible Drive Cables PN 491B1200036-

001 and PN 491B1200036-002 until 15 November 2012. 

 The discounted price for Flexible Drive Cables PN 491B1200036-001 and PN 491B1200036- 

 002 ordered through 30 June 2011 is $1,830.00 each. (This is a 67% discount of the current 

 Honeywell spare parts catalog list price for Flexible Drive Cable PN 3278500-7; therefore, the 

discounted price includes the installation labor allowance.) 

 The discounted price for Flexible Drive Cables PN 491B1200036-001 and PN 491B1200036- 

 002 ordered from 1 July 2011 through 31 December 2011 will be $1,905.60 each. 

 The discounted price for Flexible Drive Cables PN 491B1200036-001 and PN 491B1200036- 

 002 ordered from 1 January 2012 through 15 November 2012 will be 50% of the 2012 MRAS 

 CF6 Thrust Reverser Spare Parts Catalog list price. 

 Operators with CF6-80C2 fan reversers not having Flexible Drive Cables PN 491B1200036-

001 and PN 491B1200036-002 installed and having less than 3,500 Flight Hours Since New 

 may submit a No-Charge Purchase Order to MRAS for Flexible Drive Cables PN 

491B1200036-001 and PN 491B1200036-002. The No-Charge Purchase Order must include 

the serial numbers of the fan reverser halves and the number of fan reverser flight hours 

accumulated since new. Without this information, MRAS will not accept the No-Charge 

Purchase Order. 

 After 15 November 2012, MRAS will not provide a discount for Flexible Drive Cables PN 

491B1200036-001 and PN 491B1200036-002. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 8 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

2. C. Configuration Chart 

*** CF6-80C2B1/B2/B4/B6/B1F/B2F/B4F/B5F/B6F/B6FA/B7F/B8F *** 

New Part Number 

Qty / 

F/R Part Name 

Old Part Number / 

IPC Location 

Qty / 

F/R 

Op 

Code 

Chg / 

Sprt 

Code 

(Production) 

 

683L307G19 (1) Kit – TRAS Lock (LH) 

(767 / 747) 

(Pos 1 / Pos 1 & 2) 

(Pos 2 / Pos 3 & 4) 

683L307G14 

(VIN 3283094-14) 

78-32-00-6-050 

78-32-00-16-050 

(1) RE 1 / A 

 

683L307G20 (1) Kit – TRAS Lock 

(RH) 

(767 / 747) 

(Pos 1 / Pos 1 & 2) 

(Pos 2 / Pos 3 & 4) 

683L307G15 

(VIN 3283094-15) 

78-32-00-11-050 

78-32-00-21-050 

(1) RE 1 / A 

(Production / Field) 

.491B1200036-001 

.491B1200036-002 

(1) 

(1) 

Flexible Drive Cable 

(LH) 

Flexible Drive Cable 

(RH) 

.1806M47P05 

 (VIN 3278500-7) 

 78-36-10-1-020 

 78-36-10-1-030 

 78-36-10-1A-020 

 78-36-10-1B-020 

(2) RE 1 / A 

 

 Operation Code Change Code Spare Parts Support Code 

 RE = Replace 1 = One-way interchangeable A = Old parts will no longer be supplied. 

 D. Parts Disposition 

 At the operator’s option, quarantine, scrap or retain TRAS Lock Flexible Drive Cables PN 

1806M47P01/P02/P05. To determine serviceability of TRAS Lock Flexible Drive Cables PN 

1806M47P01/P02/P05, refer to Flexible Shaft Assembly Component Maintenance Manual 

(CMM) GEK 103024 (ATA 78-32-57), Section 2, Testing and Fault Isolation. 

 E. Tooling 

 Mechanic’s hand tools 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 9 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

3. ACCOMPLISHMENT INSTRUCTIONS 

 NOTE: The following Accomplishment Instructions are for both left and right hand fan reverser 

halves. Figure 1 in this Service Bulletin shows the right-hand fan reverser half only. The 

left-hand fan reverser half is a mirror image of the right-hand fan reverser half. 

 A. Job Set-up 

 WARNING: MAKE CERTAIN THAT CIRCUIT BREAKERS ARE OPEN, SAFETIED, AND 

TAGGED BEFORE ATTEMPTING MAINTENANCE PROCEDURES. 

INADVERTENT ENGINE START OR FAN REVERSER OPERATION COULD 

RESULT IN DEATH OR SERIOUS INJURY TO PERSONNEL. MAKE CERTAIN 

THAT THROUGHOUT THE JOB SET-UP, THE AIRCRAFT PNEUMATIC 

SYSTEM IS NOT PRESSURIZED BY PNEUMATIC GROUND POWER, APU, OR 

ANOTHER ENGINE. 

 (1) Open, safety, and tag the appropriate circuit breakers (ensure that the fan reverser PRSOV 

 circuit breaker is open to disable the fan reverser auto re-stow function), and open the fan 

cowl doors to the full open position and the fan reversers to the lower open position. Be 

sure the fan cowl doors and the fan reversers are secured. Refer to the applicable Aircraft 

Maintenance Manual (AMM). 

 (2) Get access to the fan reverser half upper torque box area. 

 B. Remove the TRAS Lock Flexible Drive Cable from the Fan Reverser Half 

 (1) Refer to Figure 1. Disconnect the electrical connector from the TRAS lock (Item 1). 

 (2) Remove the two bolts (Item 3) and the two washers (Item 4) that attach the flexible drive 

cable (Item 2) to the upper end actuator top drive pad (Item 5). Retain the bolts and 

washers. 

 (3) Remove the three bolts (Item 6) and the three washers (Item 7) that attach the TRAS lock 

(Item 1) to the bracket (Item 8). Retain the bolts and washers. 

 (4) Remove the TRAS lock (Item 1) and the flexible drive cable (Item 2) from the bracket (Item 

8). 

 (5) Disconnect the flexible drive cable (Item 2) from the TRAS lock (Item 1). 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 10 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

3. C. Install Left-Hand TRAS Lock Flexible Drive Cable PN 491B1200036-001 or Right-Hand TRAS 

Lock Flexible Drive Cable PN 491B1200036-002 on the Fan Reverser Half 

 (1) Obtain TRAS Lock Flexible Drive Cable PN 491B1200036-001 for the left-hand fan 

reverser half or TRAS Lock Flexible Drive Cable PN 491B1200036-002 for the right-hand 

fan reverser half. 

 NOTE: TRAS Lock Flexible Drive Cable PN 491B1200036-001 is labeled “LH ONLY” in 

two places. TRAS Lock Flexible Drive Cable PN 491B1200036-002 is labeled “RH 

ONLY” in two places. 

 (2) Refer to Figure 1. Slide the flexible drive cable (Item 2) into the TRAS lock (Item 1) until it 

stops. 

 (3) Put the TRAS lock/flexible drive cable assembly (Items 1 & 2) on the bracket (Item 8). 

Slide the assembly into the upper end actuator top drive pad (Item 5) by inserting the 

square drive end of the flexible drive cable (Item 2). 

 (4) If it is necessary, pull up the manual release handle of the TRAS lock (Item 1) from its 

retaining clip to disengage the TRAS lock (Item 1) and permit the flexible drive cable (Item 2) 

to turn. 

 NOTE: This will allow alignment of the square drive end of the flexible drive cable with the 

top drive pad of the upper end actuator. 

 (5) Attach the flexible drive cable (Item 2) to the top drive pad of the upper end actuator (Item 

5) with the two retained bolts (Item 3) and the two retained washers (Item 4). Install the 

bolts (Item 3) wet with anti-seize compound (C02-032). Torque the bolts to 24-27 lb-in. 

(2,7-3,1 N.m). 

 CAUTION: THERE ARE TWO ALTERNATE BOLT HOLE PATTERNS ON THE TRAS LOCK 

BRACKET (FIGURE 1, SHEET 2). USE THE BOLT HOLE PATTERN THAT BEST 

ALIGNS THE FLEXIBLE DRIVE CABLE (ITEM 2) TO THE UPPER END 

ACTUATOR. DO NOT LET THE FLEXIBLE DRIVE CABLE MAKE AN S-TYPE 

CURVE. THE FLEXIBLE DRIVE CABLE MUST BE STRAIGHT OR MAKE A 

CONTINUOUS ARC, OR THE FLEXIBLE DRIVE CABLE CAN BECOME 

DAMAGED. 

 (6) Refer to Figure 1, Sheet 2. Align the TRAS lock (Item 1) with the bolt hole pattern of the 

bracket (Item 8) that gives the straightest configuration of the flexible drive cable (Item 2). 

 (7) Attach the TRAS lock (Item 1) to the bracket (Item 8) with the three retained machine bolts 

(Item 6) and the three retained flat washers (Item 7). The machine bolts are installed from 

under the bracket (Item 8). Install the bolts (Item 6) wet with anti-seize compound (C02-

032). Torque the machine bolts to 55-70 lb-in. (6,2-7,9 N.m). 

 (8) Attach the electrical connector to the TRAS lock (Item 1). 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 11 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

3. C. (Continued) 

 (9) Pull down the manual release handle of the TRAS lock (Item 1) until the handle fully 

engages its retaining clip. 

 D. Repeat Sections 3.B. and 3.C. for the Other Fan Reverser Half 

 E. Do the TRAS Lock Holding Torque Check per AMM 78-34-07/501 or an equivalent approved 

procedure.

 F. Complete the Installation Record & Operator Torque Checks Feedback Form and Return to 

MRAS (Optional). 

 Refer to Figures 2 and 3. Complete the appropriate Installation Record & Operator Torque 

Checks Feedback Form (one form for 767; two forms for 747). Return the Installation Record & 

Operator Torque Checks Feedback Form to MRAS via fax or e-mail (refer to the fax number 

and the e-mail address at the bottom of the Installation Record). 

 G. Record Service Bulletin Accomplishment (Optional) 

 (1) If CF6-80C2 Service Bulletin 78-1133 has been accomplished, mark “S/B 78-1168” on 

Identification Plate PN MS27253-2. Method of marking (e.g., metal stamp or vibropeen) 

is the operator’s choice. 

 NOTE: Step 3.G.(2) installs an identification plate used to record Service Bulletin 

accomplishment. The operator may choose not to accomplish Step 3.G.(2). 

(2) If CF6-80C2 Service Bulletin 78-1133 has not been accomplished, accomplish SB 78-

1133, then mark “S/B 78-1168” on Identification Plate PN MS27253-2. Method of 

marking (e.g., metal stamp or vibropeen) is the operator’s choice. 

 H. Job Close-up 

(1) Close the fan reverser halves and the fan cowl doors. Refer to the applicable AMM. 

(2) Remove safety clips and tags and close previously opened circuit breakers. Refer to the 

applicable AMM. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 12 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

4. DOCUMENT PERIODIC POST-SB 78-1168 TRAS LOCK HOLDING TORQUE CHECK RESULTS 

(OPTIONAL). 

 Following installation of Flexible Drive Cables PN 491B1200036-001 and PN 491B1200036-002, 

TRAS Lock Holding Torque Checks per AMM 78-34-07/501 (or an equivalent approved procedure) 

are accomplished (refer to Section 3.E.). MRAS requests operators to record accomplishment of 

the initial TRAS Lock Holding Torque Checks following installation of the new flexible drive cables on 

the Installation Record & Operator Torque Checks Feedback Form (refer to Figures 2 & 3) and to 

return the Installation Record & Operator Torque Checks Feedback Form to MRAS (refer to the fax 

number and the e-mail address at the bottom of the Installation Record). 

 NOTE: Two forms are required for the four fan reversers on a 747. 

 FAA Airworthiness Directives require accomplishment of TRAS Lock Holding Torque Checks at an 

interval of 1,000 Flight Hours (FH). MRAS requests operators to record the results (pass or fail) of 

these periodic torque checks on the same Installation Record & Operator Torque Checks Feedback 

Form completed for each fan reverser half following installation of the new flexible drive cables and 

to return the Installation Record & Operator Torque Checks Feedback Form to MRAS after each 

torque check. 

 After MRAS has collected the initial and three subsequent periodic torque checks results for fan 

reverser halves with the new flexible drive cables installed, Boeing will petition FAA for an extension 

of the torque check interval based on anticipated positive results. 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 13 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

MR70950-00-A 

Replacement of TRAS Lock Flexible Drive Cable 

Figure 1, Sheet 1 of 2 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 14 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

MR70951-00-A 

Replacement of TRAS Lock Flexible Drive Cable 

Figure 1, Sheet 2 of 2 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 15 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

Legend for Figure 1 

 

Item 

No. 

Part Name Part Number 

Quantity 

Per 

TR Half 

 

1 Thrust Reverser Actuation System 

(TRAS ) Lock 

1806M46P05 1 

 

2 Flexible Drive Cable 

1806M47P01 (Removed – RH only) 

or 

1806M47P02 (Removed – LH or RH) 

or 

1806M47P05 (Removed – LH or RH) 

491B1200036-001 (LH – Installed) 

or 

491B1200036-002 (RH – Installed) 

1 

 

3 Machine Bolt MS9489-07 2 

 

4 Flat Washer AN960C10L 2 

 

5 Upper End Actuator Top Drive Pad --- 1 

 

6 Machine Bolt MS9490-11 3 

 

7 Flat Washer AN960C416 3 

 

8 TRAS Lock Bracket 1806M48P01 or P03 (RH) 

1806M48P02 or P04 (LH) 

1 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 16 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

INSTALLATION RECORD & OPERATOR TORQUE CHECKS FEEDBACK FORM (OPTIONAL)

This installation record and operator torque checks feedback form is optional. The TRAS lock holding 

torque check data will be used to justify an extension of the current 1,000 flight-hour TRAS lock holding 

torque check interval for fan reversers with Flexible Drive Cables PNs 491B1200036-001 & 

491B1200036-002 installed. 

Aircraft Model 767 Operator: _______________________________ Date: ____________________ 

Aircraft Tail No. _____________________________ 

FLEXIBLE DRIVE CABLES PART NUMBER 491B1200036-001 WERE INSTALLED ON THE 

FOLLOWING LEFT-HAND FAN REVERSER HALVES: 

Wing Position 1 Left-Hand Fan Reverser Half Serial No. __________________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Wing Position 2 Left-Hand Fan Reverser Half Serial No. __________________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

FLEXIBLE DRIVE CABLES PART NUMBER 491B1200036-002 WERE INSTALLED ON THE 

FOLLOWING RIGHT-HAND FAN REVERSER HALVES: 

Wing Position 1 Right-Hand Fan Reverser Half Serial No. _________________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Wing Position 2 Right-Hand Fan Reverser Half Serial No. _________________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Return to: Middle River Aircraft Systems 

 ATTN: Product Support Engineering 

 E-mail: technical_support@mras-usa.com 

 Fax: 410.682.0100 

Installation Record & Operator Torque Checks Feedback Form (767) 

Figure 2 
CF6-80C2B SERVICE BULLETIN

EXHAUST - Fan Reverser – Thrust Reverser Actuation System (TRAS) Lock Flexible Drive Cables 

Part Numbers 491B1200036-001 (Left-Hand) and 491B1200036-002 (Right-Hand) - Introduction 

17 August 2010 CF6-80C2B S/B 78-1168 

Revision 2, 19 April 2011 Page 17 

MRAS PROPRIETARY INFORMATION – Subject to the restrictions on the first page. 

INSTALLATION RECORD & OPERATOR TORQUE CHECKS FEEDBACK FORM (OPTIONAL)

This installation record and operator torque checks feedback form is optional. The TRAS lock holding 

torque check data will be used to justify an extension of the current 1,000 flight-hour TRAS lock holding 

torque check interval for fan reversers with Flexible Drive Cables PNs 491B1200036-001 & 

491B1200036-002 installed. 

Aircraft Model 747 Operator: _______________________________ Date: ____________________ 

Aircraft Tail No. _____________________________ 

FLEXIBLE DRIVE CABLES PART NUMBER 491B1200036-001 WERE INSTALLED ON THE 

FOLLOWING LEFT-HAND FAN REVERSER HALVES: 

Wing Position 1 or 3 (circle) Left-Hand Fan Reverser Half Serial No. ________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Wing Position 2 or 4 (circle) Left-Hand Fan Reverser Half Serial No. ________________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

FLEXIBLE DRIVE CABLES PART NUMBER 491B1200036-002 WERE INSTALLED ON THE 

FOLLOWING RIGHT-HAND FAN REVERSER HALVES: 

Wing Position 1 or 3 (circle) Right-Hand Fan Reverser Half Serial No. _______________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Wing Position 2 or 4 (circle) Right-Hand Fan Reverser Half Serial No. _______________________ 

TRAS LOCK HOLDING TORQUE CHECK DATE (MM/DD/YYYY) RESULTS 

INITIAL (STEP 3.E.) PASS / FAIL (circle) 

+ 1,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 2,000 FLIGHT HOURS PASS / FAIL (circle) 

+ 3,000 FLIGHT HOURS PASS / FAIL (circle) 

Return to: Middle River Aircraft Systems 

 ATTN: Product Support Engineering 

 E-mail: technical_support@mras-usa.com 

 Fax: 410.682.0100 

Installation Record & Operator Torque Checks Feedback Form (747) 

Figure 3