### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Number: 777-27A0109**  Original Issue: December 01, 2011 ATA System: 2711 **SUBJECT:** FLIGHT CONTROLS - Rudder and Tab - Rudder Power Control Units Reaction Link Assembly Replacement or Repair 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2011 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 1 of 22 3.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 2 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes ............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 14 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 18 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 FIGURE 1: REACTION LINK ASSEMBLY, END CAP ASSEMBLY BUSHINGS REPLACEMENT . . . 21

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 3 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 4 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Summary**  **Number: 777-27A0109** Original Issue: December 01, 2011 ATA System: 2711 **SUBJECT:** FLIGHT CONTROLS - Rudder and Tab - Rudder Power Control Units Reaction Link Assembly Replacement or Repair 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 vibration caused by the bushing liners of the rudder power control unit (PCU) reaction link end cap assemblies coming out of the bushing bores. Loss of the bushing liners in each of the three PCU reaction link assemblies can cause the rudder control surface to have excessive freeplay which may cause rudder vibration and could result in structural damage severe enough to prevent continued safe flight and landing. Boeing received a report from a 777-300ER operator of abnormal airframe vibration in the aft fuselage during flight. A subsequent inspection of the rudder PCU installations found that the bushing liners were missing from all six end cap assemblies There have also been several reports from other 777-300ER operators of either partial or complete loss of the bushing liners. An investigation revealed that the cause of the problem was a failure of the bond between the liner and the bushing substrate because of the use of liquid nitrogen during installation of the bushing into the reaction link end cap housing. All of these reports are associated with one bushing supplier and limited to bushings manufactured before 2008, after which the installation procedure for the bushings in the end cap assemblies was changed from liquid nitrogen to a dry ice alcohol bath. Because 777-200LR's use the same bushings, they are subject to the same condition. This Service Bulletin gives instructions to install serviceable Rudder PCUs and related Reaction Link Assemblies or PCU Reaction Link Assemblies which have been repaired on airplanes in which bushings have been installed using liquid nitrogen. Installation of serviceable PCUs and their related reaction link assembly with bushings installed using a dry ice ethyl alcohol or Dowanol DPM bath procedure will prevent the loss of rudder power control unit (PCU) reaction link assembly bushing liners and subsequent rudder vibration. Boeing Service Related Problem (SRP) 777-SRP-27-0212 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 777 FTD 27-07005 is related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 5 of 22**ACTION** For Each Rudder PCU, check maintenance records to identify if its related Reaction Link Assembly end cap assembly bushings have been replaced in accordance with Part 1. Remove each affected Rudder PCU with its related Reaction Link Assembly from the airplane and install a serviceable Rudder PCU and its related Reaction Link Assembly in accordance with Part 2. As an alternative, a PCU Reaction Link Assembly which has been repaired in accordance with Part 3 can be installed. **EFFECTIVITY** 777-200LR/-300ER Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are available for airplanes in warranty as of October 28, 2010. Please refer to Paragraph 2.B., Industry Support Information. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** Boeing Supplied Parts. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 6 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 7 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 8 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 777 Service Bulletin **ALERT Number: 777-27A0109**  Original Issue: December 01, 2011 ATA System: 2711 **SUBJECT:** FLIGHT CONTROLS - Rudder and Tab - Rudder Power Control Units Reaction Link Assembly Replacement or Repair 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 D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 777-200LR airplanes line numbers 504 through 679, and 777-300ER airplanes line numbers 540 through 686 - 1

Airplane Models: 777-200LR, 777-300ER **Group Variable Number**  1 WD001 - WD002 1 WD011 - WD014 1 WD031 - WD033 1 WD046 - WD048 1 WD505 - WD507 1 WD532 - WD537

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 9 of 22**Group Variable Number**  1 WD546 - WD552 1 WD564 - WD571 1 WD585 - WD594 1 WD606 - WD609 1 WD625 - WD632 1 WD653 - WD658 1 WD672 - WD675 1 WD691 - WD701 1 WD741 - WD745 1 WD761 - WD768 1 WD786 - WD787 1 WD796 - WD800 1 WD826 - WD828 1 WD846 1 WD871 - WD872 2. Spares Affected Examine your spares records for any original rudder Power Control Units (PCUs) removed and held as a spare and also, any Reaction Link Assemblies held as spare to identify assemblies where the end cap bushing liners have not been installed using a dry-ice ethyl alcohol or Dowanol DPM bath. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of this service bulletin will prevent vibration caused by the bushing liners of the rudder power control unit (PCU) reaction link end cap assemblies coming out of the bushing bores. Loss of the bushing liners in each of the three PCU reaction link assemblies can cause the rudder control surface to have excessive freeplay which may cause rudder vibration and could result in structural damage severe enough to prevent continued safe flight and landing. Boeing received a report from a 777-300ER operator of abnormal airframe vibration in the aft fuselage during flight. A subsequent inspection of the rudder PCU installations found that the bushing liners were missing from all six end cap assemblies There have also been several reports from other 777-300ER operators of either partial or complete loss of the bushing liners. An investigation revealed that the cause of the problem was a failure of the bond between the liner and the bushing substrate

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 10 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**because of the use of liquid nitrogen during installation of the bushing into the reaction link end cap housing. All of these reports are associated with one bushing supplier and limited to bushings manufactured before 2008, after which the installation procedure for the bushings in the end cap assemblies was changed from liquid nitrogen to a dry ice alcohol bath. Because 777-200LR's use the same bushings, they are subject to the same condition. This Service Bulletin gives instructions to install serviceable Rudder PCUs and related Reaction Link Assemblies or PCU Reaction Link Assemblies which have been repaired on airplanes in which bushings have been installed using liquid nitrogen. Installation of serviceable PCUs and their related reaction link assembly with bushings installed using a dry ice ethyl alcohol or Dowanol DPM bath procedure will prevent the loss of rudder power control unit (PCU) reaction link assembly bushing liners and subsequent rudder vibration. Boeing Service Related Problem (SRP) 777-SRP-27-0212 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 777 FTD 27-07005 is related to this service bulletin. **D. Description** For Each Rudder Power Control Unit (PCU), check maintenance records to identify if its related Reaction Link Assembly end cap assembly bushings have been replaced in accordance with Part 1. Remove each affected Rudder PCU with its related Reaction Link Assembly from the airplane and install a serviceable Rudder PCU and its related Reaction Link Assembly in accordance with Part 2. As an alternative, a PCU Reaction Link Assembly which has been repaired in accordance with Part 3 can be installed. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 323, 324, 325 777-200LR, 777-300ER **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Accomplish the required action(s), based on the applicable condition(s), in Table 1 in accordance with Paragraph 3. Accomplishment Instructions.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 11 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT Table 1**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 48 monthsafter the original issue date of this service bulletin. Check maintenance records for each RudderPCU to identify the condition of its related Reaction Link Assembly EndCap Bushings in accordance with PART 1. All Airplanes

- - No further action is neces- sary. Condition 1:The two End Cap Assembly Bushings have been replaced on the ReactionLink Assembly in accordance with CMM 27-21-77 dated March 01, 2011 orlater, or an equivalent procedure has been used

- - No further action is neces- sary. Condition 2:The two End Cap Assembly Bushings have been replaced on the ReactionLink Assembly in accordance with CMM 27-21-77 dated before March 01,2011, or an equivalent procedure was used, and it can be confirmed that a dry ice ethyl alcohol or Dowanol DPM bath was used to install the bushings into the end caps.

- - No further action is neces- sary. Condition 3:The Reaction Link Assembly was replaced with a unit which was manufactured before November 1, 2004 or after October 31, 2007.

- Within 48 monthsafter the original issue date of this service bulletin.Do the Rudder PCU Reaction Link Assembly replacement in accordance with PART 2. Condition 4:The condition of the Reaction Link Assembly is notin accordance with Conditions 1, 2 or 3.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 12 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT F. Approval**  This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task hours necessary to do this task for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Airplane Work Elapsed Hours**  **Task Hours Number of Persons**  **Task** 1.00 1.00 1 Open Access 1.50 3.00 2 PCU/Reaction Link Assembly Removal 2.00 4.00 2 PCU/Reaction Link Assembly Installation and Test 1.00 1.00 1 Close Access 5.50 9.00 TOTAL FOR EACH PCU/REACTION LINK (a)(a) Open and close access only required once if multiple PCU/Reaction Link Assembly worked simultaneously. **Component Work Elapsed Hours**  **Task Hours Number of Per-**  **sons Task** 

1.00 1.00 1 FIGURE 1 1.00 1.00 TOTAL FOR EACH COMPONENT (a)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 13 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT Component Work**  **Elapsed Hours Task Hours**  **Number of Per- sons**  **Task** (a) Total given is for the repair of one Reaction Link Assembly. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data a. Boeing Service Related Problem (SRP) 777-SRP-27-0212 b. Component Maintenance Manual (CMM) 27-21-77 c. Service Bulletin Index D624W001 d. Standard Overhaul Practices Manual (SOPM) 20-50-03, 20-50-10 e. 777 Aircraft Maintenance Manual (AMM) 27-21-11 f. 777 Fleet Team Digest (FTD) 27-07005 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** 27-21 777 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 14 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT L. Interchangeability and Intermixability of Parts**  Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 15 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 16 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the parts shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION** 
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **Name Part Number** 

794.00 180 BUSHING, END CAP 251W3135-5 **B. Industry Support Information** Boeing warranty remedies are available for 777 airplanes in warranty as of October 28, 2010. For task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. The parts for airplanes in warranty as of that date will be supplied at no charge. Send a purchase order for the parts to Boeing Spares. Please refer to this service bulletin number and reference the airplane variable numbers in your purchase order. **C. Parts Necessary For Each Airplane** 1. Kits/Parts To get the parts shown below, refer to Paragraph 2.A., Material - Price and Availability.
**Notes Name**  **QTY Part Number /**  **Specification** (a) BUSHING, END CAP 2 251W3135-5 (a) The quantity specified is sufficient to replace the end cap bushing assemblies of one rudder PCU reaction link assembly. There are three rudder PCU reaction link assemblies on each airplane. 2. Parts and Materials Supplied by the Operator None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 17 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**3. Parts Modified and Reidentified The parts shown below are changed as shown in this service bulletin. The quantity (QTY) is the number of parts changed on each rudder PCU reaction link assembly.
**Notes New Part Number**  **Name QTY**  **Existing Part Number**  (a) (b) 251W3131-5 End Cap Assembly 2 251W3131-5 (a) Make the change in accordance with this service bulletin. (b) Identify on the part that the change given in this service bulletin was made. 4. Parts Removed and Not Replaced None. **D. Parts Necessary to Change Spares** It is recommended that operators check their records to see if they have any affected Reaction link Assemblies or Power Control Units with affected Reaction Link Assemblies fitted held as spare. Once this data is known, evaluate the condition and do the applicable action. To get the parts shown below, refer to Paragraph 2.A., Material - Price and Availability. The QTY given is for each rudder PCU reaction link assembly.
**QTY Name**  **Part Number** 2 (a) BUSHING, END CAP 251W3135-5 (a) The quantity specified is sufficient to replace the end cap bushing assemblies of one rudder PCU reaction link assembly. **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: December 01, 2011 777-27A0109 18 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:**  KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 4. 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. 5. 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. 6. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. **B. WORK INSTRUCTIONS PART 1 - RUDDER POWER CONTROL UNIT, REACTION LINK ASSEMBLY END CAP ASSEMBLY**  **- MAINTENANCE RECORD CHECK** 1. For each Rudder Power Control Unit (PCU) check maintenance records to identify the condition of its related reaction link assembly. a. Condition 1: The two End Cap Assembly Bushings have been replaced in accordance with CMM 27-21-77 dated March 01, 2011 or later, or an equivalent procedure has been used. b. Condition 2: The two End Cap Assembly Bushings have been replaced in accordance with versions of CMM 27-21-77 dated before March 01, 2011, or an equivalent procedure has been used, and it can be confirmed that a dry ice ethyl alcohol or Dowanol DPM bath was used to shrink fit the bushings into the end caps. c. Condition 3: The Reaction Link Assembly was manufactured before November 1, 2004 or after October 31, 2007.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 19 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**d. Condition 4: The condition of the reaction link assembly is not in accordance with Conditions 1, 2 or 3. 2. For each reaction link assembly found to have Conditions 1, 2 or 3, no further action is necessary. 3. For each reaction link assembly found to have Condition 4, do Part 2. **PART 2 - PCU REACTION LINK ASSEMBLY REPLACEMENT** 1. Do these steps for each reaction link assembly found to have Condition 4: a. Remove the applicable Rudder PCU and its related Reaction Link Assembly from the airplane. Refer to 777 AMM 27-21-11 as an accepted procedure. **NOTE:** It is not necessary to remove the Kick Link Assembly and the Damped Solenoid from the Power Control Unit. b. Install a serviceable Rudder PCU and its related Reaction Link Assembly. Refer to 777 AMM 27-21-11 as an accepted procedure. The PCU Reaction Link Assembly which is installed must be in accordance with Condition 1, Condition 2 or Condition 3. As an alternative, the PCU Reaction Link Assembly must have its bushings replaced in accordance with Part 3. 2. Put the airplane back to a serviceable condition. **PART 3 - PCU REACTION LINK ASSEMBLY END CAP ASSEMBLY BUSHING REPLACEMENT** 1. Replace the Reaction Link Assembly End Cap Assembly Bushings in accordance with FIGURE 1.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 20 of 22 **BOEING SERVICE BULLETIN 777-27A0109 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 Reaction Link Assembly.

**FIGURE 1: REACTION LINK ASSEMBLY, END CAP ASSEMBLY BUSHINGS REPLACEMENT (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 21 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT More Data**  **Qty Identification**  **Name Task**  **Step** Serial Number. (a) 2

- Reaction Link Leg Inspect 1 Serial Number. (a) 2 251W3135-5 Bushing, End Cap Inspect Refer to SOPM 20-50-03 as an accepted procedure. 2 251W3135-5 Bushing, End Cap Remove 2

Refer to CMM 27- 21-77 dated March 01, 2011 or later,Repair 2-1 as an accepted procedure. (b) 2 251W3135-5 Bushing, End Cap Install (New) 3

(c)

- SB 777-27A0109 Service Bulletin Num- ber Apply 4 (a) To make sure that marking of matched set serial numbers are legible and visible, on the outside face, on the Reaction Link Assembly link legs and their related End Cap Assemblies. If matched set markings are not visible on all of the parts, then apply markings as follows: Each Reaction Link leg and mating End Cap Assembly must be marked with the unique assembly serial number XXXX and serial dash number "-001" or "-002" where XXXX represents the digits in a unique number. When marking is complete, one Reaction Link leg and its mating/matched End Cap Assembly should be marked "S/N XXXX -001", andthe opposite Reaction Link leg and its mating/matched End Cap Assembly should be marked "S/N XXXX002". Refer to SOPM 20-50-10 code M as an accepted procedure to apply markings. (b) CMM 27-21-77 dated March 01, 2011, or later, uses dry ice ethyl alcohol or Dowanol DPM bath to shrink fit bushings into reaction link assembly end cap assemblies. (c) Use rubber stamp method. Refer to SOPM 20-50-10 as an accepted procedure. Make sure that the marking is on the outside face of each End Cap Assembly.

**FIGURE 1: REACTION LINK ASSEMBLY, END CAP ASSEMBLY BUSHINGS REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 01, 2011 777-27A0109 22 of 22 **BOEING SERVICE BULLETIN 777-27A0109 ALERT**  **ALERT**