# Boeing Alert Service Bulletin 737-27A1287: No revision named - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2009-0212; AD 2009-19-02 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-27A1287](https://openairdocs.org/service-documents/boeing/737-27a1287.md) - Title as filed: Boeing Alert Service Bulletin - Pages: 30 - PDF: https://openairdocs.org/files/sha256/55/e6/55e64ee5af3cbff3672e127b0ab6e395861d7165be4025ec750aebf6221d7901 - Page: https://openairdocs.org/service-documents/boeing/737-27a1287/file/55e64ee5af3c ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 30 ALERT ALERT Commercial Airplane Group 737 ALERTALERT Service Bulletin Number: 737-27A1287 Date: April 16, 2008 ATA System: 2721 SUBJECT: FLIGHT CONTROLS - Rudder Feel and Centering Unit - Inspection and Replacement of Spring Assembly BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2008 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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, 707, 717, 727, 737, 747, 757, 767, 777, BBJ, BOEING BUSINESS JET, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-90, the Boeing logo and the Boeing livery are among the trademarks owned by Boeing or its subsidiaries. No intellectual property license (express or implied) is granted in connection with this document or otherwise. ### Page 2 BLANK PAGE April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT BLANK PAGE ### Page 3 Table of Contents April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT Table of Contents Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 18 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 18 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 20 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 20 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 FIGURE 1: Inspection of the Inner Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURE 2: Replacement of Rudder Feel and Centering Unit Spring Assembly. . . . . . . . . . . . . 27 APPENDIX A: DATA SHEET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ### Page 4 Table of Contents April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT BLANK PAGE ### Page 5 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 30 ALERT ALERT Commercial Airplane Group 737 ALERTALERT Service Bulletin Number: 737-27A1287 Summary Date: April 16, 2008 ATA System: 2721 SUBJECT: FLIGHT CONTROLS - Rudder Feel and Centering Unit - Inspection and Replacement of Spring Assembly THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None BACKGROUND This service bulletin gives instructions to test the Rudder Feel and Centering Unit, or as an alternative to inspect the Rudder Feel and Centering Unit Inner Spring. This service bulletin has two parts. Part I describes recommended interim testing and inspection procedures. Part II provides instructions to replace the spring assembly and test the Rudder Feel and Centering Unit prior to returning the aircraft to service. The Rudder Feel and Centering Unit gives artificial feel to the rudder pedals, centers the input to the PCU, and transmits trim inputs to the aft control components. When the rudder pedals move, the rudder feel and centering unit springs provide feel force to the pilot. There are two springs that are attached to the rudder feel and centering unit, one inside the other, in a dual load path configuration. If one of these springs break, the rudder feel force decreases. If the second spring should also break, there would be very little artificial feel to the rudder pedals. This increases the susceptibility to Pilot Induced Oscillation and continued safe flight and landing of the airplane could be compromised. Boeing has received reports of low rudder pedal forces that were caused by broken inner springs in the rudder feel and centering unit. Boeing investigation of the removed parts found the root cause of the spring failure to be the result of a material defect within the raw material of the wire stock. Boeing has isolated the rudder feel and centering units that could be affected, based upon one batch of raw material. Based upon this information, Boeing has determined which airplanes could have discrepant springs installed. Boeing Service Related Problem (SRP) 737NG-SRP-27-0201 is related to this service bulletin. Boeing Service Request 1-680006998 also gives data about the broken inner spring on the rudder feel and centering unit. ### Page 6 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT ACTION At the times given in Paragraph 1.E, do the Rudder Pedal Forces Test given in Accomplishment Instructions PART I, with a minimum acceptance threshold of 60 pounds force. Alternatively, make an inspection of the rudder feel and centering unit spring, located in the vertical stabilizer. Repeat the test, or the inspection, at the intervals given in Paragraph 1.E., Compliance. Terminating action for the test and the inspection is the replacement of the rudder feel and centering unit spring assembly, located in the vertical stabilizer. Replace the two springs as a complete assembly. Before returning the airplane to service, do the Rudder Pedal Forces Test again as given in 737-600/700/800/900 AMM 27-21-00 to make sure the feel force is more than 60 pounds, and perform a Rudder Travel Test as given in 737-600/700/800/900 AMM 27-21-00. Boeing requests that the airplane identification and the serial numbers of the Rudder Feel and Centering Unit replaced be provided on the form given in Appendix A, or on a similar form. NOTE: No action is necessary on airplanes on which the Rudder Feel and Centering Unit Inner Spring has been found broken and replaced with a new spring part number 69-57900-6 before the release of this service bulletin. EFFECTIVITY All 737-600, -700, -700C, -800 and -900 airplane line numbers 1490 thru 1735, with some exceptions, plus airplane line numbers 2157. See Paragraph 1.A., Effectivity. 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. See Service Bulletin Paragraph 1.E. for compliance information. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are available for airplanes in warranty as of November 8, 2007. Please refer to Paragraph 2.B., Industry Support Information. . ### Page 7 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT MANPOWER MATERIAL INFORMATION Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability. Airplanes Total Task Hours Elapsed Hours Part I, Method I - Rudder Pedal Forces Test 0.50 0.25 Part I, Method II - Rudder Feel and Centering Unit Inner Spring Detail Inspection 3.25 3.25 Part II - Replacement of the Spring Assembly on Rudder Feel and Centering Unit 6.50 6.25 ### Page 8 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT OF SPRING ASSEMBLY IS THE REPLACEMENT TERMINATING ACTION SPRING INNER PEDAL FORCE DO A TEST OF THE RUDDER RUDDER PEDAL FORCES TEST, INNER SPRING OF THE SPRING ASSEMBLY ON THE RUDDER FEEL AND CENTERING UNIT MAKE AN INSPECTION OF THE AS AN ALTERNATE TO THE FWD A ASEE 1497511 ### Page 9 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 30 ALERT ALERT Commercial Airplane Group 737 ALERTALERT Service Bulletin Number: 737-27A1287 Date: April 16, 2008 ATA System: 2721 SUBJECT: FLIGHT CONTROLS - Rudder Feel and Centering Unit - Inspection and Replacement of Spring Assembly 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 This service bulletin is for the airplanes shown below. Airplane models: 737-700 737-700C 737-800 737-900 IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER AEROMEXICO (AMX) 1 YB858–YB859 YB861–YB862 AIR BERLIN (BER) 1 YB911 YD158–YD159 AIR CHINA (BEJ) 1 YB584–YB585 AIR EUROPA (ARE) 1 YK362–YK365 YK601 GROUP CONFIGURATION DESCRIPTION 1 - 737 600/700/800/900 airplanes line number 1490 through 1735, with some exceptions, plus airplane line number 2157. ### Page 10 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT AIR INDIA EXPRESS (IDC) 1 YJ942–YJ943 YK007 AIR NIPPON (ANK) 1Y G 2 5 1 AIR SAHARA (SAQ) 1 YM102–YM103 AIRTRAN AIRWAYS (CQT) 1 YB371 YB376–YB381 YM201–YM203 ALASKA AIRLINES (ASA) 1 YK403 YK431 ALOHA AIRLINES (ALO) 1 YB656 AUSTRIAN AIRLINES AG (AUL) 1 YC385–YC386 CHINA EASTERN AIRLINES (CEA) 1 YB571–YB574 YB576–YB577 YK457–YK459 CHINA EASTERN AIRLINES WUHAN (WUH) 1 YK456 YK460 CHINA SOUTHERN AIRLINES (GUN) 1 YB886–YB888 CHINA XINJIANG AIRLINES (XIJ) 1 YB884–YB885 CONTINENTAL AIRLINES (CAL) 1 YJ540 YJ542–YJ545 COPA AIRLINES (COP) 1 YA974–YA976 YJ593–YJ594 EASYJET (EZY) 1 YB132 ETHIOPIAN AIRLINES (ETH) 1 YB157 FLYGLOBESPAN.COM (FGS) 1 YJ941 YK136–YK137 FUTURA (FUA) 1 YJ012–YJ013 YK426 GOL AIRLINES (GOT) 1 YA631 ### Page 11 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT HAINAN AIRLINES (HNA) 1Y K 4 0 2 JET AIRWAYS (JPL) 1 YD334 YK401 YK404 KOREAN AIR (KAL) 1 YD591–YD595 LUXAIR (LUX) 1Y B 9 0 3 MALEV HUNGARIAN AIRLINES (HGA) 1 YA374–YA377 YC203 YC207 OKAY AIRWAYS COMPANY LIMITED (OKY) 1 YD333 OMAN AIR (OMR) 1Y J 9 0 2 PACIFIC BLUE AIRLINES (BLP) 1Y K 3 2 4 QANTAS (QAN) 1 YJ917–YJ922 ROYAL AIR MAROC (RAM) 1 YK303–YK304 RYANAIR (RYR) 1 YJ823–YJ826 YJ828 YJ830 YJ833–YJ853 SAS (SAS) 1 YD057 SHANDONG AIRLINES (SHG) 1Y K 5 1 1 SHANGHAI AIRLINES (SHA) 1 YC170 YD491 SHENZHEN AIRLINES (SHZ) 1 YD651 SOUTHWEST AIRLINES (SWA) 1 YA155–YA158 YA160–YA169 YA171–YA175 YA177–YA183 YA187 YA189–YA199 YM251–YM264 STERLING AIRLINES A/S (STR) 1Y J 9 3 4 ### Page 12 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT SUN COUNTRY AIRLINES (SCA) 1 YJ936 YK132 TRANSAVIA AIRLINES (TAV) 1 YB526 TRAVEL SERVICE (TSF) 1 YK405 TURKEY AIR FORCE AEW&C PGM (ZXN) 1Y G 2 1 1 UNITED STATES NAVY (USN) 1Y G 5 0 8 VIRGIN BLUE AIRLINES (VOZ) 1 YK325 YK327–YK330 WESTJET (WJI) 1 YB619–YB622 YB624–YB629 YK480–YK482 YK484 XIAMEN AIRLINES (XIA) 1 YM471 YM481–YM482 IDENTIFICATION BY VARIABLE NUMBER Variable Group YA155–YA158 1 YA160–YA169 1 YA171–YA175 1 YA177–YA183 1 YA187 1 YA189–YA199 1 YA374–YA377 1 YA631 1 YA974–YA976 1 YB132 1 YB157 1 YB371 1 YB376–YB381 1 YB526 1 YB571–YB574 1 YB576–YB577 1 YB584–YB585 1 YB619–YB622 1 YB624–YB629 1 ### Page 13 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT YB656 1 YB858–YB859 1 YB861–YB862 1 YB884–YB888 1 YB903 1 YB911 1 YC170 1 YC203 1 YC207 1 YC385–YC386 1 YD057 1 YD158–YD159 1 YD333–YD334 1 YD491 1 YD591–YD595 1 YD651 1 YG211 1 YG251 1 YG508 1 YJ012–YJ013 1 YJ540 1 YJ542–YJ545 1 YJ593–YJ594 1 YJ823–YJ826 1 YJ828 1 YJ830 1 YJ833–YJ853 1 YJ902 1 YJ917–YJ922 1 YJ934 1 YJ936 1 YJ941–YJ943 1 YK007 1 YK132 1 YK136–YK137 1 YK303–YK304 1 YK324–YK325 1 YK327–YK330 1 YK362–YK365 1 Variable Group ### Page 14 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT 2. Spares Affected None. B. Concurrent Requirements None. C. Reason This service bulletin gives instructions to test the Rudder Feel and Centering Unit, or as an alternative to inspect the Rudder Feel and Centering Unit Inner Spring. This service bulletin has two parts. Part I describes recommended interim testing and inspection procedures. Part II provides instructions to replace the spring assembly and test the Rudder Feel and Centering Unit prior to returning the aircraft to service. The Rudder Feel and Centering Unit gives artificial feel to the rudder pedals, centers the input to the PCU, and transmits trim inputs to the aft control components. When the rudder pedals move, the rudder feel and centering unit springs provide feel force to the pilot. There are two springs that are attached to the rudder feel and centering unit, one inside the other, in a dual load path configuration. If one of these springs break, the rudder feel force decreases. If the second spring should also break, there would be very little artificial feel to the rudder pedals. This increases the susceptibility to Pilot Induced Oscillation and continued safe flight and landing of the airplane could be compromised. Boeing has received nine reports of low rudder pedal forces that were caused by broken inner springs in the rudder feel and centering unit. Boeing investigation of the removed parts found the root cause of the spring failure to be the result of a material defect within the raw material of the wire stock. Boeing has isolated the rudder feel and centering units that could be affected, based upon one batch of raw material. Based upon this information, Boeing has determined which airplanes could have discrepant springs installed. YK401–YK405 1 YK426 1 YK431 1 YK456–YK460 1 YK480–YK482 1 YK484 1 YK511 1 YK601 1 YM102–YM103 1 YM201–YM203 1 YM251–YM264 1 YM471 1 YM481–YM482 1 Variable Group ### Page 15 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT Boeing Service Related Problem (SRP) 737NG-SRP-27-0201 is related to this service bulletin. Boeing Service Request 1-680006998 also gives data about the broken inner spring on the rudder feel and centering unit. D. Description At the times given in Paragraph 1.E, do the Rudder Pedal Forces Test given in Accomplishment Instructions PART I, with a minimum acceptance threshold of 60 pounds force. Alternatively, make an inspection of the rudder feel and centering unit spring, located in the vertical stabilizer. Repeat the test, or the inspection, at the intervals given in Paragraph 1.E., Compliance. Terminating action for the test and the inspection is the replacement of the rudder feel and centering unit spring assembly, located in the vertical stabilizer. Replace the two springs as a complete assembly. Before returning the airplane to service, do the Rudder Pedal Forces Test again as given in 737-600/700/800/900 AMM 27-21-00 to make sure the feel force is more than 60 pounds, and perform a Rudder Travel Test as given in 737-600/700/800/900 AMM 27-21-00. Boeing requests that the airplane identification and the serial numbers of the Rudder Feel and Centering Unit replaced be provided on the form given in Appendix A, or on a similar form. ### Page 16 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT NOTE: No action is necessary on airplanes on which the Rudder Feel and Centering Unit Inner Spring has been found broken and replaced with a new spring part number 69-57900-6 before the release of this service bulletin. 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. Table 1: Rudder Feel and Centering Unit Inner Spring, Test or Detail Inspection, and Replacement Condition Action Compliance Time (Not to exceed) Repeat Interval (Not to Exceed) All Airplanes (a) (b) Do the Rudder Pedal Forces Test as given in Accomplishment Instructions, Paragraph 3.B, Part I, Method I or Do a Detail Inspection of the Rudder Feel and Centering Unit Inner Spring as given in Accomplishment Instructions, Paragraph 3.B., Method II 30 days from the date on this service bulletin 120 days Replace the Spring Assembly on Rudder Feel and Centering Unit as given in Accomplishment Instructions, Paragraph 3.B, Part II 3 years from the date on this service bulletin - (a) Operators that have performed the Rudder Pedal Forces Test or have completed a detailed inspection of the Rudder Feel and Centering Unit inner spring prior to the receipt of this service bulletin, but have not replaced the inner spring, should repeat the testing or inspections at intervals of 120 days from the last inspection date, until the terminating action is completed. (b) Operators that have replaced the Spring Assembly prior to the receipt of this service bulletin have completed the terminating action of this service bulletin and are not required to perform any further tests or inspections of the Rudder Feel and Centering Unit inner spring. ### Page 17 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 30 BOEING SERVICE BULLETIN 737-27A1287 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 H. Weight and Balance Changes None. I. Electrical Load Data Not applicable. Task - Part A Number of Persons Task-Hours Elapsed Hours Access / Rudder Feel Force Test / Close 20 . 5 0 0 . 2 5 TOTAL FOR EACH AIRPLANE 0.50 0.25 Task - Part A, Alternative Number of Persons Task-Hours Elapsed Hours Access 1 1.50 1.50 Inspect 1 0.25 0.25 Close 1 1.50 1.50 TOTAL FOR EACH AIRPLANE 3.25 3.25 Task Number of Persons Task-Hours Elapsed Hours Access 1 1.50 1.50 Change 1 3.00 3.00 Close 1 1.50 1.50 Test 2 0.50 0.25 TOTAL FOR EACH AIRPLANE 6.50 6.25 ### Page 18 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT J. References 1. Existing Data: a. Service Related Problem (SRP) 737-SRP-27-0201, Rudder Feel and Centering Spring Issue b. 737 Maintenance Manual (AMM) Subject 12-22-21, 27-21-00, 27-21-17, 32-00-01 c. Component Maintenance Manual (CMM) 27-21-85 d. Boeing Standard Overhaul Practices Manual (BSOPM) 20-50-10 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. K. Publications Affected None. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. Drawing Number Title 251A3450 Feel And centering Instl - Rudder Control 65C25410 Centering Unit Assy - Rudder Controls ### Page 19 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT 2. MATERIAL INFORMATION A. Material - Price and Availability Boeing can supply the parts shown in Paragraph 2.C., Parts Necessary For Each Airplane as shown below. If there is a limit in the quantity (QTY) of parts, a supply sequence is given by Spares. B. Industry Support Information Boeing warranty remedies are available for 737 airplanes in warranty as of November 8, 2007. For labor hour reimbursement for airplanes in warranty as of that date, send a claim to Boeing Commercial Airplanes Group - Warranties. The part(s) 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 number(s) in your purchase order. C. Parts Necessary For Each Airplane 1. Kits/Parts: To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. Part Number Name Date QTY Unit Price thru May 31, 2008 69-57900-6 Spring Assembly for Rudder Feel and Centering Unit (a) (a) $3,138.00 (a) This part is under Boeing Spares management control. Send inquiries about the availability, terms and conditions to the Director of Spares and refer to this service bulletin number. (b) Send a no-charge purchase order and reference the airplane or airplanes that need this spring replacement. Send to the Director of Spares and refer to this service bulletin number. ### Page 20 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT NOTE: One spring assembly and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. 2. Parts and Materials Supplied by the Operator: 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability The operator can supply the tools shown in Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin. Tool price and supply data are not given. F. Special Tooling Necessary to do this Service Bulletin Tool No. F80212-30, Adapter - Force Check Tool, Rudder Pedal, is necessary to do the rudder feel force test prior to returning the airplane to service. Maintenance and overhaul tools in the manuals shown in Paragraph 1.J., References, can also be necessary. Examine operator tool supply to make sure all necessary tools are available. Part Number / Specification QTY Name Notes 69-57900-6 1 Spring Assembly for Rudder Feel and Centering Unit Part Number / Specification QTY Name Notes BACN10JC3 1 Nut, Self-Locking, Hex, Low Height (a) BACN10JC5 1 Nut, Self-Locking, Hex, Low Height (a) NAS1149D0363J 1 Washer (a) NAS1149D0563J 1 Washer (a) BMS 3-33 (preferred) or MIL-G-23827 0.5 pint Grease (a) BMS 10-60, Type I Clear 0.5 pint Coating (a) (b) (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data (b) You can use an alternative coating that is clear and is resistant to BMS 3-11 hydraulic fluid. ### Page 21 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION 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. Unless shown differently, these dimensions and tolerances are used: — Linear dimensions are in inches — Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch — Angular tolerance is plus or minus 2 degrees — Hole dimensions for standard solid rivets are given in 737 Structural Repair Manual, Chapter 51 — Torque limits to tighten nuts and bolts are given in 737 Structural Repair Manual, Chapter 51. 4. For approved fastener and process material substitutions, refer to 737 Structural Repair Manual, Chapter 51. 5. If the length of fasteners specified in this service bulletin do not meet the installation standards, fasteners of the same specification, or an approved substitute, one grip length longer or shorter may be used. B. WORK INSTRUCTIONS PART I - DETERMINE IF THE RUDDER FEEL AND CENTERING UNIT INNER SPRING IS DAMAGED OR BROKEN 1. METHOD I - RUDDER PEDAL FORCES TEST a. Do the "Rudder Pedal Forces Test" at the times given in Paragraph 1.E., Compliance, as given in 737-600/700/800/900 AMM 27-21-00. This test requires Tool Part Number F80212- 30 (Reference SPL-1681, Adapter - Force Check Tool, Rudder Pedal). The test requires access to the flight compartment, and the test requires hydraulic system pressurization. NOTE: Refer to the Work Instructions for "Part II - Replacement of Spring Assembly on Rudder Feel and Centering Unit" for more data about use of Tool Number F80212- 30. b. The acceptance data for this service bulletin is 60 lbf (266.9 N) minimum. If the pedal force is less than 60 lbf (266.9 N), then do "Part II - Replacement of Spring Assembly on Rudder Feel and Centering Unit" before further flight. ### Page 22 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT NOTE: The Rudder Pedal Forces Test given in 737-600/700/800/900 AMM 27-21-00 has an acceptance criteria of 60 lbf (266.9 N) to 82.0 lbf (364.8 N). If the forces during the Rudder Pedal Forces Test are higher than 82.0 lbf (364.8 N) you can do a Rudder Control Cables RA and RB Adjustment as given in 737-600/700/800/900 AMM 27-21-00 and than do a Rudder Pedal Forces Test again as given in 737-600/ 700/800/900 AMM 27-21-00. c. Put the airplane back to a serviceable condition. As an alternative to the PART I - RUDDER PEDAL FORCES TEST, you can make an inspection of the rudder feel and centering unit springs, as given in PART I, METHOD II - RUDDER FEEL AND CENTERING UNIT INNER SPRING DETAIL INSPECTION. 2. METHOD II - RUDDER FEEL AND CENTERING UNIT INNER SPRING DETAIL INSPECTION a. At the times given in Paragraph 1.E., Compliance, get access to panel 324BR. See Figure 1. CAUTION: MAKE SURE THAT THE RUDDER IS PREVENTED FROM MOVING WHEN YOU DO THIS INSPECTION. THE RUDDER CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT IF IT SHOULD INADVERTENTLY MOVE DURING THIS INSPECTION. b. Remove Panel 324BR, and keep the fasteners for re-use. There are 81 cross-recess fasteners that are identical plus four cross-recess grounding fasteners, one near each corner. The grounding fasteners are shorter. c. Do a close visual inspection of the inner spring. See Figure 1. Supplement the available lighting with a direct source of good lighting. Use a soft tool to push on the side of the inner spring, to make sure it is not loose or broken. d. If the inner spring is loose, or has indications of failure, do the "Part II - Replacement of Spring Assembly on Rudder Feel and Centering Unit" before further flight. e. Inspection acceptance criteria is an inner spring that is not loose and that does not have indications of failure. f. Install Panel 324BR using the fasteners that were kept for re-use. NOTE: Refer to the Work Instructions for "Part II - Replacement of Spring Assembly on Rudder Feel and Centering Unit" for more data about the fasteners that attach this panel to the structure. g. Put the airplane back to a serviceable condition. PART II - REPLACEMENT OF SPRING ASSEMBLY ON RUDDER FEEL AND CENTERING UNIT 1. Get access to panel 324BR. See Figure 1 ### Page 23 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT CAUTION: MAKE SURE THAT THE RUDDER IS PREVENTED FROM MOVING WHEN YOU DO THIS TASK. THE RUDDER CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT IF IT SHOULD INADVERTENTLY MOVE DURING THIS TASK. 2. Remove pressure from the rudder hydraulic systems A, B and Standby. Refer to 737-600/700/ 800/900 AMM 27-21-00/201. 3. Move the rudder trim knob to five (5) to seven (7) degrees NOSE LEFT, and wait until the rudder trim indicator stops. The rudder trim is electrically-powered. 4. Remove Panel 324BR, and keep the fasteners for re-use. There are 81 cross-recess fasteners that are identical plus four cross-recess grounding fasteners, one near each corner. The grounding fasteners are shorter. CAUTION: WIND GUSTS CAN CAUSE THE RUDDER TO MOVE, CAUSING INJURY TO PERSONNEL. 5. Make sure the roller, that is contained within the arm assembly of the feel unit, is centered within the detent of the cam. The cam is attached to the main shaft of the feel unit. You can move the rudder by hand in the LEFT direction to center the roller within the cam. This will help reduce the preload on the springs to a minimum force. 6. Replace the spring assembly, as given in Figure 2. 7. On the rudder feel and centering unit, use a black marker or rubber stamp to mark the letter R after the serial number. The suffix R indicates the suspect discrepant springs have been changed out. Apply a protective overcoat that is resistant to hydraulic fluid (BMS 3-11), such as BMS 10- 60 Type I, clear. Refer to SOPM 20-50-10. NOTE: For some airplanes, the serial number can be found on the left side of the rudder feel and centering unit. It can also be on the arm assembly, or near the pivot end near the three lightening holes. The serial number should be next to the part number for the assembly, which is 65C25410-7. Serial numbers should be prefixed with the abbreviation S/N, and are in the range of 3609 to 3820. You may need a strong light and an inspection mirror to find the serial number. It may help to move the rudder trim knob to NOSE RIGHT, for better access. Remember to record the serial number on the Appendix A data sheet. 8. Move the rudder trim knob until the rudder trim indicator returns to 0.00 +/- 0.25 units of trim. 9. Disconnect the steering (for the nose landing gear) from the rudder system by moving the towing lever forward, to the tow position. Refer to 737-600/700/800/900 AMM 32-00-01. NOTE: It is not necessary to disconnect the steering if the airplane is on jacks and the nose landing gear is fully extended. 10. Supply rudder hydraulic system pressure from rudder hydraulic systems A, B or Standby. Refer to 737-600/700/800/900 AMM 27-21-00/201. 11. Do the test of the rudder feel and centering system that follows: a. Operate the rudder pedals through their full travel range, three (3) times; ### Page 24 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT b. Make sure the rudder trim indicator shows zero (0) units of trim; c. Push the Captain’s LEFT rudder pedal forward approximately 0.5 inch, and release it. Make sure each side of the rudder trailing edge aligns with the tab on the rudder index plate. Refer to 737 AMM 27-21-17. d. Push the Captain’s RIGHT rudder pedal forward approximately 0.5 inch, and release it. Make sure each side of the rudder trailing edge aligns with the tab on the rudder index plate. 12. Do "Rudder Pedal Forces Test" as given in 737-600/700/800/900 AMM 27-21-00. This test requires Tool Number F80212-30, Adapter - Force Check Tool, Rudder Pedal, Reference SPL- 1681. The test requires access to the flight compartment, and the test requires hydraulic system pressurization. NOTE: The data that follows can help when you use Tool Number F80212-30: 1. There is some variability with use of the tool. Sometimes it may be useful to take three readings for each rudder pedal. 2. You need two people to do the test. One person can sit in one of the seats and push on the tool. The other person can measure the rudder pedal movement and record the results. 3. Make the measurement of the rudder pedal movement on the OPPOSITE pedal. For example, if the tool is on Captain’s right rudder pedal, make the measurement on the First Officer’s right rudder pedal. 4. You can use a ruler or straightedge that is placed against the rudder pedal, to measure the rudder pedal movement. It may help to attach a pointer to the pedal, using tape. 5. When the rudder pedal reaches 3.6 +/- 0.1 inches, DO NOT relax the force on the tool or the test will fail. If the 3.6 +/- 0.1 inch travel limit is exceeded, release the pedal to neutral and start again. 13. Test acceptance criteria is a pedal force that is between 60.0 lbf (266.9 N) to 82.0 lbf (364.8 N). NOTE: If you do not pass the Rudder Pedal Forces Test, you can do the Rudder Control Cables RA and RB Adjustment, as given in 737 AMM 27-21-00. Then do the Rudder Pedal Forces Test again, as given in 737-600/700/800/900 AMM 27-21-00. 14. Do the Rudder Travel Test as given in 737-600/700/800/900 AMM 27-21-00. 15. Put the airplane back to a serviceable condition. a. Put the Rudder Systems A, B, and Standby back to the condition before the pressure removal. Refer to 737-600/700/800/900 AMM 27-21-00. b. Install Panel 324BR using the fasteners that were kept for re-use. There are 81 cross-recess fasteners that are identical plus four cross-recess grounding fasteners, one near each corner. The grounding fasteners are shorter and are made of CRES. Install the grounding fasteners in the first hole away from the corner, in the long (lengthwise) direction and tighten to 31.5 - 38.5 in-lb torque. Tighten the 81 identical fasteners to 18 - 25 in-lb torque. ### Page 25 April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT c. Make sure you remove tow pins and landing gear downlocks, if they were installed, before returning to service. 16. Send to Boeing the airplane identification and rudder feel and centering unit serial number on the form given in Appendix A, or on a similar form. ### Page 26 FIGURE 1: Inspection of the Inner Spring April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT FIGURE 1: Inspection of the Inner Spring 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 one airplane. STEP TASK NAME PART NUMBER QTY NOTES 1 Examine Inner Spring 69-57907-3 1 (a) (a) Do a close visual inspection of the inner spring. Supplement the available lighting with a direct source of good lighting. Use a soft tool to push on the side of the inner spring, to make sure it is not loose or broken. INNER SPRING 324BR ACCESS PANEL 1 1497514 (SHEET 1 OF 1) ### Page 27 FIGURE 2: Replacement of Rudder Feel and Centering Unit Spring Assembly April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT FIGURE 2: Replacement of Rudder Feel and Centering Unit Spring Assembly A A NUT BEARING SHAFT SLIDER SPRING SEAT BEARING ARM ASSEMBLY WASHER SPRING ASSEMBLY NUT WASHER BOLT ASSEMBLY FWD FWD 1 10 6 5 A-A 1 10 91 1 9 83 2 4 7 1497519 (SHEET 1 OF 3) ### Page 28 FIGURE 2: Replacement of Rudder Feel and Centering Unit Spring Assembly April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 30 BOEING SERVICE BULLETIN 737-27A1287 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 one airplane. STEP TASK NAME PART NUMBER QTY NOTES 1 Remove Nut Washer Nut Washer BACN10JC3 NAS1149D0363J BACN10JC5 NAS1149D0563J 1 1 1 1 (a)(b) 2 Compress Spring Assembly 69-57900-6 1 Use hand pressure to compress the springs, to remove the load on the Bolt. WARNING: AFTER YOU REMOVE THE BOLT ASSEMBLY, THE RUDDER CAN MOVE, IF THERE IS WIND. THIS CAN CAUSE INJURY TO PERSONNEL. 3 Remove / Keep Bolt Assembly 69-27229-13 1 4 Remove Spring Assembly 69-57900-6 1 Disconnect the spring assembly from the arm assembly. 5 Lubricate Bearing - - Make sure you see grease on the spherical surface of the bearing which contacts the bearing seat. (c) 6 Lubricate Slider Shaft - - Make sure you see grease on the slider shaft. (c) 7 Install / New Spring Assembly 69-57900-6 1 Insert the spring assembly through the bearing seat 8 Install / Kept Bolt Assembly 69-27229-13 1 Use this Bolt Assembly to attach the Rod End Assembly to the Arm Assembly. (d) 9 Install Washer (New or Kept) Nut (New) NAS1149D0563J BACN10JC5 1 1 Tighten the nut to 50 - 60 in-lb torque. Refer to 737-600/700/800/900 IPC 27-21-82-01(a) 10 Install Washer (New or Kept) Nut (New) NAS1149D0363J BACN10JC3 1 1 Tighten the nut to 12 - 15 in-lb torque. Refer to 737-600/700/800/900 IPC 27-21-82-01 (a)(e) (a) It is acceptable to keep and install the washers removed if they are not damaged. (b) Discard BACN10JC3 and BACN10JC5 nuts. (SHEET 2 OF 3) ### Page 29 FIGURE 2: Replacement of Rudder Feel and Centering Unit Spring Assembly April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT (c) CAUTION:THE GREASE ON THE SHAFT IS NECESSARY TO PREVENT JAMMING OF THE RUDDER DUE TO FREEZING OF CONDENSED MOISTURE. APPLY A LIGHT COATING OF BMS 3-33 GREASE (PREFERRED) OR MIL-G-23827, TO THE SPHERICAL SURFACE OF THE BEARING, AND TO THE SLIDER SHAFT. REFER TO AMM 12-22-21 FOR THE TASK TO LUBRICATE THE SPRING SLIDER SHAFT. (d) Install with head at top, shank pointing down. Use hand pressure to compress the springs. (e) Do NOT tighten the BACN10JC5 nut again after you tighten the BACN10JC3 nut. STEP TASK NAME PART NUMBER QTY NOTES (SHEET 3 OF 3) ### Page 30 APPENDIX A: DATA SHEET April 16, 2008 737-27A1287 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 30 BOEING SERVICE BULLETIN 737-27A1287 ALERT ALERT APPENDIX A: DATA SHEET Boeing requests the airplane identification and the serial number of the Rudder Feel and Centering Unit. You can use this form to record the data. Airplane Identification (Line Number, Serial Number, Omni Number or Registry Number) Rudder Feel and Centering Unit Serial Number Send this form to: The Boeing Company Spares Distribution Center Repair and Overhaul Area SSA111 Building 2201, Door W10 2201 South 142nd Street Seatac, WA 98168 Attn: David Henry SB 737-27A1259 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.