### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-27A2497**  Original Issue: September 30, 2010 ATA System: 2722 **SUBJECT:** FLIGHT CONTROLS - Rudder and Rudder Trim Control System - Rudder Power Control Module Change Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 1 of 24 2.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 2 of 24 **BOEING SERVICE BULLETIN 747-27A2497 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 13 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 15 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 16 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 FIGURE 1: UPPER RUDDER POWER CONTROL MODULE - REPLACEMENT. . . . . . . . . . . . 21 FIGURE 2: LOWER RUDDER POWER CONTROL MODULE - REPLACEMENT . . . . . . . . . . . 23

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 3 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 4 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **Number: 747-27A2497** Original Issue: September 30, 2010 ATA System: 2722 **SUBJECT:** FLIGHT CONTROLS - Rudder and Rudder Trim Control System - Rudder Power Control Module Change 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 ensures that the upper or lower rudder Power Control Modules (PCM) do not create a hard-over condition in the event of a manifold cracking and separation. This will be accomplished by replacing the rudder PCM manifold access cap with a two-piece cap that includes a retention feature for the yaw damper modulating piston assembly in the rudder PCM. The secondary retention engages an existing window in the sleeve of the yaw damper modulating piston assembly. This restricts the yaw damper modulating piston assembly from significantly shifting and causing considerable uncommanded input to the Rudder PCM main control valve in an event where the primary retention endcap is detached or compromised. Uncommanded input to the Rudder PCM main control valve may create a hard-over condition. A hard-over condition can result in a high speed runway excursion after touchdown in a landing. A lower rudder hard-over left event was reported by an operator of a 747-400 series airplane. The hard-over was caused by the lower rudder PCM manifold cracking in the area of the yaw damper cavity end-cap. This allowed the yaw damper sleeve to shift, giving the system a lower rudder left input. Three additional rudder PCM manifold cracking events have been reported by other operators. These events did not result in a hard-over, but created the need for a retention feature solution. Upon investigation, it was determined that the 747-SP fleet could be susceptible to the same failure because they use the same manifold sub-assembly as the 747-400 aircraft. Boeing Service Related Problem (SRP) 747-SRP-27-0193 is related to this service bulletin. **ACTION (PRR 85656-R)** Open access to the upper and the lower rudder PCM. Replace each rudder PCM. As an alternative, you can make the change to each PCM as given in Parker service bulletin 241700-27-333. Do the operational tests. Close access. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 5 of 24**EFFECTIVITY** All 747SP 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. Boeing recommends that the change given in this service bulletin be done within 24 months or 8,400 flight hours after the original issue date on this service bulletin, whichever occurs first. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the configuration changes given in this service bulletin. **MANPOWER** Work Package 1, Option 1: Replace the Upper Rudder PCM: **Elapsed Hours Total Task Hours**  **Airplanes** 5.50 11.00 Group 1 Work Package 1, Option 2: Change the Upper Rudder PCM: **Elapsed Hours Total Task Hours**  **Airplanes** 1.75 2.75 Group 1 Work Package 2, Option 1: Replace the Lower Rudder PCM: **Elapsed Hours Total Task Hours**  **Airplanes** 5.50 11.00 Group 1 Work Package 2, Option 2: Change the Lower Rudder PCM: **Elapsed Hours Total Task Hours**  **Airplanes** 1.75 2.75 Group 1
**MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 6 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 7 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 8 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-27A2497**  Original Issue: September 30, 2010 ATA System: 2722 **SUBJECT:** FLIGHT CONTROLS - Rudder and Rudder Trim Control System - Rudder Power Control Module Change 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. An equivalent change is on subsequent production airplanes. Refer to PRR 85656-R for data about this change. Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.

**DESCRIPTION CONFIGURATION**  **GROUP** All 747SP airplanes.

- 1

Airplane Models: 747SP **Group Variable Number**  1 RG001 - RG009 1 RG091 1 RG095 1 RG101 - RG104 1 RG121 - RG126

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 9 of 24**Group Variable Number**  1 RG141 - RG142 1 RG161 - RG164 1 RG171 - RG174 1 RG191 - RG193 1 RG211 - RG213 1 RG221 - RG222 1 RH101 - RH102 1 RH111 - RH112 1 RH121 - RH122 2. Spares Affected Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for the recommended use. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of this service bulletin ensures that the upper or lower rudder Power Control Modules (PCM) do not create a hard-over condition in the event of a manifold cracking and separation. This will be accomplished by replacing the rudder PCM manifold access cap with a two-piece cap that includes a retention feature for the yaw damper modulating piston assembly in the rudder PCM. The secondary retention engages an existing window in the sleeve of the yaw damper modulating piston assembly. This restricts the yaw damper modulating piston assembly from significantly shifting and causing considerable uncommanded input to the Rudder PCM main control valve in an event where the primary retention endcap is detached or compromised. Uncommanded input to the Rudder PCM main control valve may create a hard-over condition. A hard-over condition can result in a high speed runway excursion after touchdown in a landing. A lower rudder hard-over left event was reported by an operator of a 747-400 series airplane. The hard-over was caused by the lower rudder PCM manifold cracking in the area of the yaw damper cavity end-cap. This allowed the yaw damper sleeve to shift, giving the system a lower rudder left input. Three additional rudder PCM manifold cracking events have been reported by other operators. These events did not result in a hard-over, but created the need for a retention feature solution. Upon investigation, it was determined that the 747-SP fleet could be susceptible to the same failure because they use the same manifold sub-assembly as the 747-400 aircraft. Boeing Service Related Problem (SRP) 747-SRP-27-0193 is related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 10 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT D. Description**  Open access to the upper and the lower rudder PCM. Replace each rudder PCM. As an alternative, you can make the change to each PCM as given in Parker service bulletin 241700-27-333. Do the operational tests. Close access. Put the airplane back to a serviceable condition. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 325, 326 747SP **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Boeing recommends that the change given in this service bulletin be done within 24 months or 8,400 flight hours after the original issue date on this service bulletin, whichever occurs first. **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 Work Package 1, Option 1: Replace the Upper Rudder Power Control Module (PCM)**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**

1.50 3.00 2 Open Access 2.00 4.00 2 Figure 1 0.50 1.00 2 Test 1.50 3.00 2 Close Access 5.50 11.00 Total per airplane

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 11 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT Work Package 1, Option 2: Change the Upper Rudder Power Control Module (PCM)**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**

0.50 1.00 2 Open Access 0.75 0.75 1 Test 0.50 1.00 2 Close Access 1.75 2.75 Total per airplane **Work Package 2, Option 1: Replace the Lower Rudder Power Control Module (PCM) Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task** 

1.50 3.00 2 Open Access 2.00 4.00 2 Figure 2 0.50 1.00 2 Test 1.50 3.00 2 Close Access 5.50 11.00 Total per airplane **Work Package 2, Option 2: Change the Lower Rudder Power Control Module (PCM) Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task** 

0.50 1.00 2 Open Access 0.75 0.75 1 Test 0.50 1.00 2 Close Access 1.75 2.75 Total per airplane Work Package Number 1 can be done at the same time as Work Package Number 2. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 12 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT J. References**  1. Existing Data a. Engineering Change Memo PRR 85656-R b. 747-100/200/300 Aircraft Maintenance Manual (AMM) 12-09-07, 22-16-00, 24-22-00, 27-22-15, 27-22-16, 29-11-00 c. Parker Service Bulletin 241700-27-333 **NOTE:** The supplier was told to send copies of the service bulletin to each operator. d. Service Related Problem (SRP) 747-SRP-27-0193 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**  27-22 747 Maintenance Manual 27-22 747 Illustrated Parts Catalog 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary.
**L. Interchangeability and Intermixability of Parts** Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 13 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 14 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **B. Industry Support Information** Boeing warranty remedies are not available for the configuration changes given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator
**Notes Correspond-**  **ing Existing Parker Part**  **Number Existing Boe** **ing Part Num ber**  **Name QTY**  **Correspond- ing New Park** **er Part Num ber / Specifi**  **cation New Boeing**  **Part Number / Specifica**  **tion** (a) (b) (c) 241700-1005 60B80093-3 Rudder PCM 2 241700-9007 60B80093-104 (a) (b) (c) 241700-1007 60B80093-4 (a) You cannot use the existing part to replace the new or changed part. (b) Parker service bulletin 241700-27-333 gives instructions to change the existing part to the new part. (c) The Upper and Lower PCMs in the 747SP are exactly the same and have the same part numbers. There is one Upper and one Lower PCM per airplane.
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** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 15 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT 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: September 30, 2010 747-27A2497 16 of 24 **BOEING SERVICE BULLETIN 747-27A2497 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. The instructions identified in Paragraph 3.B., Work Instructions and Figure(s), give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. The work instructions are divided into work packages. Task Hours and Elapsed Hours for each package are given in Paragraph 1.G., Manpower. You can do each work package independently. 5. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. **B. WORK INSTRUCTIONS WORK PACKAGE 1, Option 1: Replace the Upper Rudder Power Control Module (PCM)**  1. Replace the Upper Rudder PCM in accordance with Figure 1. 2. Put the airplane back to a serviceable condition. **NOTE:** It is recommended to make sure that the rudder actuators for the upper rudder are correctly adjusted. Refer to 747-100/200/300 AMM 27-22-16 "Test Rudder Actuator" as an accepted procedure. **WORK PACKAGE 1, Option 2: Change the Upper Rudder Power Control Module (PCM) while installed on the airplane**  1. Supply electrical power. Refer to 747-100/200/300 AMM 24-22-00 as an accepted procedure. 2. Remove power from hydraulic systems 1 and 3. Refer to 747-100/200/300 AMM 29-11-00 as an accepted procedure.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 17 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT NOTE:**  Make sure to depressurize hydraulic systems 1 and 3 when you remove power from these systems. 3. Set ELEVATOR/RUDDER FLT CONTROLS HYD POWER system switches No. 1 and 3 on pilot's overhead panel P5 to OFF. 4. Open ELEVATOR/RUDDER FLT CONTROLS circuit breakers for systems No. 1 and 3 on panel P12. 5. Open the yaw damper circuit breakers on P7. 6. Remove the access panels 324HR and 324HL for access to the Upper Rudder PCM. Refer to 747-100/200/300 AMM 12-09-07 as an accepted procedure. **WARNING:** RELEASE HYDRAULIC SYSTEM PRESSURE BEFORE YOU OPEN THE HYDRAULIC SYSTEM. HYDRAULIC FLUID THAT HAS PRESSURE CAN CAUSE INJURIES TO PERSONNEL. **WARNING:** DO NOT LET THE HYDRAULIC FLUID STAY ON YOUR SKIN. YOU CAN ABSORB POISONOUS MATERIALS FROM THE FLUID THROUGH YOUR SKIN. **CAUTION:** IMMEDIATLY CLEAN ALL THE HYDRAULIC FLUID THAT FALLS ON THE AIRPLANE PARTS. THE FLUID CAN CAUSE DAMAGE TO THE PAINT AND CORROSION TO SOME PARTS. 7. Change the Upper Rudder PCM in accordance with Parker service bulletin 241700-27-333. 8. Close the yaw damper circuit breakers on P7. 9. Close ELEVATOR/RUDDER FLT CONTROLS circuit breakers for systems No. 1 and 3 on panel P12. 10. Set ELEVATOR/RUDDER FLT CONTROLS HYD POWER system switches No. 1 and 3 on pilot's overhead panel P5 to NORM. 11. Supply power to hydraulic systems 1 and 3. Refer to 747-100/200/300 AMM 29-11-00 as an accepted procedure. 12. Do an operational test of the rudder control system. Refer to 747-100/200/300 AMM 27-22-15 "Test Rudder Control Module" as an accepted procedure. 13. Do an operational test of the yaw damper system. Refer to 747-100/200/300 AMM 22-16-00 "Operational Test - Yaw Damper System" as an accepted procedure. 14. Make sure that the Upper Rudder PCM does not have hydraulic leaks. 15. Install the access panels 324HR and 324HL. Refer to 747-100/200/300 AMM 12-09-07 as an accepted procedure. 16. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 18 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT WORK PACKAGE 2, Option 1: Replace the Lower Rudder Power Control Module (PCM)**  1. Replace the Lower Rudder PCM in accordance with Figure 2. 2. Put the airplane back to a serviceable condition. **NOTE:** It is recommended to make sure that the rudder actuators for the lower rudder are correctly adjusted. Refer to 747-100/200/300 AMM 27-22-16 "Test Rudder Actuator" as an accepted procedure. **WORK PACKAGE 2, Option 2: Change the Lower Rudder Power Control Module (PCM) while installed on the airplane**  1. Supply electrical power. Refer to 747-100/200/300 AMM 24-22-00 as an accepted procedure. 2. Remove power from the hydraulic systems 2 and 4. Refer to 747-100/200/300 AMM 29-11-00 as an accepted procedure. **NOTE:** Make sure to depressurize the hydraulic systems 2 and 4 when you remove power from these systems. 3. Set ELEVATOR/RUDDER FLT CONTROLS HYD POWER system switches No. 2 and 4 on pilot's overhead panel P5 to OFF. 4. Open ELEVATOR/RUDDER FLT CONTROLS circuit breakers for systems No. 2 and 4 on panel P12. 5. Open the yaw damper circuit breakers on P7. 6. Remove the access panels 324DR and 324DL for access to the Lower Rudder PCM. Refer to 747-100/200/300 AMM 12-09-07 as an accepted procedure. **WARNING:** RELEASE HYDRAULIC SYSTEM PRESSURE BEFORE YOU OPEN THE HYDRAULIC SYSTEM. HYDRAULIC FLUID THAT HAS PRESSURE CAN CAUSE INJURIES TO PERSONNEL. **WARNING:** DO NOT LET THE HYDRAULIC FLUID STAY ON YOUR SKIN. YOU CAN ABSORB POISONOUS MATERIALS FROM THE FLUID THROUGH YOUR SKIN. **CAUTION:** IMMEDIATLY CLEAN ALL THE HYDRAULIC FLUID THAT FALLS ON THE AIRPLANE PARTS. THE FLUID CAN CAUSE DAMAGE TO THE PAINT AND CORROSION TO SOME PARTS. 7. Change the Lower Rudder PCM in accordance with Parker service bulletin 241700-27-333. 8. Close the yaw damper circuit breakers on P7. 9. Close ELEVATOR/RUDDER FLT CONTROLS circuit breakers for systems No. 2 and 4 on panel P12. 10. Set ELEVATOR/RUDDER FLT CONTROLS HYD POWER system switches No. 2 and 4 on pilot's overhead panel P5 to NORM.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 19 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**11. Supply power to the hydraulic systems 2 and 4. Refer to 747-100/200/300 AMM 29-11-00 as an accepted procedure. 12. Do an operational test of the rudder control system. Refer to 747-100/200/300 AMM 27-22-15 "Test Rudder Control Module" as an accepted procedure. 13. Do an operational test of the yaw damper system. Refer to 747-100/200/300 AMM 22-16-00 "Operational Test - Yaw Damper System" as an accepted procedure. 14. Make sure that the Lower Rudder PCM does not have hydraulic leaks. 15. Install the access panels 324DR and 324DL. Refer to 747-100/200/300 AMM 12-09-07 as an accepted procedure. 16. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 20 of 24 **BOEING SERVICE BULLETIN 747-27A2497 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 this figure.

**FIGURE 1: UPPER RUDDER POWER CONTROL MODULE - REPLACEMENT (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 21 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) (b) (d) 1 60B80093-( ) Rudder PCM Remove 1 (c) (e) 1 60B80093-104 Rudder PCM Install (New) 2 (a) Refer to Paragraph 2.C.2 for existing Rudder PCM part number. (b) Refer to 747-100/200/300 AMM 27-22-15 "Remove Rudder Control Module" as an accepted procedure. (c) Refer to 747-100/200/300 AMM 27-22-15 "Install Rudder Control Module" as an accepted procedure. (d) Corresponding Parker part number 241700-100( ). (e) Corresponding Parker part number 241700-9007.

**FIGURE 1: UPPER RUDDER POWER CONTROL MODULE - REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 22 of 24 **BOEING SERVICE BULLETIN 747-27A2497 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 this figure.

**FIGURE 2: LOWER RUDDER POWER CONTROL MODULE - REPLACEMENT (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 23 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) (b) (d) 1 60B80093-( ) Rudder PCM Remove 1 (c) (e) 1 60B80093-104 Rudder PCM Install (New) 2 (a) Refer to Paragraph 2.C.2 for existing Rudder PCM part number. (b) Refer to 747-100/200/300 AMM 27-22-15 "Remove Rudder Control Module" as an accepted procedure. (c) Refer to 747-100/200/300 AMM 27-22-15 "Install Rudder Control Module" as an accepted procedure. (d) Corresponding Parker part number 241700-100( ). (e) Corresponding Parker part number 241700-9007.

**FIGURE 2: LOWER RUDDER POWER CONTROL MODULE - REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 30, 2010 747-27A2497 24 of 24 **BOEING SERVICE BULLETIN 747-27A2497 ALERT**  **ALERT**