# Boeing Alert Service Bulletin 747-27A2497: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2011-0571; AD 2012-03-09 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 747-27A2497](https://openairdocs.org/service-documents/boeing/747-27a2497.md)
- Title as filed: U.S. DOT/FAA - Service Bulletin
- Pages: 24
- PDF: https://openairdocs.org/files/sha256/43/7c/437cf6537aa59c0bf60940f31688c547f269c6df4e22fba564e31d7266c27d08
- Page: https://openairdocs.org/service-documents/boeing/747-27a2497/file/437cf6537aa5

## Text

Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

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.
9E991ECCN:
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Unpublished Work - All Rights Reserved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Copyright © Unpublished Work - See page 1 for details.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
2.0

### Page 2

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Copyright © Unpublished Work - See page 1 for details.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

### Page 3

Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A. Effectivity ................................................ 9
1. Airplanes ............................................. 9
2. Spares Affected ........................................ 1 0
B. Concurrent Requirements ...................................... 1 0
C. Reason ................................................ 1 0
D. Description .............................................. 1 1
E. Compliance .............................................. 1 1
F. Approval ............................................... 1 1
G. Manpower .............................................. 1 1
H. Weight and Balance Changes .................................... 1 2
I. Electrical Load Data ......................................... 1 2
J. References .............................................. 1 3
1. Existing Data .......................................... 1 3
2. Data supplied with this Service Bulletin ............................ 1 3
3. Installation Drawings Used in the Preparation of this Service Bulletin ............ 1 3
K. Publications Affected ........................................ 1 3
L. Interchangeability and Intermixability of Parts ........................... 1 3
2. MATERIAL INFORMATION ........................................ 1 5
A. Material - Price and Availability ................................... 1 5
B. Industry Support Information .................................... 1 5
C. Parts Necessary For Each Airplane ................................. 1 5
1. Kits/Parts ............................................ 1 5
2. Parts and Materials Supplied by the Operator ........................ 1 5
3. Parts Modified and Reidentified ................................ 1 5
4. Parts Removed and Not Replaced .............................. 1 5
D. Parts Necessary to Change Spares ................................. 1 5
E. Special Tooling - Price and Availability ............................... 1 5
F. Special Tooling Necessary to do this Service Bulletin ....................... 1 6
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 7
A. GENERAL INFORMATION ..................................... 1 7
B. WORK INSTRUCTIONS ....................................... 1 7
FIGURE 1: UPPER RUDDER POWER CONTROL MODULE - REPLACEMENT ............ 2 1
FIGURE 2: LOWER RUDDER POWER CONTROL MODULE - REPLACEMENT ........... 2 3
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
ALERTALERT

### Page 4

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
ALERTALERT
BLANK PAGE

### Page 5

Commercial 
Airplanes
747
Service Bulletin
ALERT
SummaryNumber: 747-27A2497Original 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

### Page 6

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 HoursTotal Task HoursAirplanes
5.5011.00Group 1
Work Package 1, Option 2: Change the Upper Rudder PCM:
Elapsed HoursTotal Task HoursAirplanes
1.752.75Group 1
Work Package 2, Option 1: Replace the Lower Rudder PCM:
Elapsed HoursTotal Task HoursAirplanes
5.5011.00Group 1
Work Package 2, Option 2: Change the Lower Rudder PCM:
Elapsed HoursTotal Task HoursAirplanes
1.752.75Group 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
ALERTALERT

### Page 7 (OCR)

BOEING SERVICE BULLETIN 747-27A2497
ALERT  ALERT
POWER CONTROL MODULE (PCM)
REPLACE THE UPPER AND LOWER
RUDDER PCMS OR MAKE THE CHANGE
GIVEN IN PARKER SERVICE BULLETIN
UPPER PCM INSTALLATION SHOWN.
LOWER PCM INSTALLATION SIMILAR.
1834238
Original Issue: September 30, 2010
747-27A2497
BOEING PROPRIETARY -
Copyright © Unpublished Work - See page 1 for details.  7 of 24

### Page 8

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
ALERTALERT
BLANK PAGE

### Page 9

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.
DESCRIPTIONCONFIGURATIONGROUP
All 747SP airplanes.-1
Airplane Models:
747SP
GroupVariable Number
1RG001 - RG009
1RG091
1RG095
1RG101 - RG104
1RG121 - RG126
BOEING PROPRIETARY -
Copyright © Unpublished Work - See page 1 for details.
Original Issue: September 30, 2010
747-27A2497
9 of 24

### Page 10

GroupVariable Number
1RG141 - RG142
1RG161 - RG164
1RG171 - RG174
1RG191 - RG193
1RG211 - RG213
1RG221 - RG222
1RH101 - RH102
1RH111 - RH112
1RH121 - 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
ALERTALERT

### Page 11

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
ZoneModel
325, 326747SP
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 HoursTask-HoursNumber of Per-
sons
Task
1.503.002Open Access
2.004.002Figure 1
0.501.002Test
1.503.002Close Access
5.5011.00Total 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
ALERTALERT

### Page 12

Work Package 1, Option 2: Change the Upper Rudder Power Control Module (PCM)
Elapsed HoursTask-HoursNumber of Per-
sons
Task
0.501.002Open Access
0.750.751Test
0.501.002Close Access
1.752.75Total per airplane
Work Package 2, Option 1: Replace the Lower Rudder Power Control Module (PCM)
Elapsed HoursTask-HoursNumber of Per-
sons
Task
1.503.002Open Access
2.004.002Figure 2
0.501.002Test
1.503.002Close Access
5.5011.00Total per airplane
Work Package 2, Option 2: Change the Lower Rudder Power Control Module (PCM)
Elapsed HoursTask-HoursNumber of Per-
sons
Task
0.501.002Open Access
0.750.751Test
0.501.002Close Access
1.752.75Total 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
ALERTALERT

### Page 13

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-SectionPublication
27-22747 Maintenance Manual
27-22747 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
ALERTALERT

### Page 14

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
ALERTALERT
BLANK PAGE

### Page 15

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
NotesCorrespond-
ing Existing
Parker Part
Number
Existing Boe-
ing Part Num-
ber
NameQTYCorrespond-
ing New Park-
er Part Num-
ber / Specifi-
cation
New Boeing
Part Number
/ Specifica-
tion
(a) (b) (c)241700-100560B80093-3Rudder PCM2241700-900760B80093-104
(a) (b) (c)241700-100760B80093-4
(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
ALERTALERT

### Page 16

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
ALERTALERT

### Page 17

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
ALERTALERT

### Page 18

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
ALERTALERT

### Page 19

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
ALERTALERT

### Page 20

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
ALERTALERT

### Page 21 (OCR)

BOEING SERVICE BULLETIN 747-27A2497
ALERT  ALERT
POWER
CONTROL
MODULE
(PCM),
UPPER PCM INSTALLATION
1834783
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)
Original Issue: September 30, 2010
747-27A2497
BOEING PROPRIETARY -
Copyright © Unpublished Work - See page 1 for details.  21 of 24

### Page 22

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
(a) (b) (d)160B80093-( )Rudder PCMRemove1
(c) (e)160B80093-104Rudder PCMInstall (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
ALERTALERT

### Page 23 (OCR)

BOEING SERVICE BULLETIN 747-27A2497
ALERT  ALERT
POWER
CONTROL
MODULE
(PCM),
LOWER PCM INSTALLATION
1834786
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)
Original Issue: September 30, 2010
BOEING PROPRIETARY -  747-27A2497
Copyright © Unpublished Work - See page 1 for details.  23 of 24

### Page 24

MORE DATAQTYIDENTIFICATIONNAMETASKSTEP
(a) (b) (d)160B80093-( )Rudder PCMRemove1
(c) (e)160B80093-104Rudder PCMInstall (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
ALERTALERT

---
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.