Removal of the Servovalve

TASK 27-26-51-000-002-A
Removal of the Servovalve

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

ZONE: 325

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 6M (20 FT) - ADJUSTABLE
No specific	AR	CONTAINER 3 L(3/4 USGAL)
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)
98D27207549000	1	PIN-RIGGING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
325	VERTICAL STABILIZER TRAILING EDGE
325BL, 325BR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 29-00-00-910-002-A	Safety Procedures of the Hydraulic System
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs
TASK 55-33-13-010-002-A	Opening/Removal of the Trailing Edge Access-Panels of the Vertical Stabilizer
Yaw Damper - Servo Actuator
Servovalve and Solenoid Valve

3. Job Set-up
Subtask 27-26-51-860-058-A

A. Aircraft Maintenance Configuration

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

(1) Obey the hydraulic safety procedures (Ref. AMM TASK 29-00-00-910-002).
(2) Put the WARNING NOTICE(S) in the flight compartment to tell persons not to operate the flight controls.
(3) Depressurize the Green and the Yellow hydraulic systems and put them in the maintenance configuration (Ref. AMM TASK 29-00-00-864-001).
(4) Make sure that the Blue hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-00-00-864-001).
(5) Depressurize the reservoir of the Green and the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-001).
(6) Put the warning notices in position to tell persons not to operate the Green, the Yellow and the Blue hydraulic systems:

in the cockpit on the hydraulic section 40VU of the overhead panel,
on the ground service panels of the Green, Yellow and Blue hydraulic systems.

(7) Put a CONTAINER 3 L(3/4 USGAL) below the yaw damper.
(8) Put the rigging pin 98D27207549000 PIN-RIGGING in the yaw damper bellcrank.

Yaw Damper - Servo Actuator

Subtask 27-26-51-010-051-B

B. Get Access
(1) Put the ACCESS PLATFORM 6M (20 FT) - ADJUSTABLE in position.
(2) Open the access panels 325BL (for the servovalve on 3CC1) and/or 325BR (for the servovalve on 3CC2) at the trailing edge of the vertical stabilizer (Ref. AMM TASK 55-33-13-010-002).

Subtask 27-26-51-865-053-A

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AUTO FLT/FAC1/28VDC	5CC1	B04
49VU	AUTO FLT/FAC1/26VAC	14CC1	B03
** ON A/C NOT FOR ALL
49VU	AUTO FLT/FAC1/28VDC	5CC1	H10
49VU	AUTO FLT/FAC1/26VAC	14CC1	H09
** ON A/C ALL
121VU	AUTO FLT/FAC2/28VDC	5CC2	M19
121VU	AUTO FLT/FAC2/26VAC	14CC2	M18

4. Procedure
Subtask 27-26-51-020-051-A

A. Removal of the Servovalve
(1) Cut and remove the lockwire which safeties the screws (12).
(2) Remove the screws (12) and the washers (11).
(3) Pull the servovalve (13) away from the yaw damper (7).
(4) Remove and discard the base plate (10).
(5) Remove and discard and the O-ring (14).

[Rev.10 from 2021] 2026.03.31 23:49:51 UTC