PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
TRAS -SYNC LOCK SWITCH
EFFECTIVITY BEJ ALL 78-34-00
Page 13
D633W101-BEJ Sep 05/2002
TRAS -SYNC LOCK VALVE
Purpose
The sync lock valve (SLV) supplies hydraulic control pressure to release the sync lock/manual drive unit.
Location
The sync lock valve is in the aft strut hydraulics bay. You must open the left access panel on the aft strut fairing to get access to the sync lock valve.
Physical Description
The sync lock valve is a solenoid operated control valve.
The sync lock valve has these electrical parts:
*
Sync lock (SL) solenoid valve
*
Electrical connector.
The sync lock valve has these hydraulic connections:
*
System return port
*
System pressure port
*
Control pressure port.
The hydraulic ports are identified on the valve housing; union fittings and packing are installed in all ports. The sync lock valve weighs 2.2 pounds (1.0 kilogram). The sync lock valve and the sync lock solenoid valve are line replaceable units (LRUs).
Sync Lock Solenoid Valve
The sync lock solenoid valve is installed on the sync lock valve (SLV) with four screws. It energizes when there is a reverse thrust command. This permits hydraulic system pressure to go to the control pressure port.
Control pressure from the sync lock valve goes to the sync lock/ manual drive unit and releases the unit. When there is no reverse thrust command, control pressure goes to the system return port.
If the sync lock solenoid valve is replaced on the valve, there is packing that is replaced on the electrical plug on the solenoid valve. In addition, a solenoid gasket which seals the base of the solenoid valve to the valve body is replaced. The screws are lockwired.
EFFECTIVITY BEJ ALL 78-34-00
Page 14
D633W101-BEJ May 05/2003
PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
TRAS -SYNC LOCK VALVE
EFFECTIVITY BEJ ALL 78-34-00
Page 15
D633W101-BEJ Sep 05/2002
TRAS -SYNC LOCK/MANUAL DRIVE UNIT
Purpose
The sync lock/manual drive unit is an hydraulically operated unit. It does these mechanical functions:
*
Provides a third lock for the thrust reverser actuation system on each thrust reverser half.
*
Turns the sync shafts and the hydraulic actuators during manual operation to extend and retract the thrust reverser sleeve.
The sync lock/manual manual drive units prevent the movement of the sync shafts when there is no reverse thrust command. This keeps the actuators and sleeves in the forward (retracted) position.
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