EFFECTIVITY BEJ ALL 78-34-00
Page 18
D633W101-BEJ May 05/2003
PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
TRAS -SYNC LOCK/MANUAL DRIVE UNIT
EFFECTIVITY BEJ ALL 78-34-00
Page 19
D633W101-BEJ Sep 05/2002
TRAS -ISOLATION VALVE
Purpose
The isolation valve isolates the airplane hydraulic system from the thrust reverser actuation system (TRAS). It also permits hydraulic power to go to the TRAS to move the thrust reverser sleeves.
Physical Description
The isolation valve has these components:
*
Hydraulic pressure switch
*
Bypass valve
*
Isolation shutoff valve
*
Directional control valve solenoid valve
*
Isolation valve solenoid valve
*
Check valve.
The isolation valve has these hydraulic connections:
*
Hydraulic system return port (SYS RTN)
*
Hydraulic system pressure port (SYS PRESS)
*
Control pressure port (CRTL)
*
TRAS pressure port (TRAS PRESS)
*
TRAS return port (TRAS RTN).
The valve body contains an isolation shutoff valve and a bypass valve. The valve is a sealed housing which in operation is filled with hydraulic fluid from the hydraulic system. The isolation valve is used to deactivate the thrust reverser actuation system (TRAS) for flight dispatch. Both valves are used to deactivate the TRAS for ground maintenance. The bypass valve and the isolation shutoff valve are an internal close tolerance slide with internal seals which moves in the valve body.
The isolation valve weighs 11.65 pounds (5.28 kilograms). The names of all ports, SYS RTN, SYS PRESS, CRTL, TRAS PRESS, TRAS RTN, are etched on the valve body. Union fittings and packing are installed in all hydraulic ports. On the valve body there are two electrical connectors and in the valve body there is internal wiring for the isolation valve solenoid valve and the directional control valve solenoid valve.
The isolation valve is mounted in the aft strut hydraulic bay. Open the strut side access doors to get access to the isolation valve.
EFFECTIVITY BEJ ALL 78-34-00
Page 20
D633W101-BEJ May 05/2003
TRAS -ISOLATION VALVE
Hydraulic Pressure Switch
The hydraulic pressure switch is installed in a hydraulic port at the TRAS pressure port (TRAS PRESS) on the isolation valve body. The pressure switch has an electrical connector. If the hydraulic pressure switch is replaced, a packing must be replace on the hydraulic fitting on the switch. The hydraulic pressure switch sends the position of the isolation shutoff valve, opened or closed, to the thrust reverser indicating and fault detection system. See section 78-36 for more information. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 发动机排气 Engine Exhaust PW 777 AIRCRAFT MAINTENANCE MANUAL(32)
