EFFECTIVITY
BEJ ALL

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Install a lock pin in the isolation shutoff valve spool on the isolation valve (IV). Push in the spring-loaded spool and install the pin. Install a hitch pin in the end of the deactivation pin. This keeps hydraulic power away from the directional control valve (DCV) and the hydraulic actuators.

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Install a lock pin in the bypass valve spool on the isolation valve (IV). Manually turn the crank to depress the plunger to move the valve to the bypass position. Install a hitch pin in the end of the deactivation pin. Use the bypass valve for ground maintenance when you manually extend and retract the thrust reverser sleeve. When you open the bypass valve, the hydraulic fluid in the TRAS hydraulic tubing can return to the hydraulic system return line which prevents hydraulic lock. However, if TRAS hydraulic components must be removed, remove the pin from the crank to close the bypass valve to prevent drainage from the hydraulic system return lines.

Thrust Reverser Deactivation for Flight Dispatch
Thrust reverser deactivation for flight dispatch procedure is used per the master minimum equipment list (MMEL) maintenance requirements as shown in the dispatch deviation guide (DDG) when the thrust reverser is found to be inoperative.
This procedure mechanically prevents the movement of each thrust reverser sleeve and stops hydraulic power to the thrust reverser actuation system (TRAS).
The procedure is summarized as follows:
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Page 55 D633W101-BEJ May 05/2003

TRAS -THRUST REVERSER DEACTIVATION

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In the flight compartment, open the applicable thrust reverser control circuit breaker and install a collar to remove electrical power to the isolation valve.

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Install a lock pin in the isolation shutoff valve spool on the isolation valve (IV). There are two lock pins in the deactivation pin container. The container is in the aft strut, below and forward of the isolation valve. Both lock pins are tethered with a cable to the container. Use the lock pin which does not have a red streamer. Push in the spring-loaded spool and install the pin. Install a hitch pin in the end of the deactivation pin. This keeps hydraulic power away from the directional control valve (DCV) and the hydraulic actuators.

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The thrust reverser sleeves must be in the fully retracted position. Install a deactivation pin through the thrust reverser sleeve and into a threaded fitting on the aft side of the thrust reverser torque box. The deactivation pin is stored on a bracket on the thrust reverser torque box between the center and lower actuators of each sleeve. This mechanically prevents the movement of each thrust reverser sleeve.

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On each thrust reverser sleeve, make sure the sync lock and one of the two locking actuators are in the locked position.

Activation

To activate the thrust reverser system, do the deactivation procedure in the reverse order.
　
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