Thrust Reverser
Each engine is equipped with a hydraulically operated thrust reverser, consisting of left and
right translating sleeves. Aft movement of the reverser sleeves causes blocker doors to
deflect fan discharge air forward, through fixed cascade vanes, producing reverse thrust.
The thrust reverser is for ground operations only and is used after touchdown to slow the
airplane, reducing stopping distance and brake wear.
Hydraulic pressure for the operation of engine No. 1 and engine No. 2 thrust reversers
comes from hydraulic systems A and B, respectively. If hydraulic system A and/or B fails,
alternate operation for the affected thrust reverser is available through the standby
hydraulic system. When the standby system is used, the affected thrust reverser deploys
and retracts at a slower rate and some thrust asymmetry can be anticipated.
The thrust reverser can be deployed when either radio altimeter senses less than 10 feet
altitude, or when the air/ground safety sensor is in the ground mode. Movement of the
reverse thrust levers is mechanically restricted until the forward thrust levers are in the idle
position.
When reverse thrust is selected, an electro–mechanical lock releases, the isolation valve
opens and the thrust reverser control valve moves to the deploy position, allowing hydraulic
pressure to unlock and deploy the reverser system. An interlock mechanism restricts
movement of the reverse thrust lever until the reverser sleeves have approached the
deployed position. When either reverser sleeve moves from the stowed position, the amber
REV indication, located on the upper display unit, illuminates. As the thrust reverser
reaches the deployed position, the REV indication illuminates green and the reverse thrust
lever can be raised to detent No. 2. This position provides adequate reverse thrust for
normal operations. When necessary, the reverse thrust lever can be pulled beyond detent
No. 2, providing maximum reverse thrust.
