Thrust Reverser Levers - BOMBARDIER LEARJET 45 Pilot's Manual

Pilot's Manual
overstowed condition. Overstowing the thrust reversers allows the un-
latch actuators to rotate the latch hooks. As the latch hooks begin to ro-
tate, the unlock switch signals the thrust reverser control unit of the
unlocked condition. As the latch hooks clear the blocker door recepta-
cles, an unlatch switch signals the thrust reverser control unit that the
blocker doors are unlatched. After the latch hooks are unlatched, hy-
draulic pressure is applied to the deploy side of the primary actuators
which push the doors open.
Stow is initiated automatically whenever an unlock condition is detect-
ed and the thrust reverser lever is forward of the thrust reverser deploy
detent. This occurs during the normal stow cycle and also to correct an
abnormal condition in flight. During autostow, hydraulic pressure is
applied to the stow side of the primary actuators and the blocker doors
move towards the overstow position. As the doors reach overstow, the
spring-loaded latches close. When the latches close, the unlock switch-
es are deactivated. The selector valve then releases stow pressure on the
primary stow/deploy actuator. Exhaust gas pressure and springs re-
turn the doors to the normal stowed position.
An automatic throttle retard mechanism is installed on each thrust re-
verser to ensure that thrust reverser stow and deploy does not occur
with an engine thrust setting above idle. The throttle retard mechanism
consists of an actuator, crank, and lever. Whenever hydraulic stow
pressure is applied to the thrust reverser actuators, the throttle retard
mechanism will position thrust lever to the IDLE position. When hy-
draulic stow pressure is removed, the mechanism will return to a neu-
tral position and release retard pressure to the thrust lever.

THRUST REVERSER LEVERS

A thrust reverser control lever for each thrust reverser is mounted
piggy-back fashion on each main thrust lever. The thrust reverser levers
are inoperable and cannot be moved unless the associated main thrust
levers are at the IDLE stop. Similarly, the main thrust levers cannot be
moved from the IDLE position until the associated thrust reverser lever
is in the stow (full down) position. When fully armed, a thrust reverser
may be independently deployed by lifting the corresponding thrust re-
verser lever to the first (idle/deploy) stop. A throttle release will acti-
vate and the thrust reverser lever may be pulled beyond the idle/
deploy stop to increase reverse thrust. If both thrust reversers are de-
ployed, a detent limits thrust reverser lever travel to approximately
MCR.
The thrust reverser is stowed by first returning the thrust reverser lever
to the idle/deploy stop and then moving the lever to the stow (full
down) position at engine idle speed.
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PM-126A