Page 2-41
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 2
ENGINES
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
Deploy
Initially the stow and latch isolation solenoids are simultaneously energized, which directs pressure to
the stow side of the primary actuators, the latch actuators and the thrust lever retard actuator.
The thrust reverser doors will be driven to the overstow position, allowing the door latches to clear the
latch receptacle. As the latch switches operate and the doors unlock, the UNLCK annunciator will
illuminate.
NOTE: The tendency of the exhaust forces on the doors is toward deploy whenever the engine is
running. When engaged, the latches cannot be disengaged unless the overstow condition
can be realized.
When the unlatch switches operate, the stow solenoid is de-energized and the deploy solenoid
energized retracting the primary actuators to deploy the reverser doors and extend the fan flaps into the
engine bypass airstream. The UNLCK and REVRS annunciators will illuminate.
After initial deployment, the reverse thrust lever baulk is released and additional reverse thrust may be
commanded by pulling the levers toward maximum reverse. A mechanical stop is set at a
predetermined thrust setting.
A deploy command inhibits operation of rudder bias to prevent rudder movement due to asymmetric
thrust. The airbrake warning horn and the ELEV/AIL trim annunciator is also inhibited.
Stow
Moving the reverse thrust lever to the stow position de-energizes the stow/deploy relay and closes the
unlatched solenoid. Deploy power is removed from the latch switches, the stow valve solenoid is
energized and hydraulic power is routed to the close side of the primary actuator, closing the reverser
doors.
Fan flaps are spring-loaded closed and the engine thrust lever retard actuator is limited to IDLE. When
the reverser doors reach fully locked, stow pressure is removed.
The stow valve solenoid is energized and hydraulic power operates the primary actuator to close the
reverser doors. The fan flaps will return to the closed position under spring pressure from an internal
system. Pressure is applied to the thrust lever retard actuator to limit it to the idle position. When the
reverser doors reach the fully locked position, stow pressure is removed.
Pushing the POWER switch off removes hydraulic pressure from the deploy, stow and latch valves and
the pressure switch in the control selector valve.
