Page 2-40
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 2
ENGINES
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
OFF
Power to the thrust reverser system is OFF and indicated by the illumination of this white annunciator.
UNLCK
An amber annunciator which illuminates if one or more thrust reverser door latches are not locked and
when the doors are moving or deployed.
REVRS
A green annunciator which illuminates when the thrust reverser doors are fully deployed. Each thrust
reverser is actuated through an independent and identical hydraulic sub-system powered from the
airplane’s main system. The two systems both share a common accumulator.
Thrust reverse levers are mounted in a
piggyback configuration on the engine thrust levers and each
thrust lever provides control for stow, deploy and reverse thrust for its respective engine.
Each engine thrust lever has a solenoid-operated baulk (lockout) which mechanically prevents selection
of reverse thrust until the reversers are fully deployed. Each engine thrust lever also has a stop to
mechanically limit the obtainable reverse thrust when the thrust reverser lever is increased to its
maximum thrust position.
An automatic engine thrust lever retard system is incorporated in the event of a stow or deploy
malfunction.
REVERSER ASSEMBLY and OPERATION
Each thrust reverser assembly is an electromechanically controlled, hydraulically operated, target-type
thrust reverser consisting of:
• Upper and lower clamshell type doors located on the rear of each engine nacelle.
• Hydraulic actuators and associated linkages that position the reverser doors upon either stow or
deploy commands.
• Latches which hold the reverser doors in the stowed position until released by sequentially
actuated switches and relays.
• Fan flaps, located within each fan duct, assist in temperature reduction on the doors. They deploy
and stow in conjunction with the doors.
The complete sequence of operation to cycle the reverse thrust system from stowed to deployed and
return to stowed can be grouped into three main phases of initiate, deploy and stow.
Initiate
When the POWER switch is pushed, the ARM annunciator will illuminate and an isolation solenoid
energizes to make pressure available to the latch, deploy and stow solenoid valves if the following
conditions are met:
• Weight-on-wheels switches recognize an on-the-ground condition.
• Engine thrust lever is in the IDLE position.
• Hydraulic pressure is available (400 psi minimum).
