Page 2-36
Pilot’s Operating Manual
Revision A2: Nov, 2004
Sub-section 2
ENGINES
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
AIRPLANE SERVICES
Each engine has two bleed ports used for the airplane services
• One low pressure (LP) bleed port on the inboard side of each engine takes bleed air aft of the last
stage of the axial compressor.
• A high pressure (HP) bleed port takes air from downstream of the centrifugal compressor.
Each bleed air system contains check valves that prevent air from returning to the engines at low engine
speeds or during engine shutdown. The airplane uses LP bleed air for air conditioning, normal
pressurization, emergency pressurization and hydraulic reservoir pressurization. HP bleed air
supplements LP bleed air supplying these services at low power settings. The rudder bias system
receives power from the LP bleed air system only.
NOTE: For further information, refer to Sub-section 10 Environmental System and
Sub-section 6 Flight Controls.
AUTOMATIC PERFORMANCE RESERVE (APR)
When armed, the APR system allows an automatic increase in engine performance in the event of an
engine failure or transient fault during takeoff, or during a go-around following a single engine approach.
There will be no increase in thrust if the ambient conditions are such that the engines are N
1
RPM
limited (at normal rating). The APR system is powered from the PE busbar and consists of two
mechanically latching, push on/push off, control switches in the flight compartment plus an APR/
Sychronizer control unit in the rear equipment bay.
CONTROLS
Two control switches, the LH one labelled APR OVRD and the RH one APR ARM are mounted on the
pilots center instrument panel. The ARM switch has an APR ARMED white annunciator which will be
illuminated when the switch is pushed to arm the system and will not illuminate when the switch is
pushed again to disarm the system. The APR OVRD switch has an APR green annunciator which will
illuminate when the system is armed and triggered, either automatically by N
2
difference or manually
by pushing and latching the OVRD switch.
MFD
MFD
PFD
PFD
Copilot Instrument Panel
Pilot Instrument Panel
Center Instrument
Panel
APR
APR
ARMED
APR
APR OVRD
APR ARM
