Hawker Beechcraft Hawker 800XP, Руководство по эксплуатации для пилотов

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Page 5-5
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 5
HYDRAULICS
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
POWER GENERATION
Fluid is supplied from the reservoir through a suction filter to the two variable-delivery engine driven
pumps, one per engine.
An on/off valve in each suction line is interconnected to the related HP cock lever. Isolation of the
hydraulic fluid supply is therefore simultaneous with engine shut-down. When an on/off valve is closed,
a closed-circuit via the valve provides a full volume supply to the pump for lubrication.
Each pump delivers fluid at a nominal pressure of 3000 psi via a low pressure switch, snubber and
check valve, to the pressure filter in the main delivery line to the airplane systems.
A capacitor is installed in the delivery line from the No. 1 pump.
High Pressure Relief
Two full-flow relief valves are located in tappings off the delivery line from each pump and are provided
to limit the maximum pump pressure in the event of the failure of the pump pressure control.
Should the pump delivery pressure rise above 3750 psi, the relief valve operates to pass fluid into the
return line.
Low Pressure Indication
The low pressure switch operates if the pump pressure falls to 1500 psi. A time delay prevents the
associated HYD # LO PRESS annunciator illuminating until the timed period has elapsed. This prevents
a spurious annunciation due to temporary low pressure conditions caused by system fluctuations. Once
the annunciation is illuminated, it remains so until the pressure rises above 1850 psi.
Hand Pump
The Main system can be pressurized for ground servicing purposes by a hand pump located in the rear
equipment bay. The hand pump inlet is connected to the line from the suction filter. When operated, the
pump passes pressurized fluid through a check valve, into the main system.
MAINTAINED PRESSURE PATHS
Fluid passes through a Pressure Maintaining Valve (PMV) to the normal wheel brake and stall
identification paths.
The PMV shuts off if the pressure upstream of it falls to 2300 psi. This makes sure the pressure in the
main accumulator is sufficient for several operations of the stall identification system and operation of
the normal wheel brakes when landing.
Thrust Reversers
Fluid stored in the thrust reverser accumulator is prevented from leaking back to the main system by a
check valve.