Page 5-4
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 5
HYDRAULICS
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
MAIN SYSTEM
FLUID STORAGE
System fluid is stored in a spherical shaped reservoir located in the rear equipment bay. Fluid contents
are displayed in a level indicator tube, integral with the reservoir.
Air, tapped from both engines is used to pressurize the reservoir to make sure a supply is fed to the
pumps under all flight conditions.
The air is supplied to the reservoir via check valves and a pressure reducing valve.
The reservoir has an inward and outward relief valve as well as a pressure gauge.
Table 1: Indicators and Annunciators
Item
Location
Parameter
Combined BRAKES (2)
and SUPPLY indicator
Center instrument panel
psi
Brakes: 2000
Supply: 3000
Main MWS panel
Hydraulic fluid overheat warning 90
°
C
Main MWS panel
Main supply low pressure warning
≤
1500 psi
Main MWS panel
Emergency brakes accumulator low
pressure warning
≤
2250 psi
Accumulator pressure
indicators
(main and wheel brakes)
Rear equipment bay
Initial charge at 1000 psi
Accumulator pressure
indicators (thrust reversers)
Rear equipment bay
Initial charge at 1500 psi
Main reservoir contents level
tube
Rear equipment bay
Parameters stated on label next to
reservoir
Main reservoir air pressure
gauge
Rear equipment bay
0 to 30 psi is normal
HYD OVHT
HYD 1
LO PRESS
EMRG BRK
LO PRESS
