Hawker 800 XP, Pilot Training Manual

Page: 190 / 504

either from the opposite wing tank or from
the ventral tank, depending on the selection of
the appropriate transfer valves. It cannot draw
any fuel if both transfer valves are closed.
Under normal conditions, each electric boost
pump delivers fuel under pressure to the engine
on the same side via a low-pressure fuel cock.
Should both electric boost pumps fail, fuel
gravitates into each number one compartment.
This enables the engine-driven fuel pumps to
draw fuel for operation by suction feed.
With both electric boost pumps operating and
the ventral transfer valve open, fuel from the
ventral tank transfers to both wings due to jet
pump operation. Fuel transfer takes about 12
minutes. With a single electric boost pump
operating, fuel transfers to the wing tank con-
taining the operating pump; transfer time, in
this condition, may increase to more than 20
minutes. Should both electric boost pumps
become inoperative, ventral tank fuel cannot
be transferred.
Fuel in the left wing tank is normally supplied
to the number one engine and auxiliary power
unit (APU), and fuel from the right wing is sup-
plied to the number two engine. Fuel from both
wing tanks can be made available to either or
both engines through the crossfeed valve. In
the event of single electric boost pump failure,
opening the crossfeed valve enables the oper-
ating pump to supply both engines. The wing
transfer valve allows fuel to be drawn from one
wing tank to the other.
The low-pressure fuel cocks, one in each sup-
ply line, isolate the engine fuel feed pipes
from the tanks.
Pressure switches, tapped into each engine
fuel line, are connected to FUEL 1 and 2 LO
P R E S S a n n u n c i a t o r s ( A p p e n d i x B ) .
Illumination of these annunciators during nor-
mal fuel operation indicates a loss of pres-
sure and signals a possible electric boost pump
failure. A temperature bulb permits a fuel tem-
perature indication to be read from the num-
ber one engine fuel supply line. The fuel in
each engine fuel supply line passes through a
flowmeter on each engine.
CONTROLS AND
INDICATORS
CONTROLS
The electric boost pumps are controlled by
three-position switches (ON, OFF, EMERG)
on the FUEL section of the roof panel (Figure
5-3). The left and right electric boost pumps
are normally supplied from bus bars PS1 and
PS2, respectively, with the pump switch on.
When the pump switch is on and the start
power switch depressed (ON), the power
source switches to PE. The pumps are con-
nected to bus bar PE when EMERG is selected.
Two LP levers, an AUX FUEL TRANSFER
lever, and a single WING FUEL X FEED
TRANSFER lever are provided. The control
levers are cable connected to low pressure,
auxiliary, wing transfer, and crossfeed valves.
The control levers are located on the aft part
of the center console. Each lever moves in a
gated quadrant. Before selection can be made,
the knob on each lever must be pulled out
against spring pressure. The lever locks in the
selected position when the knob is released.
The WING FUEL X FEED TRANSFER lever
is X shaped for ease of identification.
A ventral tank transfer valve is operated by the
single AUX FUEL TRANSFER lever. A hinged
guard fits over the lever in the closed (up) po-
sition. This guard must be lifted before the lever
can be moved to the open (down) position.
The WING FUEL X FEED TRANSFER lever
has three positions: closed, X FEED, and
TRANSFER. Fuel from the left wing is sup-
plied to the No. 1 engine, and fuel from the
right wing is supplied to the No. 2 engine
when the lever is in the closed position.
Moving the lever to the X FEED position opens
the crossfeed valve. Fuel from both wings is
available to either or both engines. A nonre-
turn valve in the outlet of each pump prevents
fuel being transferred from one wing tank to
the other during crossfeeding.
5-4
FOR TRAINING PURPOSES ONLY
HAWKER 800 XP PILOT TRAINING MANUAL
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