Learjet 60 - Fuel; Fuel Indicator; Fuel Quantity Probes

Learjet60'

Pilot's Manual
FUEL
GAGING
SYSTEM
The fuel gaging system consist of a fuel quantity indicator installed
in
the cockpit, fuel quantity probes located in the various fuel
tanks, and
an optional total quantity indicator located
near the single point pres-
sure refueling controls .
The fuel gaging system operates on 28 VDC
supplied through
the 2-amp FUEL QTY PWR 1 and FUEL QTY PWR 2
circuit breakers an the pilot's and copilot's circuit breaker panels . The
fuel gaging system is operative during EMER BUS mode .
FUEL
QUANTITY INDICATOR
The fuel quantity indicator, on the instrument panel,
indicates fuel
quantity in pounds (or optionally kilograms) of
fuel . The indicator has
four digital readouts - one
for the left wing tank, one for the right
wing tank, one for the fuselage tank, and one which shows
the
total of
e other three summed together . On aircraft 60-159
and subsequent
and
prior aircraft modified by SB 60-28-10
(Installation of Improved Fuel Quanti-
ty Indicator), inputs
from the
attitude
heading reference system are used
to correct
the fuel quantity indication for aircraft pitch attitude . The in-
dicator incorporates a feature to alert the crew of a fuel imbalance be-
een the left and right wing tanks . Should a fuel
imbalance of 500
pounds, (200 pounds if flaps are 8° or
lower)
or
more occur, the fuel
quantity reading
representing the heavy wing and the IMB annuncia-
tor, on
the fuel quantity indicator, will flash . The flashing annunciations
may be cancelled by depressing and releasing the mute switch in the
right thrust lever .
FUEL QUANTITY PROBES
Fuel quantity is sensed by four capacitance-type fuel quantity probes
in
each wing tank and a capacitance-type fuel quantity probe
in the fuse-
lage fuel tank . The left
inboard
fuel
quantity probe incorporates a fuel
temperature compensater which compensates for fuel density changes
due to temperature .
TOTAL
QUANTITY INDICATOR (SPPR)
The optional total quantity indicator, located with the single point pres-
sure refueling controls, indicates total fuel quantity
in pounds
of
fuel .
The system may also be configured to
indicate kilograms of fuel . The
indicator has a
digital
readout
which repeats the total indication shown
on the cockpit indicator . Refueling personnel can use the indicator to
determine the total fuel load without reference to the cockpit indicator
.
PM-123
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2-35
Change 4