NOTE
I f t h e l e f t i n b o a r d c o m p e n s a t o r
probe becomes dry, it will cause
erroneous fuel quantity indications
at all switch positions.
Each probe uses an electrical capacitance meas-
uring system to sense the fuel level. It then trans-
mits an electrical signal to the cockpit indicator
where it is read as pounds x 1,000 on the dial.
NOTE
The total position of the selector
switch should be used for flight plan-
ning purposes. The quantity indicat-
ing system is set to indicate properly
in level flight.
Each wing tank has a fuel low-level float
switch. When either wing tank fuel level
reaches 400 to 500 pounds remaining, the re-
spective float switch actuates the red LOW
FUEL light on the annunciator panel to indi-
c a t e d l o w w i n g f u e l q u a n t i t y. ( S e e
“Annunciator Panel” section.) When flying
with the LOW FUEL light on, limit pitch at-
titude and thrust to the minimum required.
When the fuel quantity gage indicates
600 pounds or less remaining in either
wing tank, prolonged noseup attitude
of 10º or more may cause fuel to be
trapped in the aft area of the wing
tank outboard of the wheel well. Fuel
starvation and engine flameout may
occur. Reducing pitch attitude and
thrust to the minimum required will
prevent this situation.
FUEL FLOW INDICATING
SYSTEM
A fuel flow indicator provides a readout of
pounds of fuel flow per hour. The indicator
(Figure 5-5) may have one or two pointers (L and
R) and uses DC power. Gages with one pointer
have a L–R selector switch. The fuel counter,
located on the fuel control panel, provides a
WARNING
5-7
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
SINGLE POINTER
DUAL POINTER
Figure 5-5. Fuel Flow Indicators
