Learjet 20 Series Pilot Training Manual page 117

failure has occurred. Four or five motorized
shutoff valves are installed throughout the
fuel system for isolating various tanks and
fuel lines. Drain valves for the sumps and fuel
vent system are located at the low points in the
fuel system to drain any accumulation of water,
sediment, and/or fuel. Two high-pressure
relief valves, one in each fuel line between the
LH
TIP
TANK
F
S
I
H
R
U
E
T
W
O
A
F
L
F
L
L FUEL PRESS
LH ENGINE
LEGEND
SUPPLY
LOW PRESSURE
TRANSFER/
FILL
Figure 5A-2.
LEARJET 20 SERIES PILOT TRAINING MANUAL
EMPTY LIGHT-LH
LOW
FUEL
LH WING TANK
MAIN FUEL
SHUTOFF VALVE
FUEL
FILTER
FUEL FILTER
FLOWMETER
FUEL PROBE
CHECK VALVE
Fuel System–SNs 23-070 through 23-099
FOR TRAINING PURPOSES ONLY
e n g i n e m a i n fi r ew a l l s h u t o ff va l ve a n d
engine, are installed to relieve any pressure
buildup caused by thermal expansion of
trapped fuel when the engine is shut down.
Figures 5A-1 through 5A-3 illustrate the early
series Learjet fuel system.
CROSSFLOW
TIP TANK
EMPTY
CROSS
FLOW
FUS
FILL
TRANSFER
VALVE
FUSELAGE FUEL TANK
FUEL COUNTER
FILLER CAP ELECTRICAL
BOOST PUMP FLOAT SWITCH
PRESSURE SHUTOFF VALVE
SWITCH
FlightSafety
international
VALVE
EMPTY
FUS
ON
FUSELAGE
TANK
OFF
TRANSFER
SWITCH
FULL
0 0 0 0
5A-3