Two vent drain valves are located at the fuel
vent sumps. (Figure 5A-4). They must be
drained prior to every flight to ensure that the
vent line is unobstructed.
FUEL INDICATING
SYSTEMS
FUEL QUANTITY INDICATING
SYSTEM/LOW FUEL WARNING
The fuel quantity indicating system includes
an indicator and tank selector switch located
on the fuel control panel (Figure 5A-5). One
or two LOW FUEL warning lights illuminate
whenever either wing tank fuel level is low
on all airplanes except SNs 23-003 through
23-014 (see Figures 5A-1 through 5A-3).
The six-position rotary selector switch en-
ables the pilot to check the fuel quantity in
each of the five tanks and the airplane total
fuel quantity. The fuel quantity for the posi-
tion selected is read on the fuel quantity in-
dicator. The quantities printed beside each
selector switch position indicate usable fuel
capacities in pounds.
5A-6
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
VACUUM-RELIEF
VALVE
PRESSURE-RELIEF
VALVES
CHECK VALVE
RAM-AIR MAST
FORWARD SUMP
ASSEMBLY
CHECK VALVE
AFT SUMP ASSEMBLY
OVERBOARD VENT LINE
Figure 5A-4.
Fuel Vent System