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
engine main firewall shutoff valve and
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.
5A-3
FOR TRAINING PURPOSES ONLY