Auxiliary Power Units Flashcards
Frequently, an aircraft’s auxiliary power unit (APU) generator…
is identical to the engine-driven generators.
Fuel is normally supplied to an APU from the what?
airplane’s main fuel tank.
An APU is usually rotated during start by what?
an electric starter.
The function of an APU air inlet plenum is to what?
stabilize the pressure of the air before it enters the compressor.
When in operation, the speed of an APU…
remains at or near rated speed regardless of the load condition.
Generally, when maximum APU shaft output power is being used in conjunction with pneumatic power…
pneumatic loading will be automatically modulated to maintain a safe EGT.
When necessary, APU engine cooling before shutdown may be accomplished by what?
closing the bleed air valve.
Usually, most of the load placed on an APU occurs when…
the bleed air valve is opened.
Fuel scheduling during APU start and under varying pneumatic bleed and electrical loads is maintained…
automatically by the APU fuel control system.
On APU’s equipped with a free turbine and load compressor, the primary function of the load compressor is to what?
provide bleed air for aircraft pneumatic systems.
