APU Flashcards
Which FADEC controls the APU?
It has it’s own DEDICATED FADEC
How does the APU get it’s fuel when only DC power is available?
The DC fuel pump located in the right wing
Where does the APU get it’s fuel when the engines are running?
From the right wing tank via the ejector pump.
Up to what altitude can the APU be used to supply AC power?
33,000 ft
Up to what altitude can the APU be used to supply bleed air for engine starts?
21,000 ft
Up to what altitude can the APU be used air conditioning and pressurization?
15,000 ft
What is the max altitude the APU can be started?
30,000 ft
What is the cool down period for normal APU shutdown?
One minute
Does the APU go through a one minute cool down period if the EMER STOP button is pressed?
NO
The APU will automatically shutdown on the ground when??
Overspeed Underspeed FADEC critical fault APU Fire APU EGT overtemp APU high oil temp Low Oil Pressure Sensor Fail
The APU will automatically shutdown in the air for the following conditions:
Overspeed
Underspeed
FADEC Critical Fault
Will the APU shutdown in flight for a fire?
NO
Will the APU shutdown in flight for high oil temp or low oil pressure?
NO
Why do you need both batteries for APU start?
Battery one provides FADEC
Battery two powers the APU Start Bus
What does the EMER STOP push button do?
It shuts off the APU immediately with no cool down period by closing APU fuel shutoff valve
