APU Flashcards
1
Q
Elec sources for starting?
A
Ground power
Engine driven generator
APU battery provided DC ESS bus powered
2
Q
Key altitudes for function
A
Starts below FL200
Supplied bleed air and elec power <22,500’
Only 1 APU generator can operate in flight
3
Q
Basic structure
A
2 rotors
N1 - Power rotor
N2 - High Pressure rotor
Air enters via the flap which closes automatically when APU not in use
2 APU generators (A and B) that supply constant 400Hz elec. Each cam replace any other generator and total AC can be supplied by both gens operating (although only 1 can operate in flight)
4
Q
ECB? Electrical Control Box
A
Controls operation, start and shutdown of APU
5
Q
How long wait between APU MASTER SW and APU START PB?
A
5 secs
