APU Flashcards
APU restart attempts. How many and how long before the next attempt?
3 consecutive starts, crew must wait 60 mins before a new start attempt
APU Rotor Speed
Max N = 107%
EGT for APU running
675degC
Max APU EGT (below and above 35,000ft)
1,090 / 1,120 degC
If the APU failed to start or automatically shuts down, when can we attempt a new start?
Not permitted. Do not start the APU
If fuel spill occurs during refueling and fuel spill occurs, what to do?
Do a normal shut down
APU Operation normal restart limit? What does it provide at this altitude?
39,000ft. Provides electrical power only. (Not pressurization or air conditioning).
*or no altitude limit or 39,800ft in some aircrafts
APU with battery only restart limit altitude? What does it provide? When is it applicable?
FL250. Electrical power only. Limit is applicable during dual engine failure. Otherwise, in a single engine operation, the APU can be started at any level.
Max altitude for APU Bleed use for air conditioning and pressurization? How many packs used?
22,500ft (1 pack used)
Max APU Bleed use engine assist restart altitude using 1 pack air conditioning and pressurization?
FL200
Max altitude for APU Bleed for 2 packs, engine start, air conditioning and pressurization?
15,000ft (in a dual engine situation, Pack 2 - On)
Can APU Bleed Air and Wing Anti Ice used together?
Not permitted
APU lowest and highest normal ground operation limits?
-2,000 until 14,500ft
If fire occurs in flight or on the ground, what happens to the APU?
On the ground, the APU shuts down and automatically operates to extinguish the fire. In flight, this must be done by the crew manually
