APU

Question 1

Voltaggio e Amperaggio erogato dall’APU

Answer 1

115 V 40KVA

Question 2

Cosa succede quando si preme APU EMERGENCY STOP?

Answer 2

It closes fuel shutoff valve without cooling period.

Question 3

Describe APU fuel supply

Answer 3

When only DC, from the DC fuel pump (right tank).
When AC but with no engine running, from AC fuel pump (right tank)
When engine is running, fuel will be provided via the ejector fuel pump.
It is also possible to provide fuel via crossfeed from left tank.

Question 4

How many second is better to wait after EICAS is energized, to start the APU? To avoid unsuccessful start.

Answer 4

30”

Question 5

When is electrical and pneumatic available?

Answer 5

3” after APU speed has reached 95%.

Question 6

Cosa succede in un normale shutdown?

Answer 6

Pneumatic power is immediately removed;
electrical power is removed after at the end of a 1’ cooldown, which is followed by a spool down period, at the END of the spooldown period the message APU SHUTTING DOWN disappears.

Question 7

In which cases FADEC provides automatic shutdown ON GROUND?

Answer 7

Overspeed, Underspeed, Fire, EGT overtemp, high oil temp, low oil pressure, sensor fail, FADEC critical fault.

Question 8

In which cases FADEC provides automatic shutdown ON GROUND?

Answer 8

Overspeed, Underspeed, Fadec Critical Fault

Question 9

Apu starter limits, cool period after each attempt:

Answer 9

1st 2nd attempt, 60” OFF
3rd 5’ OFF