APU Flashcards
When does the APU external flap open?
When APU master witch is pushed ON
When is the APU ECAM page displayed?
When pressing APU master switch ON with Ground or generator power connected
What is the APU fuel supply?
Left side of the fuel system, through normal tank pumps if available
When will the APU fuel pump run?
If no fuel pressure is available on the left side
What controls and monitors automatic APU operation?
Electronic Control Box (ECB)
Which bleed supply has priority, Engine or APU?
APU
When will the AVAIL light on the APU start switch illuminate?
When APU N is >99,5% or >95% for 2 seconds.
What is the meaning of amber XX over the bleed pressure indication on ECAM?
- ADIRS 1 or 2 data not available or OFF
- Invalid ECB data
What is the redline N for the APU which will trigger an automatic shutdown?
107% N
When can the APU “LOW OIL LEVEL” advisory be displayed on the ECAM page?
Only on the ground with the APU NOT running
To which altitude can the APU provide electrical power?
To the airplane max certified altitude
What is the APU battery restart limit altitude?
25.000’
What is the normal APU maximum restart altitude?
Airplane max certified altitude
What is the maximum altitude for single pack operation from the APU bleed?
20.000’ (22.500’ NEO)
What is the maximum altitude for dual pack operation from the APU bleed?
15.000’
Can the APU be used to supply bleed air for wing anti-ice?
No
Can the APU be started using battery power only?
Yes
Are there any limitations to APU start on battery power?
Start is inhibited for 45 seconds following BAT switches to AUTO or loss of AC power.
When does the APU inlet flap close on APU shutdown?
At 7% N
What happens when pressing the APU master switch ON?
- Electrical power to APU system, ECB power up test
- APU intake flap opens
- APU fuel isolation valve opens
- If on battery power only, APU fuel pump starts
- APU page displayed if on external or generator power
What is the APU starter duty cycle?
3 attempts, then 60 minutes cooling
