APU Flashcards
1
Q
Pushing APU Emerg stop button
A
- closes APU fuel shutoff valve
- shuts down APU without cooling period
2
Q
Normal fuel supply for APU
A
Right wing tank via:
- DC Pump when only DC power is avail
- AC Pump when AC power is avail and engine not running
- ejector fuel pump when engine is running
3
Q
APU altitude limits
A
– Electrical AC power up to 33000 ft.
– Bleed air for engine starting up to 21000 ft.
– Bleed air for air conditioning and pressurization up to 15000 ft.
*Maximum altitude for APU start is 30000 ft.
4
Q
Normal APU Shutdown sequence
A
- rotate APU selector know to OFF
- APU pneumatic power removed immediately
- 1 or 2 minute cooldown period after which electrical power is removed
*EICAS message APU SHUTTING DOWN
5
Q
Auto APU Shutdown on the ground
A
- APU Fire
- EGT overtemperature
- High oil pressure
- Low oil pressure
- Sensor fail
6
Q
Auto Shutdown of APU in flight
A
- Overspeed
- underspend
- FADEC fault