APU CBT's Flashcards
The APU can be started on the ground and left running up to ________.
20,000’
NOTE: Not certified for starting in the air
Is electrical power from the APU available in flight?
No
How many APU generators?
2
On the ground, can the APU power all packs?
yes
In flight, can the APU power all packs?
No, it can only power 1 in flight. And that limit is up to 15,000’ only.
Can the APU power all electrical systems?
Yes, BUT only on the ground. No electricity in flight.
Where does the APU fuel normally come from?
Main tank 2
When AC power is available, what fuel pump supplies APU fuel?
Main pump 2 aft.
NOTE: Main pump 3 aft is also running, but that’s to prevent tank to tank transfer of fuel
If AC power is not available, what fuel pump supplies fuel to the APU?
The DC pump in main tank 2
On the ground, an APU fire is detected. What happens?
-Shuts down the APU
-Triggers EICAS warning
-Triggers siren
-Illuminates Fire handle red
If the main battery is dead, but the APU battery is charged, can you start the APU?
No, you need both batteries working to start the APU.
When does the EICAS MEMO message “APU RUNNING” display?
When the APU selector is in the ON position and the APU RPM is above 95%
The APU is running. You select it to OFF. What happens?
The APU bleed air valve closes right away, and then the APU goes through a 60 second cooldown period before it shuts down.
What position should the battery switch be during APU shutdown?
ON position. If you turn it off, the APU shuts down immediately with no cooldown.
Wait at least ____ minutes before placing the battery switch to OFF after selecting the APU selector to OFF.
2
