APU use
Just a quick couple of questions. I'm curious on the use of an APU within ops.
Do you just use them on the ground for power and engine start and for an inflight emergency, or are there more requirements?
When do you turn them off, just after engine start, climb out?
Do you ever leave them running for the entire flight?
What would cause you to start one up again, an engine failure, generator failure, other?
Thanks for any info.
JM.