Not likely to be a Part 91 but rather Part 121 issued ferry permit. The paperwork required for going from 121 to 91 and back to 121 is akin to a sex change.
Izzat so?
It's been quite a while but I've certainly ferried a widebody Part 91 for a Part 121 carrier without a Part 121 ferry permit. At least I think I have.
The paperwork looks the pretty much the same except there is no signature line for the captain on the Part 91 dispatch release. I'll let the purists argue over whether you are actually dispatched in this instance.
I was thinking that you needed a ferry permit for certain maintenance problems but that you could carry an otherwise functional non-ETOPs twin overwater Part 91 empty without a permit. Even with the ferry permit, I believe the operation is considered Part 91 for crew rest and weather purposes.
But a lot of this stuff depends on the OPSPEC's and FOM for a particular carrier. Anybody know how AA does it (this week
)?