Mutt,
"The APU is not certified for use during takeoff". Ummm, I was not aware of any such limitation. In fact our MEL allows for it's continuous operation for dispatch on Non-ETOPS flights with a generator inoperative.
Maybe my colleagues and I are guilty of an AFM infringement or 2
Do you have a reference from Boeing on the matter? T'would be appreciated.
Regards,
Old Smokey