wrote:
The question, in the context of FAA IR training, is whether

a) I (assume I am legally PIC in the airspace in question) can carry a
CFII as a mere passenger,


You can carry whomever you like as a passenger.



b) can the instructor take over as an instructor at an agreed point in
the flight


Yes.


c) can the instructor revert to being a passenger at an agreed point
after the training took place


Yes. Instruction officially begins whenever the two of you agree it begins. It
ends when you agree it ends. There is no preset being/end point dictated by
regs. Also, since you brought it up, I don't think this is really all that rare
an occurance.



--
Mortimer Schnerd, RN

VE