Yes. There are CFIs that instruct today who have lost their medical. The
limitation is that the "student" must be currently qualified to act as PIC
for the phase of flight in which the CFI will provide instruction.

wrote:

Hello,

I can't find a reference for this in the FAR/AIM.

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, and

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

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

I am sure the answer to a) must be yes - it would be silly otherwise.
It's b) and c) I am not sure about.

Any response would be very interesting - with references please if
anyone feels this is illegal.