Originally Posted by
localizer
If one is requested to be onboard as an instructor in the interest of safety, and acts mainly as pilot monitoring but also flies the plane and assists the operation, is that not legally acting as an instructor?
Keyword: safety. And the owner wanted a CFI onboard.
If the CFI wasn’t there perhaps the pilot would have killed himself trying to do the operation solo.
Also, we are hypothetically talking 100 hours total here. Not hundreds.
It's obviously a grey area, as you can see here. My one case study was a more extreme example, but may be worth considering. You have to make the call.
If you could find an FAA legal opinion that JB mentioned, that might help.