Originally Posted by rickair7777

DANGER! No, you cannot just retroactively claim previous 121 SIC time for 61.159(a)(5). It must have been premeditated, ie the actual PIC knew and agreed to it. Also as with any time for FAA purposes it must be logged in some fashion to reflect what it is. I have seen this done in personal logbooks, counter-signed by the actual PIC, and also on a company form, also signed by the PIC.

Since the PIC in this case does not have to be a CFI in order to give this training, there is technically no requirement that you have his signature, but as was mentioned good luck selling a DPE on that. Don't even try it, because if somebody bothers to contact one of the PICs in question you would be in very deep doo doo when he didn't have any idea what the FAA was talking about.

Also PF/PM has nothing to do with it. This is not about control manipulation.

Possible work-around, if you flew enough with one CA to meet the requirement, and can get hold of him, he might agree to counting the time for 61.159(a)(5). I would probably agree to that if I thought the FO in question was up to 121 PIC standards at the time the flights occurred.