Originally Posted by Dash8widget

Ok, I was a 121 chief check airman and APD for a number of years so I will try to answer your questions.

Your company (i.e. dispatch) has to designate a PIC for a particular flight - if you are not that person then you should not log PIC. Doesn't matter what seat you are in or what duties you are performing.

If you are giving OE to a captain - then by definition that captain is not yet qualified in that position, therefore you are PIC even if you are preforming the duties of the SIC. Of course, if you are giving OE, then you should be the designated PIC anyway - and the one signing the release.

LCA in 121 operations are not required to be CFI's nor are you automatically qualified to be a company instructor - why? because you are not giving dual instruction during OE (not officially though it may feel like it at times!). So I would not log time giving OE as "dual given" since you are not acting as an instructor. So to answer you senario - if you in the right seat giving a line check to a qualified captain, and that captain is designated by the company as the PIC for that flight - then you should not log it as PIC or dual given - only SIC.

If you are giving a LC from the jumpseat then you should not log that time at all.

So, to recap - if you are designated by the company as the PIC then log it as PIC. If not, then log it as SIC. If you are in the jumpseat it doesn't get logged. And none of the above counts as dual given.

Edited to add: dual instruction - that is time where you are using your CFI or instructor qualifications - is never given during 121 (or 135) revenue operations.