Originally Posted by
IDIOTPILOT
"(2) Must hold at least a second class medical certificate when exercising:
(i) Second-in-command privileges of an airline transport pilot certificate in part 121 of this chapter (other than operations specified in paragraph (a)(1)(ii) of this section)"
If you didn't keep track of things, they changed the reg in July 2013 to reflect the ATP requirement. Your company might require it for other reasons but the FAA does not require it for domestic 121 FOs.
Somehow missed that, I'll have to go read it. I still have yet to hear of a single domestic airline that doesn't require a 1st class as a minimum requirement to be a FO candidate.