aa73, you've got a valid point about "co-captain." (Not my term, by the way, but I'll consider it dropped from my glossary!)
Just to clarify the situation I was referring to, all 3 pilots were type-rated and qualified, and during the rotations, the pilot assigned left seat was captain, the assigned right-seater was FO.
Just to clarify the situation I was referring to, all 3 pilots were type-rated and qualified, and during the rotations, the pilot assigned left seat was captain, the assigned right-seater was FO.