FAA license outside of USA
Let's assume the pilot with FAA ATPL license works in airline operator that is registered in country "A" ( ICAO member). However, all aircrafts in that company registered in another country "B".
So, aviation regulations in country A state that each crewmember have to get a validation from country B ( 83bis agreement)
Questions are:
How can the pilot comply with airman currency requirements? Do i need to be current according to FAA rules(part 121 or 135)? Or regular line checks, FFS sim checks conducted by airline are accepted?
I know a couple of such examples. I just confused what regulations must i comply with.
P.S. Country A doesn't have any license conversion process from FAA or EASA to it's national ATPL.