"It was with reference to the flight deck crew, pilot and co-pilot"
Yes, even the flight crew here have worked that out!!!
But without a context we are all guessing - Where did you hear or see the mystery abbreviations "FC" and "FCM".. Public address announcement, Crew Badge, Customs Declaration?
(edited to add: It might be worth asking the same question on the Nordic Forum...maybe it's a Nordic Abbreviation)