I have had zero luck with this but several differing opinions
We were trying to judge the ampacity of an existing cable, 3 conductors 500KCM in one jacket or cable.
This cable is attached to building rafters, about 10 ft between rafters and the cable is surrounded by air above below beside and is indoors near roof no other conductors
Some say it is 3 cables in same jacket and free air table does not apply.
Others say its in free air so it is free air rating
I cant find any definitions or specific chapter that deals with this