Originally Posted by
rt112
The vast majority of BA's flights from Heathrow depart from Terminal 5, with a small number form Terminal 3. Terminal 5 has three buildings (A, B, and C). As a general rule long haul flights depart from B and C gates, although gates are not announced until 60-90 minutes before departure (even less for short haul flights). The cynics amongst us suspect this may be to keep people in the shops...
New York flights (JFK and EWR) will inevitably leave from T5B or T5C.
While BA avoids to have these flights board from A10 (bus gate), I've had two EWR flights from A10 and have also seen a JFK flight depart from there, which did stand out.
Don't forget A18 which is a widebody gate at T5A. So yes, certainly the vast majority do depart from B/C, but it is not a given.