Originally Posted by
bisonrav
OK, I'll bite.
The capacity requirement for the TATL flights is constrained anyway, and the number of BA passengers who are eligible is known ahead of time. So the capacity is reserved. That means the TATL passengers have space when they arrive. Even with that provision, the lounge is routinely full anyway.
It may be that having arrived in F may help since that could open up access to First Dining which isn't busy. Maybe something to ask You First about.
Arriving in TATL F connecting to domestic J does not give access to the First Dining at IAD and I’m pretty sure it wouldn’t even as a GGL