jabird: BTW, IAD ultimately has just the one big "terminal", with various concourses as mentioned.
AFAIK, this would mean that you would not have to go through security again to make the onward connection.
Do you have to go through security on arrival, like at ATL?
On the assumption that IAD follows the practice at all US airports through which I've done international->domestic connections, international arriving pax will have to clear IAD security before being allowed into the airside area.
There are at least two good reasons for this:-
- Whatever you might think of the merits of allowing direct airside domestic->domestic transfers without a further security check, at least everyone airside should theoretically have been checked to TSA standards at some stage. Inbound international pax may have been checked only to a lower standard (although, as we know, many will have been security checked before departure by better and more competent screeners
).
- Because inbound international pax have to claim their bags and clear customs before going to their domestic flight, they will have had the opportunity to access the contents of the checked bags, which may contain items that are prohibited from carry-ons. So they're no longer sterile and must be checked again.
I can't think of any reason why IAD would be different.
However, if you're arriving and being processed at the main terminal immigration facility and you're
not connecting onto a domestic flight, that facility tips you out into the landside area so there's no further security check for you.