Originally Posted by
kbooks66
This is wrong, I recently had a CPH to LHR to SEA routing which had me land at T5 and Leave at T5. If you go into Terminal 5 before transferring to terminal 3 you will not be marked ready to fly and be able to access the concorde lounge. Once you enter terminal 3 you are marked ready to fly and cannot leave.
I was able to do the reverse upon landing at T5 I immediately transferred to T3 to check out the Cathay and Qantas Lounges, I then was able to transfer back to T5 without any issue. Just make sure to leave sufficient time for the bus transfer.
what BertieBager noted was entirely correct, with an onward bp for a flight departing from t3 you can’t access the airside departures area in T5 where the ccr is - unless you have some significant manual intervention from ba.
what has been done sometimes is on arriving at T5 from another flight people will go to t3 to access to the lounges there before departing T5. Not something I would recommend due to timing and general faff tbh. T3 does not have ready to fly.