Originally Posted by
to25sw
Last week coming on a LHR-MAD which arrived at T4, IB disembarked through the back door all connecting passengers to T4S and brought them there by bus. We had about 20 min delay, that might have been the reason.
No the delay would have had nothing to do with that.
(This applies to IB flights from LHR into T4(main) at MAD)
You were arriving from an European security screened origin (the UK), from inside the European common customs and VAT area (the UK) - the only thing was you were arriving from outside the schengen area.
T4(main) arrivals are sent up the bridges into the departure lougne to connect, or to then exit the airport if going to Madrid. This departure lougne area is inside Schengen.
As a result everyone coming off the flight needed to be schengne imigration entry checked, so it was done as you came off the plane.
However that would have resulted in thouse people connecting to non-schengen destrinations being entry checked, then exit checked again when to T4(S) upstairs. And some people needing schengen visas.
As a result, the busy connecting passengers direct from the aircraft at T4(main) to T4(S).
(BA operated flights from LHR to MAD arrive and depart from T4(S) upstairs non-schengen gates).