Originally Posted by
CarsTrainsPlanes
How do the authorities separate people who need transit visas from those who don't, if transit passengers don't actually enter the country? Is it done when they are clearing security?
No, from the passenger manifest. They'll know what nationalities are on board, and have a record of what visas they've issued. If necessary, immigration can meet a flight. In addition, airlines get a hefty fine for allowing passengers without correct documentation to travel.
That doesn't sound good. According to your description, I'd say that Heathrow was designed more like airports in Brazil, with corridors running parallel to the concourse and separating gates from jetways. Bu the way, have you had a chance to fly in or out of LHR's new T5? I wonder how is the whole international arrival and connection experience there, since it was recently built and was designed with all the post-9/11 security measures in its architecture.
Well, T1 and T2 are pretty old - the main parts opened in the '60s. More recent airport design (including Heathrow 4 & 5, Gatwick, and many others) separated incoming and outgoing passengers - it's just that the situation at T1 and T2 wasn't considered a problem until later.
Sadly, I've not managed to travel from T5 yet.
The general design for UK airports, though, is to have departures upstairs, arrivals downstairs, and the airbridges on the inbetween level, with ramps in both directions, the flow controlled by doors. Alternatively, bus/apron gates will be on the lower level, with arrivals directed to a central arrivals point. There are exceptions, of course, and the separation of UK vs CTA vs international arrivals still varies.
Another note to make is about EU vs non-EU passengers. Intra-EU passengers don't have to clear customs, and so are directed down a separate channel at international arrivals. Entry to this channel is allowed if you have green fringes on your luggage tags. If you have hand luggage only... Then they just have to go on trust.