Staxx
As you approach London Heathrow Airport you could be put in any one of four stacks by air traffic controllers, (clockwise, starting top-left) Bovindgon, Lambourne, Biggin and Ockham. Your flight slots into the top track and descends in a spiral until it’s ready to be called for final approach, like in Flight Control.
http://planefinder.net lets you see these tracks in near-real-time and look at the history, giving you the snail trail of flights approaching LHR.
Today there’s a broadly Easterly wind, so planes are approaching from the West.
