According to Concorde FO Christopher Orlebar's The Concorde Story
, there were three fixed supersonic tracks: SM
(eastbound), and SO (not used in scheduled service). SM
is the most northerly and is approximately the shortest great-circle route that avoids placing a boom on Canada or Ireland. SM
, and SO had about one degree of latitude in lateral separation.
On the other hand, the seven subsonic transatlantic tracks are not fixed; they are recomputed every day based on wind patterns. Head- and tailwinds had a much smaller effect on Concorde due to its high cruising speed, so it was not worthwhile to vary the supersonic tracks.
Here is a scan from The Concorde Story
showing the SM
track and the subsonic tracks on one particular day. Diversion airports are also shown.
Wake turbulence was not an issue. Even if the subsonic and supersonic tracks happened to coincide on a given day, vertical separation between Concorde and other aircraft generally would have been 15-20,000 feet. Much heavier subsonic aircraft routinely fly with just 1,000 feet of vertical separation on the subsonic tracks.
Concorde's unique delta vortices also dissipated much more quickly than the wingtip vortices left by other aircraft, so I doubt wake turbulence was a problem at takeoff and landing.
Keynes is dead and we are living in his long run.