Originally Posted by
4forward8back
Are you sure about that?!
That is not at all correct, as
this crew discovered.
Also see:
https://www.flightsafetyaustralia.co...ke-turbulence/
"What makes wake vortexes particularly dangerous is that they can persist some distance behind, and below, the aircraft generating them. En route, an aircraft’s wake can extend for more than 25 nm, and descend very slowly downwards and outwards—levelling off around 1000 ft below the generating aircraft.This means encounters can occur when an aircraft passes below the flight path of another aircraft—even though ATC vertical separation is being applied."
I think there is a confusion of timings.
Of course a big flying thing creates wake turbulence that propagates and persists in all kinds of - sometimes unexpected - directions, including more than 500’ below it. It’s just that at the moment in time the big flying thing is 500’ above another aircraft, the big flying thing is not creating turbulence that will affect the aircraft 500’ below
at that point in time. And if the aircraft have tracks that are approximately at right angles, the aircraft below will be a long way away when the turbulence from the aircraft above ‘washes through’ the airspace where the aircraft below used to be
but is no longer.