RVSM it should be 1000ft 
Snoopy wrote:
Why?
Another plane passing underneath?
Snoopy wrote:
I’ve seen the Radar Altimeter display 2000ft when up in the flightlevels (FL300+). Why?
Could be just radio interference.
Usually it’s based on the time taken by a wave to go from the plan to ground and then back to the plane, and the duration is converted into a distance, taking into account that emitter and receiver mustn’t be at the same place. May be the wave bumped on a heavily loaded cloud. RA may also activate only when close to the ground. when RA is connected to GPWS, it has the power to trigger alerts.
