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.
Snoopy wrote:
I’ve seen the Radar Altimeter display 2000ft when up in the flightlevels (FL300+). Why?
Could be just radio interference.
Snoopy wrote:
Why?
Another plane passing underneath?
RVSM it should be 1000ft 
Awesome plane and nice groundspeed! Congrats!
I’ve seen the Radar Altimeter display 2000ft when up in the flightlevels (FL300+). Why?
Radar altitude indeed, doesn’t help if the thing is shut off ;-)
greg_mp wrote:
what is tha RA indication with a red line in the AI part?
Radio Altitude – At that height it won’t give a reading, but lower it would show a figure
Usually RA refers to Resolution Alert, related to TCAS message, but I assume aspen 1000 doesn’t come with such tool.
It’s the last level of alert of a TCAS, and in airline, you must disengage AP and follow RA order (pull or push, and the minimum angle you must take).
But these TCAS are equipped with directional 1090Mhz antenna that can localize exactely where the plane is, learn the trajectory and deduce the way to resolve it.
If the other plane has a TCAS, they agreed both on the good manouever to do.
It may be radar altitude, I found aspen 1000pro max guide here EFD1000_PRO_MAX_PFD_PLTS_GUIDE local copy
I’s just strange that it is still appearing once in the air.
greg_mp wrote:
, what is tha RA indication with a red line in the AI part?
I’m only guessing: Radar Altitude?
Super plane, the Aspen suits it well.
