Yes. What the air traffic controllers see is actually a return signal from a box called a transponder...it receives the radar signal and sends back a coded burst of information such as altitude, airspeed, etc. The pilots set a four-digit code on the transponder as assigned by ATC.
If they turn off the transponder, then all that controllers will see is the "primary return" of the radar hitting the skin of the plane...just a blip without other information, and maybe not even that if the plane is far from a radar site.
The 9/11 hijackers turned the transponders off on all four aircraft after seizing control. It made it harder for ATC to track them.
}:-)4
Soooo, If I understand what you are saying: The transponder could be shut off, the plane could still be in the air and flying, destination unknown, and the quality of radar in Europe is such that they might re-locate it, if it is still flying, because it is very difficult to get a radar return off just the plane?
Can you flesh this idea out just a little more?
Is there any chance the plane could still be in the air and heading for Athens? I get really confused with time zones, but I know Athens is 10 hours ahead of me here in Calif. I don't know the time split to Moscow from here, and I don't know the flying time (approx) to Athens from where the plane took off.
What I am asking here is: Could this plane be flying to Athens and be able to avoid being picked up by radar?