No ATC audio alarms if a transponder return goes off (disappears from the scope).
The equipment wouldn't know if was an aircraft transponder failure or a ground receiver/processor issue. Transponder returns are sometimes lost for short periods of time, more so in a single radar head environment than in a multi head situation.
Last edited by Captain Charisma; 16th Mar 2014 at 10:42.
Reason: grammatical sense