also...

it means the aircraft flying into British airspace had its Transponder turned off..... this is the little box of electronics that is interrogated by British secondary radar for its IFF (identity "friend or foe") - so basically the primary radar will pick up the planes "echo" and shoe a "blob" on the radar screen for the air traffic controller, and the secondary radar will send out a pulse to interogate the IFF.... when switched on the planes transponder will give not just the planes pre-agreed identity code, but its fuel state and destination info.... when this facility is turned off it normally means squeaky bum time......

(i was a radar tech in the falklands and we had this game with the argies weekly!)

Posted By: Cheltenham_Canary, Jul 25, 17:11:56