It's not clear to me that civilian primary radar was necessarily available in that region and the " dropping off of radar " was really a lack of transponder interrogations.
42.
The PA-28 was not in communication with Air Traffic Control, and was not transponder equipped, and there was no evidence it appeared as a primary radar target on the radarscope.
43.
It's a tricky problem with a primary radar signature and no transponder because everything else has to be ruled out .-- talk ) 06 : 23, 13 March 2014 ( UTC)
44.
The advantages of the primary radar are no on-board equipment in the aircraft is necessary for detecting the target and can be used to monitor the movement of vehicles on the ground.
45.
I need a direction, a destination . " Because the hijackers had turned off the plane's transponder, NEADS personnel spent the next minutes searching their radar scopes for the primary radar return.
46.
Since the TLS operates using the long range band of SSR ( 1030 / 1090 MHz ) there is no rain fade such as experienced with a traditional PAR that uses primary radar.
47.
The system also provides for a combined air picture derived from primary radar and IFF ( identification, friend or foe ), as well as a command and control system for effective air defence control.
48.
The first radar problem occurred at 6 : 50 a . m . and lasted until 8 : 30 a . m . The backup system kicked in when the primary radar system failed.
49.
"' 9 : 32 "': Controllers at the Dulles Terminal Radar Approach Control in Virginia observe " a primary radar target tracking eastbound at a high rate of speed ", referring to Flight 77.
50.
After last contact by primary radar west of Malaysia, the following records were recorded in the log of Inmarsat's ground station at Perth, Western Australia ( HH : MM : SS; UTC times 7 8 March ):
