5 May 2001. Thanks to Anonymous.

EN ROUTE LONG RANGE RADAR DEACTIVATION PLAN

Draft

U.S. Department of Transportation
Federal Aviation Administration

Prepared by: Surveillance Working Group (SWG) ASD-140
July 10-August 11, 1997

Comments: An FAA draft report is found below in PDF format.

The FAA is "studying" the deactivation of one of the two redundant radar systems used for air traffic control. The two systems are not completely redundant because they perform slightly different functions.

One system uses a radio signal to address the transponder box onboard the aircraft. This transponder box then responds with the aircraft information. If the transponder is not functioning no aircraft information is displayed.

The second system, the one they are thinking about eliminating, bounces the radar signal off the aircraft. This return does not depend on a transponder box, and shows all aircraft, not just those equipped with a transponder. There is no plan for a replacement system.

Among the items discussed in the report are:

• the need to require general aviation aircraft to be equipped with a transponder

• the reduced safety due to potential transponder failures (the aircraft would then become invisible)

• the fact that not all military aircraft use their transponders all the time.

• the possible reduced capacity of the air traffic system.

Several basic security issues are not discussed such as how a terrorist might purposely subvert a transponder-only based system. The issues raised by this report represent what is quite likely a major reduction in safety of the air space above the United States.

You will need Adobe Acrobat Reader to see the report.

The report is found here: http://cryptome.org/deact.pdf  (85K).