One of the issues facing the FAA and its project partners is security. The new system depends on air-to-ground and air-to-air broadcast. In a pure ADS-B environment, an intruder who disables the broadcast capability could essentially become invisible. What’s needed is “some backup surveillance system that would find you even if you don’t want to be found,” says Basil Barimo, vice president of operations and safety at the Air Transport Association. That may require retaining at least some primary radars.
The brass ring in developing ADS-B and related services is a national airspace system that can handle more aircraft.
That probably means an air network that doesn’t depend on radar. Unlike radar, ADS-B’s accuracy does not degrade with distance, so airplanes can fly closer without sacrificing safety.
The FAA plans to make the ADS-B system mandatory for general aviation and transport airplanes by 2014.