Cessna pilot sets Hijack squawk code..gets chased by Police helicopter

A Cessna pilot inadvertently entered 7500 on the transponder — the universal code for a hijacking — instead of 7600, the code for a radio failure. The two codes sit close together on a transponder dial, and mis-dials between them happen periodically across general aviation.

Accident Facts

Because a 7500 squawk carries no way to distinguish an accidental entry from a genuine hijacking, controllers treated it by the book: full activation of aviation security protocols, immediate law enforcement notification, and a police helicopter sent to observe the aircraft. Once the pilot re-established radio contact and corrected the transponder code, controllers were able to resolve the situation and stand down the response.

Sources

FAA Aeronautical Information Manual, squawk code 7500 procedures