Definition

Signals used for communication between an intercepting military aircraft and the intercepted aircraft.

Description

Military aircraft are often tasked to intercept unknown aircraft, aircraft which are not in communication with the appropriate ATC agency, and aircraft which are not responding to attempted ATC contact or have departed from their current clearance.

A civil aircraft is most likely to be intercepted if it has lost communication with ATC or strays into airspace without appropriate diplomatic or other clearance and without contact with the appropriate controlling authority.

Since the events of 11 September 2001, military interception of aircraft which are not responding to communications with ATC has become more likely. Furthermore, because of the potential security issues, such intercepts are potentially hazardous and it is important that crews know what to expect when intercepted and are aware of the signals used by military aircraft and how to respond.