AIRPROX. The code word used in an air traffic incident report to designate aircraft proximity. Source: ICAO Doc 4444 PANS-ATM
Description
An AIRPROX is a situation in which, in the opinion of a pilot or air traffic services personnel, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved may have been compromised. (ICAO Doc 4444: PANS-ATM).
ICAO defines a series of classifications for AIRPROX events which have been reported and subsequently investigated by an appropriate body. It is required that this classification should be assigned on the basis only of actual risk, not potential risk. This means that only the residual risk after any avoiding action is considered. The available classification categories are: