An AIRPROX is a situation in which, in the opinion of a pilot or air traffic control employee, the distance between aircraft, as well as their relative position and speed, may have endangered the safety of the aircraft involved. An AIRPROX occurs in airspace classes where no prescribed minimum distance applies between the aircraft involved.
AIRPROX – short for “Aircraft Proximity’
The International Civil Aviation Organisation (ICAO) defines a number of classifications for reported AIRPROX events. This classification must be based only on actual risk and not on potential risk. The following classification categories are available:
A - Risk of collision. The risk classification of an aircraft proximity in which serious risk of collision has existed.
B - Safety not assured. The risk classification of an aircraft proximity in which the safety of the aircraft may have been compromised.
C - No risk of collision. The risk classification of an aircraft proximity in which no risk of collision has existed.
D - Risk not determined. The risk classification of an aircraft proximity in which insufficient information was available to determine the risk involved, or inconclusive or conflicting evidence precluded such determination.
Collision-related events that may pose a risk to aviation safety must be reported via the ECCAIRS2 | Report an Occurrence reportable occurrence reporting system.
In Switzerland, there is a separate and additional reporting requirement for serious incidents and accidents to the SUST. Report aviation incident - Swiss Transportation Safety Investigation Board SUST
A collision-related event is classified as a serious incident or as an AIRPROX in category A in the following cases:
- a near-collision between aircraft in the air that required an avoidance manoeuvre;
- a dangerous situation has arisen
- an avoidance manoeuvre would have been appropriate.
If a collision can no longer be avoided, it is referred to as a mid-air collision.
Whether an airborne conflict is considered an AIRPROX or a Separation Minima Infringement (SMI) depends on the type of airspace and the flight rules the two aircraft are subject to. The definitions of both, an AIRPROX and an SMI are not linked to the actual or perceived air conflict.
Separation Minima Infringement (SMI)
To facilitate the safe navigation of aircraft in controlled airspace, authorities specify vertical and horizontal distances, known as separation standards. The standards ensure that aircraft are separated in a safe manner. If this minimum distance between two aircraft is not achieved, aviation terminology refers to as a Separation Minima Infringement (SMI). This can happen if a pilot fails to follow air traffic control instructions or if air traffic control itself is unable to ensure the minimum separation.
Monitoring and risk analysis
All incident reports are continuously monitored by the responsible safety analysts in the FOCA Safety and Risk Management (SRM) division. As soon as an increasing number of occurrences is detected, the FOCA initiates an in-depth risk analysis. This approach enables potential weaknesses to be identified at an early stage and targeted measures to be introduced to reduce the risk. In this way, the FOCA ensures that the highest safety standards are maintained.
Airprox Analysis Board Switzerland (AAB)
The Airprox Analysis Board (AAB) is an interdisciplinary working group consisting of aviation infrastructure operators and airspace users, as well as the FOCA. The focus is on exchanging safety information and experiences. Collision-related occurrences are analysed and systemic hazards identified that might not be recognised by individual organisations.
The Airprox Analysis Board Switzerland (AAB) is based on the requirements of ICAO Annex 19 and the Safety Management Manual (Doc 9859). The AAB is organised in accordance with these international requirements, the FOCA's safety policy and the Swiss government's safety programme (SSP).
