An Airprox is defined as '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.'
UK airspace saw 280 reported Airprox events in 2017, an increase of 6% on 2016, 40% of reports being related to Small Unmanned Air Systems (SUAS) / drones. The number of aircraft-aircraft Airprox has reduced (from 171 to 159 - 7% decrease from 2016) whilst airprox involving SUAS has increased (from 94 to 121 - 29% increase from 2016).
The number of drone sightings by pilots and airports has seen an increase to 378 in 2017 from 282 in 2016.
Of the aircraft-aircraft Airprox, 79% occurred in Class G airspace. Of those in controlled airspace, only 3 were rated by UK Airprox Board (that assesses incidents) as risk bearing - safety was not assured or there was a risk of collision. Outside UK airspace, there were 50 reports of Airprox where UK registered aircraft were involved, 24% were airprox with SUAS.
Although the majority of reports relate to events that are not risk bearing, they provide valuable insights into the effectiveness of the safeguards that prevent a collision. The number of Airprox involving large commercial aeroplanes, which primarily operate in controlled airspace is extremely low.
The safeguards and barriers that make controlled airspace so safe are not always available for other airspace users, such as General Aviation operating in uncontrolled (less restrictive) airspace. This is particularly the case when aircraft are not equipped with a radio or a transponder (a device that communicates an aircraft's position and flight path information). In response, the CAA has been working to assist aircraft owners in the UK to acquire and use this technology and so help improve the safety of the environment that they are flying in.
The Airprox annual reports are available on the UK Airprox Board Website