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The initial report

The person submitting an Airprox Report will receive acknowledgement by email. The Reference Number in the acknowledgment is important - reporters should use it in any future correspondence. Note that UKAB will only accept an instruction to withdraw an Airprox report from the person who made that report in the first instance.

The investigation phase

Filing triggers an extensive information-gathering phase. Such things as radar recordings are called forward for inspection and R/T transcripts are produced of what was said over the radio at the time. Most importantly, reports are collected from each of the pilots and/or controllers involved allowing them to say what they think happened. Further investigation is then carried out either by staff from the Safety Airspace and Regulation Group (SARG) of the CAA and/or by their counterparts from the Ministry of Defence. For example, when an Airprox involves an airliner and a military aircraft, both the SARG and Ministry of Defence investigate their respective parts in parallel. When the investigation phase is completed, a comprehensive report - known as the 'Part A' - is then presented to the Airprox Board for assessment.

Airprox board assessment

There are eight civilian and six military disciplines represented on the Airprox Board which is chaired by Director UKAB. Board Members are almost always either air traffic controllers or pilots. These 'hands-on' practitioners bring their expertise and experience to each Airprox assessed. The task of the Board is to consider carefully all of the information presented in the investigation report and then to determine two things: first, what factor(s) caused the Airprox and second, the degree of risk of collision. Unlike findings on 'cause', where more than one reason can influence the final outcome, there is only ever one finding on 'risk'. The Board are further assisted in their deliberations by a panel of ten Advisors, drawn from civilian and military airspace and operations authorities.

Small unmanned air system (SUAS) assessment

For Airprox reporting purposes, SUAS are broken down into 4 categories: drones; balloons (including toy balloons and meteorological/research balloons); model aircraft; and unknown objects. SUAS Airprox usually involve only a fleeting encounter wherein the reporting pilot is often only able to give an outline description of the other air vehicle; as a result, the distinction between a drone, model aircraft and object is often down to the choice of wording by the reporting pilot. UKAB policy is to review the associated description and, if the reporting pilot has positively described something with drone-like properties (e.g. ‘4 rotors’) then that is taken at face-value as a drone; if the reporting pilot can only vaguely describe ‘an object’ then that is classified as an unknown object. The distinction between ‘drone’ and ‘model aircraft’ is more difficult given that many fixed-wing drones are not easily distinguishable from model aircraft. Although the UKAB tries to take the context of the sighting into account, it is therefore likely that some reported ‘Model Aircraft’ or ‘Unknown Object’ incidents were probably drones, and vice versa.

Communicating the Airprox Board's assessment

All relevant points from the Board's deliberations are added to the Report - as 'Part B' - together with a statement of Cause, any Contributory Factor(s) and/or Safety Recommendation(s) - the 'Part C'. Copies of the completed Report are then sent to those pilots and air traffic controllers involved in the incident. Subsequently, all Reports are published so that safety lessons identified can be disseminated in the interest of flight safety for the benefit of all.

Latest from UK Airprox Board

  1. May reports are now available
  2. April UKAB Insight newsletter
  3. Airprox Digest 2024