Avoiding Mid Air Collisions (MACs): 5 Seconds to Impact

The UK Airprox Board (UKAB) has released a video with tips for pilots on preventing mid air collisions.

The Airprox Board explain that:

Every year there’s an increase in Airprox as spring and summer arrives. On average, statistics show one mid-air collision occurs for every 60 Airprox incidents in UK airspace.

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.

five seconds to impact avoiding mid-air collisions UK airprox board

So much can happen in a matter of seconds:

Research shows that in normal circumstances the average pilot needs anything from nine to 12.5 seconds from spotting another aircraft to processing the closure geometry and manoeuvring to avoid a potential collision in a controlled manner. You may only have 5 seconds or so between the eye detecting an aircraft head-on and impact.

MAC Prevention: 6 Themes

There are six themes from previous incidents that the Board say: “can help cut the risks if pilots apply them every time they fly” (click on the image for more details):

six themes avoiding mid-air collisions UK airprox board

The UK Airprox Board

The role of the UK Airprox Board is to assess reported Airprox to enhance air safety.

To emphasise both the scope of its work and its independence, UKAB is sponsored jointly, and funded equally, by the UK Civil Aviation Authority (CAA) and the UK Military Aviation Authority (MAA).

Other MAC Safety Resources

The UK CAA provides further guidance in Safety Sense Leaflet 13 – Collision Avoidance.

The US National Transportation Safety Board (NTSBhave issued a Safety Alert on MACs: Prevent Midair Collisions: Don’t Depend on Vision Alone

Aerossurance has previously published:

Back in 1991 the then Bureau of Air Safety Investigation (BASI), now the Australian Transport Safety Bureau (ATSB) published:  Limitations of the See-and-Avoid Principle

The European Aviation Safety Agency (EASA) has published this research report: EASA.2011.07 Scoping improvements to ‘see and avoid’ for General Aviation

UPDATE 30 August 2017: NTSB: Do We See and Avoid or Avoid Seeing?

UPDATE 24 November 2018: AAIB Highlight Electronic Conspicuity and the Limitations of See and Avoid after MAC (Cessna 152 G-WACG and Guimbal Cabri G2 G-JAMM)

Some other past MAC accident reports include:

Avoiding mid-air collisions UK airprox board

Aerossurance has extensive air safety, operations, airworthiness, human factors, aviation regulation and safety analysis experience.  For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com