Avoiding Mid Air Collisions (MACs): 5 Seconds to Impact
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.
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):
The UK Airprox Board
The role of the UK Airprox Board is to assess reported Airprox to enhance air safety.
Other MAC Safety Resources
The UK CAA provides further guidance in Safety Sense Leaflet 13 – Collision Avoidance.
The US National Transportation Safety Board (NTSB) have issued a Safety Alert on MACs: Prevent Midair Collisions: Don’t Depend on Vision Alone
Aerossurance has previously published:
- Military Mid Air Collisions
- Military Airprox in Sweden
- Mid Air Collision Typhoon & Learjet 35
- USMC CH-53E Readiness Crisis and Mid Air Collision Catastrophe
The European Aviation Safety Agency (EASA) has published this research report: EASA.2011.07 Scoping improvements to ‘see and avoid’ for General Aviation
UPDATE 2 July 2017: North Sea S-92A Helicopter Airprox Feb 2017
UPDATE 30 August 2017: NTSB: Do We See and Avoid or Avoid Seeing?
UPDATE 30 December 2018: Fatal Biplane/Helicopter Mid Air Collision in Spain, 30 December 2017
UPDATE 25 January 2019: Airbus Helicopters AS350B3 I-EDIC engaged in heli-skiing and Jodel D.140E Mousquetaire IV F-PMGV collided in mid air over the Rutor Glacier in Italy. Eight of the nine persons on board the two aircraft died.
UPDATE 2 February 2019: A319 / Cougar Airprox at MRS: ATC Busy, Failed Transponder and Helicopter Filtered From Radar
UPDATE 16 February 2019: Merlin Night Airprox: Systemic Issues
UPDATE 18 March 2019: UK CAA has launched a call for evidence on proposals for the wider roll out of Electronic Conspicuity in the UK (CAP1776).
UPDATE 19 April 2019: Enabling ADS-B OUT for General Aviation gathers pace says NATS
NATS, the CAA and EUROCONTROL worked with EASA to draft standard modification CS‑SC005a, and a significant number of aircraft owners with ADS-B capable transponders can now take advantage of it, with the view that the more aircraft that are electronically conspicuous to other airspace users, the safer it is for everyone in the air.
Details of standard modification CS-SC005a can be found on the EASA website.
UPDATE 12 May 2019: Alaskan Mid Air Collision at Non-Tower Controlled Airfield
UPDATE 5 August 2019: In response to the Cessna 152 G-WACG and Guimbal Cabri G2 G-JAMM accident the Buckinghamshire coroner has issued a recommendation to UK CAA on electronic conspicuity.
Some other past MAC accident reports include:
- United Air Lines DC-7 collided with a TWA Super Constellation over Grand Canyon, Arizona, 30 June 1956
- Hughes Airwest McDonnell Douglas DC- 9-31 collided with a US Marine F-4B Phantom over the San Gabriel Mts, California, 6 June 1971
- North Central Airlines Convair CV-580 and Air Wisconsin Twin Otter DHC-6 near Appleton, Wisconsin, 29 June 1972
- Report on the accident to British Airways Trident, G-AWZT and Inex Adria DC9 YU-AJR, Zagreb Yugoslavia, 10 September 1976
- Report on the accident involving RAF Tornado GR1, ZG 754 and Bell 206B JetRanger III, G-BHYW at Farleton Knott near Kendal, Cumbria, 23 June 1993
- Midair Collision of Tupolev Tu154M RA-85816 and Boeing 757 A9C-DHL, en-route over Uberlingen Germany, 1 July 2002
- Midair Collision of Electronic News Gathering Helicopters KTVK-TV, Eurocopter AS350B2, N613TV, and U.S. Helicopters, Inc., Eurocopter AS350B2, N215TV, 27 July 2007
- Mid-air collision – Cessna Aircraft 152, VH-FMG and Liberty Aerospace XL-2, VH-XLY, Casula NSW, 18 December 2008
- Report on the accident to Grob 115E Tutor, G-BYUT and Grob 115E Tutor, G-BYVN near Porthcawl, South Wales on 11 February 2009
- Midair collision -VH-TGM, Grob G-115, VH-YTG and TB-10 Tobago Parafield Airport, South Australia, 7 February 2009
- Midair Collision Over Hudson River, Piper PA-32R-300, N71MC, and Eurocopter AS350BA, N401LH, 8 August 2009
- Mid-air collision involving a Cessna 152, VH-TNV and Jabiru J160, 19-4430, Tyabb aerodrome, Victoria, 10 November 2013
- Mid-air collision between Cessna 172P, C-GJSE and Cessna A185E, C-FAXO Fort McMurray, Alberta, 21 June 2015
- NTSB Staff Presentations: 2 Mid-Air Collisions Cessna 150 with Lockheed-Martin F-16CM over Moncks Corner, South Carolina, 7 July 2015 and Cessna 172M with North American Rockwell NA265-60SC over San Diego, California 16 August 2015 and see also: The unanswered question
- UPDATE 5 September 2018: Mid-air collision Cessna 152s C-GPNP and C-FGOI Montréal/St-Hubert Airport, Quebec 17 March 2017