Event Details

Title:Near-Miss: Air Force 1 and UPS Boeing 747s on Mary 27, 1997 (Recommended)
Micro summary:An ATC error results in a clearance that would have caused a mid-air collision between Air Force 1 and a UPS 747, were it not for backup automation.
Event Time:1997-05-27 at 0420 UTC
File Name:1997-05-27-IE.pdf
Publishing Agency:Air Accident Investigation Unit (AAIU)
Publishing Country:Ireland
Report number:1998/006
Site of event:53N 15W
Latitude/Longitude:53N 15W
First AirplaneSecond Airplane
Airplane Type(s):Boeing 747-200Boeing 747
Flight Phase:CruiseCruise
Operator(s):United States Air ForceUnited Parcel Service (UPS)
Type of flight:MilitaryCargo
Serious Injuries:00
Other Injuries:00
Executive Summary:The Boeing 747 USAF 1 was routing from the United States to Paris at flight level 290. The Boeing 747 UPS 6080 was routing from Europe to the United States at flight level 310. The position 53N 15W, is one of the entry/exit points from the Shannon Upper Information Region (UIR) to oceanic airspace.


In ensuring separation of aircraft in controlled airspace differing levels of automated and human centred systems are used, and at the final level the visual acquisition of the pilot, of his conflicting traffic may have to be relied on. Analysis in the UK of Airprox incidents indicates that most are attributed to flight deck errors which lead to deviation from the altitude arranged by ATC.

This case differs in that an ATC clearance was given which did not provide the required separation. However, the safety tools, STCA and TCAS, as distinct from separation tools, activated to provide timely intervention by the controller.

This occurrence should have been reported by way of the MOR. This would have allowed a timely examination by the ANS management and possibly have prevented some of the subsequent media attention. Notwithstanding this, the identity of the aircraft "USAF 1" would more than likely have triggered media attention. This event may also have been used unfairly to illustrate the differing requirements for the carriage of TCAS, i.e. for passenger aircraft only, as distinct from cargo aircraft by some sections of the U.S. pilot community.

The event however has served as a useful purpose in prompting both an IAA investigation and an AAIU investigation and has helped to identify possible deficiencies in the handling of Airprox Reports, and the manner in which controller induced separation losses are dealt with.

It also re-affirms the effectiveness of the automated safety tools of STCA and TCAS and the wisdom of their provision.

Human factors played the major role in the cause of this incident and this further reinforces the requirements to examine the role of human factors in Air Traffic Control as well as in the Flight Crew Operations. The occurrence also highlighted the lack of a critical incident response programme for controllers who may have been traumatised by an incident or indeed the subsequent investigations into such events, and illustrates the requirement of a similar programme for ATC personnel as exits for most aircrew.

Learning Keywords:Operations - Airspace - Air Proximity
Operations - Airspace - Air Traffic Control
Operations - Airspace - TCAS


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