Event Details

Title:Near-miss between Swissair MD-11 and American Airlines Boeing 767-300 at 050N 013W, July 3, 2000
Micro summary:An ATC systems error results in a faulty clearance, resulting in a near miss between a MD-11 and Boeing 767.
Event Time:2000-07-03 at 0348 UTC
File Name:2000-07-03-IE.pdf
Publishing Agency:Air Accident Investigation Unit (AAIU)
Publishing Country:Ireland
Report number:2001/016
Site of event:050N 013W, in Shannon Oceanic Transition Area (SOTA)
Latitude/Longitude:050N 013W
First AirplaneSecond Airplane
Departure:General Edward Lawrence Logan International Airport, Boston, Massachusetts, USAJohn F. Kennedy International Airport, New York, USA
Destination:Zurich International Airport (Kloten Airport), Kloten, SwitzerlandFrankfurt/Main, Frankfurt, Germany
Airplane Type(s):McDonnell Douglas MD-11Boeing 767-300
Flight Phase:CruiseCruise
Operator(s):SwissairAmerican Airlines
Type of flight:RevenueRevenue
Serious Injuries:UnknownUnknown
Other Injuries:UnknownUnknown
Executive Summary:On Monday 3 July, 2000, circa 0348 hours, a Swissair MD-11 aircraft, callsign SWR 127, reported a near miss with another aircraft, identified as an American Airlines B767, callsign AAL 176. The event occurred at 050N 013W in the Shannon Oceanic Transition Area (SOTA) (Annex A), approximately 210 nautical miles South West of the Cork VOR. SOTA is a designated Reduced Vertical Separation Minima (RVSM) area.

SWR 127 was en route from Boston to Zurich and maintaining Flight Level (FL) 320. AAL 176 was en route from JFK, New York, to Frankfurt and, at the time of the event, was climbing from FL 290 to FL 370, having received clearance from Shannon Radar. The aircraft commander of SWR 127 had been observing AAL 176 to his left and below him for more than five minutes when he got the impression that it had started climbing. This was confirmed by warnings on his Traffic Alert and Collision Avoidance System (TCAS). He immediately turned his aircraft 10 to his right and observed AAL 176 climbing through his assigned level, within 0.5 nautical miles (NM) of his left wing.

Prior to leaving the Shannon frequency some minutes later, the commander of SWR 127 advised that he intended filing an air traffic incident report involving AAL 176 with the Swiss authorities.

Causal Factors
The primary cause of this serious incident was the loss of SWR 127 radar signal due to a functional anomaly in the software, which led the Radar Controller to incorrectly give climb clearance to AAL 176 from FL 290 to FL 370.

Other factors contributing to the incident include the breakdown in communications between the Radar Controller and SWR 127 subsequent to their initial radio contact, the eight minutes non-communication between the Radar Controller and the Planning Controller in relation to SWR 127 and the inoperative TCAS on AAL 176.
Learning Keywords:Operations - Airspace - Air Proximity
Operations - Airspace - Air Traffic Control
Operations - Airspace - TCAS


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