Investigators are citing operational error by an air traffic controller after an American Airlines Boeing 777-200 converged head-on with a pair of US Air Force Boeing C-17 transports near New York.

The 20 January incident, disclosed by the National Transportation Safety Board, involved American flight 951 from New York JFK, tracking southeast to Sao Paulo, while the C-17s were heading northwest to New Jersey's McGuire air force base.

"The air traffic controllers talking to each of the aircraft received conflict alerts, and immediately provided traffic advisories and turned their aircraft to resolve the conflict," says the NTSB. "In addition, the American Airlines crew responded to directions provided by the [traffic collision avoidance system]."

Investigators state that the incident occurred in darkness at 22:30, 80 miles southeast of the city, and led to the aircraft approaching head-on, coming "within a mile of each other at their closest point". Their altitude has not been given.

Reporting collision-avoidance resolution advisories to the NTSB became mandatory in January 2010.

Source: Flight International