American Airlines flight 951 was en route to San Paulo, Brazil, about 10:30 p.m. on Jan. 20 when its proxmity warning system alerted it to the impending collision with the two U.S. Air Force C-17s, the National Transportation Safety Board said in a statement.
The American pilot, responding to the collision warning, took evasive action, the board said. Air traffic controllers in contact with each of the planes also received conflict alerts that prompted them to order the planes to change direction, the safety board said.
It's not clear yet how exactly how close the airliner came to the C-17s, but it was within a mile of the transport planes, the board said. Airlines typically travel at hundreds of miles per hour and can close that distance within seconds.
It's not clear whether the planes were over water or New Jersey at the time of the incident, board spokeswoman Bridget Serchak said.