The deadly mid-air collision at Reagan Airport in January was years in the making, the operations manager of the DCA air traffic control tower on the night of the accident told the National Transportation Safety Board on Friday.

A small-engine plane crashed Friday on Morton Hill Road in the town of Hornellsville, leaving one person dead and triggering a multi-agency investigation. New York State Police confirmed the fatality,

Investigators so far have highlighted several factors that may have contributed to the collision, which left 67 people dead.