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.

The National Transportation Safety Board questioned witnesses Friday on collision avoidance technology and organizational systems to manage risk. It is the third and final day of investigative hearings probing January’s midair collision between a US Army Black Hawk helicopter and an American Airlines regional jet,

A three-day hearing into the January mid-air collision between an Army Blackhawk helicopter and an American Airlines jet concluded today. The National Transportation Safety Board's hearing focused on the breakdown of safety systems that led to the deaths of 67 people,