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.

In January, 67 people died when an American Airlines passenger flight crashed with a military helicopter near Washington, D.C.

Tuesday was day two of a three-day hearing on the deadly plane crash at Reagan Airport that took the lives of 67 people in January.