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,

Friday was the final day of the National Transportation Safety Board's (NTSB) three-day hearing on the deadly plane crash at Reagan Airport that took the lives of 67 people in January.

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

Although the D.C. Council cleared the RFK Stadium deal in its first vote, the advancement showed several members had to be convinced to do so.

A second vote will be scheduled for September and will require the green light from nine members of the council.