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,

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

The National Transportation Safety Board wrapped up a three-day investigative hearing into the mid-air collision between a helicopter and passenger jet in Washington that killed 67. New information confirms the crew of the Army helicopter faced several problems,