The National Transportation Safety Board will question witnesses Thursday about air traffic control training, a key part of the investigation into January’s deadly midair collision at Ronald Reagan Washington National Airport.

The NTSB concluded three days of investigative hearings into the collision between an Army helicopter and a passenger plane that killed 67.

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,