The pilots of a U.S. Army helicopter that collided with a passenger jet over Washington in January would've had difficulty spotting the plane while wearing night vision goggles, experts told the National Transportation Safety Board on Friday.

The hearings in Washington will involve NTSB board members, investigators and witnesses. Panels will focus on military helicopter routes in the Washington area, collision avoidance technology and training for air traffic controllers at Ronald Reagan National Airport, among other subjects.

Flight instruments probably led the Black Hawk crew to believe the helicopter was lower than it actually was before the collision with a commercial airplane on Jan. 29.