The NTSB enters a second day of public hearings on the January midair collision between an Army Black Hawk helicopter and a passenger plane.

The Army helicopter that collided with a plane over D.C. in January had incorrect altitude readings, contributing to the aircraft getting too close.

Military helicopter traffic over Washington was a longtime worry among aviators operating around the airport where an Army helicopter and commercial airliner collided this year, killing 67 people, federal investigators heard during testimony on Thursday.