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

The NTSB is holding three days of hearings to uncover insights into what caused the fatal crash between the passenger jet and the army helicopter over Ronald Reagan National Airport in January.

Three days of investigative hearings on the deadly midair collision between a military helicopter and passenger plane over Washington begin Wednesday morning and may reveal new insights into the crash