The first of the National Transportation Safety Board’s three days of investigative hearings is underway to help determine what caused the deadly midair collision on January 29 between an Army helicopter on a training mission and American Airlines flight 5342 landing at Ronald Reagan Washington National Airport.

Investigators have found that a helicopter involved in a deadly crash with a passenger plane over Washington was flying above its height limit

On the eve of the investigative hearings, Republican Sen. Ted Cruz introduced legislation called "The Rotor Act," which would require all aircraft, including military, to transmit ADSB location when flying -- a system that allows aircraft to transmit its location to other aircraft as well as to air traffic controllers.