Investigators trying to determine what caused last week’s deadly midair collision between a US military Black Hawk helicopter and an American Airlines plane near Washington, DC, briefed lawmakers Thursday on what they’ve learned after combing through data from both aircraft and air traffic control.

Senator Ted Cruz told reporters that the chopper's Automatic Dependent Surveillance-Broadcast (ADS-B) system was not on before the crash over the Potomac River in Washington, D.C.