A key safety system was turned off on a U.S. Army helicopter that collided with an American Airlines regional jet last week near Washington Reagan Airport, killing 67.

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.

After American Airlines Flight 5342 and a U.S. Army helicopter collided mid-air, officials shared insight into the respective pilots’ communication with air traffic control.

An American Airlines regional jetliner coming from Wichita, Kansas, collided midair with a Black Hawk military helicopter near Washington D.C.'s Ronald Reagan Washington National Airport, officials said.

The American Airlines Bombardier CRJ-700 collided in midair as it approached the D.C. airport around 9 p.m. local time, according to the Federal

Readings have been compared from the black box recovered from American Eagle flight 5342 and the air traffic control tower about the Black Hawk helicopter

Army Blackhawk helicopter that collided with an American Eagle flight over the Potomac River​ late last month was flying with a safety system turned off, Sen. Ted Cruz told reporters after a briefing from the FAA and NTSB.