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.

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.

The Army helicopter that collided with a passenger plane above the Potomac River boasted an experienced crew doing “an unforgiving job.” Friends and relatives are still baffled and mourning their loss.

The Federal Aviation Administration and National Transportation Safety Board plan to brief senators Thursday on last week's midair collision between an American Airlines passenger jet and a military helicopter near Washington's Ronald Reagan National Airport that killed 67,

The pilots of the US Army helicopter that collided with an American Airlines Group Inc. regional jet near Washington last week were likely wearing night-vision goggles at the time of the accident. Preliminary information including the type of mission they were flying and crew communications indicates the pilots were using the device,