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.

Authorities have confirmed the identities of all 67 victims killed in a devastating midair collision between an American Airlines plane and a U.S. Army Black Hawk helicopter near Reagan National Airport on Jan.

The deadliest plane crash in U.S. history was in May 1979, when American Airlines Flight 191 lost an engine during takeoff at Chicago O’Hare International Airport and crashed moments later, killing 258 passengers and 13 crew. Two people on the ground also were killed.

All of the "major" pieces of wreckage from the collision between a Black Hawk helicopter and American Airlines Flight 5342 have been cleared from the Potomac River, officials said.

Investigators with the National Transportation Safety Board (NTSB) are examining the wreckage after an American Airlines plane and Black Hawk helicopter collided midair near Reagan National Airport (DCA),

All major pieces of the American Airlines plane and Black Hawk helicopter that collided last week in Washington, DC, have been recovered, the National Transportation Safety Board announced Saturday.