An American Airlines plane carrying 60 passengers and four crew members collided with an Army Black Hawk helicopter outside Reagan National Airport near Washington, D.C. Wednesday night. A D.C. fire official said Thursday that “we don't think there are any survivors from this accident" and "we are switching from a rescue operation to a recovery operation.

An American Airlines regional jet went down in the Potomac River near Washington, D.C.'s Ronald Reagan Washington National Airport after colliding with a U.S. Army Black Hawk helicopter on Wednesday night, with no survivors expected.

U.S. authorities said on Thursday it was not yet clear why a regional jet crashed into a U.S. Army helicopter at a Washington airport, killing 67 people in the deadliest U.S. air disaster in more than 20 years.