While landing at Ronald Reagan Washington National Airport in Washington, D.C., on Wednesday shortly before 9 p.m., American Airlines Flight 5342 collided with an Army Black Hawk helicopter and crashed into the icy Potomac River.

A regional jet carrying 64 people collided with an Army Black Hawk helicopter. Reagan National Airport grounded all flights.

The last major collision of a commercial U.S. airline dates back to 2009, when a Colgan Air incident left 50 dead near Buffalo, New York. Federal regulators tightened safety requirements following the crash, including bolstering aircraft carrier inspection requirements and pilot training hours.