The airspace around Washington, D.C., is congested and complex — a combination aviation experts have long worried could lead to catastrophe.

An American Airlines jet with 60 passengers and four crew members aboard collided Wednesday with an Army helicopter while landing at Ronald Reagan National Airport near Washington, prompting a large search-and-rescue operation in the nearby Potomac River.

At about 9pm local time (02:00 GMT) on Wednesday, an inbound American Airlines aircraft (flight 5342), manufactured by the Canadian firm Bombardier, collided with a Sikorsky Black Hawk army helicopter as it approached the Ronald Reagan airport, located along the Potomac River southwest of Washington, DC.

A jet with 60 passengers and four crew members collided with an Army helicopter while preparing to land at Ronald Reagan National Airport near Washington, D.C., sending the aircraft plummeting into the Potomac River and killing everyone on board.

Sixty-seven passengers and crew died in Wednesday night's crash between a regional American Airlines jet and a Blackhawk helicopter from Fort Belvoir near Reagan National Airport.

It collided with a military helicopter on a training flight while landing at Ronald Reagan National Airport, near Washington DC. The airport's runways have since been closed while a search for survivors takes place.

As the American Eagle Flight 5342, a CRJ jet, approached the helicopter, the tower controller asked the helicopter pilot if he had the CRJ in sight. The helicopter pilot cannot be heard responding to the question before the two aircraft collided.

Washington DC's Ronald Reagan Airport has suspended all aircraft take-offs and landings in response to the incident at the airfield

In the three years before the deadly collision between an Army helicopter and an American Airlines flight near Reagan National Airport, at least two other pilots reported near-misses with helicopters while landing at the airport,

One onlooker said that he initially “didn’t think much of it” and thought the collision resembled “shooting stars.”

At least 28 bodies have been recovered after an American Airlines jet carrying 60 passengers and four crew members collided with an Army helicopter while landing at Ronald Reagan National Airport near Washington,