Near-misses were warning signs ahead of Washington crash

An American Airlines flight that had departed from Wichita, Kansas, coming in for a landing when it collided with a Sikorsky H-60 Black Hawk helicopter on Wednesday evening. The army helicopter had taken off from Fort Belvoir, close by in Virginia, on a training mission.

Recordings of air traffic control conversations published online suggest that a controller warned the helicopter about the jet in the seconds before the collision. The helicopter pilot appeared to confirm they were aware of the plane, but moments later the two aircraft collided.

Located in Virginia at the heart of the capital area, the airport has become exceptionally popular with travellers, but it faces numerous logistical challenges, such as congestion in the air space and shorter runways.

With nearly 400 flights daily and around 22,000 commercial flights per year, it provides direct service to 98 destinations in the US and Canada and is a feeder airport to international hubs in areas like Philadelphia, Charlotte, Atlanta and New York.

Several pilots the BBC spoke with said that flying in and out of the small airport on the edge of the US capital can be a nail-biting experience.

“There are times when we are watching planes land and we find ourselves saying ‘whoa that is close’,” said pilot Mo Khimji, noting that strong crosswinds can push a plane into restricted airspace “by a whisker” if the pilot is not careful.

Multiple types of aircraft share the airspace, from Air Force One carrying the president to commercial flights and military helicopters. And at night, city lights reflect off the Potomac River, making visibility and spotting other aircraft even tougher.

It is also smaller than other airports, such as nearby Dulles International Airport, with Mr Slack calling it a postage stamp.

“It’s a challenging arrival, challenging approach. You’ve got traffic all around you – above, below and to each side,” he said.