How did the DC crash happen? Experts reveal what may have caused deadly collision

WASHINGTON — A short runway and intersecting flight paths with precariously close altitude requirements may have played a role in Wednesday night’s deadly collision of an American Airlines plane and a US Army Black Hawk helicopter near Ronald Reagan National Airport, experts told The Post.

Officials have not yet provided any causal information behind the crash — the deadliest aviation disaster in the US in more than two decades — however, Transportation Secretary Sean Duffy said Thursday that the tragedy was “absolutely” preventable.

The Post spoke to several aviation experts about a number of factors that may have contributed to the fatal collision.

Originally built to shuffle VIPs into the nation’s capital on private or government jets, Reagan is a smaller airport and the only one physically in the District.

With a runway nearly half as long as the standard 13,000-foot runways of other airports built to accommodate large commercial jets, landing is tricky for incoming planes, according to former DC-based American Airlines pilot John Wright.

“The first few times you fly there, you usually are with [a fellow pilot] who’s really experienced. He’s kind of talking through it, too,” Wright told The Post.

“Where you land on [runways] that are 13,000 feet long, you’ve got plenty of room to play with. But at [Reagan] it’s only 7,000 feet.”

The shorter runway makes the descent difficult, creating the need for pilots to be intensely focused, he said.

Air traffic controller audio captured operators warning the military helicopter that it was getting close to American Airlines Flight 5342 and directing it to pass behind the passenger plane, which would have had the right of way for the trickier landing.

“It’s such a challenging airport to land a jet airplane at your focus is really on your airspeed, your altitude, your rate of descent,” he said, adding that “the last thing you’re looking for is to see if somebody’s crossing in your path.”

Still, he insisted, “it’s totally possible to operate safely at Reagan International — I did it for 50 years, of course.”

In addition to the shorter runway, intersecting flight paths with close altitude requirements could have also played a role in the tragedy.

There are two flight paths — one for helicopters and another for airplanes — that converge near the Reagan airport, according to an official flight map.

Helicopters are directed to fly no higher than 200 feet in their path, while airplanes should be at roughly 500 feet, aircraft aviation attorney and former pilot Jim Brauchle told The Post.

“That approach to that runway, the commercial aircraft published approach, is to basically fly down the east side of the [Potomac] river and then about a mile and a half from the touchdown, the aircraft would make this 50-degree turn to go land,” he said.

“And when it makes that turn, it’s just under 500 feet, and then obviously it’s going to descend,” he explained.

“Well, there’s also a helicopter route that goes right down the river that’s at or below 200 feet. And so you’ve got intersecting routes that are apparently de-conflicted by, you know, only several hundred feet — which is not a lot of room for a margin of error.”

What’s more, Federal Aviation Administration rules allow pilots a standard 75-foot deviation from the prescribed altitudes, which could potentially drop that margin even lower, Brauchle said.

“Hypothetically … that’s a 150-foot difference,” he said.

“If there’s only initially going to be about a 200-foot separation, that gets the [airplane and helicopter] within 50 feet of each other.”

Wright said the helicopter “should not have been crossing the flight path at any altitude at that time,” regardlessly.

“Somehow something broke down between the helicopter’s clearance to be there and air traffic control tower,” the former pilot surmised.

“It’s kind of a seems like a very preventable accident that shouldn’t have happened if normal procedures were followed.”