US investigators probing a deadly crash between an airliner and a military helicopter near Washington said Tuesday that air corridors serving the capital city are too risky and should be changed.
In that January 29 tragedy, a passenger plane preparing to land at Ronald Reagan National Airport collided with a US Army helicopter flying along a designated air corridor.
A total of 67 people died and there were no survivors in the worst US air disaster in two decades.
The National Transportation Safety Board published a preliminary report Tuesday into the accident.
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NTSB chair Jennifer Homendy said helicopters should be barred from that corridor when planes are planning to use the runway, known as number 33, that the American Eagle Bombardier CRJ-700 jet was headed for that day.
The plane and helicopter ended up plunging into the cold waters of the Potomac River.
US authorities have already temporarily banned helicopter flights at the airport because of the accident. But the NTSB is now recommending that this be made permanent for part of that particular helicopter corridor, known as Route 4.
"We've determined that the existing separations between helicopter traffic operating on Route 4 and aircraft landing on Runway 33 are insufficient and pose an intolerable risk to aviation safety by increasing the chances of a mid-air collision," Homendy told a news conference.
She said those two routes had a separation of just 76 feet (23 meters.)
Reagan National is located in the heart of metropolitan Washington, a few miles from the White House and just across the river in Virginia, and helicopter flights over the city are common.
Homendy said the probe has determined that between October 2021 and December 2024 there were 85 recorded incidents near the airport in which a plane and a helicopter had a lateral separation of less than 1,500 feet (460 meters) and vertical separation of less than 200 feet (60 meters).
The Federal Aviation Administration, she said, "could have used that information any time to determine that we have a trend here and a problem here, and looked at that route."
Homendy added that despite repeated warnings in recent years, "that didn't occur, which is why we're taking action today."
"It shouldn't take tragedy to require immediate action," Homendy said.
The probe of the January collision remains ongoing and it could take a year for a final report to come back.
So far it has determined that faulty instruments and communication problems may have caused the accident.