The National Transportation Safety Board on Tuesday issued two urgent recommendations to reduce and reroute helicopter traffic around Ronald Reagan National Airport near Washington after a midair crash of a passenger jet and an Army helicopter in January killed 67 people.
Jennifer Homendy, the investigative board’s chair, said that a review of air traffic at the airport from 2011 to 2024 found that an airplane alert was triggered at least once a month, instructing pilots to take emergency action to avoid hitting helicopters. Airline pilots are expected to follow the alerts, known as resolution advisories, over other commands, including air traffic control instructions.
In more than half those instances, which were documented in voluntary safety reports and F.A.A. data, the helicopter may have been flying above permitted altitudes for the route. Two out of three such collision threats took place at night.
Investigators have been trying to understand why an Army Black Hawk helicopter was flying above the maximum height for its route and how it ended up in the path of an American Airlines regional jet on the evening of Jan. 29.
In response to the data review and other findings, the safety board recommended that the Federal Aviation Administration permanently ban helicopter traffic along a corridor known as Route 4 — which the Black Hawk was traveling on the night of the collision — when airport Runways 15 or 33 are in use. The corridor runs between Hains Point of East Potomac Park and the Wilson Bridge near National Airport.
Airplane traffic on those runways accounts for less than 10 percent of departures and arrivals, so the helicopter closures would be limited, the agency said.
It also recommended that the F.A.A. designate an alternative helicopter route when that segment is closed to helicopter traffic.
“We’ve determined the existing separation distances between helicopter traffic operating on Route 4 and aircraft landing on Runway 33 are insufficient and pose an intolerable risk to aviation safety,” Ms. Homendy said in a news conference.
She said the data on the near collisions near National Airport clearly indicated a problem and it should not have required a tragedy for action to have been taken.
Two days after the fatal collision, the F.A.A. temporarily closed two heavily used helicopter routes running along the Potomac River and around National Airport. The Black Hawk helicopter traveled both routes during a training mission before its fiery collision with American Airlines Flight 5342.
The N.T.S.B.’s recommendations reinforce recent calls from Congress and U.S. airlines for the F.A.A. to permanently restrict some helicopter traffic around National Airport.