The agency has taken steps to reduce the risk of midair collisions after a military helicopter struck a commercial flight in January, killing everyone on both crafts.
The Federal Aviation Administration is making the areas where helicopters can fly near Ronald Reagan National Airport smaller and farther away, in the latest round of changes aimed at reducing the risk of midair collisions.
The airport sits on the southwest edge of Washington, across the Potomac River in Arlington, Va. New maps released by the F.A.A. on Thursday push the zones in which helicopters can operate farther east and south on either side of the Potomac. The plan replaces parts of certain flight routes that ran along or across those sections of the river with a transition route that crosses the Potomac farther south of the airport.
Since the deadly midair crash between a commercial flight and a military helicopter on Jan. 29, the F.A.A. has issued a series of new restrictions on helicopter flights with the aim of making the airspace around one of the country’s busiest flight hubs safer while investigations into the accident continue.
In March, the F.A.A. restricted all nonessential helicopter operations around the airport, and permanently closed the route that the Army Black Hawk helicopter had been using the night it struck American Airlines Flight 5342, killing everyone on board both crafts.
The changes came days after the National Transportation Safety Board, which is investigating the Jan. 29 crash, released urgent recommendations calling for the cessation of helicopter activity around Reagan National Airport whenever certain runways were in use, and the creation of alternative routes.
In early May, the military’s helicopter training missions were also suspended after two Delta flights were forced to abort landings at Reagan National Airport because of an Army Black Hawk helicopter that was circling the Pentagon, which is only about a mile northwest of the airport, on the western side of the Potomac.
The N.T.S.B. is expected to complete its inquiry into the Jan. 29 accident within one year, its chairwoman, Jennifer Homendy, told members of the Senate Committee on Commerce, Science and Transportation during a closed-door meeting on Wednesday, according to Senator Jerry Moran, Republican of Kansas, who was present.
In the meantime, the F.A.A. and the Army are also expected to agree to a memorandum of understanding that will govern how the two agencies coordinate their operations near Reagan National Airport and the Pentagon.
Chris Rocheleau, the acting F.A.A. administrator, told reporters on Wednesday that the two sides were “getting close” to completing that agreement.
Earlier this week, most of the senators on the Commerce panel called for the government watchdogs overseeing the F.A.A. and the Army to conduct separate audits of air safety protocols for the area around Washington.
Sean Duffy, the transportation secretary, threw his support behind the idea on Wednesday, pledging to fully support an inquiry.