An F.A.A. report raised questions about staffing at the air traffic control tower.
Staffing at the air traffic control tower was “not normal for the time of day and volume of traffic,” said a preliminary F.A.A. safety report, which was reviewed by The New York Times.
A controller was performing jobs typically assigned to two controllers: handling helicopters in the airport’s vicinity and also instructing planes that were landing and departing from runways.
Secretary of Transportation Sean Duffy said at a news conference there had not been a “breakdown” in communication between the two aircraft and the control tower.
“This was not unusual with a military aircraft flying the river and aircraft landing at DCA,” he said, referring to the code for Reagan Airport. Investigators from the National Transportation Safety Board and the F.A.A. would analyze the debris, he said.
The moments before the collision appeared to have been captured in an audio recording, according to LiveATC.net, which streams air-traffic control radio transmissions. In the recording, an air traffic controller is heard instructing the helicopter to pass behind the jet.
Shortly before the collision, the plane’s pilots were asked to pivot its landing route from one runway to another, according to a person briefed on the event and conversations between an air traffic controller and the pilots overheard on audio recordings.
The helicopter was operating out of Davison Army Airfield in Fort Belvoir, Va., south of Washington.
It was taking part in an annual proficiency training flight with a “fairly experienced crew” operating with night-vision goggles, Defense Secretary Pete Hegseth said in a video statement.
The National Transportation Safety Board said it had recovered two so-called black boxes from the plane — a cockpit voice recorder and a flight data recorder — that may offer insights into the final moments before the crash.
Senator Jerry Moran, a Republican of Kansas, said in a post on X that the F.A.A. had indefinitely shut down all low-altitude helicopter flights near Reagan National Airport. Mr. Moran, who is on the Senate subcommittee on aviation operations, safety and security, added that he expected the restrictions to be in effect until the investigations were complete.
The closures were confirmed by a second person who was briefed on them. An F.A.A. spokesman said the agency could not comment.
Figure skaters and hunters were among the plane’s passengers.
Figure skaters, their family members and their coaches were among those onboard the plane, according to U.S. Figure Skating, the American governing body for the sport.
Russian nationals, including figure skaters, were also onboard. Among them were the married skating champions Yevgeniya Shishkova, 52, and Vadim Naumov, 55, according to the Skating Club of Boston. They worked as coaches in the United States.
Two skaters from New England — Spencer Lane, 16, of Barrington, R.I., and Jinna Han, 13, of Mansfield, Mass. — were also killed. Their mothers, Christine Lane and Jin Han, also died.
A group of friends who had spent days in Kansas on a hunting trip were also on the plane. Michael Stovall of Maryland was flying with at least six of his friends after the trip, said his cousin Shawna Slarb.
Kiah Duggins, who was set to become a law professor at Howard University next fall, also died in the crash, according to the university.
Officials had not released a list of the victims.
Reporting was contributed by Mark Walker, Jack Healy Julie Bosman, Jenna Russell, Jesus Jiménez and Mitch Smith.