The US Army helicopter that collided with a passenger jet near Washington was being operated on a training flight by a "fairly experienced crew" with night-vision goggles, US Defence Secretary Pete Hegseth said on Thursday.
The Pentagon has ordered a 48-hour pause in flying for the Virginia-based unit involved.
In addition, Daniel Driscoll, President Donald Trump's nominee for Army secretary, told a Senate hearing that the crash on Wednesday night appears to have been preventable, and he raised questions about whether training should take place near a busy airport.
The Black Hawk helicopter struck an American Airlines passenger jet near Ronald Reagan Washington National Airport, with both aircraft plunging into the Potomac River.
Authorities have said there were no survivors. The cause of the crash is under investigation. The airport is located in Arlington, Virginia, across the river from Washington.
In a video statement, Hegseth said there was a crew of three soldiers on the training flight. Officials have not identified the soldiers involved.
"It was a fairly experienced crew and it was doing a required annual night evaluation," Hegseth said in the video.
"We anticipate that the investigation will quickly be able to determine whether the aircraft was in the corridor and at the right altitude at the time of the incident," Hegseth added.
During an appearance later with Trump at the White House, Hegseth told reporters that there appears to have been an elevation issue with the Black Hawk, and said Army investigators were on the ground looking into the matter.
The helicopter was from the 12th Aviation Battalion, which is based at Fort Belvoir in Virginia.
The unit, which is responsible for helicopter flights in the US capital area and can be used to carry senior US government officials, will be grounded for 48 hours, Hegseth said.
One official, speaking on condition of anonymity, said that other helicopters, like those from the National Guard, could be allowed to help in recovery efforts following the crash.
Driscoll appeared on Thursday at his confirmation hearing before the Senate Armed Services Committee.
"I am seeing the same things I believe you are, on television. It is an accident that seems to be preventable from what we can tell today," Driscoll told the senators.
Driscoll added that if he was confirmed there would be a focus on a culture of safety in the Army.
"I think we might need to look at where is an appropriate time to take training risk, and it may not be near an airport like Reagan," Driscoll added.
Military helicopters are a common sight around the Washington region that is home to numerous military bases. It is not uncommon for the military to order pauses after accidents or crashes.

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