Washington, D.C. Fire and EMS Chief John Donnelly said officials are confident all will be found. Divers are working diligently to locate remains as crews prepare to lift wreckage from the chilly Potomac River as early as Monday morning, Donnelly said at a news conference.

Col. Francis B. Pera of the Army Corps of Engineers said divers and salvage workers are adhering to strict protocols and will stop moving debris if a body is found. The “dignified recovery” of remains takes precedence over all else, he said.

“Reuniting those lost in this tragic incident is really what keeps us all going,” Pera said. “We’ve got teams that have been working this effort since the beginning, and we’re committed to making this happen.”

Divers have high-definition cameras with feeds monitored on support boats, Pera said, putting “four or five sets of eyes” inside of the wreckage. Owing to the frigid conditions, one diver was treated at a hospital for hypothermia, Donnelly said.

Portions of the two aircraft that collided over the river Wednesday night near Reagan Washington National Airport — an American Airlines jet with 64 people aboard and an Army Black Hawk helicopter with 3 aboard — will be loaded onto flatbed trucks and taken to a hangar for investigation.

Family members were taken in buses with a police escort to the Potomac River bank near where the two aircraft came to rest after colliding. The jet, en route from Wichita, Kansas, was about to land. The Black Hawk was on a training mission. There were no survivors.

Federal investigators were working to piece together the events that led to the collision.

The National Transportation Safety Board didn’t hold a press briefing on Sunday, but did release a photograph showing investigators on a small boat looking at wreckage and another of them examining a flight data recorder.

Transportation Secretary Sean Duffy said he wanted to give investigators space to conduct their inquiry. But he posed a range of questions on Sunday morning TV news programs.

“What was happening inside the towers? Were they understaffed? … The position of the Black Hawk, the elevation of the Black Hawk, were the pilots of the Black Hawk wearing night vision goggles?” Duffy asked on CNN.

Army Staff Sgt. Ryan Austin O’Hara, 28, of Lilburn, Georgia; Chief Warrant Officer 2 Andrew Loyd Eaves, 39, of Great Mills, Maryland; and Capt. Rebecca M. Lobach, of Durham, North Carolina, were in the helicopter.

The plane’s passengers included figure skaters returning from the 2025 U.S. Figure Skating Championships in Wichita and a group of hunters returning from a guided trip.

The NTSB said Saturday that preliminary data showed conflicting readings about the altitudes of the airliner and the helicopter.

Investigators also said that about a second before impact, the jet’s flight recorder showed a change in its pitch. But they did not say whether that change in angle meant that pilots were trying to perform an evasive maneuver to avoid the crash.

Data from the jet’s flight recorder showed its altitude as 325 feet (99 meters), plus or minus 25 feet (7.6 meters), when the crash happened, NTSB officials told reporters. Data in the control tower, though, showed the Black Hawk at 200 feet (61 meters), the maximum allowed altitude for helicopters in the area.

The discrepancy has yet to be explained.

Investigators said they hoped to reconcile the difference with data from the helicopter’s black box and planned to refine the tower data, which can be less reliable.

“This is a complex investigation,” investigator in charge Brice Banning said. “There are a lot of pieces here.”

Banning said the jet’s cockpit voice recorder captured sound moments before the crash.

“The crew had a verbal reaction,” Banning said, and the flight data recorder showed “the airplane beginning to increase its pitch. Sounds of impact were audible about one second later, followed by the end of the recording.”

Full investigations typically take a year or more. Investigators hope to have a preliminary report within 30 days.

NTSB member Todd Inman said he has spent hours meeting with victims’ families.

“Some wanted to give us hugs. Some are just mad and angry,” Inman said. “They are just all hurt. And they still want answers, and we want to give them answers.”

More than 300 responders were taking part in the recovery effort at a given time, officials said. Two Navy barges were also deployed to lift heavy wreckage.

On Fox News Sunday, Duffy said the Federal Aviation Administration was looking into staffing in the Reagan Airport control tower.

Investigators said there were five controllers on duty at the time of the crash: a local controller, ground controller, assistant controller, a supervisor and supervisor in training.

According to an FAA report obtained by The Associated Press, one controller was responsible for helicopter and plane traffic. Those duties are often divided between two people but the airport typically combines them at 9:30 p.m., as traffic slows. On Wednesday, the supervisor combined them earlier, which the report called “not normal.”

“Staffing shortages for air traffic control has been a major problem for years and years,” Duffy said, promising that President Donald Trump’s administration would address shortages with “bright, smart, brilliant people in towers controlling airspace.”

With the nation already grieving, an air ambulance crashed in Philadelphia on Friday, killing all six people on board, including a child returning home to Mexico from treatment, and at least one on the ground.

Also Friday, the FAA heavily restricted helicopter traffic around Reagan Airport, hours after Trump wrote on social media that the helicopter had been flying higher than allowed.

Wednesday’s crash was the deadliest in the U.S. since Nov. 12, 2001, when a jet slammed into a New York City neighborhood just after takeoff, killing all 260 people on board and five on the ground.

Experts stress that plane travel is overwhelmingly safe, but the crowded airspace around Reagan Airport can challenge even experienced pilots.