Aviation experts believe the Black Hawk helicopter pilot may have mistaken another aircraft for the American Airlines jet before the deadly midair collision over Washington, D.C., on January 29. The crash killed 64 passengers and crew members aboard the PSA Airlines Bombardier CRJ700 and three U.S. soldiers on the military helicopter.

"I guarantee it was basically pilot error," an active-duty Army helicopter pilot told PEOPLE. The source, who has experience investigating helicopter crashes but is not part of this inquiry, explained that the Black Hawk crew had taken responsibility for maintaining visual separation from other air traffic. "That took [the responsibility] off Air Traffic Control's shoulders," the pilot said.

According to air traffic control recordings obtained by the Associated Press, a controller asked the helicopter crew if they had visual contact with the landing plane before instructing, "PAT 25 pass behind the CRJ."

However, some analysts believe the Black Hawk crew may have misidentified another plane rather than the aircraft they ultimately collided with. "It does appear that [the Black Hawk pilot] thought he had sight on the aircraft, but there were multiple aircraft in the area," Laurie Garrow, a professor at Georgia Tech, told PEOPLE.

Garrow described D.C.'s airspace as having "lanes in the sky that you need to stay [in]." She explained, "In D.C., those lanes are very narrow because we have a lot of buildings that are close by the airport."

A preliminary Federal Aviation Administration (FAA) report found that a single air traffic controller was monitoring both airplane and helicopter operations at the time of the collision. According to the New York Times, the staffing levels were "not normal for the time of day and volume of traffic."

The New York Times further reported that the control tower at Reagan National Airport was operating nearly a third below targeted staff levels, with 19 fully certified controllers instead of the FAA-recommended 30.

According to a New York Post report, the Black Hawk was flying more than 300 feet above the Potomac River-well above the 200-foot altitude limit for that corridor.

Former President Donald Trump addressed the report on Truth Social, writing, "The Black Hawk helicopter was flying too high, by a lot. It was far above the 200-foot limit. That's not really too complicated to understand, is it???"

Barges arrived Saturday to assist with salvage operations in the Potomac River, where at least 40 bodies had been recovered. The D.C. Medical Examiner's Office is working to identify remains.

Among those killed were members of the U.S. figure skating community, including 16-year-old skaters Spencer Lane and Jinna Han, as well as 1994 world champions Evgenia Shishkova and Vadim Naumov.

The U.S. Army identified two of the soldiers killed as Chief Warrant Officer 2 Andrew Loyd Eaves, 39, of Great Mills, Maryland, and Staff Sgt. Ryan Austin O'Hara, 28, of Lilburn, Georgia.

Following the crash, the FAA announced new restrictions on helicopter traffic near Reagan National Airport, with support from Trump and Secretary of Defense Pete Hegseth, according to Transportation Secretary Sean Duffy.

Duffy wrote on X, "Today's decision will immediately help secure the airspace near Reagan Airport, ensuring the safety of airplane and helicopter traffic."

The NTSB's preliminary findings are expected within 30 days, while a final report could take over a year.