Investigators were able on Friday to recover the helicopter's black box, which captures flight data and voices in the cockpit, National Transportation Safety Board member Todd Inman said at an afternoon briefing.

The information from the box, along with the cockpit voice recorder and flight data recorder from the CRJ700 airplane, could help authorities piece together what happened just before the two aircraft collided on Wednesday night and plunged into Washington's freezing Potomac River in the deadliest US air disaster in two decades.

The board has also conducted interviews with air traffic controllers, Inman said, including the lone controller working inside Reagan's tower at the time of the crash on Wednesday.

Authorities have not identified a cause, and Inman said the board would not engage in speculation before completing its investigation.

"The NTSB is an independent, bipartisan board - 58 years as the gold standard. Our job is to find the facts, but more importantly, our job is to make sure this tragedy doesn't happen again, regardless of what anyone may be saying," Inman said, adding that he had not spoken to President Donald Trump or anyone at the White House.

Following the Washington crash, the FAA sharply restricted helicopter flights near Reagan to reduce the risk of another collision, Duffy said earlier on Friday, confirming news first reported by Reuters.

Duffy said the decision "will immediately help secure the airspace near Reagan Airport, ensuring the safety of airplane and helicopter traffic."

The FAA is barring most helicopters from parts of two routes near the airport and only allowing police and medical helicopters, air defense and presidential air transport in the area between the airport and nearby bridges.

The restrictions will last at least until the NTSB releases a preliminary report into the fatal collision, which typically takes 30 days. At that point they will be reviewed, Duffy said.

American Airlines CEO Robert Isom said the airline would work with the government "to make our aviation system even safer."

Crews have recovered 41 bodies thus far, officials said. Pulling the debris from the Potomac River will begin "in earnest" on Sunday, Inman said, an effort that will likely last all week.

Washington, DC Fire Chief John Donnelly told reporters that 28 bodies have been positively identified and that he expected all victims would eventually be recovered.

The American Airlines plane was trying to land when it collided with an Army Black Hawk helicopter, killing all 60 passengers and four crew members aboard. Two of the three service members killed in the helicopter were identified Friday.

Safety questions

The crash has shone a spotlight on concerns about air safety and a shortage of tower controllers at the heavily congested airport that serves the US capital.

The FAA is about 3,000 controllers behind staffing targets. The agency said in 2023 that it had 10,700 certified controllers, about the same as a year earlier.

One controller rather than two was handling local plane and helicopter traffic on Wednesday at the airport, a situation deemed "not normal" but considered adequate for lower volumes of traffic, according to a person briefed on the matter. Duffy on Thursday vowed to reform the FAA.

Airspace is crowded around the Washington area, home to three commercial airports, multiple military bases and some senior government officials who are ferried around by helicopter.

Over a three-year period ending in 2019, there was an average of 80 helicopter flights per day within 48 kilometers of Reagan National Airport, with the majority either military or law enforcement flights, according to a 2021 Government Accountability Office report.