Investigators have recovered the cockpit voice recorder, commonly known as the black box, from the U.S. Army Black Hawk helicopter involved in the devastating mid-air collision that killed 67 people at Ronald Reagan Washington National Airport on Wednesday.

Emergency teams are ramping up efforts to retrieve debris from the crash site, with the U.S. Navy set to begin major salvage operations on Saturday.

Officials say large sections of the wreckage, including the submerged passenger aircraft, must be lifted from the Potomac River before divers can continue recovery efforts.

Recall that the crash involved an American Airlines flight carrying 64 passengers and crew and a Black Hawk helicopter transporting three U.S. Army soldiers.

So far, 28 victims have been identified, and 41 bodies have been recovered. Authorities say additional remains are unlikely to be found until the sunken aircraft is removed from the riverbed.

Investigators retrieved the black boxes from the passenger plane the day after the accident. National Transportation Safety Board (NTSB) officials are currently drying and analyzing the data, with expectations that crucial flight details will be available soon.

NTSB member Todd Inman stated that authorities are still unsure what led to the collision. Investigators are mapping debris patterns to determine how the aircraft reacted upon impact.

Audio recordings from air traffic control, released online, suggest that a controller attempted to warn the helicopter pilot about the approaching American Airlines jet just seconds before the crash. The pilot acknowledged the warning but was unable to avoid the collision.

The Federal Aviation Administration (FAA) has since restricted helicopter traffic near Reagan National Airport due to concerns about airspace congestion. Additionally, investigators are reviewing air traffic control staffing, including whether a single controller was managing both airplane and helicopter movements in the moments leading up to the crash.

More than 500 personnel have been working around the clock at the crash site, according to Washington, D.C., Fire Chief John Donnelly.

The White House has been monitoring the situation, though officials have not directly commented on the crash’s cause.

President Donald Trump has suggested, without evidence, that the Black Hawk helicopter was “flying too high” and has linked the accident to FAA hiring practices.

Inman dismissed speculation, stating that the investigation is focused on uncovering facts and preventing future tragedies.

“Our job is to find the facts,” he said, adding: “more importantly, our job is to make sure this tragedy doesn’t happen again—regardless of what anyone may be saying.”