The NTSB gave an update Friday on the devastating crash in Washington, D.C., between an American Airlines plane and U.S. Army Black Hawk helicopter.

The US National Transportation Safety Board on Friday gave a much-anticipated update on its investigation into a deadly collision between two aircraft late last month, saying that officials were looking into an inconsistency in the data with regard to the height of the helicopter at the time of the crash.

An American Airlines regional passenger jet and a U.S. Army Black Hawk helicopter collided midair and crashed into the Potomac River near Reagan Washington National Airport on Wednesday night. Officials have not provided a death toll but said all passengers and crew on both flights were feared dead.