Investigators will offer updates Tuesday in the probe into the devastating crash between an American Airlines plane and a U.S. Army Black Hawk helicopter that killed all 67 people on board both aircraft.

The crash happened on the night of Jan. 29 when the PSA Airlines Bombardier CRJ700 regional jet, which had departed from Wichita, Kansas, with 64 people on board, was about to land at Washington, D.C.’s Ronald Reagan Washington National Airport. The three soldiers on the helicopter were conducting an annual training flight and night vision goggle check ride for one of the pilots at the time when the two aircraft collided.

Both aircraft plunged into the Potomac River.

National Transportation Safety Board Chairman Jennifer Homendy said last month that there was no indication the helicopter crew could tell there was an impending collision.

The soldiers may have had “bad data” on the altitude from their altimeter, as the pilots had differing altitudes in the seconds before the crash, Homendy said. One helicopter pilot thought they were at 400 feet and the other thought they were at 300 feet.

The transmission from the tower that instructed the helicopter to go behind the plane may not have been heard by the crew because the pilot may have keyed her radio at the same second and stepped on the transmission from ATC, the NTSB added.

The Black Hawk crew was likely wearing night vision goggles throughout the flight, Homendy said.

The NTSB will hold a news conference at 2 p.m. ET Tuesday.