The crew of the Army helicopter that hit a jet may have had inaccurate altitude readings and may not have heard air traffic controllers' instructions, officials say.

The National Transportation Safety Board said the helicopter’s cockpit voice recorder didn’t capture key directions from air-traffic control and is investigating whether the crew might have seen a different altitude on the flight instruments.

The National Transportation Safety Board is investigating the role of 'bad data' in a recent fatal collision between an Army Black Hawk helicopter and a passenger jet near.C. NTSB Chair Jennifer Homendy noted the helicopter's pilots were using night vision goggles at the time of the crash.