The Black Hawk helicopter may have been flying with “bad data” and didn’t hear all air traffic control instructions before colliding with a passenger plane, officials said.

That transmission was interrupted — it was stepped on,” said Jennifer Homendy, chair of the National Transportation Safety Board.

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.