The helicopter’s altitude-measuring instrument was also inaccurate, investigators said at the first of three days of hearings examining the January crash.

The National Transportation Safety Board will hold three days of hearings on the fatal midair collision between a passenger jet and an Army helicopter

On Wednesday morning, the NTSB released thousands of pages of evidence from the crash and the subsequent investigation -- including new video from the end of the runway showing the crash that killed 67 people.