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

NEW YORK: An investigative hearing into a deadly mid-air collision of a US Army helicopter and a passenger plane that killed 67 people in Washington has revealed a discrepancy in the chopper’s altitude displays.

The head of the National Transportation Safety Board sharply criticized U.S. officials for failing to act before the January 29 collision of a U.S. Army helicopter with an American Airlines regional jet in Washington that killed 67 people.