WASHINGTON, June 10 (Reuters) - The National

Transportation Safety Board will hold a three-day investigative

hearing into the Jan. 29 collision of a Black Hawk helicopter

with an American Airlines ( AAL ) passenger jet near Reagan

Washington National Airport killing 67 people, the board's chair

said Tuesday.

The hearing will be held from July 30-Aug. 1 at the board's

headquarters, said NTSB Chair Jennifer Homendy. She said the

hearing is critical to the board's safety investigation. "It's

meant to get additional evidence in order to complete our

investigation," she said.