Pilots of both aircraft were responsible for an in-flight collision that injured actor Kirk Douglas and two others in a helicopter and killed two men in an airplane, a federal investigator said.

"There were four co-pilots involved in the crash, four sets of eyes that failed to see and avoid" Wednesday's crash, Thomas Wilcox, an investigator with the National Transportation Safety Board, said Thursday.But Wilcox said the aerobatic biplane had the right of way when it crashed with the helicopter carrying Douglas, Noel Blanc, the voice of Bugs Bunny and other cartoon characters, and a third man.

Douglas, 74, was hospitalized in good condition in Los Angeles. Blanc, 52, was hospitalized in serious but stable condition in Santa Paula. Beverly Hills police Officer Michael Carra, the third occupant of the helicopter, was treated for minor injuries at a hospital and released.