The Experimental/exhibition category aircraft was destroyed at 1628 Pacific time after colliding with terrain while maneuvering at an air show. The Commercial pilot was fatally injured. Visual conditions prevailed. The airplane had taken off at about 1627. Witnesses reported the airplane entering a right downwind for Runway 30. Shortly after entering the downwind, at approximately midfield, the airplane began to lose altitude, eventually descending below a tree line east of the airport. The witnesses reported observing heavy black smoke in the area shortly after the airplane descended below the tree line.