At about 1750 Pacific time, the airplane made an off-airport forced landing following a loss of engine power. The private pilot and two passengers sustained serious injuries, and the airplane was substantially damaged. Visual conditions prevailed. During the landing sequence, the airplane touched down on flat ground and then collided with a ditch. There were oil stains along the bottom of the fuselage, on the struts and horizontal stabilizers. The left side of the engine had more oil staining than the right side, and the oil staining began between the number two and number four cylinders. The number four cylinder (left rear) had fractured and separated circumferentially in the area where the head joins the barrel. The component was an Engine Components, Inc., (ECi) cylinder assembly, part number AEL65102. The cylinder head was part number AEL85099, The cylinder was retained for further examination.
