The pilot, who was flying a Rans S-5 Coyote over desert near Lake Pleasant, Ariz., had been in cruise flight for about 30 minutes when he advanced the throttle to increase airspeed. The engine power unexpectedly dropped to idle.
The pilot restarted the engine and discovered it would only operate at idle power before it quit.
The terrain in the area was rocky with a river running through it. The pilot thought his best course of action was to ditch the airplane in the river. He was able to swim to shore as the airplane sank. The airplane was not recovered.