What happened
The incident occurred when the pilot attempted to reduce power to initiate a descent for landing. During this maneuver, the pilot was unable to decrease engine power because the throttle rod end had separated in flight. Consequently, the aircraft entered a spiraling descent pattern. The pilot subsequently shut down the engine.
During the approach, the pilot misjudged both altitude and the remaining distance to the runway. As a result, the aircraft landed 600 feet short of the runway threshold, striking the runway threshold lights during the landing roll.
The investigation
The investigation focused on the mechanical failure of the throttle control system. Examination revealed that the throttle rod end had separated while the aircraft was in flight. This separation prevented the pilot from reducing engine power as intended for descent and landing preparation.