JDT 1600R — Chesaning, MI

What happened

Several witnesses reported seeing the airplane heading north, turning, and then losing control. One witness stated that engine was "inordinately loud" and that the airplane appeared to enter a "nose dive." Another witness reported that the engine sounded like it was "cutting out" as the airplane spun to the ground.

The pilot had been issued a student pilot certificate about 7 years before the accident; however, no pilot flight logbooks were recovered, so the pilot's level of training could not be determined. A postaccident examination of the airframe and flight control system revealed no anomalies. An examination of the engine showed that all of the teeth of one of the two gears in the propeller reduction gearbox were broken off. Additionally, the ball retaining cage on one of the ball bearings that supported the propeller shaft had failed, and several of the balls were missing from the bearing. A sludgelike substance resembling old oil was found in the gear reduction case, and no liquid oil was found, which is indicative of inadequate maintenance. No airplane maintenance records were found. Based on the available evidence, it is likely that the bearing and gear in the propeller reduction gearbox failed as a result of inadequate maintenance (lack of lubrication), which resulted in a loss of propeller thrust and reduced the airplane's airspeed. The pilot did not obtain adequate airspeed (by lowering the nose), which led to the exceedance of the airplane's critical angle-of-attack and a subsequent stall and spin to the ground. Because the pilot only held a student pilot certificate with an unknown level of training over the previous 7 years, it is likely that he did not have sufficient experience to handle the in-flight emergency.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.