Observations
The aircraft was observed flying westbound at a point where it would enter the traffic pattern on the downwind leg. Without warning, the aircraft suddenly nosed over, rotated slightly to the left, and descended vertically, impacting the ground in a near-vertical descent. Cut trees at the impact site indicated an impact speed of approximately 145 knots.
Investigation Findings
Examination of the aircraft revealed no evidence of failure or malfunction of the aircraft structure, flight controls, or engine. Additionally, no evidence of an inflight collision with objects was noted.
Pilot Medical Information
Postmortem examination of the 78-year-old pilot indicated that he had arteriosclerotic heart disease.