What happened
The pilot was conducting a visual flight rules (VFR) traffic pattern for landing on a lake characterized by smooth, glassy surface conditions. While maneuvering from the base leg to the final approach, the pilot misjudged the aircraft's height above the water. Consequently, the left wing impacted the water, causing the aircraft to cartwheel. Approximately five minutes after coming to rest, the aircraft sank in water that was approximately 50 feet deep.
The investigation
The investigation focused on the circumstances surrounding the impact with the lake surface. Key findings included the presence of glassy water conditions which likely contributed to the pilot's difficulty in judging altitude and distance. The left wing was identified as the initial point of contact with the water, leading to the loss of control and subsequent cartwheeling motion.
Findings
The primary factor contributing to this accident was the misjudgment of aircraft height above the water during the final phase of the traffic pattern. The glassy water conditions on the lake surface reduced visual cues necessary for accurate altitude assessment, leading to a controlled flight into terrain (water). The depth of the water at the impact site facilitated the rapid sinking of the aircraft after it came to rest.