What happened
Prior to the flight, the pilot obtained multiple weather briefings, including computer-generated reports and a telephonic briefing from a Flight Service Station (FSS). These briefings warned of rain showers, thunderstorms, and cloud tops that exceeded the planned cruising altitude along the direct route. Despite receiving a recommendation from the FSS briefer to utilize an alternate route, the pilot proceeded on the original path toward the destination.
During the flight, the pilot, who lacked an instrument rating, encountered instrument meteorological conditions (IMC). This area of weather presented an 80 percent chance of encountering icing. During the encounter, the aircraft was observed emerging from the bottom of an overcast layer with a large portion of the left wing detached. Following this structural failure, the aircraft entered a steep, high-velocity descent into the ground.
Findings
An investigation into the aircraft's structure revealed no mechanical anomalies or pre-existing defects that would have caused the wing to detach. Investigators concluded that the wing separation was likely caused by the aircraft exceeding its structural design limits after the pilot lost control of the aircraft while operating within instrument meteorological conditions.