What happened
The pilot filed a visual flight rules flight plan after weather conditions improved from instrument flight rules to visual flight rules, with a chance of thunderstorms en route. Intermittent moderate turbulence below 5000 feet was forecast due to strong and gusty low-level winds. While the aircraft was en route, a ground witness heard the engines rev up more than normal, then saw the aircraft on a northerly heading. Shortly thereafter, the witness heard a loud noise and saw two or more pieces separate from the aircraft. It then entered an uncontrolled descent and crashed.
The investigation
Evidence indicated that the aircraft suffered an in-flight separation of the fiberglass nose assembly. Portions of the separated nose struck the stabilator. A damaged area on the right stabilator acted as a trim tab, causing a pitch-up of sufficient magnitude to cause positive bending in the wings. The loading on the stabilators caused them to fail in negative bending.
Findings
The aircraft then entered a descending counter-clockwise spin which continued until ground impact occurred. Parts of the aircraft and its contents separated and descended in scattered fragments.