Accident Summary
During an unknown phase of flight, the pilot lost control of the aircraft. The aircraft descended with wings level and nose 45 degrees low before impacting terrain. The impact destroyed the aircraft, and a post-crash fire ensued.
Aircraft Examination
Examination of the wreckage revealed that the rear seat control stick, which was the pilot's control, was found lying loose. Inspection of the control stick showed no impact damage, and there was no evidence that a bolt and nut used to secure it had been installed. The pilot reportedly had removed the bolt and nut and sanded the inside of the stick to facilitate its removal. The flight controls operationally checked good. The front seat control stick was installed but not secured.
Engine and Propeller Examination
The engine and propeller were removed for further examination. Examination of the engine revealed valve continuity and compression sufficient to sustain engine operation. Fire damage affected the magnetos, ignition harnesses, and carburetor. Spark plugs were operationally tested, and only one tested good. The aircraft and engine logbooks were not located. Fuel quantity was sufficient.
Conclusion
The investigation determined that the loss of control occurred, but no probable cause was explicitly stated in the source.