What happened
During an unknown phase of flight, the pilot lost control of the aircraft. The aircraft descended with wings level at a 45-degree nose-low attitude and impacted the terrain. The subsequent impact resulted in the aircraft being destroyed by fire.
The investigation
Investigators examined the wreckage and discovered that the rear seat control stick, used by the pilot, was lying in the debris. An examination of this control stick showed no evidence of impact damage; however, there was no bolt or nut installed to secure it. It was reported that the pilot had previously removed the securing hardware and sanded the interior of the stick to make its removal easier. While the flight controls were found to be operationally functional, the front seat control stick was installed but not secured.
The engine and propeller were removed for further inspection. The examination of the engine revealed that valve continuity and compression were sufficient to maintain engine operation. Although fire damage was present on the magnetos, ignition harnesses, and carburetor, the fuel quantity remaining at the time of the accident was sufficient. Testing of the spark plugs showed that only one plug functioned correctly.
No aircraft or engine logbooks were located during the investigation.