Witness Observation
A witness on the ground observed the airplane performing a wing-rocking maneuver followed by a nose-down spin. The aircraft subsequently impacted trees and the ground, erupting into flames. The witness reported not hearing any engine noise during the event.
Fuel System Examination
Post-accident examination of the fuel selector valve showed it was positioned to the left tank. Inspection of the fuel system revealed an obstruction in the right wing fuel tank supply line leading to the engine. The interior walls of both fuel tanks had a heavy application of fuel tank sealing compound.
The left tank fuel screen assembly appeared normal, but ash and unidentified debris were found within the fuel line. In contrast, the right tank fuel screen assembly was determined to be an unapproved parts configuration; the screen material appeared hand-fabricated to fit the supply line. Additionally, an obstruction was located in the end of the right wing fuel tank supply line. This obstruction was a metal sleeve of unknown origin, lodged sideways within the fuel line end.
Maintenance History
A review of the airplane's maintenance records indicated that the fuel tanks had undergone previous repair work.
Investigation Findings
The investigation identified specific fuel system anomalies: an unapproved fuel screen in the right tank and a metal sleeve obstruction in the right fuel supply line. The presence of debris in the left fuel line and the heavy sealing compound in both tanks were also noted. However, no direct causal link was established between these findings and the engine failure or accident sequence.