What happened
During an approach to the destination airport, the pilot reported encountering engine problems. In an attempt to manage the situation, the pilot executed a forced landing in a field located short of the airport. During this maneuver, the left wing of the aircraft made contact with the ground, causing the airplane to tumble through a sequence of impacts. The accident resulted in 2 fatal injuries for the pilot and the front seat passenger.
The investigation
An examination of the engine following the accident revealed debris and corrosion within the carburetor and the main jet passage. A Safety Board metallurgist analyzed the particles found, determining they were likely a combination of soil and lead that had accumulated over time. The presence of corrosion suggested the components had been exposed to water for a prolonged period. Investigators determined that this buildup likely restricted the air-fuel mixture flow in the main jet, leading to a loss of engine power.
Records indicated that the carburetor had not been overhauled during its 46-year history. While the manufacturer had issued a service bulletin recommending carburetor overhauls every 10 years or at the engine's overhaul interval, no such maintenance was documented. Additionally, investigators found that the aircraft was not equipped with a shoulder harness restraint system. Although the pilot had purchased a shoulder harness installation kit, the harnesses remained in their original packaging and were discovered by the investigation team within the debris field.
Findings
- The accumulation of lead and soil particles caused a restricted fuel flow.
- Corrosion in the carburetor was caused by long-term water exposure.
- The fatal injuries to the occupants, specifically head and upper torso trauma, were attributed to the lack of restraint during the impact sequence.