What happened
During flight operations, the engine began exhibiting irregular performance characteristics, described as running roughly. Simultaneously, oil began leaking from the engine compartment and spreading across the windshield, obscuring visibility. The engine subsequently ceased operation entirely. The pilot selected an area for a forced landing. During the descent and touchdown phase, the aircraft impacted trees and sustained damage.
The investigation
A post-accident examination of the airframe and powerplant was conducted to determine the cause of the failure. Inspections revealed that the number three exhaust valve, identified by Franklin part number 18084, had failed. This mechanical failure is consistent with the reported oil leakage and subsequent engine stoppage.
Findings
The primary contributing factor to the accident was the in-flight failure of the Franklin 18084 exhaust valve. This component failure led to oil leakage onto the windshield, impairing the pilot's ability to see during the critical landing phase. The resulting loss of power necessitated a forced landing, which resulted in the aircraft contacting trees and sustaining substantial damage.