Accident Summary
While cruising at an altitude of 2,500 feet, the pilot noticed a rise in engine RPM and detected the presence of smoke within the cabin. In response, the pilot reduced the throttle to a manageable RPM level and observed that the engine oil pressure had fallen to zero. Subsequently, the pilot executed a forced landing to the best available terrain, which was an open brushy area. During the landing rollout, the nose gear became embedded in the soft ground, causing the airplane to flip over.
Investigation Findings
Post-accident examination revealed that the propeller governor oil line fitting had separated from the governor housing. The separation was attributed to the stripping of threads from the governor housing. Additionally, the fitting was found to be incorrect for the intended application.
Prior Incident
The aircraft had experienced a forced landing 13 days prior to this event. That incident was also caused by an oil leak accompanied by a loss of oil pressure. The leak resulted from a jam nut on the same fitting having backed off. On that occasion, a mechanic tightened the oil line, after which the airplane was cleared for flight.