NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The commercial pilot was conducting a cross-country business flight. While en route to the destination airport, the pilot reported to an air traffic controller that they were going to lose an engine. The flight was over mountainous terrain; the controller provided nearby airports to the pilot, and the pilot chose a diversionary airport. The pilot then reported that the airplane was experiencing vibrations and that he could not see anything due to oil on his windscreen, as well as smoke that had entered into the cabin. The controller told the pilot that he would report an emergency for him; no further communications were received from the pilot. The airplane was located the following morning in mountainous terrain.
The airplane struck a mountain at an elevation of 3,554 ft. On-site examination of the wreckage revealed that the airplane came to rest inverted with the undercarriage covered in oil from the nose to the tail. An examination of the airframe revealed no mechanical anomalies that would have precluded normal operation.
The engine teardown examination revealed a hole in the engine crankcase above the No. 6 connecting rod. The No. 5 connecting rod had fractured and separated from the crankshaft, which caused internal damage to the engine and led to the loss of engine power. The internal components exhibited signs of oil starvation; however, the cause of the oil starvation could not be determined.
Although a small amount of ethanol was detected in the pilot's cavity blood, no ethanol was detected in the vitreous or urine, indicating that the detected ethanol was likely due to postmortem production and did not contribute to the accident. Although the pilot's tissue samples tested positive for small amounts of the inactive metabolite of marijuana, no active drug was detected in the pilot's blood; therefore, the pilot was likely not experiencing significant effects from his marijuana use at the time of the accident.