What happened
While operating in cruise flight over a wilderness area, the aircraft's engine sputtered and subsequently lost power. The pilots attempted to restart the engine before searching for a suitable landing site. The pilot successfully landed the aircraft on a gravel and sand bar located near a river.
The landing resulted in structural damage to the firewall and a wing strut, as well as leading edge damage to the horizontal stabilizer. Prior to the engine failure, the pilots reported that both the oil pressure and cylinder head temperature gauges were within normal operating ranges, with no prior indications of mechanical issues.
The investigation
An inspection of the engine was conducted following the event. Investigators found that the master rod end had broken. While no metal fragments were discovered in the oil filter or the oil sump, further examination revealed that the supercharger impeller shaft bearings (blower bushing) had failed. The failure of these bearings can allow raw oil to be pumped into the induction system, potentially leading to engine issues such as detonation.