Incident Synopsis
During flight, the engine lost power and the pilot performed a ditching in the ocean near the beach. Post-incident examination of the engine revealed a fractured connecting rod.
Mechanical Findings
The number 4 connecting rod shank was broken at the crankpin bearing housing. One rod bolt had its head broken off, and the bolt grip was necked down. The nut on this bolt remained attached and was flush with the threaded end. The other bolt and nut were still attached to the crankpin bearing housing halves, with approximately three threads visible beyond the nut.
Torque measurements were taken on the connecting rod bolts. The number 1 rod upper and lower bolts recorded 660 inch-pounds. The number 2 rod upper bolt measured 250 inch-pounds, and the lower bolt measured 300 inch-pounds. The number 3 rod upper and lower bolts both registered 0 inch-pounds. The required torque for these bolts is 480 inch-pounds.
Conclusion
The investigation documented the mechanical failures but did not assign a probable cause.