What happened
The aircraft was operating en route at an altitude of 6,000 feet when it experienced a complete loss of engine power. As the pilot realized that reaching Barnes Municipal Airport was no longer possible, he initiated a descent through a scattered layer of clouds to find a suitable landing site. The pilot selected a grass-covered field located approximately one and a half miles north of the airport.
Attempting to execute the emergency landing at a low altitude, the pilot did not have sufficient airspeed to perform the necessary flare maneuver. Consequently, the aircraft impacted the ground with significant force, shearing off the nose landing gear. The impact caused the aircraft to roll over, and it came to rest in an inverted position.
The investigation
A detailed teardown of the engine was conducted to determine the root cause of the power loss. The examination revealed that the number 2 connecting rod bearing, its bolts, and the connecting rod itself had failed catastrophically. Further inspection identified that the oil port for the number 3 connecting rod was obstructed by sealant material.
This sealant was found to be similar to the type used during a previous oil cooler change. Investigators discovered that excess sealant had accumulated and formed beads on the interior surface of the oil cooler, which likely contributed to the blockage and subsequent lubrication failure.