Loss of Engine Power
The single-engine airplane was in cruise flight at 1,500 feet mean sea level when the pilot, who held about 1,200 hours of flight experience, noticed a gradual decrease in engine power. He performed a series of troubleshooting steps including switching fuel tanks, checking the magnetos, applying carburetor heat, and checking the primer. The primary engine instruments indicated normal operation throughout. The pilot then pumped the throttle, which appeared to make a positive difference momentarily. However, the engine subsequently suffered a total loss of power.
Forced Landing
With no engine power available, the pilot initiated a forced landing to a field that was saturated with water. During touchdown, the nose wheel sank into the mud, causing the airplane to nosed over and come to rest inverted. The aircraft sustained substantial damage.
Engine Examination
Post-accident examination and teardown of the engine revealed a catastrophic failure. A large hole was present in the engine case under the No. 2 cylinder, and several small breaks were found on the top left of the case near the No. 2 and No. 4 cylinders. The No. 1 cylinder spark plug seat was cracked and showed evidence of impact damage. Inside the No. 1 spark plug seat, a circular impression corresponding to the end of the No. 1 piston rod was observed. The No. 1 piston head was completely disintegrated, and fragments of metal were found throughout the engine case. The exhaust and intake valves did not appear to be damaged.
Engine Records
According to Federal Aviation Administration records, the engine was last overhauled on April 20, 2003, and had accumulated 304.2 hours since that overhaul. The total time on the engine since new was 6,214.2 hours.