What happened
During a night cross-country flight under instrument flight rules, a single engine airplane was cruising at an assigned altitude of 6,000 feet mean sea level in visual meteorological conditions. The pilot notified air traffic control of a rough running engine before transmitting a distress call.
While attempting to reach a local municipal airport, the pilot discontinued the approach and began a forced landing in a cleared pasture. Radar data indicated the aircraft was descending toward the area with a reduction in ground speed consistent with an imminent forced landing. Before reaching the intended clearing, the aircraft struck unmarked powerlines that were running perpendicular to the selected landing site. There were no eyewitnesses to the event, and the wreckage was discovered the following morning.
The investigation
The investigation of the wreckage revealed that the ground signature at the site was consistent with an impact in an inverted position. A post-impact fire consumed most of the airframe, leaving only the right wing and the aft section of the tail intact.
An examination of the engine showed that both engine case halves had matching serial numbers. While approximately half of the engine oil pan was destroyed by the fire, a large hole was identified on top of the engine case between the number 4 and number 6 cylinders. Thermal signatures indicating a lack of oil lubrication were present on both the number 4 and number 6 cylinders. Additionally, the number 5 cylinder had separated from its mount, and the number 5 connecting rod cap had separated from the connecting rod and was not recovered. Due to the intensity of the fire and the separation of components from the engine mounts, engine control continuity could not be established. Maintenance records for both the airframe and the powerplant were not located during the investigation.