Accident Details
On August 14, 2018, at approximately 0800 central daylight time, a Cessna 150M, registration N6341K, was involved in a forced landing to a corn field near Madison, South Dakota. The aircraft was being operated as a solo instructional flight under 14 Code of Federal Regulations Part 91. The student pilot reported that the airplane's engine began running rough while flying north of Madison Municipal Airport (MDS). He attempted to return to MDS but was unable to reach the airport and subsequently landed in a corn field. During the landing, the airplane nosed over and came to rest inverted in corn standing about 7 feet tall. Substantial damage occurred to both wings.
Engine Examination
Examination of the engine revealed that the No. 3 cylinder exhaust valve was stuck in its valve guide, and the No. 3 exhaust valve rocker arm was fractured. The airplane remained in the corn field for approximately six weeks before recovery, which occurred after the crop had been harvested.
Maintenance History
According to maintenance records, the engine's most recent overhaul was completed on March 12, 2018. A subsequent maintenance entry dated August 11, 2018, indicated that the Nos. 1, 3, and 4 cylinders had been removed and returned to the vendor that performed the overhaul due to sticking valves. The cylinders were later reinstalled. The tachometer time noted at that maintenance entry showed the engine had accumulated 207 hours since the overhaul.