Accident Overview
On October 4, 2016, at 1511 central daylight time, a Cessna 172K single-engine airplane, registration N46377, impacted a cornfield during a forced landing near Wilmot, Wisconsin. The private pilot, the sole occupant, was not injured. The airplane sustained substantial damage to the right wing. The flight departed Burlington Municipal Airport (BUU) in Burlington, Wisconsin, about 1445 and was conducted under Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Pilot Actions
According to the pilot, while maneuvering after takeoff from BUU, the engine began to lose power. The pilot switched fuel tanks, applied carburetor heat, and set the mixture to full rich, but the engine remained at reduced power. The pilot attempted to land at Westosha Airport in Wilmot, Wisconsin, but overshot the runway. He then decided to execute a forced landing to an adjacent cornfield. During the forced landing, the right wing impacted the corn, and the airplane came to rest upright.
Engine Examination
The accident engine was a 150-horsepower, four-cylinder Lycoming O-320-E2D engine, serial number L-22806-27A. It was examined at Myers Aviation in Oshkosh, Wisconsin, under the supervision of National Transportation Safety Board (NTSB) investigators and Federal Aviation Administration (FAA) inspectors. Visual examination of the engine exterior and components revealed no anomalies that would have precluded normal operation. The engine oil filter was removed and disassembled, revealing heavy deposits of metal material. Due to these deposits, the engine was disassembled. Partial disassembly revealed that the number 1 cylinder piston pin plug was destroyed, with metal debris found in the engine oil and oil filter. The engine crankshaft and connecting rods displayed discoloration and heat signatures consistent with oil starvation. The number 3 and 4 connecting rod bearings were extruded and melted from the rod journals. The cylinder bores exhibited corrosion and discoloration on their inner surfaces.
Engine Records
According to engine records, the engine underwent its most recent annual inspection on October 1, 2015, at a total time of 3,160 hours and 1,176 hours since major overhaul. At the time of the accident, the engine had accumulated 34 hours since that inspection.