Background
On July 29, 2010, at 1320 eastern daylight time, a Cessna model T188C airplane, registration N2085J, sustained substantial damage during a forced landing following a total loss of engine power near Montezuma, Indiana. The airplane was operated by Swing Wings, Inc., under 14 CFR Part 137 for aerial application purposes. The flight originated from Clinton Airport, Clinton, Indiana, at 1315. Day visual meteorological conditions prevailed, and no flight plan was filed.
Accident Sequence
The pilot reported that while en route to the field to be sprayed, the engine experienced a total loss of power and the windshield became obscured with oil. The pilot turned into the wind and executed a forced landing into a nearby corn field. After touchdown, the left main landing gear collapsed, and the left wing impacted the terrain, resulting in substantial damage to the airframe. The pilot was not injured.
Postaccident Examination
A Federal Aviation Administration inspector conducted a postaccident examination. The No. 2 connecting rod had separated from the engine crankshaft, with a portion protruding through a hole in the engine crankcase. The engine was partially disassembled, and the connecting rod components were sent to the NTSB Materials Laboratory Division for metallurgical examination. The laboratory found polishing and wear patterns on the washer faces of one rod bolt and a corresponding nut. Similar wear was observed on the No. 2 connecting rod and rod cap. These patterns indicated relative motion between components. The nut threads were sheared, consistent with impulse loading. The engine, a Continental TSIO-520-T, had accumulated 1,193 hours since its last major overhaul.
Weather Conditions
At 1325, the automated surface observing system at Edgar County Airport, approximately 16 miles west of the accident site, reported variable wind at 6 knots, visibility 10 miles, scattered clouds at 3,000 to 4,400 feet above ground level, temperature 28°C, dew point 21°C, and altimeter setting 30.10 inches of mercury.