N2085JCessna T188C · 1978

The commercial pilot was conducting an aerial application flight to a field that had a small hill on the north side. After the completion of the second pass, the pilot maneuvered the airplane out of the field to turn away from the hill and to get turned around for another pass. Upon starting the turn back towards the field, the pilot realized that he had not allowed adequate space to perform the turn given the airplane's "current load and environmental conditions." The pilot leveled the wings and attempted to fly over the hill; however, the airplane encountered an aerodynamic stall about 30 ft above ground level and subsequently impacted trees and rocky terrain. The airplane sustained substantial damage to the fuselage, the left wing, and the empennage. The pilot reported there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.

On July 29, 2010, at 1320 eastern daylight time, a Cessna model T188C airplane, N2085J, was substantially damaged during a forced landing following a total loss of engine power near Montezuma, Indiana. The pilot was not injured. The airplane was registered to and operated by Swing Wings, Inc., under the provisions of 14 Code of Federal Regulations Part 137 without a flight plan. Day visual meteorological conditions prevailed for the aerial-application flight that originated from Clinton Airport, Clinton, Indiana, at 1315.

The pilot reported that while en route to the field to be sprayed there was total loss of engine power and the windshield became obscured with oil. The pilot immediately turned into the wind and made a forced landing into a nearby corn field. The airframe was substantially damaged after touchdown when the left main landing gear collapsed and the left wing impacted terrain.

A postaccident examination conducted by a Federal Aviation Administration inspector established that the No. 2 connecting rod had separated from the engine crankshaft. A portion of the No. 2 connecting rod was found protruding through a hole in the engine crankcase. The engine was partially disassembled and the connecting rod components were sent to the National Transportation Safety Board's (NTSB) Materials Laboratory Division for metallurgical examination.

The NTSB lab examination established that there were polishing and wear patterns on the washer faces of one rod bolt and a corresponding nut. Further examinations found similar wear and polishing on the No. 2 connecting rod and a rod cap. The observed polishing and wear patterns were indicative of relative motion between the connecting rod components and associated rod bolt head/nut. The nut threads were sheared, consistent with impulse loading. A review of available maintenance information revealed that the engine, a Continental model TSIO-520-T, had accumulated 1,193 hours since its last major overhaul.

At 1325, the automated surface observing system at the Edgar County Airport, located about 16 miles west of the accident site, reported the following weather conditions: variable wind direction at 6 knots; visibility 10 miles; scattered clouds between 3,000 and 4,400 feet above ground level (agl); temperature 28 degrees Celsius; dew point 21 degrees Celsius; altimeter setting 30.10 inches of mercury.