CHI03LA322

The airplane sustained substantial damage during a forced landing. The pilot reported that the engine failed at 3,000 feet mean sea level during cruise flight. While on his landing roll on a sod field, the airplane struck a concrete marker and the airplane nosed over. The inspection of the airplane revealed the accessory gear drive was fractured in two pieces and had become dislodged from the crankshaft. A metallurgical examination of the accessory gear drive revealed a fatigue fracture at the key way.

On September 27, 2003, at 1530 central daylight time, a Stinson 108-3, N6624M, piloted by a commercial pilot, sustained substantial damage when it lost engine power and nosed over while attempting to land in a field 6 nautical miles north-northeast of Lincoln Municipal Airport (LNK), Lincoln, Nebraska. Visual meteorological conditions prevailed at the time of the accident. The flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot sustained minor injuries. The flight departed the Fremont Municipal Airport (FET), Fremont, Nebraska, at 1510.

The pilot reported that the engine failed while in cruise flight at 3,000 feet mean sea level. The engine could not be restarted, and a forced landing was made to a sod field. During the landing roll, the airplane struck a concrete marker and nosed over.

A Federal Aviation Administration (FAA) airworthiness inspector examined the airplane. The exam revealed that the accessory gear drive was fractured in two pieces, and had become dislodged from the crankshaft. He reported, "a corrosion spot was observed protruding off of the keyway propagating towards the outside of the gear." Metal shavings were found in the accessory area and in the oil reservoir.

The accessory gear drive was inspected by Engineering Systems Inc., (ESI), Aurora, Illinois, on January 13, 2004. The inspection revealed that a fatigue fracture had initiated at the key way that held the gear on the rotating shaft.