ATL97LA136

According to the pilot, a loss of engine power occurred, while he was applying insecticide to a farm. A force landing was made in a plowed field. During the landing, the airplane encountered a small ditch in soft terrain, and the airplane nosed over. Examination of the maintenance records revealed that a top overhaul of the engine had been accomplished, 7 days before the accident. Postaccident examination of the engine revealed a fractured crankshaft. Multiple origin sites of the fracture were found from the surface of the journal radius. There was evidence that inadequate torque had been applied to the crankcase through-bolts. The #2 main bearing had moved fore and aft in the bearing bore and had rotated in the crankcase; there was heavy fretting at the #2 and #3 main bearing boss parting surfaces; and there was evidence of severe pounding from lack of support that had started a breakup of the #2 bearing.

On September 22, 1997, about 0933 eastern daylight time, a Cessna A188B, N53172, collided with a ditch after an emergency landing in Zellwood, Florida. The airplane was operated by Aduda & Sons under the provisions of Title 14 CFR Part 137. A flight plan was not filed for the aerial application flight. The commercial pilot was not injured, and the airplane was substantially damaged. The flight originated from a grass strip near the accident site at about 0900.

The pilot stated that after about 15 minutes of spraying, and nearing the end of his load he initiated a pull up for a turn around following a west to east pass. At approximately 100 feet above ground level (AGL) in a left pitch out, the engine lost most of its power. The pilot force landed in a carrot field and collided with a ditch, substantially damaging the airplane.

Post accident examination of the engine revealed a fractured crankshaft at the number two main bearing forward radius. The inside of the crankcase and the camshaft showed evidence of rubbing. There was fretting on the number two main bearing supports and on the lower number three. The number 2 crankshaft main journal showed score marks on the journal surface. A small crack was found on the outside of the crankcase by the number two cylinder.

The engine logbooks indicated that a top overhaul had been accomplished on September 15, 1997, 7 days prior to the accident. During the overhaul, the cylinders were removed and new piston rings were installed.