Indianola, MS, USA
N8478D
Bell 47
The pilot reported that while enroute to the next field to be sprayed, at 500 feet, the engine lost power. After attempts to restore full power, the pilot selected a nearby field. During the autorotative touchdown, the helicopter rolled over on the right side. During the engine examination, metal particles were recovered from the engine oil pump screen and the engine oil filter element. Further examination showed that # 1 cylinder connecting rod cap was wedged between the second crankshaft lobe and the engine case. The examination of the helicopter also revealed that the landing skid and cross-tubs were fractured into several pieces. The fracture examination showed all fractures were in overload. The engine had accumulated a total of 935.1 hours since the last major overhaul.
On July 10, 2001, at 1030 central daylight time, a Bell 47 helicopter, N8478D, registered to Talon Air, Inc., collided with the ground and rolled over during an autorotation following a loss of engine power near Indianola, Mississippi. The aerial application flight was operated under the provision of Title 14 CFR Part 137 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The helicopter sustained substantial damage, and the commercial pilot was not injured. The flight departed Indianola, Mississippi, at 1025. The pilot reported that while enroute to the next field to be sprayed, at 500 feet, the engine lost power. After attempts to restore full power were not successful, the pilot selected a nearby field for an autorotation. The pilot stated the autorotative maneuver was normal, but when the helicopter touched down, it rolled over on the right side. During the engine examination, metal particles were recovered from the engine oil pump screen and the engine oil filter element. Examination of the engine assembly approximately four to six ounces of water were recovered from the airframe fuel system. During the subsequent engine teardown examination, a large hole was discovered in the engine case adjacent to the No. 1 cylinder. Further examination showed the No. 1 cylinder connecting rod cap was wedged between the second crankshaft lobe and the engine case. The examination of the helicopter also revealed that the landing skid and cross-tubs were fractured into several pieces. The fracture examination showed all fractures were in overload. A review of the airframe and engine maintenance logs showed that the airframe had accumulated 10,378 flight hours. The engine had accumulated a total of 935.1 hours since the last major overhaul.
The pilot's improper use of flight controls during an autorotation that resulted inn the collapse of the skids and cross tube assembly. A factor was the loss of engine power due to the failure of # 1 connecting rod and the overload failure of the skids and cross tub assembly.
Source: NTSB Aviation Accident Database
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