CEN10LA408

While en route to the destination airport, the pilot began detecting heavy vibrations emanating from the helicopter. He performed a scan of the engine instruments, all of which indicated that it was operating within the normal ranges. Unsure of the malfunction, the pilot elected to perform a cautionary autorotation to a plowed field. During the autorotation, the pilot landed hard and the helicopter subsequently rolled over. During the touchdown sequence the helicopter incurred substantial damage. A postaccident examination of the airframe and engine did not reveal any evidence of a preimpact anomaly.

On July 8, 2010, approximately 2050 central daylight time, a Schweizer 269C, N410JM, was substantially damaged upon impact with terrain during a precautionary landing near Minden, Nebraska. The private pilot and one passenger were not injured. Visual conditions prevailed and no flight plan was filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The local flight departed Pioneer Village Field (0V3), Minden, Nebraska, at approximately 2000. According to a written statement provided by the pilot, the helicopter was approximately four miles from 0V3, at an altitude of 2,550 feet mean sea level, when the helicopter began producing vibrations. The pilot described the vibrations as "heavy" and at a "slow frequency." A scan of the engine instruments did not reveal any abnormalities with the helicopter, although the gages were difficult to read due to the heavy vibrations. The pilot chose to perform a precautionary autorotation to a field. Prior to touchdown, the pilot increased his flare in order to reduce ground-run. The helicopter made a hard impact with the ground and rolled before coming to rest on the helicopter's left side. An inspector from the local Federal Aviation Administration (FAA) examined the helicopter and engine. The inspector did not find any signature of pre-impact failure or malfunction of any component.