WPR17LA062

The private pilot reported that, about 10 minutes after departing for a personal, local flight and when the airplane was about 1,000 ft above ground level, the engine began running roughly, and the rpm surged several times despite the engine monitoring gauges all indicating normal operation. The pilot chose to make a precautionary landing on a snow-covered dirt airstrip. The pilot reported that, after reducing power to land, he did not recall the engine experiencing further roughness or surging. During the landing roll, the airplane nosed over in the deep snow and then came to rest inverted. During postaccident test runs, the engine ran normally through various power settings with no anomalies noted that would have precluded normal operation. The reason for the engine momentarily running roughly and surging could not be determined.

On January 27, 2017, about 1645 Pacific standard time, an Aviat Aircraft Inc. A-1C, N382US, was substantially damaged when it nosed over in the snow during a precautionary landing at an airstrip near Jiggs, Nevada. The private pilot was not injured. The airplane was registered to Canyon State Aviation LLC., and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight which originated from Elko Regional Airport (EKO), Elko, Nevada, around 1630. The pilot stated that the purpose of the flight was to overfly the vicinity of his ranch and look for horse tracks. About 10 minutes after departure, with the airplane at an altitude of about 1,000 ft above ground level (agl), the engine began to run rough and the rpm surged several times. The cockpit gauges and engine monitoring device all indicated normal ranges, with no anomalies. The pilot opted to make a precautionary landing and observed he was about 2 miles from the snow-covered dirt airstrip on Corta Ranch, which his family owns and where he frequently lands during the summer months. The pilot reported that after reducing power to land, he did not recall the engine experiencing further roughness or surging. He touched down about five minutes later and during the landing roll, the airplane nosed over in the snow coming to rest inverted. He estimated the snow was between 24 to 30 inches deep. The airplane incurred substantial damage to the struts and wings as a result of the impact. A Federal Aviation Administration inspector spoke with maintenance personnel at Aviat that examined the engine after the accident. The mechanic stated that he ran the engine and no anomalies could be found. The engine operated normally through various power settings without incident.