N8494K

On February 23, 2010, about 1330 Pacific standard time, a Schweizer Aircraft Corporation G-164B, N8494K, experienced a loss of engine power near Byron, California. Haley Flying Service, Inc., operated the airplane under the provisions of 14 Code of Federal Regulations Part 137 as an agricultural crop dusting operation. The airplane sustained substantial damage after making a forced landing on a soft dirt field and nosing over onto its back. The commercial pilot, the sole occupant, was not injured. Visual meteorological conditions were prevalent in the area, and no flight plan had been filed.

The pilot reported that after finishing the application flight he initiated a turn towards the airstrip when the engine started to run rough and lose significant power. The pilot turned the airplane into the wind and initiated a forced landing into a deeply furrowed field. As the airplane touched down, the landing gear sunk into the soft ground and the airplane nosed over, coming to rest inverted.

Postaccident examination of the airframe and engine revealed substantial damage to three of the four airplane’s wings, along with the vertical stabilizer and rudder. No visual anomalies were observed with the engine. The spark plugs were removed and appeared normal. The fuel system was examined and found to be clear of water and debris. The engine was started and no anomalies were noted.

The nearest weather reporting station was located at Livermore Municipal Airport, Livermore, California, about 12 nautical miles southwest of the accident site. At 1253 it reported, overcast skies at 400 feet; light rain showers; temperature 9 degrees Celsius (C); dew point 7 degrees C; and an altimeter setting of 30.19 inches of mercury.

Review of the carburetor icing probability chart revealed that the temperature and dew point at the time of the accident were conducive to serious icing at cruise power.