Incident Overview
Aircraft owner and pilot was conducting a local instructional flight to fulfill the biennial flight review requirement. The pilot and instructor reported performing a series of slow flight maneuvers and stalls when the engine lost power. Attempts to restart the engine were unsuccessful, and the pilots executed a forced landing in a vineyard. During the landing, the aircraft collided with grapevines and their supporting wooden posts and wires, resulting in damage to the aircraft.
Post-Accident Examination
An Federal Aviation Administration (FAA) inspector examined the engine. Rotation of the crankshaft produced compression in each cylinder, and continuity of the accessory gear and valve train was established. Examination of the carburetor and fuel system revealed no abnormalities. Both magnetos produced sparks when rotated by hand.
Weather and Carburetor Icing Conditions
Approximately 13 miles west of the accident site, at Ukiah, California, the 0845 weather observation recorded a temperature of 60 degrees Fahrenheit and a dew point of 51 degrees Fahrenheit. Review of a carburetor icing probability chart indicated that these temperature and dew point values fell within an area annotated as "serious icing - cruise or climb power."