N35JBCessna 510 · 2010

On March 20, 2009, about 1556 Pacific daylight time, an amateur-built experimental Barnett J4B gyroplane, N35JB, sustained substantial damage during a forced landing following a loss of engine power near Sheridan, California. The airline transport pilot, the sole occupant, was not injured. The gyroplane was registered to an individual and operated by the pilot. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under Title 14 Code of Federal Regulations Part 91. The flight departed from Marysville, California, about 1540, en route to Lincoln, California.

The owner of the gyroplane reported that while en route to Lincoln, the engine experienced a loss of power and the pilot initiated a forced landing onto a highway. After an uneventful landing, the pilot steered the gyroplane off the side of the road to avoid a vehicle. The gyroplane encountered a ditch and rolled onto its right side. Examination of photos revealed that the vertical stabilizer and rudder were bent and wrinkled, and the rotor head was destroyed.

Post-accident examination of the engine by the owner revealed no evidence of mechanical failures or malfunctions with the engine and its components. The owner stated that the high humidity weather condition and the pilot's description of the power loss indicated carburetor icing had occurred. The owner further stated the gyroplane was equipped with carburetor heat; however, the pilot did not use it.

At 1555, the nearest weather reporting station at Beale Air Force Base, located about 10 statute miles north of the accident site, reported that the temperature was 74 degrees Fahrenheit and the dew point was 51 degrees Fahrenheit. Plotting these values on a carburetor ice probability chart indicated that the conditions were conducive to icing conditions at cruise power and serious icing conditions at glide power.