GORMAN, CA, USA
N6790V
MOONEY M20C
THE AIRPLANE WAS IN CRUISE FLIGHT AT ABOUT 9,500 FEET MEAN SEA LEVEL WHEN THE ENGINE HAD A TOTAL LOSS OF POWER. THE PILOT ENTERED A POWER OFF FORCED LANDING AND PERFORMED EMERGENCY PROCEDURES ATTEMPTING TO RE START THE ENGINE. HE COULD NOT GET THE ENGINE STARTED. THE PILOT LANDED THE AIRPLANE ON A TWO LANE ROAD ADJACENT TO AN INTERSTATE HIGHWAY. THE PILOT ENCOUNTERED AN UNFAVORABLE LEFT CROSSWIND WHICH CAUSED THE AIRPLANE TO DRIFT TO THE RIGHT SIDE OF THE ROAD. DURING LANDING ROLL THE AIRPLANE'S RIGHT WING CONTACTED METAL FENCE POSTS AND SPUN THE AIRPLANE INTO AN EMBANKMENT. DURING AN FAA SUPERVISED ENGINE RUN FUEL WAS NOTED AS LEAKING FROM THE CARBURETOR. AN EXAMINATION OF THE CARBURETOR REVEALED THAT THE INLET FUEL FITTING HAD GALLED OR CROSSFED THREADS. METAL SHAVINGS FROM THE THREADS BYPASSED THE FUEL SCREEN AND TRAVELED DIRECTLY INTO THE FUEL FLOAT VALVE WITHOUT GOING THROUGH THE FILTER SCREEN. THIS CAUSED THE FLOAT VALVE TO BECOME INOPERATIVE, WHICH RESULTED IN FLOODING THE ENGINE WITH FUEL CAUSING A TOTAL LOSS OF ENGINE POWER. THE AIRPLANE'S ENGINE HAD A TOTAL TIME OF 7 HOURS SINCE OVERHAUL.
1) THE CARBURETOR INLET FUEL LINE BEING IMPROPERLY INSTALLED BY MAINTENANCE PERSONNEL WHICH ALLOWED THE CARBURETOR TO BECOME CONTAMINATED WITH METAL PARTICLES, AND 2) THE CARBURETOR FLOAT VALVE BEING JAMMED BY METAL PARTICLES WHICH ALLOWED EXCESSIVE FUEL TO BE INTRODUCED INTO THE CARBURETOR RESULTING IN FLOODING AND THE TOTAL LOSS OF ENGINE POWER. A FACTOR IN THIS ACCIDENT WAS THE PILOT ENCOUNTERING AN UNFAVORABLE CROSSWIND DURING FINAL APPROACH WHICH LED TO THE AIRPLANE'S WING COLLIDING WITH FENCE POSTS DURING LANDING ROLL.
Source: NTSB Aviation Accident Database
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