N202AW

On September 2, 1998, at 0630 hours Pacific daylight time, a Cessna 188B, N202AW, experienced a loss of engine power after takeoff and made an emergency landing in an alfalfa field near Dixon, California. The aircraft, operated under 14 CFR Part 137 as an agricultural crop dusting operation by the William D. Joslin Corporation, was destroyed in a postimpact fire. The commercial instrument rated pilot, the sole occupant, was not injured. Visual meteorological conditions existed for the flight and no flight plan was filed.

The pilot stated that this was the first flight of the day and he was going to spray sulfur dust on a tomato field. After departure, he reduced power at approximately 100 feet agl. He experienced a partial loss of power, and made a forced landing in an adjacent alfalfa field. The pilot stated that after landing the aircraft caught fire and was destroyed in the ensuing fire.

A Federal Aviation Administration (FAA) inspector responded to the scene and interviewed the owner. Aircraft and engine testing were not conducted due to the postimpact fire. The owner reported that the aircraft had flown the day before the accident flight with no discrepancies noted. This was the first flight of the day and the aircraft was carrying a full load of sulfur. After takeoff the pilot made a turn to the left and the engine quit. The owner stated that the pilot attempted to return to the runway, and when he saw he was not going to make it made a slight banking turn to the right and aimed for an open field. The owner reported that the aircraft was in a nose high attitude with a high sink rate due to the full load of chemicals. The aircraft landed hard and bounced into the air. After the first bounce, the aircraft was simultaneously on fire and was rotating 180 degrees. The aircraft struck the ground again and the pilot exited the aircraft.

The chemical manufacturer was contacted and the representative stated that the powdered sulfur dust compound used in aerial application operations is considered a moderate fire hazard according to the National Fire Protection Association criteria. While the compound has a flash point of 374 degrees Fahrenheit, published studies (page 48, INVESTIGATION OF FIRE AND EXPLOSION HAZARDS IN CHEMICAL, MINING AND FUEL RELATED INSDUSTRIES Bureau of Mines, U.S. Department of Interior) demonstrate that atomized layers of clouds of dust may ignite at ignition temperatures of 190 degrees in air to substance density limits of less than 0.1 ounces per cubic foot. The test was conducted in a Hartman apparatus with a high voltage 24-watt spark source for ignition.

The manufacturer's representative noted that sulfur is processed in an inert atmosphere during manufacture into the powdered form to prevent potential explosions or fires.