NTSB Factual Report

On July 23, 2006, about 1000 Pacific daylight time, a Cessna 182P airplane, N9886M, sustained substantial damage during a precautionary landing on a dirt strip near Hemet, California. The private pilot and the passenger were uninjured. The pilot operated the airplane under the provisions of 14 CFR Part 91 as a personal flight. Visual meteorological conditions prevailed and a flight plan was not filed for the flight that departed Upland, California, at 0930. The flight was destined for the Hemet-Ryan Airport (HMT), Hemet.

According to the written statement provided by the pilot, he departed Upland and headed to Hemet. As the flight neared the Hemet area at 2,500 feet, the pilot started "feeling a couple of violent shakes of the engine, then backfiring." He decreased the power to 15 inches of manifold pressure to reduce the shaking and backfiring and then checked the fuel selector and ensured it was selected to both fuel tanks. Additionally, he verified that the magnetos were both selected, and that the propeller and mixture controls were full forward. The pilot kept the engine power set at 15 inches of manifold pressure and looked for a suitable landing site.

The pilot noted a dirt strip next to a highway and began his descent. He touched down with both main landing gear and kept the nose wheel up and applied left rudder to offset the crosswind, until both the elevator and rudder lost control authority. With the crosswind, the airplane was blown off of the strip into soft plowed dirt. The nose landing gear dug into the dirt and collapsed. The right wing impacted the ground during the event resulting in substantial structural damage to the right wing and fuselage.

According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the airplane underwent its last annual inspection on June 23, 2006, at an aircraft total time of 6,817.5 hours. The airplane accumulated 27 hours since that inspection.

The airplane was transported by Aircraftsman to their facility in Chino, California. According to the personnel at Aircraftsman, and to the Federal Aviation Administration (FAA) inspector who examined the airplane following the event, the engine, mounted on the accident airplane, was test run. The Continental O-470-S engine produced full power and no anomalies were noted. The magnetos were tested with normal drops of 75 rpm per magneto noted. Following the engine test run, the FAA inspector oversaw the teardown examination of the carburetor. The floats were properly set and the bowl and inlet screen were clear and free from debris. No anomalies were noted that would have resulted in the backfiring and engine shakes.

The weather observation facility located at the Riverside Airport, approximately 11 miles northwest of the accident site, reported the following conditions at 0955: wind from 280 degrees at 11 knots; visibility 35 statute miles; a few clouds at 8,000 feet, broken clouds at 13,000 feet and 18,000 feet; temperature 36 degrees Celsius; dew point 17 degrees Celsius; and an altimeter setting of 29.86 inches of Mercury.

Review of a carburetor icing probability chart with the temperature and dew point noted above revealed that a chance of light carburetor icing probability existed at cruise or descent power.

NTSB Probable Cause

the shaking and backfiring of the engine for undetermined reasons.