WPR10LA087

The pilot reported that after he was established on the downwind leg for landing the engine experienced a partial loss of power, followed by a total power loss after turning into the base leg. The pilot subsequently made an emergency descent and forced landing to an open field. The airplane hit a fence and nosed over, sustaining substantial damage to both wings. A Federal Aviation Administration inspector reported that an examination of the airframe and engine revealed no anomalies that would have precluded normal operation. Atmospheric conditions at the time of the accident were not conducive to the formation of carburetor ice. The reason for the reported loss of engine power could not be determined.

On December 17, 2009, about 1435 Pacific standard time, a Cessna 172F, N8520U, sustained substantial damage following a loss of engine power and subsequent forced landing about 4 nautical miles southwest of the Corona Municipal Airport (AJO), Corona, California. The private pilot, who was the sole occupant, received minor injuries. The airplane was operated by Fly Corona, of Corona, California. Visual meteorological conditions prevailed for the local flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, and no flight plan was filed. The flight departed AJO about 1420. In a written statement submitted to the NTSB investigator-in-charge (IIC), the pilot reported that prior to the flight he checked the fuel level and confirmed that both fuel tanks were full. The pilot also reported that he checked for water in the fuel system, and no water was detected. The pilot stated that after taking off and when established on right downwind abeam the runway numbers, "I began my pre-landing checklist including carburetor heat and decreasing throttle. I pulled out the throttle and the RPM (revolutions per minute) dropped to 1,000. I was aiming for 1,500 rpm, so I pushed in the throttle to reach 1,500, and I got no response. I pushed further and the engine started to 'bog' and 'sputter,' and could not be increased above about 1,200 rpm." The pilot added that shortly after turning on to base leg "…the propeller slowed and stopped." The pilot stated that due to trees in front of his position, he decided to make a 180-degree left turn and land in an open field, which he described as "rough with loose gravel." During the landing the airplane impacted a fence and nosed over, which resulted in substantial damage to both wings. In a statement provided to the IIC, a Federal Aviation Administration (FAA) inspector stated that in an interview with the pilot, the pilot revealed that he had received 1.5 hours of flight instruction in the Cessna 172 prior to the accident flight. The pilot added that this was the only flight time had had in a Cessna 172, and that he had a total flight time of 90 hours. On December 21, 2009, an examination of the airplane’s engine was performed by a certified FAA airframe and powerplant mechanic, and supervised by a FAA inspector. The mechanic reported that the examination revealed no cracks in the cylinders or crankcase, no evidence of engine oil leakage, and that when the engine crankshaft was rotated freely by hand, compression was noted on all cylinders. The mechanic stated that the spark plugs were removed and that they appeared normal with no signs of fouling. The magnetos were tested by installing spark plugs on leads and rotating the engine crankshaft; the magnetos produced spark on all ignition leads and no abnormalities were detected. The mechanic reported that the fuel tanks were sumped 3 times and no water was found, and that upon removal and inspection of the gascolator the filter/screen wasobserved to be clean and free of debris. Positive fuel flow was noted with the fuel selector in the ON positions (Left, Right and Both). The mechanic added that the fuel line was removed from the carburetor and found to contain no blockages. The mechanic also added that on December 22, 2009, he and the FAA inspector removed the top of the carburetor and observed a small amount of fuel present, which contained no water or particles. A review of maintenance records revealed that the engine's most recent 100-hour inspection was conducted on October 23, 2009, at a time since major overhaul of 1,164 hours, and a total tachometer time of 4,398.6 hours. The airplane's most recent annual inspection was conducted on July 10, 2009, at a total airframe time of 8,498.61 hours. At 1456, the Automated Surface Observing System (ASOS) weather reporting facility located at AJO indicated wind 150 degrees at 5 knots, visibility 10 miles, sky clear, temperature 24 degrees Celsius, dew point -1 degree Celsius, and an altimeter setting of 29.99 inches of Mercury. Atmospheric conditions at the time of the accident were not conducive to the formation of carburetor ice. The reason for the reported loss of engine power could not be determined.