CEN16LA287

The commercial pilot reported that, about 30 minutes into the cross-country flight, while cruising at 1,000 ft above ground level, the engine began to lose power, decreasing from about 2,350 rpm to about 2,100 rpm. The pilot pulled the carburetor heat to the on position for a few seconds, then pushed it back in to turn it off. The pilot then diverted to a nearby airport; however, the engine continued to lose power and the pilot chose to land in a field next a road. During the landing, the airplane nosed over and came to rest inverted. Examination of the airplane did not reveal any mechanical anomalies that could have resulted in the loss of engine power. Given the temperature and dew point in the area about the time of the accident, the airplane was operating in conditions conducive to the development of light carburetor icing at cruise or descent power. It is likely that the loss of engine power was the result of carburetor ice, and the pilot's brief application of carburetor heat was insufficient to clear the ice from the carburetor, which resulted in a further loss of engine power.

On July 22, 2016, about 1200 central standard time, a Stinson 108-2 single engine airplane, N8019K, registered to a private individual, sustained substantial damage during a forced landing after a loss of engine power near the Dodge Center Airport (TOB), Dodge Center, Minnesota. Of the 3 occupants on board, the private pilot and one passenger sustained minor injuries and one passenger was not injured. The personal cross country flight was being under the provisions of Federal Code of Regulations Part 91. No flight plan was filed and visual meteorological conditions prevailed in the vicinity of the accident. The flight originated from Mankato Municipal Airport (MKT), Mankato, Minnesota about 1130 and was enroute to Oshkosh, Wisconsin. According to the pilot, the airplane had stopped at MKT for fuel and took off with no problems. After about 30 minutes of flight and cruising at 1,000 AGL, the engine was developing power at a steady 2,350 RPMs when the engine started to lose power to about 2,100 RPMs. The pilot pulled the carburetor heat ON for a few seconds and then pushed it back. The pilot started to look for a place to land and diverted to the Dodge Center Airport. The power remained at 2,100 RPMs for about 10 miles while flying to the airport and then began to lose more power. At this point, the pilot initiated maneuvers to land on a road about 1 mile from Dodge Center. The airplane landed in a field and rolled over. All three occupants exited the airplane through the cabin doors. Examination of the airplane wreckage by an FAA inspector at the accident site did not reveal any anomalies. The reported weather observation METAR at Dodge Center (TOB) about the time of the accident was: METAR KTOB 221654Z AUTO 11004KT 10SM SCT013 SCT040 31/24 A3005 RMK AO2 According to the Icing Probability Chart (included in the docket), with a temperature of 31 degrees and dew point of 24 degrees, the aircraft engine was operating in conditions susceptible to light carburetor icing at cruise or descent power.