The sport pilot reported that, before departing on a cross-country flight, he contacted the flight service station for a weather briefing for his flight route. He then conducted a preflight inspection of the Arion Lightning LS-1, started it to allow it to warm up, and ran the carburetor heat before departing.
The climb to cruise at 2,000′ was normal. About 10 miles from the departure airport, the engine started to run “rough,” so he applied carburetor heat. When this did not have any effect on engine performance, he decided to return to the departure airport.
He added that, during the return, the engine “power was very poor” and that the airplane was losing altitude rapidly.
He spotted a clear field near Goshen, Indiana, and performed a soft-field landing approach. Upon landing, the gear dug into the soft plowed field. The airplane continued forward on its belly, which resulted in substantial damage.
The weather conditions were conducive to the accumulation of serious icing at any power setting. Although the pilot reported that he used carburetor heat, it is likely that the ice had already accumulated to the degree that the carburetor heat was insufficient to melt the ice and restore full engine power.
Probable cause: A partial loss of engine power due to carburetor icing and the subsequent forced landing on a rough/soft field.
NTSB Identification: CEN17LA048
This December 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.