The airline transport pilot flew his experimental, amateur-built biplane on a cross-country flight with multiple legs and refueling stops. About one hour, 15 minutes into the flight and 15 miles from his destination, he initiated a descent from 3,500′ to 2,500′.
When he added power to level off, the Acro Sport II’s engine began to run rough and experienced a partial loss of power.
The pilot said he immediately applied carburetor heat, but observed no improvement in engine operation. The engine continued to lose power and “sputter.”
During the subsequent forced landing near Loudonville, Ohio, the airplane touched down on unsuitable terrain at the edge of a soybean field, decelerated rapidly, and nosed over.
A post-accident examination of the wreckage revealed no pre-impact anomalies that would have precluded normal operation of the engine. Nearby weather was conducive to serious icing at descent power about the time of the engine power loss.
Although the pilot reported that he applied carburetor heat, it is likely that, at the time of application, the ice had already accumulated in the carburetor to the extent 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.
NTSB Identification: CEN17LA295
This July 2017 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.