Background
A pilot received a weather briefing indicating occasional instrument flight rules (IFR) conditions along the intended route and that visual flight rules (VFR) flight was not recommended. Despite this, the pilot filed a VFR flight plan and departed.
Event Sequence
While flying on top of an overcast layer at approximately 14,500 feet mean sea level (MSL), the pilot observed the carburetor air temperature gauge needle moving into the yellow caution zone. Simultaneously, the engine began running roughly. In response, the pilot applied carburetor heat.
The ambient air temperature was 0 degrees Fahrenheit, and the pilot noted water rivulets running from the underside of the wing while in clear air. Recognizing that conditions were conducive to clear air icing, the pilot kept carburetor heat on. However, the carburetor air temperature gauge needle remained in the yellow cautionary area.
Subsequently, the engine quit. The pilot stated that it was immediately obvious that the carburetor had failed due to icing.
Forced Landing and Outcome
The pilot executed a forced landing to a mountainous area. During the landing roll, the aircraft collided with rough terrain.