Piper PA-18-150 N4287Z accident near Surfside Beach, South Carolina

Probable cause

A loss of engine power due to carburetor icing. Contributing to the accident was the obstruction of the carburetor heat flapper by a mud dauber's nest.

NTSB analysis

During the second banner-tow flight of the day, the pilot noticed a slight vibration emanating from the engine, which several seconds later became a "very intense" vibration. The engine power began to diminish rapidly, so the pilot began searching for a suitable forced landing site. During the descent, the pilot attempted to restore engine power, and applied carburetor heat, but his efforts were unsuccessful. During the forced landing, the wheels of the airplane encountered an area of soft ground and the airplane subsequently nosed-over resulting in substantial damage. Post-accident examination of the engine revealed that the carburetor heat flapper was obstructed by a mud dauber's nest. Examination of carburetor ice probability charts indicated "serious icing at glide power," or "light icing - glide or cruise power."

Text from the NTSB. Open the NTSB docket for NYC08LA249 for the full record.