This September 2010 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.
Aircraft: Cessna 172. Injuries: None. Location: Palm Beach, Fla. Aircraft damage: Substantial.
What reportedly happened: According to the pilot, the airplane was flying at an altitude of 1,200 feet, about 3/4-mile offshore when the engine started to sputter then lost power.
The pilot attempted to troubleshoot the problem but was not successful. He could not recall if he activated carburetor heat as part of the procedure. He made a forced landing to an unpopulated area of the beach, during which the airplane sustained substantial damage.
A post-accident test run of the engine revealed no evidence of any mechanical anomalies. The weather at the time of the accident included 31° C, and a dew-point of 21° C. According to the FAA icing probability chart, the airplane was operating in conditions conducive to serious carburetor icing at glide power at the time of the accident. Without carburetor heat carburetor ice can form, resulting in loss of power and possible engine roughness.
Probable cause: The pilot’s failure to use carburetor heat, which led to a loss of engine power due to carburetor icing.
For more information: NTSB.gov. NTSB Identification: ERA10LA494