Intake icing on takeoff brings down Cessna

Aircraft: Cessna 182. Injuries: 2 Serious. Location: West Milford, N.J. Aircraft damage: Substantial.

What reportedly happened: A representative from the FBO stated that when the pilot arrived he requested a heater for his airplane, as the temperature was below freezing and the airplane was parked outside on the ramp.

The FBO employee set up the heater and observed the pilot conducting a preflight inspection noting that the pilot rocked the wings during the wing sumping process. The pilot explained that he was being sure to get any water trapped in the fuel tanks because of the bladder system. The FBO employee did not observe the pilot drain the gascolator, which is located on the engine firewall, during his time at the airplane. The engine pre-heat service was applied for an estimated 15 minutes.

There were no abnormalities during the engine start, taxi, and engine run-up before takeoff. The takeoff was normal, but the engine lost power during the climb out. The pilot applied carburetor heat and attempted to turn back to the airport. The airplane stalled and landed hard on a runway adjacent to the one the pilot intended to land on.

The post-accident examination revealed a chunk of ice with debris frozen in the gascolator fuel bowl. Investigators determined that the ice chunk was not large enough to block the fuel flow to the engine. No water was found in the carburetor. The closest official weather observation station, about 14 miles west of the accident site, reported the temperature as 4° C and the dew point as -1°C 35 minutes after the accident. Based on the ambient temperature and the dew point, serious carburetor icing conditions were possible at cruise power. The Pilot Operating Handbook states that “appropriate use of carburetor heat is recommended; full carburetor heat may be required for temperatures below -12 Celsius whereas partial heat could be used in temperatures between 4° and -12° Celsius. Use the minimum carburetor heat required for smooth operation in takeoff, climb, and cruise.” The investigation determined that the pilot’s application of carburetor heat, while consistent with guidance in the POH, was still inadequate to prevent carburetor icing.

Probable cause: The pilot’s delayed application of carburetor heat while taking off in weather conditions conducive to serious carburetor icing, which resulted in a partial loss of engine power.

NTSB Identification: ERA11LA093

This December 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.

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