Attention Aviators: Beware of Carburetor Icing!

The Safety In­ves­ti­ga­tion Au­thor­ity, Fin­land has com­pleted an in­ves­ti­ga­tion into an ac­ci­dent where an am­a­teur-built air­plane force-landed in wooded ter­rain and was dam­aged be­yond re­pair af­ter ex­pe­ri­enc­ing rough-run­ning en­gine and even­tu­ally en­gine cut-out. The pi­lot sus­tained fa­tal in­juries.

“The engine was disassembled and thoroughly examined. It is possible that the engine cut out due to the accumulation of ice or condensed fuel in the carburetor or in the inlet ducting because investigation revealed no technical fault that could have caused the cut-out; also, the amount of fuel on board was sufficient, and the fuel was of the correct grade.In addition, the configuration of the engine intake manifold and the weather conditions were conducive to ice accumulation,” says investigator-in-charge Janne Kotiranta.

Investigation found that little Finnish language information of carburetor icing is available and concluded that all factors that affect the risk of carburetor icing are not apparent from aeronautical weather information. Conditions conducive to carburetor icing may come as a surprise because icing can occur over a wide temperature and humidity range and in all seasons.

Investigation also considers essential that attention is paid on the safety aspects of amateur-build aircraft construction.

“Efforts should be made to improve knowledge of safe aeronautical practises in recreational aviation communities by coordinating and enhancing training. Current aviation regulations do not define training and experience requirements for builders of amateur-built aircraft, and incorrect or inappropriate knowledge or skills may lead to dangerous structural solutions or incorrect component installations,” Kotiranta adds.

The Safety Investigation Authority, Finland issues three safety recommendations directed to the Finnish Transport and Communications Agency Traficom, emphasizing information availability and training and supervision of construction work.