The Cure For Carburetor Ice

That nobody in the industry wanted

Gus Fossum was a simple guy on a mission. Raised on a farm in Minnesota, he never attended high school – while still a teenager in 1924 he went to the city to study automobile engines. He wanted to become an Army pilot, but obeyed his father and instead moved to Los Angeles in 1927. He studied aircraft mechanics in 1929-30 while owning and operating an auto garage (1928-1942). He owned several planes and flew often, including over the 1932 Olympic Games. In 1943 he joined the Navy and spent the war in Hawaii preparing planes for battle. After WWII he spent the next 25 years working for aircraft companies, including Northrop and General Electric, as an inspector. Over the years he constantly was thinking of ways to improve on the things he knew. He wanted to forever end the dreaded killer of so many in aviation – carburetor ice.

Carburetor ice has been a problem since airplanes were first invented, and even today is the most frequent cause of unexplained engine failure. It has been studied for generations, and some innovative fixes by some brilliant engineers have been proposed, but none implemented by General Aviation manufacturers. Teflon coating of the throttle plate and venturi was proposed by the Canadians after their tests showed virtually ice free operation. The Teflon simply won’t allow ice to stick. The cost to implement this was $1.50 per carburetor. It never happened. Others have proposed fuel additives to prevent ice formation, and still others have recommended that all carburetors be equipped with ice detectors so a pilot won’t have to guess if his loss of power is due to carburetor ice or some other cause.

But only one invention, Gus Fossum’s invention, puts an end forever to carburetor ice and all the injuries and deaths that have come from it. Gus designed, built, and installed in his airplane a prototype small updraft carburetor, the kind that Marvel Schebler and now Precision have built since the 1940s. He carefully machined oil channels in the casting, throttle plate and throttle plate shaft so hot engine oil would constantly warm the carburetor and prevent the formation of any ice. At his own great expense of time and money, he obtained patents for the device in 1975 (3,916,859) and in 1979 (4,169,442). Manufacturing costs would have risen slightly, but in production this remarkable innovation would have resulted in a negligible increase in cost. Gus tested his amazing invention, and then tried desperately to sell the concept to aircraft and engine manufacturers. While none denied his invention was not the cure that Gus proudly proclaimed it to be, not one manufacturer would entertain the idea of using it. Gus Fossum’s invention is still not being manufactured for any aircraft – and carburetor ice deaths and injuries continue unabated. 

Gus Fossum died in 1999 before his dream of improving aviation safety by eliminating carburetor ice from the litany of causes of aircraft accidents was realized, but he should not be forgotten. It takes a courageous man to put his reputation and skill on the line, face off multi-billion dollar aircraft and engine manufacturers and show them the way to save lives and them from their own product liability exposure. They didn’t listen, but we should. The Gus Fossums of this world make it a better place. His widow Helen, now 94, and family savor the memory of the simple man who just wanted to help keep everyone safe in the aviation field he loved so much.

Rest in peace, Gus. 

- Arthur Alan Wolk