Aviation carburetor icing failures

Tom's consulting work in aviation failures from carburetor icing. Drove the question of whether Teflon coating would prevent ice — answer depends on icing mechanism: water droplets in rain (non-wetting, Teflon helps) vs. vapor deposition from humid air (vapor-deposited frost adheres to Teflon and cannot be removed). Real solution is the cockpit deicing switch.

Even at room temperature, with the lower pressures and the fuel vaporization, even at ambient temperature, 70 degrees, depending on the humidity in the air, you can develop ice in the carburetor. If that blocks the carburetor then you're in trouble — you get no fuel to your engine, and it just doesn't run as well. If you're in an airplane that's really not a good thing. One of the problems is, you're up there very high and it could be low temperature — even if it's a nice day here, it gets colder as you go up. Icing in the carburetor is something you have to worry about, so they put heaters in the carburetors, and there's a little switch in the cockpit, and the pilot can turn on the deicing switch to heat up the carburetor so you don't get water deposited.