Ancillary Controls lesson Carburetor Heat Mixture Control Carburetor Heat: Icing ice can form in the induction system:Moist atmospheric condition.-5°C to +30°C .Caused by the absorption of heat from the air during vaporization of the fuel.Also caused by venturi effect.Indication of icing:Loss of RPM with a fixed piched controllerLoss of manifold pressure with a constant speed controler.What to do:Immediately use: full carburetor heat .Note:In general carburetor heat should not be used while taxiing because in the “on” position the intake air usually bypasses the carburetor.Avoid using carburetor heat during take-off, except during special procedures (very low temperature), since it may cause detonation and engine damage. Carburetor Heat: system Mixture Control Mixture too rich:Lower powerUneven running of engineEngine too coolFuel is wastedPossible spark plug foulingRange is reduced Mixture too lean:Power will be lostEngine may run rough and vibrateEngine too hotEngine damage due to detonation Review questions What effect does too rich a mixture have on the aircraft ?What effect does too lean a mixture have on the aircraft ?What is the first indication of icing to the pilot ?Why don’t we use carb heat during taxiing?