What is the impact of carburetor heat on the fuel/air mixture?

Carburetor heat is primarily used to prevent or remove ice that can form in the carburetor, particularly in conditions with high humidity and low temperatures. When carburetor heat is applied, it draws warm air from around the engine instead of the cooler ambient air. This warm air reduces the density of the intake air, as warmer air is less dense than cooler air.

As a result, introducing this warm air into the carburetor alters the fuel/air mixture. Specifically, because the warm air is less dense, there is relatively less air in the mixture for the same volume, which leads to a higher proportion of fuel in relation to the air. Consequently, the mixture becomes richer, meaning that it has more fuel than it would if only cooler air were used. This enrichment can help improve engine performance and aid in the smooth operation of the engine, especially when ice has overcome the air passage in the carburetor.

Understanding this principle is crucial for pilots, as managing the fuel/air mixture impacts engine performance and safety.