FAA Powerplant Written Practice Test

What is a common method to prevent carburetor icing?

1. Heating the induction air

2. Cooling the fuel supply

3. Using high-octane fuel

4. Adjusting the idle RPM

The correct answer is: Heating the induction air

Heating the induction air is a common and effective method to prevent carburetor icing. Carburetor icing can occur when the temperature of the fuel-air mixture drops due to the vaporization of fuel and the cooling effect this process has on the air passing through the carburetor. When the air around the carburetor is cold, moisture in the air can freeze and form ice, obstructing air flow and disrupting the proper operation of the engine. By heating the induction air, you can raise the temperature of the air entering the carburetor, thus decreasing the likelihood of ice forming. This can be accomplished through various methods, such as using exhaust gas heat or specific heating elements designed to warm the air before it reaches the carburetor. Maintaining a higher temperature helps to ensure that any moisture present in the air remains in a gaseous state, minimizing the risk of ice accumulation. Cooling the fuel supply does not address the problem of ice formation, as colder temperatures can actually contribute to the formation of ice. Using high-octane fuel is unrelated to the occurrence of icing; it primarily affects engine performance and efficiency. Adjusting the idle RPM may affect engine operation but does not directly influence the conditions under which carburetor icing occurs.