FAA Powerplant Written Practice Test

What is a common method used to prevent carburetor icing?

1. Reduce engine RPM

2. Heat the induction air

3. Increase fuel flow

4. Adjust the mixture ratio

The correct answer is: Heat the induction air

Heating the induction air is a common and effective method used to prevent carburetor icing. Carburetor icing occurs when moisture in the air freezes inside the carburetor, which can restrict airflow and disrupt engine operation. By raising the temperature of the incoming air, the likelihood of moisture freezing is minimized, promoting smoother airflow and efficient engine performance. This method leverages the fact that as air passes through the carburetor, it expands and cools, which can lead to a drop in temperature and the potential for ice formation. By introducing heated air into the induction system, it counteracts this cooling effect and helps maintain a temperature that prevents icing. Other methods, such as reducing engine RPM, increasing fuel flow, or adjusting the mixture ratio, do not directly address the issue of carburetor icing in the same way that heating the induction air does. These alternatives might affect engine performance or efficiency but do not specifically target the prevention of ice formation within the carburetor.