Which of the following is a means of engine cooling?

• A. Reducing the boost (manifold pressure)
• B. cowl flaps
• C. mixture control
• D. Radiator fan operation

Answer: (B)

Cooling in many aircraft engines is managed by moving air through the engine compartment. Opening cowl flaps increases the amount of air flowing over the cylinders and around the engine, which carries heat away and helps prevent overheating during high-power or hot-day operations. This direct control of cooling airflow is why cowl flaps are a primary means of engine cooling.

Reducing manifold pressure lowers engine power and, as a result, heat produced, but it isn’t a physical cooling mechanism itself—it’s an indirect way to manage temperature. Mixture control changes the fuel–air ratio and can affect cylinder temperatures, yet it doesn’t actively move cooling air through the engine. Radiator fan operation is typical of liquid-cooled engines; many light aircraft use air cooling with no radiator and, thus, a radiator fan isn’t part of the standard cooling method in those engines.