Commercial Pilot License (CPL) Practice Exam

When the cowl flaps are closed during descent, the engine temperature typically increases. Cowl flaps are designed to regulate cooling airflow to the engine, and when they are closed, airflow around the engine is restricted. As the airplane descends, the engine may still generate heat; however, with reduced airflow, heat dissipation is diminished. This means that the engine does not cool as effectively, which can lead to an increase in engine temperature over time.

In contrast, if the cowl flaps were to remain open during descent, the engine would benefit from increased airflow, allowing for better cooling and potentially a decrease in temperature. Therefore, the closed position of the cowl flaps contributes to a less effective cooling system, resulting in rising temperatures in the engine compartment. Understanding how engine temperature is affected by cowl flap position is essential for maintaining engine performance and safety during flight, especially in various phases of operation like descent.