Commercial Pilot License (CPL) Practice Exam 2025 – The Complete All-in-One Guide to Achieve Your Pilot Certification Success!

If detonation is suspected, the appropriate action to take is to open the cowl flaps when on the ground. This action helps to reduce engine temperatures and allows for better cooling, which can mitigate the risk of further detonation. Detonation is a harmful condition that can occur when fuel-air mixture combustion happens too early or in an uncontrolled manner, leading to increased pressure within the engine cylinder.

Opening the cowl flaps enhances airflow over the engine, assisting in cooling it down and possibly preventing damage caused by overheating due to detonation. Maintaining the engine within safe temperature ranges is critical for avoiding further operational issues.

In contrast, increasing the power setting to maximum could exacerbate the situation by further stressing an engine already at risk of detonation. Leaning the mixture during takeoff can also ignite detonation by causing excessive combustion temperatures. Reducing altitude might not be appropriate immediately; it could be ineffective in addressing the core issue related to engine performance and temperatures unless it is part of a broader strategy to manage an emergency. Thus, opening the cowl flaps serves as a direct and beneficial response to suspected detonation conditions.