Commercial Pilot License (CPL) 2025 – 400 Free Practice Questions to Pass the Exam

Detonation in an aircraft engine refers specifically to the uncontrolled explosion of the fuel-air mixture within the combustion chamber or cylinder. This phenomenon occurs under conditions where the compression of the mixture causes it to ignite spontaneously, rather than in a controlled manner initiated by the spark plug.

When detonation takes place, it can create a sudden and violent pressure spike that may damage engine components. This can happen due to factors such as high engine temperatures, excessive compression ratios, or low-quality fuel. Understanding detonation is crucial for pilots and aircraft operators as it can significantly impact engine performance and safety.

The other choices address issues that can affect engine performance but do not accurately define detonation. Inadequate fuel supply can lead to engine performance problems but is a different issue than detonation. A fuel mixture that is too rich may cause incomplete combustion rather than detonation. Finally, a failure of the spark plug ignition relates to issues in starting or maintaining combustion rather than an explosion of the fuel in the cylinder.