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

Using a lower fuel grade than specified by the manufacturer can indeed lead to detonation. Detonation occurs when the fuel-air mixture in the cylinder ignites prematurely due to excessive heat or pressure. Each engine is designed to operate with a specific fuel grade that matches its combustion characteristics. When a lower fuel grade is used, it may not withstand the pressure and heat generated during combustion, resulting in an uncontrolled explosion rather than a smooth burn. This premature ignition can create shock waves and lead to a significant increase in pressure, causing damage to the engine.

On the other hand, operating the engine at low power settings typically does not induce detonation; it can actually promote smoother combustion. Running the engine at rich fuel mixtures generally helps cool the combustion process and avoid detonation. Additionally, flying with a balanced load is unrelated to fuel type or detonation risks; rather, it refers to weight distribution in the aircraft for stability and performance. Hence, the choice of using a fuel grade that aligns with the manufacturer's specifications is critical to preventing detonation and ensuring optimal engine performance.