What causes detonation in an aircraft engine?

Detonation in an aircraft engine is primarily caused by low-grade fuel or a too lean air/fuel mixture. When low-grade fuel is used, it may not have the necessary octane rating to withstand the pressures and temperatures within the combustion chamber without igniting prematurely. A too lean air/fuel mixture exacerbates this situation by increasing the combustion temperature, making it easier for the fuel-air mixture to ignite before the spark plug fires.

The conditions that lead to detonation are characterized by rapid combustion that can cause shock waves within the cylinder, leading to potential engine damage. Using fuel with an appropriate octane rating and maintaining the proper air/fuel mixture are critical to preventing detonation and ensuring smooth engine operation.