What is one of the first steps to take if experiencing preignition symptoms?

Richen the fuel mixture is a critical initial step when experiencing preignition symptoms in an aircraft engine. Preignition occurs when the fuel-air mixture ignites prematurely in the combustion chamber, which can lead to higher than normal engine temperatures and potential engine damage. By enriching the fuel mixture, you introduce more fuel into the combustion process, which can help to cool the combustion temperatures and reduce the likelihood of preignition occurring.

Implementing this adjustment helps maintain proper engine operation and can alleviate the symptoms associated with preignition, giving the pilot more time to assess the situation and execute any necessary emergency procedures.