Certified Flight Instructor - Flight Instructor Airplane Practice Exam

If the engine oil temperature and cylinder head temperature gauges have exceeded their normal operating range, you may have been?

1. Operating with the mixture set too rich.

2. Using fuel with a higher-than-specified fuel rating.

3. Operating with too much power and the mixture set too lean.

4. Flying at too low an altitude.

The correct answer is: Operating with too much power and the mixture set too lean.

Operating with too much power and the mixture set too lean can lead to elevated engine oil and cylinder head temperatures. When the mixture is set too lean, there is insufficient fuel in the air-fuel mixture, which results in higher combustion temperatures. This heightened combustion temperature can cause the engine to produce excessive heat that is not effectively dissipated, leading to increased oil temperature and cylinder head temperature readings. This scenario emphasizes the importance of maintaining the proper mixture settings, particularly during high power settings, such as in climb or maximum performance flight scenarios. Proper mixture adjustment ensures optimal performance and cooling within the engine. If the mixture is too lean, it can adversely affect engine performance and longevity. In contrast, other responses suggest conditions such as richness in the mixture, incorrect fuel ratings, or altitude considerations, which do not directly correlate with the mechanical stress implied by elevated temperatures in this context. Thus, recognizing the relationship between mixture settings and engine temperatures is essential for safe and effective flight operation.