When trimming, where should ambient temperature be measured?

• A. In a shaded area near the engine inlet.
• B. In a shaded area as near the engine inlet as practical.
• C. In direct sunlight near the engine inlet.
• D. In a shaded area away from the engine inlet.

Answer: (B)

Measuring ambient temperature for trimming is about getting a true reading of the air the engine actually ingests. Sunlight and radiant heat from the engine can falsely raise the reading, which would skew air-density calculations and any trim adjustments based on them. Therefore the sensor should be placed in shade and as close to the engine inlet as practical so the temperature reflects the intake air without heat bias or ducting effects. That’s why the best placement is in a shaded area near the inlet, as close as practical.