FAA Powerplant Written Practice Test

Which two atmospheric factors must be considered when making trim adjustments of a turbine engine?

1. Humidity and Wind Speed

2. Ambient Temperature and Barometric Pressure

3. Temperature and Engine Load

4. Altitude and Air Density

The correct answer is: Ambient Temperature and Barometric Pressure

When making trim adjustments of a turbine engine, it is essential to consider ambient temperature and barometric pressure because these two factors significantly influence engine performance and operation. Ambient temperature directly affects the density of the air entering the engine. As temperature increases, air density decreases, which can lead to a reduction in engine thrust and efficiency. Adjustments may be necessary to compensate for changes in ambient temperature to maintain optimal engine performance. Barometric pressure also plays a critical role in atmospheric conditions. Changes in barometric pressure indicate variations in the weight of the air and its density. A decrease in pressure typically results in a thinner atmosphere, which can impact the engine’s ability to generate thrust. Thus, trim adjustments may be needed to account for these changes to ensure the engine operates within its designed performance parameters. Together, these factors must be carefully monitored and adjusted to maintain the balance and efficiency of turbine engines during operation.