FAA Powerplant Written Practice Test

Why is the temperature of turbine engine fuel often kept above 32°F?

1. To optimize combustion efficiency

2. To prevent ice crystals from forming in the filter

3. To reduce the wear on the engine

4. To improve fuel atomization

The correct answer is: To prevent ice crystals from forming in the filter

Keeping the temperature of turbine engine fuel above 32°F is essential primarily to prevent ice crystals from forming in the filter. When fuel temperatures drop to or below freezing, water that may be present in the fuel can freeze and form ice crystals. These crystals can block fuel lines and filters, leading to fuel starvation, which can severely affect engine performance or even lead to engine failure. By maintaining the fuel temperature above this critical threshold, the integrity of the fuel delivery system is ensured, and the risk of ice formation is minimized. This practice is crucial for the reliable operation of turbine engines, especially in cold weather conditions where moisture in the fuel is more likely to freeze. While combustion efficiency, wear reduction, and fuel atomization are important factors in turbine engine performance, the primary reason for maintaining fuel temperature above 32°F is specifically related to the prevention of ice formation that could disrupt fuel flow.