FAA Powerplant Written Practice Test

How are propeller deicer boots energized for effective operation?

1. Continuous power supply

2. Short periods by a cycling timer

3. Thermostatic control

4. Manual activation

The correct answer is: Short periods by a cycling timer

Propeller deicer boots are typically energized by short periods governed by a cycling timer. This method allows for effective operation by alternating between heating the deicer boots to remove ice and allowing them to cool. The cycling of power ensures that the deicer boots get adequately heated without overheating, which can potentially damage the boots or reduce their lifespan. This controlled approach allows for efficient ice removal while minimizing energy consumption. Using continuous power can lead to overheating, which is not desirable, while thermostatic control, although effective for other heating applications, is not commonly used for propeller deicer boots due to the specific operational needs of the boots in icy conditions. Manual activation would require constant monitoring and intervention from the pilot, which is not practical during flight operations. Hence, utilizing short periods with a cycling timer effectively balances operational needs and equipment protection.