FAA Powerplant Written Practice Test

How are propeller deicer boots energized?

1. Continuously

2. Via a manual switch

3. For short periods by a cycling timer

4. With constant voltage

The correct answer is: For short periods by a cycling timer

Propeller deicer boots are designed to prevent ice accumulation on propellers during flight, which is critical for maintaining performance and safety. The correct method for energizing these deicer boots involves the use of a cycling timer. This system intermittently activates the boots for short periods, allowing them to heat up and prevent ice buildup without overheating the deicer material. Using a cycling timer is effective because it balances the need for consistent de-icing with the risk of excessive heat, which could damage the boots if energized continuously. By cycling the power on and off, the system can provide adequate heat to remove ice while minimizing the risk of overheating. In contrast, continuous energization or constant voltage would not allow for the necessary cooling periods for the deicer boots, potentially leading to damage. Moreover, relying solely on a manual switch would not provide the automatic cycling that allows for effective and safe de-icing operations during flight.