When should manual fuel heaters be operated?

Operating manual fuel heaters when the fuel temperature approaches positive thirty-two degrees Fahrenheit is crucial to ensure that the fuel remains in a usable state. This temperature marks the critical point at which the risk of fuel gelling or freezing increases, particularly in cold weather conditions. When the fuel temperature drops to or below this level, it can significantly impair the fuel flow and performance, potentially leading to engine inefficiencies or failures.

By activating the fuel heaters as the temperature nears thirty-two degrees Fahrenheit, you can proactively manage the fuel's viscosity and maintain its flow characteristics, ensuring optimal engine operation and safety. This approach is standard practice in aviation to prevent issues related to cold-soaked fuel systems, especially in environments subjected to low temperatures.