Which statement is true about the use of a fuel heater?

A fuel heater functions as a heat exchanger, which means it effectively warms the fuel to prevent issues associated with the fuel's temperature dropping too low. This warming process is crucial because cold fuel can lead to the formation of ice crystals, which can obstruct fuel lines and filters, potentially causing engine performance problems or even failure.

By transferring heat from a hot fluid—typically engine oil or exhaust gases—into the fuel, the heater ensures that the fuel remains at an optimal temperature for combustion. This is particularly important in colder weather conditions where fuel may be prone to freezing or jelling.

The other options do not accurately depict the primary function of a fuel heater. For instance, while it may assist in melting some ice, its main purpose is not solely to thaw ice but to maintain a consistent fuel temperature. Moreover, while fuel heaters may utilize electrical methods in some systems, many operate on heat exchange principles rather than relying exclusively on electrical heating. Thus, acknowledging the operation of the fuel heater as a heat exchanger provides a comprehensive understanding of its significance in aviation fuel systems.