What does specific fuel consumption refer to?

Specific fuel consumption (SFC) is a critical metric in aviation that measures the efficiency of an engine or powerplant by indicating how much fuel is consumed to produce a specific amount of thrust or power over time. It is typically expressed in units such as pounds of fuel per hour per horsepower or thrust produced.

Understanding SFC involves recognizing that it quantifies the fuel efficiency of an engine in the context of the power it generates. The lower the specific fuel consumption, the more efficient the engine is, as it indicates that less fuel is being used for the amount of power produced. This is especially important for aircraft design and operation, as it helps in calculating operational costs and optimizing performance.

The other options describe different aspects of fuel consumption, but they do not align with the definition of specific fuel consumption. For instance, measuring the quantity of fuel burned to produce thrust does not account for how efficiently that fuel is used over time, and simply stating fuel used per distance traveled does not relate directly to engine output or time, which are crucial to the specific definition of SFC.