Which statement best describes power in aviation?

• A. Power is the rate of fuel consumption.
• B. Power is the maximum engine horsepower available at sea level.
• C. Power is the rate at which work is done and depends on the speed at which the force is developed.
• D. Power is the energy stored in the propeller.

Answer: (C)

Power is the rate at which work is done, and it depends on how quickly the force is developed. In flight, this means the engine delivers energy to move the airplane, and the useful form of power is the thrust the aircraft makes times its forward speed. So as speed increases, the same thrust produces more power, and increasing thrust raises the rate at which work is done.

This definition distinguishes power from fuel flow, which is about energy input to the engine rather than how fast that energy is being converted into motion. It also isn’t simply the maximum engine horsepower rating, which is a limit or specification, nor is it the energy stored in the propeller—that stored energy isn’t the rate at which work is being done.