Which of the following is a listed use of aircraft fuel besides propulsion?

• A. Lubrication
• B. Lighting
• C. Structural cooling
• D. Acoustic dampening

Answer: (A)

Beyond propulsion, aircraft fuel can serve as a lubricant for certain components in the fuel system and engine. As fuel flows through pumps and metering units, its lubricating properties help reduce wear on moving parts and can aid sealing in small clearances. It also helps carry away some heat, providing a bit of cooling in the areas where fuel is circulating. That’s why lubrication is the listed non-propulsion use for aircraft fuel among the options.

Lighting, structural cooling, and acoustic dampening aren’t standard or listed uses for aircraft fuel. Lighting is handled by separate lighting systems, structural cooling relies on air or dedicated cooling loops, and acoustic dampening uses sound-absorbing materials, not fuel.