During fueling, what action helps remove water and contaminants from the fuel system?

• A. Drain sumps
• B. Add soap
• C. Shake the tanks
• D. Heat the fuel

Answer: (A)

During fueling, draining the sumps is the action that removes water and contaminants from the fuel system. Sumps are designed to collect any water and sediments that settle out of the fuel, so opening the sump drains allows that unwanted liquid to exit the system before it reaches the engine. This helps ensure the fuel entering the engine is clean and dry, reducing the risk of fuel-ice formation, corrosion, or fuel-system damage. The other options don’t accomplish this: adding soap would contaminate the fuel, shaking the tanks could mix contaminants and spread them, and heating the fuel doesn’t reliably remove water and can introduce safety risks.