What is the procedure when contaminated fuel is found while draining a fuel sump?

When contaminated fuel is found while draining a fuel sump, the appropriate procedure is to drain out the contaminated fuel until no more is found. This action ensures that any impurities, such as water, sediment, or other foreign substances, are completely removed from the fuel system before the aircraft operates. Contaminated fuel can lead to engine performance issues or even failure, making it essential to address any contamination thoroughly.

By draining the contaminated fuel, the pilot or technician helps maintain the safety and reliability of the aircraft. Ensuring that only clean fuel enters the system supports proper engine function and reduces the risk of potential accidents due to fuel-related issues. This procedure is a critical part of pre-flight checks and maintenance to ensure the aircraft operates safely.

Replacing the fuel filter immediately may not effectively address the entire contamination issue, as sediment may still be present in the fuel tank. Drilling a hole in the tank would compromise the tank's integrity and is not a standard procedure for addressing fuel contamination. Running the engine to clear debris could potentially cause more harm than good since contaminants could clog the engine's fuel system components, leading to further damage. Therefore, systematically draining the contaminated fuel is the most responsible and safe approach.