FAA Ground School Practice Test

What is the first step a pilot should take to purge water from the fuel system of an aircraft?

1. Drain fuel from the engine

2. Drain fuel from the fuel strainer drain and the fuel tank sumps

3. Inspect the fuel filter for contamination

4. Check the fuel levels

The correct answer is: Drain fuel from the fuel strainer drain and the fuel tank sumps

The first step a pilot should take to purge water from the fuel system of an aircraft is to drain fuel from the fuel strainer drain and the fuel tank sumps. This process is essential because water can accumulate in the fuel system and pose a significant risk to engine performance and safety. The fuel strainer drain is specifically designed to remove contaminants, including water, that can collect at low points in the system due to gravity. By draining the fuel strainer and the tank sumps, the pilot effectively ensures that any water present in the fuel is removed before the aircraft attempts to start or operate. This proactive measure not only preserves the integrity of the fuel but also enhances flight safety by minimizing the risk of engine failure caused by water in the fuel system. While draining fuel from the engine and inspecting the fuel filter for contamination are also important maintenance steps, these actions should typically occur after ensuring that the fuel supply itself is free from water. Checking fuel levels does not directly address the presence of water in the system, which is the primary concern when purging water from the fuel system. Therefore, draining the fuel strainer and tank sumps is the most immediate and effective action in this context.