A fuel sample should be taken prior to the __________ of the day.

• A. Departure
• B. Preflight
• C. 1st Flight
• D. 2nd Flight

Answer: (C)

The main idea here is to verify fuel quality before any flights start for the day. Overnight storage can allow water to settle in the fuel or contaminants to accumulate in tanks. If water or sediment makes it into the fuel system, it can clog filters, fuel pumps, or injectors and cause fuel-system trouble or engine issues during flight. By taking a fuel sample before the first flight, you catch any problems at the start of operations and can take corrective action—such as draining contaminated fuel or sourcing clean fuel—before the day’s departures. Sampling later in the day wouldn’t provide the same protection for the initial flight, and waiting until the second flight could expose the first flight to contaminated fuel.