When flying under VFR 'night' conditions at 18,000 ft, how much usable fuel is typically required for optimal performance?

When operating under VFR (Visual Flight Rules) night conditions at 18,000 feet, the amount of usable fuel required is essential for maintaining safe and optimal performance. The correct choice, which indicates 318 pounds, aligns closely with the recommended fuel planning standards for such conditions.

At this altitude, various factors come into play, including the additional fuel needed for increased safety margins during night flight, potential diversions, and any air traffic or weather complications that may arise. The 318 pounds represents a quantity that allows for adequate fuel reserves not only for the planned route but also for unforeseen circumstances that could occur during flight.

Choosing this amount reflects a balance between regulatory requirements and practical safety measures, ensuring that pilots have sufficient fuel for the duration of their flight while accounting for typically higher fuel burn rates at altitude, especially under VFR conditions.