How much flight time would be available with a night VFR fuel reserve remaining, if the fuel quantity is 47 gallons and the power-cruise setting is at 55 percent?

To determine how much flight time is available with a night VFR fuel reserve, one must consider the fuel quantity, the engine's power setting, and the fuel consumption rate at that setting.

With 47 gallons of fuel and a power-cruise setting of 55 percent, the calculation involves knowing the aircraft's fuel burn rate at that specific power setting. Typically, at 55 percent power, an aircraft's fuel consumption is generally lower than at full power, allowing for extended flight time.

For proper calculation, if you assume a hypothetical fuel burn rate — this could typically be around 10 gallons per hour at that cruising power. Dividing the available fuel quantity (47 gallons) by the fuel burn rate (for instance, 10 gallons per hour) provides a rough estimate of flight time. This yields approximately 4.7 hours of flight time.

However, to comply with night VFR flight regulations, a pilot must reserve a specific amount of fuel for safety. The regulations usually require a minimum of 30 minutes of fuel reserve during nighttime operations. This means that the available flight time converts into usable fuel:

If 0.5 hours (30 minutes) of fuel is set aside as a reserve from the earlier calculated 4