How much AvGas is required to fly 600 NM with a 12 knot headwind at 18,000 ft with standard temperature?

To determine the amount of AvGas needed for a 600 NM flight with a 12 knot headwind at 18,000 feet in standard temperature conditions, several factors must be taken into account, including ground speed, fuel consumption rates, and time aloft.

Firstly, the true airspeed (TAS) of the aircraft must be determined. Assuming a standard cruising speed for a piston-driven aircraft at that altitude might be around 120 knots, the headwind needs to be factored in. Therefore, the effective ground speed would be:

Ground Speed = True Airspeed - Headwind

Ground Speed = 120 knots - 12 knots = 108 knots

Next, calculate the flight time required for the 600 NM journey at the effective ground speed:

Flight Time = Distance / Ground Speed

Flight Time = 600 NM / 108 knots ≈ 5.56 hours

With the flight time calculated, the next step is to determine the fuel consumption. Assuming the aircraft has a fuel burn rate of approximately 10 gallons per hour, which is a reasonable number for many general aviation aircraft at that altitude:

Total Fuel Consumption = Fuel Burn Rate × Flight Time

Total Fuel Consumption = 10 gallons/hour × 5.56 hours