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Fuel Consumption

How much and how fast an aircraft uses fuel is known as fuel consumption. The same calculation used for determining a car's fuel consumption is also used for an aircraft with additional consideration for the weight of the payload (passengers and/or cargo). All aircraft have an operator's manual that gives specifications such as fuel consumption at different payload weights and fuel amounts. Remember the weight of the fuel also needs to figure into the equation! For example, let's say a small aircraft has a speed range of 120 - 170 mph and holds up to 50 gallons of fuel. According to the aircraft's specifications at full payload and fuel weight, the aircraft uses 10 gallons of fuel per hour. Take the total amount of fuel (50 gallons) and divide that by the number of gallons used per hour (10) and you will find that the aircraft could be flown for 5 hours. Remember that a good pilot will never fly on fumes, and would stop for re-fueling long before the 5 hours were up.

Now let's say that the same aircraft is flying with a full tank of fuel, but only half its full payload weight. According to the fuel consumption specifications for this aircraft it will use 7 gallons of fuel per hour. How long will it be able to fly? Do the math: 50 gallons divided by 7 gallons per hour will provide a little over 7 hours of flight time.