Before introducing the payload rang

Before introducing the payload range curve, wedefine the important weight parameters of the vehicle.Table 1 lists the important weight parameters of theaircraft model we are using. The first column containsthe fixed weights of the vehicle. The empty weight of the vehicle is the weight of the vehicle excluding fuel,passengers, and crew. The modified weight is the sum of the empty weight, reserve fuel weight, and crewweight. The reserve fuel is included because it adds tothe weight of the vehicle but will not be consumedduring flight unless an emergency occurs. The secondcolumn in Table 1 contains the maximum take offweight, the usable fuel capacity, and the payloadcapacity. The maximum take off weight is determined by the length of the runway and by the vehicle's ability to get off the ground. Normally this weight is less thanthe weight of the vehicle fully loaded with passengersand fuel. Thus, the vehicle must be loaded with theoptimum combination of fuel and passengers to get it toits destination while generating the greatest amount ofrevenue for the airline. The usable fuel capacity is thecapacity of the fuel tanks minus the reserve fuel, andthe payload capacity is determined by the number ofseats on the airplane.