From this graph, Fujita then released the following descriptions for the F-Scale http://www.spc.noaa.gov/faq/tornado/f-scale.html. Over the years, the F-Scale has revealed the following weaknesses: 1  It is subjective based solely on the. 2  caused by a tornado.
9 Answers. The empty weight is the weight of the airplane including anything that is permanently attached to it and includes any un-drainable fluids. There is a maximum gross weight for takeoff and on larger aircraft there may be a maximum landing weight. The useful load is the difference between the maximum gross weight and the empty weight. To the empty weight, you have to add the fuel, oil, any other fluids, pilot and passengers, and baggage.
The wing spar. The spar is the main structure of the wing that supports the load of the entire airplane. All the loads go through the wing into the wing spar and down to theâ¦ center of it, which is called the wing box. (You could call this the most important part,)  An airplane may fly without its engines. It might be able to fly without its flight controls. But it can not fly if the wing spar breaks.