This app is unique in that it shows you interactively the position of the center of gravity of an airplane within its envelope as you manipulate its loading through a set of sliders. The graph shows the center of gravity at the beginning of the flight, at the end of the flight and with full tanks. You get a clear warning in case of overloading, if at any point during the flight the center of gravity exits the envelope, or if the quantity of fuel is less than the hourly consumption at the end of