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 working load is strictly a guideline for the use of a rope in non-critical applications and should be reduced in situations where life, limb or valuable property are involved, or for exceptionally severe service such as shock or sustained loading etc.