Structural load
For aircraft, loading is divided into two major categories: limit loads and ultimate loads. Limit loads are the maximum loads a component or structure may carry safely. Ultimate loads are the limit loads times a factor of 1.5 or the point beyond which the component or structure will fail. Gust loads are determined statistically and are provided by an agency such as the Federal Aviation Administration. Crash loads are loosely bounded by the ability of structures to survive the deceleration of a major ground impact. Other loads that may be critical are pressure loads (for pressurized, high-altitude aircraft) and ground loads. Loads on the ground can be from adverse braking or maneuvering during taxiing. Aircraft are constantly subjected to cyclic loading. These cyclic loads can cause metal fatigue.