The dynamic simulation of a gas turbine engine is shown to be a valuable tool for the component design of the engine. A brief discussion of simulation methodology is followed by three examples of how a dynamic simulation can be used. The first example discusses the design of an engine when the conflicting requirements of rapid engine acceleration and distortion tolerance are considered; and how dynamic simulation can point out trouble areas. The second example discusses how dynamic simulations can aid the engine designer in the selection of engine configuration. The third example shows how dynamic simulations can be used to select and modify the operation of the engine control system so that overall engine stability is improved.