Manned flight simulation plays a key role in the design and development of modern aircraft systems where pilot interaction is an important consideration. Examples of the systems simulated during an aircraft project include the flight control system, the head-up display, the weapons system and the warnings system. Flight simulation allows the pilot to assess the system operation at an early stage in the design process, and modifications can be quickly implemented so that optimum system operation can be finalized. At British Aerospace (Military Aircraft Division), Warton, three differently configured simulators are currently utilized in the evaluation of aircraft systems.