Flight sim is not just used during airplane design. New airline, combat, and even space shuttle pilots get trained in flight simluators before they fly the real thing. The world's largest motion-based simulator is the Vertical Motion Simulator at NASA Ames Research Center. Because it stays on the ground the whole time, the simulator has to provide different cues or signals to the pilot to make the experience as authentic as possible. To accompany these sights, the pilot hears simulated sounds like the wind blowing by, or the flaps, engines, or landing gear at the appropriate times.
Engineers can learn about how easy and safe it is for a pilot to control a certain airplane.
Simulators can also reproduce bad weather, emergency situations, or other procedures to see how pilots react. Using the information that comes from flight simulation, engineers can make additional adjustments before going on to building an actual airplane for research flights. A research flight is usually one of the last steps in the airplane design process. After a new type of airplane has been planned out on paper and on the computer screen, it's time to build a full-size working version, or a prototype . Because only one or two prototypes are made at a time, they are usually quite expensive to build.