A flight management system (FMS) is a computer system that uses a large database to allow routes to be preprogrammed and fed into the system by means of a data loader. The system is constantly updated with respect to position accuracy with reference to conventional navigation aids. The sophisticated program and its associated database ensure that the most appropriate aids are automatically selected during the information update cycle.
A flight management system is a fundamental part of any modern aircraft, and it is principally responsible for controlling aircraft navigation. The flight management system is an avionic device that holds a variety of navigational information, including the aircraft’s flight plan, and allows the pilot to modify it as required in flight. A flight management system uses a variety of sensors and navigation tools to determine the aircraft's position. Once given the aircraft’s position and the desired flight plan, the FMS provides the pilot with guidance to help the aircraft navigate its entered route.
Flight management systems are located in the aircraft cockpit and are normally controlled through a small screen and multi-function keypad. A flight management system will often be integrated with the rest of the navigation systems on the aircraft and will send flight plan and other navigation information to the electronic flight information system (EFIS), navigation display (ND), and/or multifunction display (MFD).