A flight management system comprising: a plurality of flight management system components, including a civil flight management system component and a tactical flight management system component, each having a processor programmed to execute a flight management software product; and a multi core flight management system manager configured to control a plurality of flight management systems and being coupled to the plurality of flight management system components, the multi core flight management system manager comprising: a plurality of flight management system managers, each coupled to one of the plurality of flight management system (650,654) components; characterised by a common platform interface manager coupled to an avionics system, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the flight management system component to which the flight management system manager is coupled, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the common platform interface manager, and the common platform interface manager adapted to provide each flight management system component access to the avionics system, such that an aircraft operator can control each flight management system component via the common platform interface manger. a plurality of flight management system components, including a civil flight management system component and a tactical flight management system component, each having a processor programmed to execute a flight management software product; and a multi core flight management system manager configured to control a plurality of flight management systems and being coupled to the plurality of flight management system components, the multi core flight management system manager comprising: a plurality of flight management system managers, each coupled to one of the plurality of flight management system (650,654) components; characterised by a common platform interface manager coupled to an avionics system, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the flight management system component to which the flight management system manager is coupled, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the common platform interface manager, and the common platform interface manager adapted to provide each flight management system component access to the avionics system, such that an aircraft operator can control each flight management system component via the common platform interface manger. a plurality of flight management system managers, each coupled to one of the plurality of flight management system (650,654) components; characterised by a common platform interface manager coupled to an avionics system, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the flight management system component to which the flight management system manager is coupled, each flight management system manager adapted to transmit flight management data to, and to receive flight management data from, the common platform interface manager, and the common platform interface manager adapted to provide each flight management system component access to the avionics system, such that an aircraft operator can control each flight management system component via the common platform interface manger.