FMSS is an acronym used in the aviation industry that stands for Flight Management System (FMS). This system is a combination of hardware and software used in aircraft to manage and control various aspects of flying such as navigation, fuel consumption, and flight planning. Synonyms for FMSS include Flight Management Computer (FMC), Flight Management Unit (FMU), and Avionics Management System (AMS). All of these systems work together to ensure the safe and efficient operation of commercial and military aircraft. Although the names may differ slightly, they all serve the same purpose of managing the complex systems that are involved in the modern aviation industry.