Definition
Onboard avionics that determine the aircraft's position and provide guidance for navigation. A Flight Management System (FMS) is an integrated computer that stores flight plans, calculates routes, and drives the autopilot and flight instruments using inputs from multiple navigation sources. A Global Positioning System (GPS) receiver determines aircraft position by processing signals from a constellation of satellites. Aircraft may be equipped with one or both, and the FMS often uses GPS as one of its primary position inputs.
Plain English
The flight computer and/or satellite-based position equipment the aircraft uses to know where it is and where it needs to go.
Context Anchor
Seen in discussions of aircraft navigation, route planning, instrument procedures, and approved onboard navigation equipment.
Derivation
Flight Management System is a plain descriptive name -- a system that manages the flight. Global Positioning System describes its function: a system that gives position anywhere on the globe. The phrase 'and/or' is regulatory language meaning either one alone or both together satisfy the requirement.
Why Pilots Care
Allows precise navigation and approach capability; failure to have suitable equipment can limit routes or prevent flight in certain airspace.
Intuition Check
Do not read “and/or” as requiring both systems. It means the aircraft may use an FMS, a GPS, or both, depending on how it is equipped and what the operation allows.
Example Sentence 1
The approach chart specified that FMS and/or GPS navigational equipment was required to fly the RNAV procedure.
Example Sentence 2
Modern training aircraft are typically fitted with FMS and/or GPS navigational equipment to support area navigation.