Definition
An integrated avionics system that automates a wide range of in-flight tasks, including navigation, flight planning, performance management, and guidance. It uses a central computer combined with a navigation database and inputs from sensors such as GPS, inertial reference systems, and radio navigation aids to compute the aircraft's position, the planned route, and the commands needed to fly that route.
Plain English
A computer system in the cockpit that the pilot programs with the planned route. It then keeps track of where the aircraft is, works out where it should go next, and feeds that information to the autopilot and flight displays.
Context Anchor
Seen in modern instrument cockpits when entering a route, checking navigation guidance, loading an arrival or approach, or reviewing the airplane’s planned path.
Derivation
From 'flight' (the act of flying) and 'management' (organizing and directing tasks). The name reflects what the system does: it manages the many small tasks that used to be handled separately by the pilot, navigator, and flight engineer.
Why Pilots Care
Reduces pilot workload and improves accuracy in complex airspace.
Analogy
Think of it like a car's GPS combined with cruise control and a fuel computer, all working together. You enter the destination and route, and the system continuously calculates where you are, where to turn, and how the trip is going.
Intuition Check
Do not assume the FMS flies the airplane by itself. The FMS manages and computes guidance; the pilot must enter, check, and select the right information, and the autopilot follows it only when properly connected and commanded.
Example Sentence 1
Before pushback, the first officer loaded the departure, route, and arrival into the FMS and cross-checked it against the clearance.
Example Sentence 2
During the approach, the FMS provided vertical guidance to the runway.