Definition
A Flight Management Computer (FMC) is the central onboard computer that handles flight planning, navigation, performance calculations, and guidance for the autopilot and autothrottle. The pilots load a route and aircraft data into it, and the FMC then computes the most efficient path, speeds, and altitudes, and feeds steering and thrust commands to the relevant systems throughout the flight.
Plain English
It is the main flight computer on the aircraft. The pilots tell it where they are going and what the aircraft weighs, and it works out how to get there and tells the autopilot what to do.
Context Anchor
Seen in aircraft with advanced cockpit systems, especially when entering a route, checking navigation guidance, or troubleshooting flight deck computer systems.
Why Pilots Care
The FMC reduces pilot workload, improves fuel efficiency, and maintains precise navigation by automating complex calculations that would otherwise require constant manual effort.
Intuition Check
Do not think of the FMC as the autopilot itself. The FMC calculates and supplies route and performance guidance; other systems may use that guidance to display or fly the path.
Example Sentence 1
Before pushback, the crew loaded the route and takeoff weights into the FMC.
Example Sentence 2
In cruise the FMC continuously updated the optimum altitude and speed to save fuel.