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This glossary is written for virtual airline and flight simulation use within Virtual Air Canada Airline. It is not intended as a real-world aviation reference.
The Flight Guidance Control System is an integrated avionics system that combines the functions of the autopilot, flight director, and autothrottle into a single, coordinated architecture. The FGCS receives inputs from the FMS, navigation sensors, air data computers, and inertial reference systems, then computes and outputs guidance commands to maintain or achieve target flight path parameters. The system continuously arbitrates between the different guidance modes - lateral, vertical, and speed - ensuring that the autopilot, flight director cues, and thrust management all work in harmony. Different manufacturers use different terminology for this system. On Boeing aircraft it is closely associated with the Autopilot Flight Director System (AFDS), while Airbus integrates these functions within the FMGC (Flight Management and Guidance Computer). Regardless of the naming convention, the core concept is the same: a centralized system that manages and coordinates automated guidance across all flight axes and thrust. The FGCS monitors itself for failures and can automatically revert to degraded modes or alert the crew when its own integrity is compromised.

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In Virtual Airline Operations

In complex add-ons such as the PMDG 737 or the FlyByWire A32NX, the flight guidance system is simulated in detail. Understanding how the FGCS coordinates autopilot and autothrottle modes helps virtual pilots troubleshoot situations where the aircraft is not following the expected path - for example, when a mode reversion occurs due to reaching an altitude constraint or losing a navigation signal.
  • FCU - Flight Control Unit
  • FD - Flight Director
  • FMC-FMGC - Flight Management Computer/Flight Management Guidance Computer
  • FMS - Flight Management System