Skip to main content
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 Management System is an integrated avionics system that automates a wide variety of in-flight tasks including navigation, flight planning, performance optimization, and trajectory management. It combines the Flight Management Computer (or FMGC on Airbus), the navigation database, the performance database, and the crew interface units (CDU or MCDU) into a unified system. The FMS uses data from GPS, VOR, DME, IRS, and other sensors to continuously determine the aircraft’s precise position, then compares it against the programmed route and issues guidance commands to the autopilot and flight director. Beyond navigation, the FMS manages vertical profiles - computing the optimal top-of-climb and top-of-descent points, determining speed targets for each phase of flight based on cost index and weight, and predicting fuel and time remaining to destination. Pilots can enter altitude constraints, speed restrictions, and airways directly into the FMS, and it will automatically calculate a profile that satisfies all of them. The navigation database is updated every 28 days (known as an AIRAC cycle) to keep SIDs, STARs, approaches, waypoints, and airways current with real-world procedure changes.

​
In Virtual Airline Operations

Using the FMS correctly is central to professional virtual airline operations at VACA. Before every flight, virtual pilots should initialize the FMS with the departure airport, route, cruise altitude, cost index, fuel, and weight data drawn from the SimBrief OFP. During flight, monitoring FMS predictions - such as estimated fuel at destination, top-of-descent, and approach path - is part of the pilot’s ongoing workload. Most high-fidelity add-ons model the FMS in significant depth, and learning to operate it correctly greatly enhances the realism of your flights.
  • FMC-FMGC - Flight Management Computer/Flight Management Guidance Computer
  • FGCS - Flight Guidance Control System
  • ACARS - Aircraft Communications Addressing and Reporting System
  • OFP - Operational Flight Plan