飛行管理システム（FMS） (Flight Management System)

飛行管理システム（FMS）とは？

A Flight Management System (FMS) is an integrated avionics computer that centralizes navigation, performance optimization, and fuel management. Pilots enter the route, aircraft weight, cost index, and performance parameters before departure; the FMS then computes an optimized flight profile from takeoff to landing and guides the aircraft along it — either by providing steering cues or by directly commanding the autopilot. The FMS is the brain behind modern airline operations, enabling precise 4D trajectory management (latitude, longitude, altitude, and time).

仕組み

The FMS contains a large navigation database (updated every 28 days per AIRAC cycles) holding airways, waypoints, SIDs, STARs, approaches, and airport data worldwide. It cross-references inputs from GPS, VOR, DME, and inertial reference systems to compute a best-estimate position — a process called sensor fusion. The system then calculates:

• Lateral profile (LNAV): The horizontal route, including arc transitions and procedure turns
• Vertical profile (VNAV): Optimized climb, cruise altitude, step climbs, and descent based on the cost index and wind data
• Performance predictions: Top of climb, top of descent, fuel remaining at each waypoint, estimated times of arrival

Pilots interact with the FMS through the Control Display Unit (CDU) or, on newer aircraft, touchscreen interfaces. The FMS sends guidance commands to the autopilot and displays the active flight plan on the glass cockpit navigation display.

進化と現代のシステム

The first commercial FMS, the Sperry SPZ-8000, entered service on the Boeing 767 in 1982. Honeywell and Thales (formerly Thomson-CSF) became the dominant FMS manufacturers. The Honeywell PEGASUS FMS on the 777 introduced Required Navigation Performance (RNP) approaches. Modern FMS units like the Airbus FMGS (Flight Management and Guidance System) on the A350 support datalink (ACARS/ATC datalink) for real-time weather and routing updates, and can sequence ILS approaches automatically.

規制要件

FMS navigation databases must comply with RTCA DO-200B / EUROCAE ED-76A standards for aeronautical data quality. RNP AR approaches require FMS with specific accuracy certifications. FAA Advisory Circular AC 90-105A governs RNP operations. Navigation database update cycles (every 28 days) are mandated globally to ensure currency of procedure data.