Glossary of Aviation Terminology

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FCS: Flight control system

Filter: A device to alter a signal; software to alter a data steam; See Also: averaging filter, band-pass filter, complementary filter, first-order filter, high-pass filter, hysteresis, Kalman filter, limiter, low-pass filter, rate limiter, second-order filter, smoothing filter, wash-out filter;

Filtered: Data that is the result of filtering a signal; filtering is usually more sophisticated than smoothing Compare: derived, estimated, measured, raw, selected, smoothed;

First-order filter: A filter in which the output follows the input, only more slowly; It is usually implemented in software as a difference equation of period T. The first-order filter is commonly used in avionics to smooth data, and to wash out transients at mode change. It is also used as a low-pass filter. When implementing a second-order filter on normalized variables, such as angles, the discontinuities require special treatment.

Fix: A determination of one's position based on external data, such as a known terrain point

Fixed wing: An airplane, as opposed to a rotory wing / helicopter;

Flaps: A control surface on fixed-wing aircraft, usually mounted to the fore edge of the wings, that extends the wing to provide added lift at low speeds; Compare: slats; Symbols: delta sub F; Typical Units: rad, deg,percent;

Flight control system (FCS): A primary flight control system or an automatic flight control system;

Flight controls: Controls in a cockpit for flying an aircraft; primary flight controls are wheel, yoke, cyclic, pedals, throttle, and collective; secondary flight controls are flight controls other than primary, such as flaps, slats, stabilizer, and landing gear;

Flight director: System, usually software, that generates stick position cues from state errors - typically three cues:. pitch, roll, and throttle for fixed-wing and longitudinal cyclic, lateral cyclic, and collective for rotory wing;

Flight path angle (FPA): Angle in vertical plane of earthspeed vector and groundspeed vector (usual definition), earth-referenced flight path angle; angle in vertical plane of airspeed vector and groundspeed vector (occasional definition), air-mass flight path angle; Symbols: gamma; Typical Units: rad, deg;

Flight plan: A predetermined route, possibly including guidance modes, communications, and mission objectives, used by guidance and mission management for moding and planning; Series of navigation reference points, waypoints, and mode commands for navigation, radio navigation, guidance, and flight director

FLIR: Forward-Looking Infrared

Flux valve: A device to measure the earth's magnetic flux; a compass

Fly over: A position update by flying directly over a known point

Forward-Looking Infrared (FLIR): Sensor equipment used to supplement AGR, extend the aircraft visual search capability and provide position information for guidance and navigation update capability. Imagery derived from the FLIR sensor is displayed in the cockpit. FLIR pointing can be controlled manually using a tracking handle or automatically by the Mission Computer. FLIR converts a heat image into a video image and determines azimuth, elevation, and sometimes range of a point; Synonyms: Infrared Detecting Set;

FPA: Flight path angle

A , B , C , D , E , F , G , H , I , J - K , L , M , N , O , P , Q - R , S , T , U , V, W, X - Z