Aviation Glossary - G

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g - the acceleration force of gravity, normally 1g on earth. Zero g (0g) is weightlessness, as experienced by orbiting astronauts. g is expressed as positive (+) and negative (-) values. During a normal loop a pilot experiences positive g, tending to force him down in his seat. In an outside loop, with the pilot's head on the outside of the vertical circle, negative g forces him up against his straps. Aircraft structural load limits are expressed in positive and negative values, the positive limit usually greater than negative, except in specialist aerobatic types.

g - loc-g-induced loss of consciousness. Pilot blackouts caused by excessive g or by too-rapid onset of g forces. Experienced mostly by pilots of high performance military jets and competition aerobatic aircraft, has led to fatal crashes.

G/S - groundspeed. The speed an aircraft makes over the ground, a product of its airspeed and wind speed.

GA - general aviation, all flying other than airlines and the military.

GAAC - General Aviation Awareness Campaign.

GAFOR - General Aviation Visual Flight Forecast. Met briefing service in operation in France, Germany, the Netherlands and some other European countries.

gall imp/U.S. - gallons, imperial or USA. One imp gall = 1.201 U.S. gall.

GAMA - General Aviation Manufacturers Association, an American trade organisation.

GAMTA - General Aviation Manufacturers & Traders Association, UK.

GAPAN - Guild of Air Pilots and Air Navigators.

GASIL - General Aviation Safety Information Leaflet. Monthly safety and accident prevention bulletin for pilots and engineers published by the CAA.

GCA - ground controlled approach. A landing approach in which a ground controller gives verbal guidance in azimuth and elevation to a pilot using precision approach radar (PAR) to monitor the aircraft's approach path. Still used by the military, but defunct in civil aviation.

GFT - General Flying Test, taken by student pilots to qualify for the PPL, and also by candidates for the BCPL and CPL. Also NFT, navigation flight test, which is part of the practical examination for the PPL.

Glonass - Russian equivalent of GPS/Navstar satellite navigation system.

glove - non movable part of a variable geometry wing.

gnd - ground

GNSS - Global Navigation Satellite Systems.

go - around to climb away from a runway after making an approach, either to make a further attempt at landing or to divert to an alternate airport (formerly 'overshoot').

Goxio - VHF direction finding (France)

GP - glidepath

gph - gallons per hour, an expression of fuel consumption or fuel flow (FF) in either imperial or U.S. gallons. Usually lb/hr for turbine-powered aircraft.

GPS - Global Positioning System (Navstar). A U.S. developed satellite based high precision navigation system, intended primarily for military use but now in widespread use by commercial and private operators, though with reduced accuracy compared with military versions.

GPWS - ground proximity warning system. A radar based flight deck system to give pilots audible warning by means of horns, hooters, taped or synthetic voices of terrain close beneath an aircraft's flight path.

GRADU - gradual (term used in Met reports).

GRP - glass fibre reinforced plastic; also CFRP, carbon fibre reinforced plastic. Composite materials seeing increasing use in entire airframes for GA aircraft (e.g. Beech Starship) and for components for helicopters, airliners and military aircraft.

GS - glide slope. The vertical guidance part of an instrument landing system which establishes a safe glidepath (usually three degrees) to a runway.