Glossary

This glossary contains information on terms, phrases and abbreviations used by the Aviation industry. While this list does not include all aviation terminology, it is the purpose of this glossary to aid the general viewer in better understanding aviation terms as it pertains to content on this website. A full list of aviation terminology can be found here.
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G

GAMA

General Aviation Manufacturers Association.

Gimbal ring

A type of support that allows an object, such as a gyroscope, to remain in an upright condition when its base is tilted.

Satellite navigation system that provides autonomous geospatial positioning with global coverage. It allows small electronic receivers to determine their location (longitude, latitude, and altitude) to within a few meters using time signals transmitted along a line of sight by radio from satellites.

Global positioning system (GPS)

Navigation system that uses satellite rather than ground-based transmitters for location information.

GNSS

See global navigation satellite system.

GPS

See global positioning system.

GPWS

See ground proximity warning system.

Graveyard spiral

The illusion of the cessation of a turn while still in a prolonged, coordinated, constant rate turn, which can lead a disoriented pilot to a loss of control of the aircraft.

Great circle route

The shortest distance across the surface of a sphere (the Earth) between two points on the surface.

Ground adjustable trim tab

Non-movable metal trim tab on a control surface. Bent in one direction or another while on the ground to apply trim forces to the control surface.

Ground effect

The condition of slightly increased air pressure below an airplane wing or helicopter rotor system that increases the amount of lift produced. It exists within approximately one wing span or one rotor diameter from the ground. It results from a reduction in upwash, downwash, and wingtip vortices, and provides a corresponding decrease in induced drag.

Ground proximity warning system (GPWS)

A system designed to determine an aircraft’s clearance above the Earth and provides limited predictability about aircraft position relative to rising terrain.

Groundspeed

Speed over the ground, either closing speed to the station or waypoint, or speed over the ground in whatever direction the aircraft is going at the moment, depending upon the navigation system used.

GWPS

See ground proximity warning system.

Gyroscopic precession

An inherent quality of rotating bodies, which causes an applied force to be manifested 90° in the direction of rotation from the point where the force is applied.