Aviation Terms Glossary G

Aviation Terms Glossary – G

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G-Force (Gravitational Force)	G-force is the force exerted on an aircraft and its occupants due to acceleration or deceleration. It is measured in multiples of Earth’s gravity (1G = standard gravity). High G-forces can cause physical strain on pilots, reducing blood flow to the brain and potentially leading to blackouts or G-LOC (G-force-induced loss of consciousness).
Galley	The galley is the onboard kitchen area of an aircraft where meals and beverages are stored and prepared for passengers and crew. It is equipped with ovens, refrigeration units, and secure storage to ensure safety during turbulence. Airlines optimize galley space to improve service efficiency while maintaining weight and balance considerations.
Glide Ratio	The glide ratio is the distance an aircraft can travel forward compared to the altitude it loses without engine power. A higher glide ratio indicates better aerodynamic efficiency, crucial for gliders and emergency landings. Pilots use this ratio to determine the best glide speed and approach during engine-out scenarios.
Glider	A glider is a type of aircraft designed to fly without an engine, relying on natural air currents, thermals, or tow aircraft for initial altitude. Gliders have high-aspect-ratio wings to maximize lift and minimize drag. They are used for recreational flying, military training, and research in aerodynamics.
Global Navigation Satellite System (GNSS)	GNSS is a worldwide system of satellites providing position, navigation, and timing data to aircraft. It includes GPS (USA), GLONASS (Russia), Galileo (Europe), and BeiDou (China). GNSS improves navigation accuracy, allowing for precise en-route, approach, and landing guidance, enhancing aviation safety and efficiency.
Go-Around	A go-around is an aborted landing maneuver where the pilot decides to discontinue the approach and climb away for another attempt. It can be initiated due to unstable approaches, runway obstructions, or air traffic control instructions. Pilots follow specific procedures to maintain safety while reconfiguring for a second landing attempt.
Ground Effect	Ground effect occurs when an aircraft flies close to the ground, reducing induced drag and increasing lift due to air compression between the wings and the surface. This effect is most noticeable during takeoff and landing, allowing for smoother touchdowns and improved takeoff performance.
Ground Power Unit	A GPU is an external power source used to provide electrical energy to an aircraft while on the ground. It allows aircraft systems to function without using onboard power from the auxiliary power unit (APU) or engines, conserving fuel and reducing emissions at airports.
Ground Proximity Warning System (GPWS)	GPWS is a safety system designed to alert pilots when their aircraft is at risk of controlled flight into terrain (CFIT). Using radar altimeters and flight data, GPWS provides audible and visual warnings, helping prevent crashes caused by poor visibility, pilot error, or miscalculated descent rates.
Ground Speed	Ground speed is the actual speed of an aircraft relative to the Earth’s surface. It differs from airspeed because it accounts for wind effects. Pilots use ground speed to estimate flight time, fuel consumption, and navigation accuracy when planning routes.
Gyroscope	A gyroscope is a device used in aircraft instruments, such as attitude indicators and heading indicators, to detect changes in orientation. It operates on the principle of angular momentum, maintaining a fixed orientation in space regardless of aircraft movement, providing critical flight data for pilots.
Green Arc (Instrument Markings)	The green arc on an aircraft instrument, such as the airspeed indicator, represents the normal operating range. It provides a visual reference for pilots to ensure safe operation under standard flight conditions. Exceeding this range may require adjustments to avoid structural stress or engine overload.
Glide Path	The glide path is the descent angle an aircraft follows when approaching a runway for landing. It is maintained using visual or instrument guidance, such as the Instrument Landing System (ILS). A stable glide path ensures a smooth, controlled descent to the runway.
Gross Weight	Gross weight refers to the total weight of an aircraft, including fuel, passengers, cargo, and crew. It is critical for determining takeoff performance, landing distances, and structural limits. Exceeding weight limits can impact maneuverability, stall speeds, and fuel efficiency.
Ground Handling	Ground handling involves all activities required to service an aircraft while it is on the ground. This includes fueling, baggage handling, catering, aircraft cleaning, and maintenance. Efficient ground handling ensures quick turnarounds, minimizing delays and optimizing airline operations.
Gust Factor	The gust factor is the difference between sustained wind speed and wind gusts that affect an aircraft’s performance during takeoff and landing. Pilots consider gust factors when selecting approach speeds to compensate for sudden wind changes, ensuring safer landings.
Gyro Horizon (Attitude Indicator)	The gyro horizon, also known as the attitude indicator, is an instrument that displays an aircraft’s pitch and roll in relation to the horizon. It helps pilots maintain spatial orientation, especially in low-visibility conditions or during instrument flight operations.
Glide Slope	The glide slope is the vertical component of an instrument landing system (ILS) that provides precise descent guidance to pilots. It ensures a safe approach angle for landing, preventing aircraft from descending too quickly or too slowly.
Galley Power	Galley power supplies electricity to kitchen equipment onboard, such as ovens and coffee makers. It is an essential system for long-haul flights, allowing for meal preparation and passenger service while maintaining overall electrical load balance.
General Aviation (GA)	General aviation encompasses all civil aviation operations except for scheduled airline and military flights. It includes private flying, business aviation, agricultural aircraft, medical transport, and flight training. GA plays a crucial role in connecting remote areas and supporting local economies.
Ground Idle	Ground idle is the lowest power setting of an aircraft engine while on the ground. It ensures minimal fuel consumption while maintaining enough power to operate essential systems. Pilots use ground idle when taxiing and during prolonged waits on the tarmac.
Ground Track	Ground track is the actual path an aircraft follows over the ground. It is influenced by wind drift and may differ from the heading the aircraft is flying. Pilots use GPS and navigation aids to align their ground track with planned routes.
Gust Load	Gust load refers to the additional aerodynamic forces imposed on an aircraft when encountering sudden wind gusts. Aircraft are designed to withstand gust loads within specific limits to prevent structural damage or loss of control.
Gear Retraction System	The gear retraction system allows an aircraft’s landing gear to be stowed in the fuselage or wings after takeoff. This reduces drag and improves aerodynamic efficiency. Modern aircraft use hydraulic or electric systems for smooth and reliable gear operation.
Ground Loop	A ground loop is an uncontrolled turning motion of an aircraft while taxiing, taking off, or landing. It is more common in tailwheel aircraft and can lead to loss of control or damage if not corrected quickly.
Gimbal Lock	Gimbal lock occurs in gyroscopic instruments when two rotational axes align, causing a loss of one degree of freedom. It can disrupt navigation systems and flight controls, requiring corrective action from pilots.
Glide Extension	Glide extension refers to methods used by pilots to extend the glide distance of an aircraft, such as reducing drag or increasing airspeed slightly. It is useful during emergency landings when reaching a suitable landing area is necessary.
Ground Control	Ground control is a division of air traffic control responsible for managing aircraft movement on taxiways and runways before takeoff and after landing. Ground controllers ensure safe and efficient traffic flow at busy airports.
Gust Alleviation System	A gust alleviation system automatically adjusts control surfaces or wing configurations to reduce the impact of turbulence and wind gusts. It enhances passenger comfort and reduces structural stress on the aircraft.
Glass Cockpit	A modern flight deck equipped with digital displays instead of traditional analog gauges. Glass cockpits improve situational awareness, integrate flight data, and enhance automation, reducing pilot workload and increasing operational efficiency.