ground-adjustable propeller. A type of aircraft propeller whose blade pitch angle can be adjusted when the engine is not running. The adjustment requires loosening the blades in the hub.
ground-boosted engine (reciprocating engines). An aircraft reciprocating engine with a built-in supercharger that boosts the sea-level rated horsepower of the engine.
ground clutter (radar reception). A pattern produced on the radarscope by ground returns which may degrade other radar returns in the affected area.

ground controlled approach. See GCA.
ground crew (aircraft operation). The group of people who service and maintain an aircraft when it is on the ground. The ground crew prepares the aircraft for flight and services it after its return from flight.
ground delay (air traffic control). The amount of delay attributed to ATC, encountered prior to departure, usually associated with a controlled departure time (CDT) program.
grounded-base amplifier (transistor amplifier). See common-base amplifier.
grounded-collector amplifier (transistor amplifier). See common-collector amplifier.
grounded-emitter amplifier (transistor amplifier). See common-emitter amplifier.
ground effect (aerodynamics). An increase in lift of an aerodynamic flying machine (airplane or helicopter) flying very near the ground. This additional lift is caused by an effective increase in angle of attack without the accompanying increase in induced drag and is caused by the deflection of the downwashed air. Ground effect disappears when the flying machine is about a half wing span or half rotor span above the surface.