G LOADS Loads imposed on an airframe due to inertia (centrifugal force). 1G of load factor represents the weight of the actual aircraft. 2G represents effectively twice the aircraft’s actual weight.

GLOBAL POSITION SYSTEM (GPS) A satellite-based radio positioning, navigation, and time-transfer system.

GO-AROUND The termination of a landing approach. Reference the AIM Pilot/Controller Glossary.

GO OR NO-GO DECISION Decision of whether or not to make a flight based on environmental, personal or mechanical factors. A focus area for human factors study.

GPS See GLOBAL POSITION SYSTEM.

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 EFFECT A condition of improved performance encountered when an airfoil is operating very close to the ground. When an airfoil is under the influence of ground effect, there is a reduction in upwash, downwash, and wingtip vortices. As a result of the reduced wingtip vortices, induced drag is reduced.

GROUNDSPEED (GS) The actual speed of an aircraft over the ground. It is true airspeed adjusted for wind. Groundspeed decreases with a headwind, and increases with a tailwind.

GROUND TRACK The aircraft’s path over the ground when in flight.

HAZARDOUS INFLIGHT WEATHER ADVISORY SERVICE (HIWAS) Recorded weather forecasts broadcast to airborne pilots over selected VORs.

HEADWIND A wind which blows from the direction the aircraft is flying. The ground speed of an aircraft (the speed the aircraft is moving over the ground) is less than the speed through the air by the velocity of the headwind.

HIWAS See HAZARDOUS INFLIGHT WEATH- ER ADVISORY SERVICE.

HOUR METER An instrument installed in many aircraft to show the actual number of hours the engine has operated. The hour meter is an electrical clock that starts when the engine oil pressure builds up, and runs until the engine is shut down and the oil pressure drops to zero.

HYPERVENTILATION Occurs when an individual is experiencing emotional stress, fright, or pain, and the breathing rate and depth increase, although the carbon dioxide level in the blood is already at a reduced level. The result is an excessive loss of carbon dioxide from the body, which can lead to unconsciousness due to the respiratory system’s overriding mechanism to regain control of breathing.

HYPOXIA State of oxygen deficiency in the body sufficient to impair functions of the brain and other organs.

IFR See INSTRUMENT FLIGHT RULES.

INCIDENT An occurrence other than an accident, associated with the operation of an aircraft, which affects or could affect the safety of operations.

INDUCED DRAG That part of total drag which is created by the production of lift. Induced drag increases with a decrease in airspeed.