Glossary of aviation
Terms
and abreviations.
g or G SEE LOAD FACTOR
GAP - The distance between two adjacent wings of a biplane
or multiplane.
GCA - Ground-Controlled Approach; part of ILS.
GENERAL AVIATION - That portion of civil aviation which encompasses
all facets of aviation except air carriers holding a certificate
of public convenience and necessity from the Civil Aeronautics
Board and large aircraft commercial operators.
GEOGRAPHIC NORTH - The northern axis around which the Earth
revolves; aka "Map North" and TRUE NORTH. Also see
MAGNETIC NORTH, TRUE NORTH.
GLASS COCKPIT - Said of an aircraft's control cabin which
has all-electronic, digital and computer-based, instrumentation.
GLIDER - An unpowered aircraft capable of maintaining altitude
only briefly after release from tow, then gliding to earth.
Compare SAILPLANE.
GLIDE SLOPE - (1) The angle between horizontal and the glide
path of an aircraft. (2) A tightly-focused radio beam transmitted
from the approach end of a runway indicating the minimum approach
angle that will clear all obstacles; one component of an instrument
landing system (ILS).
GPS - Global Positioning System; satellite-based navigation.
GREEN LIGHT - Approval for landing. A carryover expression
from days when aircraft for the most part had no radios, and
communication from a control tower was by means of a light-gun
that beamed various green, red, and yellow signals to pilots
in the air and on the ground.
GROSS WEIGHT - The total weight of an aircraft when fully
loaded; aka Takeoff Weight.
GROUND CONTROL - Tower control, by radioed instructions from
air traffic control, of aircraft ground movements at an airport.
GROUND CUSHION SEE GROUND EFFECT
GROUND EFFECT - Increased lift generated by the interaction
between a lift system and the ground when an aircraft is within
a wingspan distance above the ground. It affects a low-winged
aircraft more than a mid- or high-winged aircraft because
its wings are closer to the ground; aka GROUND CUSHION.
GROUND SPEED - The actual speed that an aircraft travels
over the ground—its "shadow speed"; it combines
the aircraft's AIR SPEED and the wind speed relative to the
aircraft's direction of flight.
GULL-WING - Descriptive of wing in frontal view bent as the
wing of a seagull; a distinctive shallow, inverted "V"
shape—see Stinson SR-7 or inverted gull-wing Vought
F4U.
GYROPLANE - A rotorcraft whose rotors are not engine-driven,
except for initial starting, but are made to rotate by action
of the air when the rotorcraft is moving and whose means of
propulsion, usually a conventional propeller, is independent
of the rotor system. Similar to AUTOGYRO.
HANGAR - An enclosed structure for housing aircraft. Originated
with lake-based floating homes of the original German Zeppelins
in which they were "hung" from cables, which explains
the erroneous, oft-seen spelling of "hanger." French:
shed, outbuilding, from Latin: angarium,shed.
HELICOPTER - A wingless aircraft acquiring its lift from
revolving blades driven by an engine about a near-vertical
axis. A ROTORCRAFT acquiring its primary motion from engine-driven
rotors that accelerate the air downward, providing a reactive
lift force, or accelerate the air at an angle to the vertical,
providing lift and thrust.
HIGH BLOWER - A blower-type supercharger set at high rpm.
HIGH-SPEED STALL - Any stall made to occur at more than 1g,
such as pulling out of a dive or while turning.
HORSEPOWER - The motive energy required to raise 550# one
foot in one second, friction disregarded.
HYPERSONIC - Speed of flight at or greater than Mach 5.0,
exceeding SUPERSONIC.
IFR - Instrument Flight Rules, governing flight under instrument
meteorological conditions.
ILS - Instrument Landing System. A radar-based system allowing
ILS-equipped aircraft to find a runway and land when clouds
may be as low as 200 feet (or lower for special circumstances).
INDICATED AIRSPEED (IAS) - A direct instrument reading obtained
from an air speed indicator uncorrected for altitude, temperature,
atmospheric density, or instrument error. Compare CALIBRATED
AIRSPEED and TRUE AIRSPEED.
INSTRUMENT METEOROLOGICAL CONDITIONS (IMC) - Meteorological
conditions expressed in terms of visibility, distance from
clouds, and ceiling less than minima specified for visual
meteorological conditions (VMC).
IRON COMPASS - Railroad tracks, as favored by pilots of yore
as a dependable aid to surface navigation.
Paragliding Spain Center
