guidance system /a.d(.)ns
s.st.m/ noun a system which provides signals to the flight control system for steering the aircraft
guide /a.d/ noun something that directs or indicates . rough guide a simple explanation to help a person to find his or her own way through more complex information . verb to direct or to indicate . If there is smoke in the cabin, clear commands from the crew will help to guide passengers to the emergency exits.
gust /st/ noun a strong, sudden rush of wind . a gust of 30 feet per second . On final approach, the pilot must be prepared to counteract the effect of gusts in order to maintain a smooth descent along the extended centreline of the runway. . gust load an increased load to the airframe caused by a sudden increase in wind strength . verb to increase in strength suddenly . Wind is at 10 knots gusting to 20 knots.
gyro /da.r.υ/ noun same as gyro-scope
gyro-/da.r.υ/ prefix gyroscopic gyrocompass /da.r.υkmp.s/
noun a compass which uses gyroscopic directional stability rather than magnet-ism to indicate direction . The gyro-compass should be checked against the
magnetic compass and reset if neces-sary.
gyroplane /da.r.υple.n/ noun an
aircraft fitted with an unpowered rotor for producing lift
gyroscope /da.r.sk.υp/ noun a
device consisting of a spinning wheel, mounted on a base so that its axis can turn freely in one or more directions and thereby maintain its own direction even when the base is moved . The tradi-tional attitude indicator, heading indi-cator and turn-coordinator contain gyroscopes. . directional (NOTE: The word is often shortened to gyro.)
COMMENT: A spinning gyro maintains its position even when an aircraft banks, climbs, or dives. Gyros drive the attitude indicator, direction indicator and turn coordinator to help pilots control an aircraft while flying in cloud or in poor visibility.

gyroscopic /da.r.sk.p.k/ adjec-tive referring to a gyroscope or using the properties of a gyroscope

gyroscopic compass
/da.r.sk.p.k kmp.s/ noun a com-pass which uses gyroscopic directional stability rather than magnetism to indi-cate directions. Also called gyrocom-pass

gyroscopic precession
/da.r.sk.p.k prise.(.)n/ noun a characteristic of a gyroscope, that the force applied to a spinning gyroscope will act at a point 90° in the direction of rotation, not at the point where the force is applied . Forces of gyroscopic pre-cession act on the direction indicator to keep it aligned vertically and horizon-tally.

H

hail /he.l/ noun precipitation as small pellets of ice . Precipitation is the fall-ing of water, as rain, sleet, snow or hail onto the surface of the earth. . Although hail, and in particular, heavy hail is rare and of short duration, dam-age to an aircraft may be severe.
COMMENT: In weather reports and forecasts, hail is indicated by the abbreviation ‘GR’.
hailstone /he.lst.υn/ noun a small pellet of ice which falls from clouds . A hailstone starts as a small ice particle in the upper portion of a cumulonimbus cloud.