W

W abbreviation west WAAS noun a US navigation system which processes and improves data from GPS satellites to provide location information. Full form Wide Area Aug-
mentation System (NOTE: The Euro-pean equivalent is EGNOS.) wake turbulence /we.k
tbjυl.ns/ noun the disturbance of the air remaining after the passage of an aircraft
wall /w.l/ noun the side . There is a film of oil between the piston and cylin-der wall.
warm front /w.m frnt/ noun an
advancing mass of warm air moving
over a mass of cooler air warn /w.n/ verb to give notice of pos-sible danger . A light illuminates to warn the crew.
‘…ultrasonic technology which automatically warns pilots of ice build-up on aircraft may soon be approved for general use by carriers’ [Flight International 16–22 July 1997]
warning /w.n../ noun notice of possible danger . adjective giving notice of possible danger . The main power plant fire detection system should contain an audible warning device to supplement the visual indica-tion.

warning indicator /w.n..
.nd.ke.t./ noun an indicator which gives notice of a possible problem which may require some action. . VASI
warning light /w.n.. la.t/ noun a
small light, often red, which informs of a possible danger by lighting up . At 5
knots above stalling speed, a warning light on the instrument panel will flash.
washroom /w..rum/ noun same as
toilet 2 waste /we.st/ noun something which can no longer be used . A smouldering fire in a toilet waste container or waste disposal bin could become very active due to pressure changes during descent.
water-tight /w.t. ta.t/ adjective
that does not leak water or other fluid watt /w.t/ noun the SI unit of meas-urement of electrical power . The work done by an electrical circuit or the power consumed is measured in watts.
wave /we.v/ noun 1. the motion by which heat, light, sound or electric cur-rent is spread . The speed of propaga-tion of radio waves is faster over sea than over land. 2. a mass of water mov-ing across the surface of a lake or the sea, rising higher than the surrounding water as it moves . Wind speeds increase with height, the speed of the wind at the crest of a wave being the greatest.
waveform /we.vf.m/ noun the
shape of a repetitive wave . A cycle is one complete sequence of the wave-form, from any point, to the same value 360° later.
wavelength /we.vle.θ/ noun the
distance from the highest point of one wave to the highest point of the next .
Short wavelength permits sharper beams for direction finding and more efficient reflections.
waveoff /we.v.f/ noun a signal or instruction to an aircraft that it should not land

waypoint 250
waypoint /we.p..nt/ noun a prede-termined position on a route, used for monitoring flight progress or for navi-gating around controlled airspace. Abbreviation WP
weak /wik/ adjective 1. not strong . a weak radio signal 2. overdiluted with water or air . weak mixture a fuel/air mixture in which there is more air than usual . Excessive cylinder head tem-peratures could be caused by prolonged use of a weak mixture, especially at high altitude. . weak solution a mix-ture of water and some other substance in which the amount of water is more than usual