. verb to become lower or to decrease suddenly . The temperature dropped by several degrees.
droplet /dr.pl.t/ noun a small drop of liquid . Experiments show that smaller droplets of rain can remain super cooled to much lower tempera-tures than large droplets.
drove /dr.υv/ . drive
drum /drm/ noun a cylindrical device, often with closed ends dry /dra./ adjective containing no
water or no moisture . dry air . lapse
rate dry ice /dra. a.s/ noun solidified car-bon dioxide
dual /dju.l/ adjective double, in pair
.
Most light aircraft with side-by-side seating have dual controls.
duct /dkt/ noun a channel or tube through which fluids or cables can pass
.
The modern jet engine is basically a duct into which the necessary parts are fitted.
due /dju/ adjective 1. expected to arrive . the flight is due at 10 o’clock the flight should arrive at 10 o’clock 2. . due to because of . Due to daytime heating, the stability decreases and the
wind speed increases. . adverb exactly and directly . The aircraft flew due east.
dump /dmp/ verb to offload quickly
. Normal operating cabin pressure can be reduced rapidly in the event of emer-gency landings, by dumping air. . The aircraft flew out to sea in order to dump fuel before landing.
duplication /djupl.ke..(.)n/ noun
the act of copying or doubling . Control surfaces are divided into sections oper-ated by a separate control unit, thus providing duplication to guard against failure of a unit.
durability /djυ.r.b.l.ti/ noun the
ability of a substance or device to last a long time . High quality components have good durability.
duration /djυre..(.)n/ noun the length of time for which something continues . The duration of the exami-nation is two hours. . The duration of the flight was three hours.
dust /dst/ noun a fine powdery sub-stance blown by the wind and found on surfaces . Solid particles in the air include dust, sand, volcanic ash and atmospheric pollution.
duty /djuti/ noun 1. a period of work . on duty at work . off duty not at work 2. same as import duty . the duty payable on a carton of cigarettes
dye /da./ noun a material used to change the colour of something .
Minute surface cracks which are diffi-cult to detect by visual means may be highlighted by using penetrant dyes.
dynamic /da.nm.k/ adjective
referring to something in motion . dynamic pressure pressure created by the forward movement of the aircraft .
If the dynamic pressure increases due to an increase in forward speed, the force required to move the control column will increase. Opposite static pressure
dynamic seal /da.nm.k sil/
noun a seal which is part of a moving component, e.g. in a hydraulic system .
dynamic seals require lubrication to remain effective
DZ /di zed/ abbreviation drizzle
E
E abbreviation east ear /../ noun the hearing organ ear defenders /'.. d.，fend.z / plural
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