disturbance /d.stb.ns/ noun
something that upsets the normal condi-tion of something . In general, the higher the mountain and the faster the air flow the greater is the resulting dis-turbance.
ditch /d.t./ verb to land a plane in the sea, in an emergency . Even though air-craft have ditched successfully, lives have been lost because life rafts were not launched in time.
ditching /d.t.../ noun the act of landing a plane in the sea, in an emer-gency . After all four engines stopped, the captain had to seriously consider the possibility of a ditching in the Indian Ocean.
diurnal /da.n(.)l/ adjective refer-ring to the 24-hour cycle of day and night . Diurnal changes in surface tem-perature over the sea are small.
dive 76
dive /da.v/ noun a steep nose-down attitude of an aircraft . to pull out of or from a dive to return the aircraft to level flight after a nose-down flight path
. During manoeuvring of an aircraft, when banking, turning and pulling out from a dive, stresses on the airframe are increased. . verb to put the aircraft into a steep nose-down attitude . The air-craft dived to avoid the other aircraft.
(NOTE: diving – dived) diverge /da.vd/ verb to move fur-ther apart from something else . Air diverges at low levels and converges at high levels, causing a sinking or subsid-ing effect in the atmosphere. Opposite
converge divergence /da.vd.ns/ noun the
act of moving apart . Divergence of air at high levels leads to rising air at low levels with a consequent pressure fall.
Opposite convergence divergent /da.vd.nt/ adjective
referring to something which moves further apart from something else
divergent duct /da.vd.nt dkt/
noun a duct which has an inlet area which is smaller than the outlet area
diversion /da.v.(.)n/ noun a
change in route or destination caused by bad weather, technical problem, etc. .
The aircraft had to make a diversion to another airport due to fog.
divert /da.vt/ verb to turn away from a course or a destination . An automatic cut-out valve is fitted to divert pump output to the reservoir when pressure has built up to normal operating pressure. . The aircraft was diverted to Manchester airport because of fog.
divide /d.va.d/ verb 1. to separate into parts . Air masses are divided into two types according to source region and these are known as polar and trop-ical air masses. 2. to calculate how many times a number is contained in another number . Eight divided by four equals two (8 ÷ 4 = 2).
division /d.v.(.)n/ noun 1. separa-tion into parts . the division of the lower atmosphere the separation of the atmosphere into its component layers 2.
the calculation of how may times a number is contained in another number
. The division sign is ÷.
DME abbreviation distance measuring equipment
document /d.kjυm.nt/ noun a
piece of writing, e.g. a memo, letter or report . The flight crew route flight plan is a composite document which also serves as a navigation log.
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