reactance /rikt.ns/ noun a com-ponent of impedance in an alternating current circuit . Reactance is a form of resistance which varies as the fre-quency changes.
reaction /rik..n/ noun a response to an action or stimulus . For every action there is an equal and opposite reaction. . Passenger reaction may be slower than usual in an emergency situ-ation. . Quick reactions are needed in an emergency.
reaction thrust principle /ri k..n θrst pr.ns.p(.)l/ the process by which exhaust gases coming of the back of an object cause a reaction force to act on the object and push it forwards
readback /ridbk/ noun the action of repeating an ATC message to the controller to enable him or her to check that it was correctly received
readily /red.li/ adverb 1. promptly, immediately . Fire extinguishers must be readily available for use. . Ice melts very readily at 0°C (Celsius). 2. . it can readily be seen it can be easily under-stood . It can readily be seen from the preceding paragraph that density and pressure are linked.
reading /rid../ noun 1. information indicated by an instrument or gauge . altimeter reading the altitude indi-cated by the altimeter . barometer reading the barometric pressure indi-cated by the barometer 2. . map read-ing the act of interpreting information on a map
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readout /ridaυt/ noun a display or presentation of data from calculations or storage . The rotating beam cloud base recorder/indicator operates con-tinuously, day and night and produces an automatic readout of cloud base height.
rear /r../ noun the aft part, the part fur-thest from the front . the rear of the air-craft . adjective at the back, or referring to the back . The rear part of the air-craft is called the aft section.
rearward /r..w.d/ adjective towards the aft or the rear . The expanding gas travels in a rearward direction.
reason /riz(.)n/ noun the basis or motive for an action . A rough surface is more susceptible to fatigue cracking than a smooth one and for this reason highly stressed members are often pol-ished.
reasonable /riz(.)n.b(.)l/ adjec-tive 1. acceptable or fair . a reasonable sum of money a sum of money which is not too high or which is acceptable 2. within the boundaries of common sense
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It would be reasonable to expect that radio frequencies would travel through the air in straight lines as a direct wave, but they bend, or refract.
receive /r.siv/ verb to get, to obtain
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The sides of the hills and mountains which face the sun receive more intense radiation than flat surfaces because of the angle of exposure to the sun.
receiver /r.siv./ noun a device that receives incoming radio signals and converts them to sound or light . The transponder in the aircraft consists of a transmitter and a receiver.
recent /ris(.)nt/ adjective referring to a time immediately before the present . Recent engine designs include variable angle stator blades. . A more recent development is the barograph which utilises the electrical output of the digital display barometer. . recent weather significant weather observed in the period since the previous obser-vation, but not now
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