Doppler radar To Elapse (Aviation)

Doppler radarnoun radar which can distinguish between fixed and moving targets or provide ground speed and track information from an airborne installation

Doppler VOR noun an adaptation of VOR to reduce errors caused by location dotnoun a small circular mark on paper o The highest point in a locality is marked by a dot with the elevation marked alongside.

downdraughtnoun 1. cool air which flows downwards as a rainstorm approaches. Opposite updraught 2. air which flows rapidly down the lee side of a building, mountain, etc. (note: It is also written down-draft in US English.)

downstreamadverb in the direction of flow, or further along the line of flow o Internally driven superchargers are generally used on medium and high powered engines and are fitted downstream of the throttle valve.

downwardadjective moving to a lower level o When flying in turbulent air conditions, an aircraft is subjected to upward and downward gust loads.

downwardsadverb to a lower level, towards the bottom o Pull the toggles downwards to inflate the life jacket. Opposite upwards (note: In US English, downward is used as an adverb and as an adjective.)

downwindadjective,adverb in the same direction as the wind is blowing □ turn downwind turn the aircraft so that it is flying in the same direction as the wind is blowing. Opposite upwind downwind leg noun part of the airfield traffic circuit which runs parallel to, but in the opposite direction to, the approach to land which is made into wind DR abbreviation dead reckoning draftnoun US same as draught o a down draft or an updraft drag‘ noun the resistance of the air created by moving the aircraft through the air o To reduce the effect of drag on an aircraft by the fixed undercarriage a retractable type was introduced. o If an engine failure occurs, the windmilling propeller may cause considerable drag.

comment: There are two basic types of drag called parasite drag and induced drag. Parasite drag is caused by friction between the air and the aircraft surface, aerials, landing gear, etc. Induced drag is produced by lift.

drainnoun a device to allow fluid to escape from its container o When the cabin is pressurised the drains close, preventing loss of pressure. ■ verb to allow fluid to escape by providing a hole or tube, etc., through which it can pass o The moisture drains in the lower skin of the cabin are open when the cabin is unpressurised, allowing moisture to drain.

drainage‘ noun 1. the act of allowing a fluid to escape from its container o Drainage of water from the fuel system should be carried out before the first flight of the day. 2. a system of outlets for fluid such as water or fuel to pass out of a closed area

draughtnoun a local current of air o a down draught or an updraught (note: This word is written draft in US English.)

drawverb 1. to make a picture as with a pencil, on paper, etc. o Because there is a temperature gradient across each front it is possible to draw isotherms which reduce in value from warm to cold air. 2. to pull or to take o Fluid is drawn into the pump body. 3. to pull towards oneself (note: drawing -drew – drawn)

driftnoun movement away from the desired course, created by wind blowing at an angle to the intended direction of flight o If the wind direction is not the same as the aircraft track or its reciprocal, then the aircraft will experience drift. ■ verb to move away from the desired course o When landing, a cross-wind from the right will cause the aircraft to drift to the left.

drillnoun 1. a short series of actions carried out in a particular sequence o The starting drill varies between different aircraft types and a starting check procedure is normally used. 2. a tool, often electrically powered, for making holes in metal, wood, etc.

drivenoun a series of connected devices that transmit power to the wheels, propellers, etc. o Rotation of the engine for starting is done by an electric starter motor connected to a drive shaft in the accessories gearbox. ■ verb 1. to make something move or turn □ shaft-driven using a rotating shaft as a means of transmitting power from one part to another, e.g. from a turbine engine to a helicopter rotor 2. to control and guide o He’s learning to drive. (note: driving – drove – driven)

drivendrive

drizzlenoun precipitation,often persistent, in the form of very small drops of water o Drizzle is the lightest form ofprecipitation consisting of fine water droplets.

comment: In weather reports and forecasts, drizzle is abbreviated to DZ.

drogue parachutenoun a small parachute used in releasing a larger parachute from its pack

dronenoun an aircraft whose flight is controlled from the ground

dropnoun 1. a small amount of liquid that falls o a drop of water o a few drops of rain 2. a sudden lowering o The passage of a cold front is usually followed by a drop in temperature. o A sudden drop in oil pressure is normally an indication of serious engine trouble. ■ verb to become lower or to decrease suddenly o The temperature dropped by several degrees.

dropletnoun a small drop of liquid o Experiments show that smaller droplets of rain can remain super cooled to much lower temperatures than large droplets.

drovedrive

drumnoun a cylindrical device, often with closed ends

dryadjective containing no water or no moisture o dry air i> lapse rate

dry icenoun solidified car bon dioxide

dualadjective double, in pair o Most light aircraft with side-by-side seating have dual controls.

ductnoun a channel or tube through which fluids or cables can pass o The modern jet engine is basically a duct into which the necessary parts are fitted.

dueadjective 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 o Due to daytime heating, the stability decreases and the wind speed increases. ■ adverb exactly and directly o The aircraft flew due east.

dumpverb to offload quickly o Normal operating cabin pressure can be reduced rapidly in the event of emergency landings, by dumping air. o The aircraft flew out to sea in order to dump fuel before landing.

duplicationnoun the act of copying or doubling o Control surfaces are divided into sections operated by a separate control unit, thus providing duplication to guard against failure of a unit.

durabilitynoun the ability of a substance or device to last a long time o High quality components have good durability.

durationnoun the length of time for which something continues o The duration of the examination is two hours. o The duration of the flight was three hours.

dustnoun a fine powdery substance blown by the wind and found on surfaces o Solid particles in the air include dust, sand, volcanic ash and atmospheric pollution.

dutynoun 1. a period of work □ on duty at work □ off duty not at work 2. same as import duty o the duty payable on a carton of cigarettes dyenoun a material used to change the colour of something o Minute surface cracks which are difficult to detect by visual means may be highlighted by using penetrant dyes.

dynamicadjective referring to something in motion □ dynamic pressure pressure created by the forward movement of the aircraft o 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 noun a seal which is part of a moving component, e.g. in a hydraulic system o dynamic seals require lubrication to remain effective

E abbreviation

east earnoun the hearing organ ear defendersplural noun same as acoustic ear muffs eardrumnoun a membrane inside the ear which vibrates with sound and passes the vibrations to the inner ear o Equalization of the air pressure across the eardrum is more difficult to achieve during descents than ascents. ear muffsplural noun »acoustic ear muffs

ear protectorsplural noun same as acoustic

ear muffs earthnoun 1. □ (the planet) Earth the planet where we live 2. ground or soil ■ verb to connect an electrical appliance to a position of zero potential o When refuelling a light aircraft, ensure that the aircraft is properly earthed. (note: The US expression is to ground.)

eastnoun 1. a compass point on the mariner’s compass 90° clockwise from due north and directly opposite west o London is east of New York. 2. the direction in which the Earth rotates, the direction of the rising sun ■ adjective 1. referring to areas or regions lying in the east o the east coast of Canada 2. the eastern part of a region o East Africa ■ adverb towards the east o The aircraft was flying east.

eastboundadjective travelling towards the east o an east-bound flight

easterlyadjective 1. situated towards the east 2. □ easterly component one part of the wind direction coming from the east 3. □ to move in an easterly direction to move towards the east ■ noun a wind which blows from the east

easternadjective situated in the east o one of the eastern provinces of Canada

Eastern Standard Timenoun the time zone of the eastern USA and Canada, 5 hours behind GMT.

Abbreviation EST

eastwardadjective going towards the east ■ adverb US same as eastwards

eastwardsadverb towards the east o Flying eastwards or westwards for long periods of time affects sleep patterns.

east wind‘ noun a wind blowing from or coming from the east (note: A wind is named after the direction it comes from.)

EAT abbreviation expected approach time

EATMP abbreviation European air traffic management programme ECAC abbreviation European civil aviation conference

ECAM abbreviation electronic centralised aircraft monitor

echonoun 1. the repetition of a sound by reflection of sound waves from a surface 2. the return of a signal back to the source from which it was transmitted o The strength of the returning echo from a radar transmission depends on a number of factors.

economicadjective financially rewarding o It was no longer economic to keep the maintenance operation going.

economicaladjective referring to a substance or device for which input is minimised and output maximised (thereby saving costs) □ economical engine an engine which uses less fuel to produce the same power as comparable engines o Jet engines are more efficient and economical when operated at high altitudes.

ECS abbreviation environmental control system

EDDUS abbreviation electronic data display and update system

eddynoun a current of air moving in the opposite direction to the main current, especially in a circular motion o When wind flows over an obstruction such as a building, an eddy is formed on the lee, or downwind side.

edgenoun a line of intersection or joining of two surfaces EET abbreviation estimated elapsed time

effectnoun 1. something which results from a cause o Ultra-violet radiation has the effect of warming the atmosphere. o Pressure patterns have an effect on weather. 2. the condition of being in full force □ in effect in operation □ to take effect, to come into effect to start to operate o A new regulation comes into effect tomorrow. □ with effect from starting from ■ verb to cause or carry out □ to effect a change to make a change □ modifications were effected modifications were carried out. Compare affect

effectiveadjective 1. having an expected and satisfactory result □ the new cleaning fluid was very effective it cleaned well 2. operative, in effect o The regulation is effective immediately.

effectivenessnoun how well something works o Ice covering reduces the effectiveness of an aerial.

effective pitchnoun the distance the aircraft moves forward in flight for one 360° rotation of the propeller

efficiencynoun 1. the fact of being able to act or produce something with a minimum of waste, expense, or unnecessary effort o Efficiency is a key component of a successful business. 2. the ratio of the energy delivered by a machine to the energy supplied for its operation o mechanical efficiency o propeller efficiency □ thermal efficiency the efficiency of conversion of fuel energy to kinetic energy efficientadjective able to act or produce something with a minimum of waste, expense, or unnecessary effort o At some speeds and altitudes the pure jet engine is less efficient than a piston engine. □ efficient combustion combustion in which fuel energy is used to its maximum capability

effortnoun 1. the use of physical or mental energy to do something o In order to qualify for a licence, it is necessary to put some effort into the training course. o Flying a high performance aerobatic light aircraft to its limits requires a lot of physical effort on the part of the pilot. 2. force applied against inertia o Actuators are capable of exerting low-speed turning effort. EFIS abbreviation electronic flight instrument system

eggbeaternoun a rotary-wing aircraft (informal) EGNOS noun a European system that improves the quality of data from existing satellite navigation systems to make the data suitable for use by aircraft. Full form European Geostationary Navigation Overlay Service (note: The US equivalent is WAAS.) EICAS noun a cockpit display for monitoring the engines and warning of malfunction. Full form engine indicating and crew alerting system

ejectverb to throw out force fully  On depressurization the oxygen mask is ejected automatically from the service panel.

ejectionnoun an act of throwing out forcefully o ejection seat ejection seatejector seatnoun an emergency escape seat in military aircraft

which is fired out of the aircraft while the crew-member is still in it ejector‘ noun 1. a device to throw something out forcefully 2. a device using a jet of water, air, or steam to withdraw a fluid or gas from a space o A jet transfer pump or fuel ejector is used to transfer fuel.

Elapseverb to pass o The radio altimeter works on the principle that, if the path followed by the radio wave is straight down and up, then the elapsed time between the outgoing and incoming signal is a function of the aircraft’s height.