Disadvantage To Dominate (Aviation)

Disadvantagenoun an unwanted situation or condition, or a factor which makes somebody or something less likely to succeed o The disadvantage of a booster pump is that the output is constant so that when engine demand is high, fuel pressure tends to be low and vice versa. Opposite advantage

disadvantagedadjective □ physically disadvantaged (person) a person who has a physical disability

comment: The word ‘disadvantaged’ may be regarded by some people as a politically correct term for ‘disabled’. With the help of specially-adapted controls, more and more disabled people are learning to fly.

disappearverb 1. to vanish o If air blew at right angles to isobars, the horizontal pressure differences would eventually disappear. 2. to pass out of sight o The aircraft took off, climbed out and soon disappeared from view.

disarmverb 1. to switch off an active or live system o On the ground approaching the terminal, the flight deck will instruct the cabin crew to disarm the escape devices. 2. to forcibly remove a weapon from somebody o The hijacker was disarmed by security forces.

discnoun a circular flat plate o A turbine consists of a disc on which is mounted a number of blades.

dischargenoun a release of power from a source such as a battery o A lightning flash is a large-scale example of an electrical spark, or discharge. □ battery discharge the loss or release of electrical supply from a battery ■ verb to release electrical supply from a source such as a battery o The battery discharged overnight.

disconnectverb to separate two things attached to one another o The electrical supply can be disconnected by pulling out the plug.

discriminationnoun the ability to know or see the difference between two similar things o Targets on the same bearing which are separated radially by less than half a pulse length distance will appear at the receiver as one echo, so good target discrimination requires short pulses.

discussverb to write about or talk about a subject o This chapter will discuss HF and VHF voice communications.

disembarkverb to leave the aircraft after landing o The passengers finally disembarked at 20.00 hours.

disembarkationnoun the act of leaving the aircraft after landing o The exits are used as conventional doors for disembarkation.

disengageverb to switch off a system or device o Switches on the control columns instantly disengage the autopilot when depressed.

dishnoun a shallow container for food

dish antennanoun a circular antenna with a shape like a shallow bowl

disintegrationnoun the falling apart or destruction of something o Electromagnetic radiations resulting from the disintegration of radioactive materials are known as gamma rays.

dismantleverb to take apart into single components o One type of inspection is able to reveal fatigue cracks, corrosion, internal damage, the presence of loose articles and mercury spillage without the need to dismantle the aircraft. Opposite assemble (note: The verb ‘mantle’ is not used.)

disorientationnoun a state of confusion in which there is loss of understanding of where one is or which direction one is facing, etc. o When the cabin is rapidly and completely filled by smoke and fumes passengers will suffer from disorientation.

dispensationnoun permission not to have to do something o At very high altitudes the flying pilot must be on oxygen at all times, unless an aircraft dispensation has been obtained.

dispense, dispense with verb not to include or not to use something o In some cases the rivets are dispensed with and the skin is fixed to the internal members by the redux process.

dispersalnoun 1. the act of leaving an area and going in different directions □ the dispersal of a crowd the disappearance of a crowd 2. the clearing away of something such as mist, e.g. by the wind o the dispersal of hill fog o Dispersal of cloud takes place when surface heating lifts the cloud base or drier air is adverted.

disperse‘ verb 1. to leave an area going in different directions □ the crowd dispersed the people in the crowd left the area, going in different directions, so that eventually the crowd disappeared 2. to clear away o The fluorescent green dye will disperse slowly in a calm sea but quickly in a moderate to rough sea.

displaceverb to move something out of its normal position o The atmosphere is said to be stable if, when a parcel of air is displaced vertically, it tends to return to its original level.

displacementnoun movement away from the normal position o The ILS is a cross-pointer indicator which shows the aircraft horizontal displacement from the localiser and vertical displacement from the glide path.

displaynoun 1. the appearance of information on a monitor screen or on the panel of an instrument or of an indicator o There are three different types of electronic display systems: EFIS, EICAS and ECAM. □ digital display information shown as numbers o The clock uses a digital display to show the time of 12:33. 2. a show or demonstration ■ verb to show, e.g. on a panel or a screen o Alerting and warning information is displayed.

disseminateverb to send out or spread o Meteorological stations make routine weather observations at fixed intervals and disseminate this information locally.

dissimilaradjective refer ring to something which is not the same as, or is unlike, something else o Differential expansion switches operate on the principle that the coefficients of expansion of dissimilar metals are different.

dissipateverb to spread out and lose power or strength, or to cause something to do this o Tropical storms often dissipate as they pass from sea to land.

dissipationnoun the process of spreading out and losing power or strength o The rubber used on nose or tail wheels is usually constructed to form a good electrical conductor for the safe dissipation of static electricity.

dissolveverb to become or to cause to become part of a liquid and form a solution o Sugar dissolves in water. o There is a possibility that in some types of accumulator, gas may be dissolved into the fluid and thus introduced into the system.

dissolvedadjective that has melted and become of a liquid □ dissolved water water in solution in fuel

distancenoun a space between two places or points, or the measurement of such a space o The distance from point A to point B is 100 nm. o The distance from point A to point B on the diagram is 2 cm. o The height of the aircraft is the vertical distance, measured in feet, of the aircraft above the surface of the Earth.

distance measuring equipmentnoun an airborne secondary radar whose signal is converted into distance o It is quite common to find a VOR located together with DME (Distance Measuring Equipment) to give simultaneous range and bearing from the same point on the ground. Abbreviation DME

comment: DME equipment is usually located in a VOR station. Other equipment in the aircraft transmits a signal to the VOR station, which replies. The equipment in the aircraft converts the signal into distance and also calculates ground speed and the time needed to reach the station.

distillationnoun the process by which a liquid is heated and the resulting vapour is then condensed and collected o With kerosene-type fuels, the volatility is controlled by distillation.

distinctadjective clear and easily seen or understood o When a lead-acid battery is fully charged, each cell displays three distinct indications.

distinctionnoun something which makes one thing different from another o A clear distinction is made between showers and general precipitation.

distinctiveadjective easily recognised because of particular features or characteristics o Concorde is a very distinctive-looking aeroplane.

distinguish_ „ verb to know or to see the difference between things o A receiver antenna would be unable to distinguish between signals unless they had some differing characteristics.

distinguishableadjective easily recognised as different from o Useful ground features must be easily distinguishable from their surroundings.

distortverb 1. to put out of shape o Stress could cause the body of the aircraft to distort or change its shape. 2. to produce a bad radio signal o The sound of the transmission is distorted if the volume is set too high. distortionnoun 1. the bending or twisting of something so that it is out of shape o Difficulty in closing a door may be caused by distortion of the airframe. 2. alteration of the electrical signal that makes a transmission unclear o Distortion of the signal made it difficult for the controller to understand what the pilot said.

distressnoun 1. serious danger or difficulty 2. a personal worry or anxiety o Some passengers were in distress after the incident.

distress and diversion cell,noun a unit at an air traffic control centre that provides immediate assistance to aircraft in difficulty

distress signalnoun a signal transmitted by an aircraft in danger

distributeverb 1. to give or send out o There are two basic configurations which are used to distribute electrical power, the parallel system and the split bus system. 2. to spread over a wide area o Multiple wheel undercarriage units distribute the weight of the aircraft.

distributionnoun 1. the act of giving or sending out o Parallel AC and DC power distribution systems are found on commercial aircraft containing three or more engines. 2. the fact of being spread over an area o There is a high distribution of used and disused airfields in the south of England.

distributornoun a device which sends an electrical charge to each spark plug in turn o The distributor directs the high voltage impulses to the cylinders in turn as they reach their ignition point.

disturbverb to upset the normal condition of something o Small hills can disturb the flow of air.

disturbancenoun something that upsets the normal condition of something o In general, the higher the mountain and the faster the air flow the greater is the resulting disturbance.

ditchverb to land a plane in the sea, in an emergency o Even though aircraft have ditched successfully, lives have been lost because life rafts were not launched in time.

ditchingnoun the act of landing a plane in the sea, in an emergency o After all four engines stopped, the captain had to seriously consider the possibility of a ditching in the Indian Ocean.

diurnaladjective refer ring to the 24-hour cycle of day and night o Diurnal changes in surface temperature over the sea are small.

dive/ 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 o 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 o The aircraft dived to avoid the other aircraft. (note: diving – dived)

divergeverb to move fur

ther apart from something else o Air diverges at low levels and converges at high levels, causing a sinking or subsiding effect in the atmosphere. Opposite converge

divergencenoun the act of moving apart o Divergence of air at high levels leads to rising air at low levels with a consequent pressure fall. Opposite convergence divergentadjective referring to something which moves further apart from something else divergent duct

noun a duct which has an inlet area which is smaller than the outlet area diversionnoun a change in route or destination caused by bad weather, technical problem, etc. o The aircraft had to make a diversion to another airport due to fog. divertverb to turn away from a course or a destination o An automatic cut-out valve is fitted to divert pump output to the reservoir when pressure has built up to normal operating pressure. o The aircraft was diverted to Manchester airport because ^offog.

divideverb 1. to separate into parts o Air masses are divided into two types according to source region and these are known as polar and tropical air masses. 2. to calculate how many times a number is contained in another number o Eight divided by four equals two (8 ^ 4 = 2).

division/ noun 1. separation 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 o The division sign is ^. DME abbreviation distance measuring equipment

documentnoun a piece of writing, e.g. a memo, letter or report o The flight crew route flight plan is a composite document which also serves as a navigation log.

documentationnoun a collection of letters, memos, reports, etc. o Flight crews are provided with a full meteorological briefing, backed by documentation, a short time before ETD.

domesticadjective referring or belonging to inside a country o Domestic flights usually leave from Terminal 1.

dominantadjective main or most influential o Both pressure and temperature decrease with height but the pressure change is the dominant one and so, as pressure decreases with height, so does density.

Dominateverb to have the most effect or influence on o Because the chart time and the departure/arrival times differ, it is necessary to consider the movement of any weather system which will dominate the route.