Glossary - Letter A

If you wish to find a term by name, please click the relevant letter below to be taken to a list.


A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | XYZ



AAIB |abbreviation| Air Accident Investigation Branch


AARA |abbreviation| air to air refueling area


abbreviate |verb| to shorten a word or a text / Air Traffic Control is usually abbreviated to ATC. / - abbreviated weather report > a shortened weather report


abbreviation |noun| the short form of a word or text / Aeronautical charts use abbreviations and symbols. Km is the abbreviation for kilometer. /


abeam |adverb|,|adjective| at right angles to the length and directly opposite the centre of a vessel or aircraft - abeam the runway > indicating that the runway is to the side of the aircraft, at a bearing of approximately 90° or 270°  relative to the aircraft, i.e. to the right or the left


ability |noun| the power, knowledge or skill needed to do something / Strength is the ability of a material to support a load. / - he has great ability > he has good skills or is very clever


able |adjective| skilful and competent / Is she able to carry this heavy suitcase? / - to be able to > to have the power, knowledge, skill or strength to do something    


able-bodied |adjective| referring to a person who has no physical disabilities / Physically disadvantaged as well as able-bodied people can gain a PPL. /


abnormal |adjective| not normal


abnormality |noun| something that is not normal, expected or correct, and is therefore possibly worrying / Any abnormality in engine performance should be checked. /


abnormal load |noun| a load which is heavier than normal


abort |verb|  1. to stop something taking place / They had to abort the landing because of a violent storm. /  2. to end something before it has finished


absolute |adjective| complete, total - absolute necessity > something that you cannot manage without under any circumstances - absolute silence > a condition in which no sound of any kind can be heard


absolute ceiling |noun| the maximum height above sea level at which an aircraft can maintain horizontal flight


absolute humidity |noun| the vapor concentration or mass of water in a given quantity of air


absolute pressure |noun| a unit of force per unit of area without comparison to other pressure / Aircraft show absolute pressure in inches of mercury on the inlet manifold pressure gauge. /


absolute value |noun| the size or value of a number regardless of its sign /The absolute value of –64.32 is 64.32./


absolute zero |noun| the  lowest  temperature  possible, 0 °K, or –273.15 °C


absorb |verb| to take in / Warm air absorbs moisture more easily than cold air. Our bodies absorb oxygen. / - to absorb information > to understand and remember something / Only a few passengers absorb the pre-flight safety information. /


absorption |noun| the act of taking something in / There is absorption of energy by the tire when the aircraft lands. /


AC |abbreviation|  1. alternating current  2. alto-cumulus (ICAO)


ACARS |abbreviation| airborne communication, addressing and reporting system


ACAS |abbreviation| airborne collision avoidance system


ACC |abbreviation| area control center


accelerate |verb| to increase speed / After start-up, the engine accelerates up to idling speed. The aircraft accelerated down the runway and took off. / Opposite: decelerate


acceleration |noun|  1. the act of increasing the speed of something or of going faster. Opposite: deceleration (NOTE: Acceleration can be felt as an aircraft begins its take-off run.)  2. a force that pulls outwards and is caused by a change in direction rather than a change in speed / Acceleration forces can be felt during aerobatic maneuvers. /


acceleration due to earth’s gravity |noun| the pulling force exerted on a body by the Earth. It has an international standard value of 9.80665 meters per second per second. Abbreviation: g


accelerometer |noun| an instrument that measures an aircraft’s acceleration


accept |verb|  1. to be able to take or receive / Some units accept electrical inputs from the autopilot. /  2. to take or receive something when it is given to you / She accepted the award on behalf of the whole crew. / - to accept a gift, to accept a prize > to take a prize which is handed to you  3. to be willing to receive or admit something - to accept the blame > to be willing to admit that you were the person who caused something bad to happen / The airline accepted the blame for the loss of their baggage. / - to accept responsibility > to be willing to be answerable for something / The copilot accepted responsibility for the incident. /


acceptable |adjective| allowed or approved of, although it may not be perfect - acceptable level of safety > a good enough standard of safety - acceptable limits > the limits generally regarded as correct - there must be a continuous flow of clean oil at an acceptable temperature > the temperature of the oil must be within given maximum and minimum figures


acceptance |noun|  1. willingness to believe something or agree to something / There is a growing acceptance that safety is the main priority. /  2. willingness to do or use something - acceptance of new technology > willingness to use new technology


accepted |adjective| believed or recognized / It is accepted that incorrect use of English played a part in the accident. It is generally accepted that flying is one of the safest forms of transport. /


access |noun| a way to find or get at something - to gain access to > to manage to enter a place - access to information > the means to get at, retrieve and use information - |verb| to find and use - to access data , to access information > to find, retrieve and use data or information


accessibility |noun| the ease with which something can be reached or found / Accessibility of components and equipment during servicing enables work to be done more quickly. /


accessible |adjective| easy to get at / It is a good idea to have a set of emergency charts in an accessible place in the cockpit. Instruments which need resetting in flight must be accessible to the crew. /


accessory |noun| a system or piece of equipment of secondary importance / a camera with several accessories / - |adjective| of secondary importance / There are many accessory systems which need engine power to operate them – pumps, generators, magnetos, etc. / (NOTE:The noun accessory is not connected with the noun access or the verb  to access.)


access panel |noun| a part of the aircraft skin which can be easily removed so internal components can be inspected


access platform |noun| a platform mounted on wheels with steps which allows technicians to gain access to the higher parts of the aircraft


accident |noun|  1. something which happens which seems to have no cause - it was an accident > nobody planned that it should happen or deliberately caused it to happen - by accident > by chance - we met by accident > we met by chance  2. an unfortunate or harmful event, something causing damage / An accident must be reported. The flight attendant was injured in the accident. /


accidental |adjective|  1. happening by accident, not deliberate or planned / There is a safety device to prevent accidental retraction of the undercarriage. /  2. relating to an accident, or happening as a result of an accident / We were told of his accidental death. /


accompanied |adjective| found together with - accompanied luggage > luggage which belongs to one of the passengers and is carried on the same aircraft. Opposite: unaccompanied


accompany |verb| to go together with something else / Engine failure is sometimes accompanied by fire. / - Mr Smith was accompanied by his wife and children on the flight to New York > Mr Smith’s wife and children were with him on the flight


accomplish |verb| (in formal technical texts) to do something / Feathering is accomplished by moving the pilot’s control lever. Retraction of the undercarriage is accomplished by electrical power. / - to accomplish a task > to successfully finish doing something demanding / She was the first woman to accomplish the feat in a single-engined aircraft. /


accomplishment |noun|  1. an achievement / Charles Lindbergh’s flight across the Atlantic in May 1927 was a great accomplishment. /  2. (in physics) work done / Power is measured by units of accomplishment correlated with time. /


accordance |noun| - in accordance with > in agreement with or following something such as rules, instructions or laws / Fuels must be used in accordance with instructions. /


accordingly |adverb| as needed / Check for increasing manifold pressure and reduce power accordingly. /


according to |preposition|  1. as determined by or in relation to / The force exerted by the pilot on the control column will vary according to a number of factors. /  2. as written or said by somebody else / According to the copilot, engine vibration was detected in engine number one. / 3. in agreement with something, e.g. instructions, etc. - according to instructions > exactly as said in the instructions - according to requirements > as required


account |noun| - to take something into account > to remember something and consider it carefully / When planning a flight, wind speed and direction must be taken into account. In the event of an in-flight emergency, the aircraft should be landed at the nearest suitably equipped airport, taking into account fuel available. / - on no account > under no circumstances, never / On no account should anybody fly an aircraft without carrying out pre-flight checks. /


account for |verb|  1. to make up or constitute / Kevlar and carbon fiber account for a large percentage of the materials used in modern aircraft. /  2. to provide the main reason for something / High humidity accounted for the longer take-off run. /


accrete |verb| to increase in amount by slow external addition, to accumulate - ice accretes on the rotor > ice builds up on the rotor


accretion |noun| increase or accumulation by slow external addition / Ice accretion can cause loss of lift and significantly increase the weight of the aircraft. / - accretion rate > the speed at which ice is accumulating; it is also referred to as the accumulation rate or build-up rate


accumulate |verb| to collect and increase / Due to katabatic effects, cold air flows downwards and accumulates over low ground. /


accumulation |noun| the collection and increase of something / Fire in a toilet could present difficulties due to the confined space and possible smoke accumulation. /


accumulator |noun|  1. a device for storing energy in hydraulic systems / An accumulator is fitted to store hydraulic fluid. /  2. an electric circuit in a calculator or computer, in which the results of arithmetical and logical operations are formed


accuracy |noun|  1. the state of being correct - to check for accuracy > to make certain that the result is correct  2. the ability to find, hit or show things correctly / The accuracy of modern navigational equipment is much greater than older systems. /


accurate |adjective|  1. correct / Skill in accurate flying can only be achieved by practice. / - accurate results > results which are exactly correct  2. precise / This watch is very accurate. /


ACFT |abbreviation| aircraft


achieve |verb|  1. to manage to do something demanding / In order to achieve a safe landing in a crosswind, the correct techniques must be used. /  2. to obtain / In wind shear conditions, a fly-by-wire system allows the pilot to achieve maximum lift by pulling hard back on the stick without risk of a stall. /


achievement |noun| something difficult that somebody succeeds in doing and feels proud about / For most trainee pilots, making their first solo flight is a great achievement. /


acid |noun| a chemical substance which reacts with a base to form a salt / sulfuric acid (H2SO4) / (NOTE: An acid turns a litmus indicator red and has a sour taste.)


acidity |noun| having an acid content - the acidity of a substance > the amount of acid in a substance


acid-proof |adjective| able to resist the harmful effects of an acid


acid test |noun| a difficult or exacting test of worth or quality / A pilot’s ability to react appropriately in an emergency situation is the acid test of his or her professionalism. /


acknowledge |verb| to say that you have heard and understood. It is important that the controller listens carefully to pilot input on the nature of the emergency, requests clarification if in doubt, and gives the crew reassurance that their problem is understood. Requesting and providing clarification, paraphrasing, confirming and acknowledging all play a key role in such exchanges / In case of radio failure, acknowledge by flashing headlights. /


ACMS |noun| a computer which records information from various aircraft systems during flight. Full form: aircraft condition monitoring system


ACN |abbreviation| aircraft classification number


acoustic |adjective| referring to sound


acoustic ear muffs |plural noun| coverings to protect the ears from loud noise. Also called: ear protectors , ear defenders


acquire |verb| to buy or otherwise obtain / Speed control is used to acquire and maintain a selected airspeed. /


acquisition |noun| the act of buying or otherwise obtaining / Each computer checks data acquisition. The image of the airline improved after the acquisition of the new aircraft. /


acrid |adjective| used to describe a sharp, bitter (smell), especially of smoke or fumes


acronym |noun| a word which is made up of the initial letters of a name, and is pronounced as a word / NASA is the acronym for National Aeronautics and Space Administration. VASI is the acronym for visual approach slope indicator. /


act |verb|  1. to behave in a particular way / The crew must act with authority. /  2. to take the role of / Mountain ranges act as a barrier. The governor spill valve also acts as a safety relief valve. /  3. - to act on > to produce an effect / Bending and twisting forces act on a propeller. Gravity acts vertically downwards. /


acting |adjective| temporarily taking on the responsibilities of somebody / Captain Smith will be acting Chief Flying Instructor while Captain White is absent from work. /


action |noun|  1. something done or to be done - to take action > to so something / If there is a risk of collision, the crew should take the appropriate action. /  2. an effect


activate |verb| to make a system or a piece of equipment or a procedure start to work or to operate / The system is activated by the pilot or copilot. The sounding of the alarm will activate emergency procedures. /


activation |noun| the act of making something start to work or to operate / Activation may be mechanical or electrical. /


active |adjective|  1. live, in action or use - the system is active > the system is on and working  2. not passive - in a secondary radar system, the target is active > in a secondary radar system the target transmits a signal while in a primary radar system it does not 3. - active Cb clouds > developing cumulonimbus clouds


active runway |noun| a runway that is being used ‘…never cross an active runway without permission from the tower: there may be more than one active runway’ [Civil Aviation Authority, General Aviation Safety Sense Leaflet]


activity |noun| a movement or action of some kind / Sunspot activity can affect the amount of solar radiation. /


actual |adjective| real / The actual path of the aircraft over the ground is called its track, which may not be the same as the desired course. /


actually |adverb| in fact, in reality / The design is such that, although the aircraft loses altitude rapidly, it does not actually stall. /


actuate |verb|  1. to move a device or a part / The fore and aft movement of the control column actuates the elevators. /  2. to switch on a system or a piece of equipment, or put it into operation / A lever actuates the fire deluge system. / 3. to put a procedure into action / Receipt of the distress signal will actuate the support facilities at the airport. /


actuation |noun|  1. the act of making a device or a part move - electrical actuation > the use of an electric motor to make something move - mechanical actuation > the use of a mechanical part such as a rod, arm or lever to make something move  2. a movement made by a device or part


actuator |noun| a device which changes electrical or hydraulic energy into mechanical motion / The actuator control is sensitive to engine rpm. Actuators are classified as either linear or rotary. /


AD |abbreviation| airworthiness directive


A/D |abbreviation| aerodrome


ADA |abbreviation| advisory airspace


adapt |verb|  1. to change or modify for special use / The turboprop engine is often used in transport aircraft and can be adapted for use in single-engine aircraft. / 2. to change to suit new conditions / Crew flying long-haul routes have to adapt to time changes. /


adaptation |noun| 1. the act of changing or modifying something for special use / Doppler VOR is an adaptation of VOR to reduce errors caused by location. /  2. adjustment to new conditions / Adaptation to time changes when traveling west to east takes time. /


adapter |noun|  1. a piece of equipment or device which allows a change or modification - a ‘T’ piece adapter > a device for connecting two inputs to one output or vice versa  2. a device that allows two incompatible devices to be connected


ADC |abbreviation| air data computer


add |verb|  1. to put figures together to form a sum, to make a total / Add the two numbers together to find the sum. /  2. to put together to make a larger group or a group with different properties / There are only nine chairs, add another one. A substance is added to the fuel to clean fuel injectors. /


addition |noun|  1. a mathematical operation consisting in putting numbers together / Addition is normally taught before subtraction, multiplication and division. The addition sign is +. /  2. the act of adding something / With the addition of methanol, the turbine inlet temperature is restored. /  3. - in addition > also - in addition to > as well as


additional |adjective| added or extra


additive |noun| a chemical substance, often liquid, added to another substance to give it extra qualities / Additives are used in engine oils to prolong the life of the engine. Anti-icing additives are used in radiator coolants. /


adequate |adjective| enough, sufficient / The compressor must provide an adequate airflow through the engine. / - adequate fuel > enough fuel


ADF |abbreviation| automatic direction finder


adhere |verb| to stick as if glued / Clear ice adheres strongly to airframes. /


adhesive |noun| glue - |adjective| having the sticking quality of glue / adhesive tape. Adhesive bonding of aluminum parts is widely employed. /


ADI |abbreviation| attitude direction indicator or attitude director indicator


adiabatic |adjective|  1. referring to processes through which heat cannot be lost or gained  2. referring to a change in temperature in a mass of air, which occurs when the air is compressed or expanded by an increase or decrease in atmospheric pressure and does not involve the air losing heat to, or gaining heat from, its surroundings


adiabatic compression |noun| compression caused by atmospheric factors, which makes descending air warm up


adiabatic cooling |noun| a process in which ascending air is cooled by a decrease in atmospheric pressure without heat transfer


adiabatic expansion |noun| expansion caused by atmospheric factors, which makes ascending air cool down / Cooling by adiabatic expansion may result in cloud formation. /


adiabatic heating |noun| a process in which descending air is heated by an increase in atmospheric pressure without heat transfer


adjacent |adjective| next to or near /Fire extinguishers should be positioned adjacent to the aircraft during all ground-running operations./


adjust |verb| to change and improve the position or setting of a piece of equipment / The pilot adjusts the throttle or propeller controls. / - to adjust the seat > to move the seat into a position suitable for yourself - to adjust the volume > to increase or decrease the volume to improve the sound quality


adjustable |adjective| designed to be adjusted / An adjustable stop on the throttle control ensures a positive idling speed. /


adjustment |noun|  1. a change to improve the setting, position or operation of something / A slight adjustment to the seat will make it much more comfortable to sit in. /  2. the act of changing something to improve its setting or position / Maximum system pressure is often controlled by adjustment of the main engine-driven pump. /


admit |verb| to allow to enter / Cold air can be admitted to the cabin through adjustable shutters. /


adopt |verb| to choose to use something as standard equipment or to make it standard procedure / A policy of no smoking on all flights has been adopted by many airlines. / - widely adopted > now in standard use with many companies, institutions and organizations


adoption |noun| the act of using something as standard equipment or making it standard procedure / In spite of the adoption of the axial flow type compressor, some engines retain the centrifugal type. /


ADR |abbreviation| accident data recorder


ADS |abbreviation| automatic dependent surveillance


ADT |abbreviation| approved departure time


advance |noun|  1. a change that improves something - enormous advances in aircraft design > great progress or developments in aircraft design  2. - in advance of > ahead of / The Gulf region is three hours in advance of GMT. / |verb|  1. to move forwards, or move something forwards - the throttle lever is advanced > the throttle lever is moved forwards  2. to make something happen at an earlier time - to advance the ignition > to adjust the timing of the ignition so that the spark occurs earlier


advanced |adjective| modern and sophisticated / The A340 is an advanced type of aircraft. /


Advanced Visual Docking Guidance System |noun| another term for the Nose-in Guidance System or PAPA (Parallel Aircraft Parking Aid). Different technologies are used, but basically they all use a system of lights to guide the crew to the correct position for their aircraft type


advantage |noun| a good or beneficial factor / The multi-wheel combination has the advantage of smaller and lighter undercarriage structures. / - to take advantage of > to get benefit from a situation - to take advantage of favorable winds > to use tailwinds to increase ground speed and thus save time and money. Opposite: disadvantage


advantageous |adjective| better - the most advantageous > the best / The minimum time path is the most advantageous for economy. /


advect |verb| to move in a horizontal direction due to convection / Dispersal of hill fog takes place when surface heating lifts the cloud base or drier air is advected. /


advection |noun| the movement of air in a horizontal direction


advection fog |noun| fog which forms when warmer moist air moves over a colder surface


advent |noun| an arrival, especially of something very important / With the advent of satellite navigation systems, pilots of light aircraft have a more accurate means of knowing their position. /


adverse |adjective|  1. bad or poor / Only in extremely adverse conditions should the crew evacuate the aircraft. / - adverse handling characteristics > aspects of an aircraft’s handling which are poor  2. acting or going against you


adverse yaw |noun| yaw caused by aileron drag, in the opposite direction to the direction of the intended turn


advice |noun| useful or helpful information / The instructor’s advice was of great help to the student pilot. / (NOTE: Advice has no plural form.)


advisability |noun| - the advisability of something > whether something is a good idea or not / Flying manuals often contain guidance on the advisability of flying with a cold. /


advisable |adjective| recommended, suggested / It is advisable to check the condition of the tires after each landing. /


advise |verb|  1. to inform, to notify / The flight deck advised the cabin crew that descent would start in 20 minutes. /  2. to recommend, to suggest / Because of the bad weather, the instructor advised the trainee pilot not to fly. / - to advise against > to recommend or to suggest that something should not be done


advisory |adjective| giving advice and information


advisory airspace |noun| airspace containing advisory routes in which air traffic control provide an advisory service but not full control. Abbreviation: ADA


advisory route |noun| a published route for which there is an advisory service. Abbreviation: ADR


advisory service |noun| a service in which Air Traffic Control provides advice and information to assist a pilot in the safe conduct of a flight


AEEC |abbreviation| airlines electronic engineering committee


aerate |verb| to put a gas, especially carbon dioxide or air, into a liquid so that bubbles are formed / Aerated fuel causes problems. / Opposite: de-aerate


aeration |noun| the act of putting a gas, especially carbon dioxide or air, into a liquid / The purpose of the booster pump is to prevent fuel aeration. / Opposite: de-aeration


aerator |noun| a device to put a gas – especially carbon dioxide or air – into a liquid. Opposite: de-aerator


aerial |adjective|  1. happening in the air  2. done by an aircraft in flight - |noun| a device to send or receive radio or TV signals / Ice-covering reduces the effectiveness of aerials. / (NOTE: The US English word with this meaning is antenna.)


aerial display |noun| a display of flying skills and aircraft performance


aerial photography |noun| photography done from an aircraft in the air


aero- |prefix|  1. referring to the air / aerodynamic /  2. referring to aircraft / aero-engine, aero-tow /


aerobatic |adjective| referring to aerobatics / Loops and rolls are aerobatic maneuvers. /


aerobatic aircraft |noun| an aircraft which is designed to perform aerobatics


aerobatic display |noun| a demonstration, often public, of piloting skill and aircraft performance


aerobatics |noun| the art of performing spectacular controlled movements in a flying aircraft for the purposes of entertainment or competition / The Russian pilot gave a great display of aerobatics. /


aerobatic team |noun| a team of pilots and aircraft who perform aerobatics


aerodrome |noun| any area of land or water designed for the taking off and landing of aircraft / Airports and military air bases or stations are types of aerodrome. All aerodromes are marked on charts. / Abbreviation: A/D - disused aerodrome > an aerodrome which is no longer in use for the purpose of taking off and landing aircraft


aerodrome boundaries |plural noun| the physical or geographical limits of an aerodrome


aerodrome circuit |noun| the pattern and direction of aircraft movement in the air around the aerodrome


aerodrome QFE |noun| the barometric pressure setting at which the altimeter reads zero when the aircraft is on the runway


aerodrome QNH |noun| the barometric pressure setting at which the altimeter reads aerodrome elevation when the aircraft is on the runway


aerodrome surveillance monitoring indicator |noun| same as  airport surface detection equipment


aerodrome traffic zone |noun| an area of protected airspace around an aerodrome, which pilots need permission to enter or to move in. Abbreviation: ATZ


aerodynamic |adjective|  1. referring to the way in which objects are affected when they move through the atmosphere  2. referring to a smooth rounded shape which moves easily through the air - aerodynamic design > a streamlined shape that enables something to move easily through the air


aerodynamic braking |noun| the braking effect of drag


aerodynamic forces |noun| the forces of the air which act on an aircraft in flight


aerodynamic resistance |noun| same as drag


aerodynamics |noun| the science that deals with the interaction of moving objects with the atmosphere / Aerodynamics is one of the major areas of study for a trainee pilot. /


aerodyne |noun| an aircraft that is heavier than air and whose lift in flight results from forces caused by its motion through the air, e.g. a plane or helicopter


aero-engine |noun| an engine used in aircraft / Most piston aero-engines are cooled by air. /


aerofoil |noun| a surface which is shaped to produce more lift than drag when moved through the air / Wings, ailerons, elevators, fins and propellers are all examples of aerofoils. / (NOTE: The US English word is airfoil.)


aeronautical |adjective| referring to aeronautics


aeronautical chart |noun| a map used in air navigation which may include topographic features, hazards and obstructions, navigational aids and routes, designated airspace and airports


aeronautical engineer |noun| an engineer who specializes in the design of aircraft


aeronautical engineering |noun| the science or study of the design of aircraft


aeronautical fixed service |noun| a radio communications service between fixed points that is designed to enable aircraft to travel safely. Abbreviation: AFS


aeronautical fixed telecommunication network |noun| a ground-based network of teleprinters that transmits flight plans and similar data between control centers. Abbreviation: AFTN


aeronautical information circular |noun| a notice issued by an aviation authority in which information is given about administrative, technical, safety or operational matters


Aeronautical Information Publication |noun| a document issued by a state in which information is given about aviation in that country. Abbreviation: AIP


aeronautics |noun|  1. the science of aircraft design, construction and operation  2. the theory and practice of aircraft navigation


aeroneurosis |noun| anxiety and fatigue in airline pilots as a result of long periods of flying


aeroplane |noun| a power-driven, heavier-than-air craft with fixed wings (NOTE: Many people use the words aeroplane and aircraft as if they had exactly the same meaning. However, aeroplanes, hot-air balloons, helicopters, airships and gliders are all aircraft. The US English is airplane.)


aeroplane performance |noun| a description in figures of what a plane can do, including, e.g., its speed, rate of climb, and the length of its take-off run


aerostat |noun| a hot-air or gas-filled aircraft, e.g. an airship or balloon


aero-tow |noun| a technique of using a powered aircraft to pull a glider into the air / An aero-tow to 2,000 feet costs $25. /


AFCS |abbreviation| automatic flight control system


AFDS |abbreviation| autopilot flight director system


affect |verb| to have an influence on something, or cause a change in something / Humidity and air density are factors which affect the output of the engine. /


AFI |abbreviation| assistant flying instructor


AFIC |abbreviation| assistant flying instructor course


AFIS |abbreviation| aerodrome flight information service


AFS |abbreviation|  1. aeronautical fixed service  2. auto-flight system


aft |adjective| towards the rear part of the aircraft / The rear part of the fuselage is called the aft section. / - aft cabin > the passenger compartment at the back of the aircraft |adverb| rearwards or backwards - to move the control column aft > to move the control column backwards. Opposite: fore, forward


after |adjective| positioned closer to the rear of an aircraft |adverb| closer to the rear of an aircraft


afterburner |noun| a system that injects fuel into the hot exhaust gases of a jet engine in order to increase thrust


AFTN |abbreviation| aeronautical fixed telecommunication network


against |preposition|  1. in relation to, compared with / The airspeed against angle of attack ratio was a concern. /  2. in contact with / The aircraft overran the end of the runway and came to a stop against the boundary fence. /


agent |noun|  1. a chemical substance which causes a change / If de-icing fluid is used as an anti-icing agent it should be sprayed onto the aircraft before the onset of icing. / - extinguishing agent > a substance used to put out fires  2. a person who represents a company or arranges something for a company / the agent for British Airways /


aggregate |noun| the total obtained by adding / The aggregate of the capacity of all the fuel tanks is 50 gallons. / |verb| to add or come together to form a mass or total / Ice crystals aggregate to form snowflakes. /


AGL |abbreviation| above ground level


AGNIS |abbreviation| Azimuth Guidance for Nose-In Stand


agree |verb|  1. to have the same idea or opinion about something / The crew agreed with the findings of the investigation. /  2. to come to an understanding / After hours of discussion, the cabin staff agreed to call off the planned strike. /


agreed |adjective| generally accepted / The millibar is an agreed unit of pressure. /


agreement |noun|  1. the state of having the same idea or opinion as somebody - we are in agreement > we agree  2. a document in which the things that two or more people or organizations have agreed to do are written down / Regional Air Navigation Agreements /


ahead |adverb| in front - look ahead > look some distance in front of you - straight ahead > directly in front


ahead of |preposition|  1. in front of / Air ahead of a cold front is warmer than air behind a cold front. /  2. in advance of or at an earlier time than /The flight from Paris arrived 10 minutes ahead of schedule./


AHRS |noun| a sensor which provides information on the pitch, bank and heading of an aircraft. Full form : attitude heading reference system


AI |abbreviation| attitude indicator


AIAA |abbreviation| area of intense air activity


AIC |abbreviation| aeronautical information circular


aid |noun| something which helps somebody do something |verb| to help / Computers can aid students in their studies. /


AIDS |abbreviation|  1. airborne integrated data system   2. aircraft integrated data system


aileron |noun| a horizontal control surface hinged to the main-plane, which enables an aircraft to bank or roll / By rotating the yoke the ailerons are moved and the aircraft rolls into a turn. / (NOTE: The word comes from the French ‘aile’, meaning ‘wing’.)


aileron power control unit |noun| a hydraulically powered servo-control which moves the ailerons on the outer wings


aim |noun| a goal or objective / A 100% safe operation is the aim of all airline companies. / |verb| to intend or to try to do something - we aim to succeed > we intend to succeed


AIP |abbreviation| Aeronautical Information Publication


air |noun| the mixture of gases which forms the Earth’s atmosphere / Air enters the cabin through an inlet. /


AIRAC |abbreviation| aeronautical information regulation and control


Air Accident Investigation Branch |noun| the department of the CAA of the United Kingdom responsible for establishing the cause of accidents. Abbreviation: AAIB


Air Navigation Service Provider |noun| organisation providing air traffic control within a given region for example, Aerothai, Airways NZ, DFS, FANA, FAA, NAV Canada, NATS, PANSA, ENAV etc. Abbreviation: ANSP


Air Safety report |noun| a report written after an operational incident. Transparent, non-blaming reporting of incidents contributes significantly to improvements in safety and a better understanding of error chains


Air Start Unit |noun| ground support vehicle which compresses air and delivers it to the aircraft engine if the APU is not available. Abbreviation: ASU


airborne |adjective| lifted and kept in the air by aerodynamic forces / Shortly after the aircraft becomes airborne, the undercarriage is retracted. /


Airborne Collision Avoidance System |noun| an aircraft system using Secondary Surveillance Radar (SSR) transponder signals, which operates independently of ground equipment to alert the flight crew about conflicting aircraft. Abbreviation: ACAS


airborne installation |noun| a radio device in an aircraft which operates in conjunction with a ground installation / The airborne installation comprises an antenna, receiver and indicator(s). /


airborne weather radar |noun| a radar installation in an aircraft to give the flight crew information about the weather along their route. Abbreviation: AWR


air-breathing engine |noun| an engine that burns a mixture of liquid fuel and air (NOTE: There are four types of air-breathing engine: turbojet, turbo prop, turbofan and ramjet.)


air bridge |noun| a link provided by aircraft that carry people and supplies between two places, especially in situations where travel by land is not possible


Airbus |noun| a trademark for a large passenger jet aircraft manufactured by aerospace companies from different European countries working together


air conditioner |noun| a device which filters and cools the air in a room or in an aircraft / In order to obtain maximum engine power, the air conditioner should be switched off for take-off. /


air conditioning |noun| a system for controlling the temperature of the air in a building or in an aircraft


air-cooled |adjective| cooled by means of a flow of air - air-cooled engines > piston aero-engines cooled by air, not water


air corridor |noun| a route that aircraft must take through an area in which flying is restricted


aircraft |noun| a machine that is able to travel through the air / Airplanes, gliders, balloons, airships, helicopters, etc., are all aircraft. / Abbreviation: ACFT (NOTE: Aircraft has no plural form.)


aircraft classification number |noun| a number expressing the relative effect of an aircraft on a pavement for a specified sub-grade strength. Abbreviation: ACN


aircraft condition monitoring system |noun| full form of ACMS


aircraft configuration |noun| a particular combination of moveable parts such as flaps and landing gear that affects the aerodynamics of the aircraft


aircraft maintenance technician |noun| an aircraft mechanic or engineer who inspects and services the aircraft (engine oil levels, tire pressure and wear, signs of fuel or hydraulic leaks, impact damage to the engine air intakes and wing leading edges etc.), performs any small repairs and makes entries in the aircraft technical logbook. These activities are also called line maintenance.


aircraft proximity hazard |noun| same as airprox


aircraft stability |noun| the tendency of an aircraft to return to its original attitude after being deflected


aircrew |noun| the pilot, navigator and other crew members of an aircraft


air cushion vehicle |noun| same as  hovercraft


air data computer |noun| an electronic device which provides information such as air temperature, airspeed and static pressure. Abbreviation: ADC


air density |noun| the density of the atmosphere


airfield |noun| an area of land given over to runways, taxiways and aprons / When the pressure setting on the altimeter is set to 1013.25 millibars, the pressure altitude of the airfield is known as QNE. /


air filter |noun| a device to filter solid particles out of the air in engine and ventilation systems


airflow |noun|  1. the movement of air over the aircraft as it travels through the atmosphere  2. a current of air flowing through or past an object or body /The compressor must provide an adequate airflow through the engine./


airfoil |noun| US same as aerofoil


airframe |noun| the body of the aircraft without the engines, instruments and internal fittings / The airframe has to be built to very specific requirements. /


airframe icing |noun| ice that forms on the aircraft structure as opposed to on components such as carburetors


air gap |noun| a space between two things - air gap type spark plug > a spark plug with a space between the electrodes, across which the spark jumps


air intake |noun| the front part of a jet engine where air enters


air lane |noun| a regular route that aircraft fly along


airline |noun| a company which manages air transport services for passengers or goods / Which airline is she working for, Air France or Air Canada? Most airlines do not allow passengers to smoke during flight. /


airliner |noun| an aircraft designed to carry large numbers of passengers /Concorde is the world’s fastest airliner./


airline representative |noun| a person who acts on behalf of an airline, or a person who works for an airline / Passengers should assemble in the departure lounge where an airline representative will meet them. /


airline security area |noun| an area in which measures are taken by an airline to ensure the safety of people and property


Airline Transport Pilot’s License |noun| the license that a person must have to be the pilot-in-command or co-pilot of a public transport aircraft. Abbreviation: ATPL


airman |noun| a person who is a member of a country’s Air Force


airmanship |noun| all-round skill in piloting an aircraft which includes academic knowledge, common sense, quick reactions, awareness, experience, consideration for other people and property / Keeping a careful lookout for other aircraft in the circuit is good airmanship. / ‘I was always told by my airmanship instructor, in an emergency, to find the largest piece of asphalt with the biggest fire trucks’


air mass |noun| a very large mass of air in the atmosphere in which the temperature is almost constant and which is divided from another mass by a front / Air masses are divided into two types according to source region, and these are known as polar and tropical air masses. /


air-park |noun| a small airport, usually found near a business or industrial center


airplane |noun| US  same as  aeroplane


air pocket |noun a| small area where the air is less dense or where there is a downward air current, and which makes an aircraft lose height suddenly


air pollution |noun| pollution of the air by gas, smoke, ash, etc. / Solid particles in the air include dust, sand, volcanic ash and atmospheric pollution. / Also called: atmospheric pollution


airport |noun| a civil aerodrome designed for the take-off and landing of passenger-carrying aircraft for the general public and/or cargo aircraft / London Heathrow is one of the busiest airports in the world. / Abbreviation: A/P


airport authority |noun| the organization responsible for the running of an airport


airport security officer |noun| a person employed by an airport authority to check passengers and baggage for illegal substances or devices, e.g. drugs, guns


airport surface detection equipment |noun| short-range radar equipment that scans the surface area of an airport and tracks the movement of aircraft and other vehicles on the ground


airprox |noun| a situation in which aircraft are too close to one another in an area of airspace and there is the possibility of danger to them. Also called: aircraft proximity hazard


air-sea rescue |noun| a rescue at sea in which aircraft, especially helicopters, are used


airship |noun| a powered, gas-filled balloon which can be steered / An airship is classified as a lighter-than-air craft. /


airshow |noun| a public display of aircraft in flight and on the ground, held at an airfield


air-side |noun| the part of an airport where the aircraft take off and land, load, or unload


air sock |noun| same as  wind-sock


airspace |noun| the part of the atmosphere that is above a particular geographical area and is subject to the laws of a particular country or controlling authority / The Korean 747 flew into Soviet airspace and was shot down. /


airspeed |noun| the speed of the aircraft relative to the air around it / Maintain a constant airspeed on final approach. /


airspeed indicator |noun| a primary cockpit or flight deck instrument which shows the pilot the speed of the aircraft in relation to the air around it / Airspeed is shown in knots on the airspeed indicator. / Abbreviation: ASI (NOTE: The position of the pitot tube and the attitude of an aircraft can affect the accuracy of the airspeed indicator. Aircraft operating handbooks usually have a table to help pilots calculate calibrated airspeed (CAS).


air-stairs |noun| mobile stairs used at outlying stands for passengers to board and disembark


air station |noun| a small airfield with facilities for the maintenance of aircraft


airstream |noun| the flow of air caused by the movement of the aircraft through the air / Pressure is built up inside the pitot tube by the airstream. / (NOTE: Unlike airflow, airstream does not refer to the movement of air around the airframe and its aerodynamic effect).


airstrip |noun| a place for aircraft to take off and land that has no facilities and is often temporary


air taxi |noun| a small commercial aircraft used for short flights between places not on a regular airline route


air terminal |noun|  1. an airport building with a range of facilities where passengers check in before boarding their plane and where they arrive when their plane lands  2. a building in a city for receiving passengers who are being transported to or from an airport by train or bus


air terrorism |noun| violent actions that aim to frighten or kill passengers, disrupt air services, or damage or destroy aircraft in an attempt to achieve a political objective


air-tight |adjective| closed or sealed so that air cannot get in or out


air-to-air |adjective| between one airborne aircraft and another - air-to-air communications > communications between one airborne aircraft and another


air to air refueling area |noun| an area of airspace in which tanker aircraft are permitted to refuel other aircraft in flight. Abbreviation: AARA


air-to-ground visibility |noun| a description of how easily seen an object on the ground is from the air / Glare caused by reflection of sunlight from the top of a layer of fog or haze can seriously reduce the air-to-ground visibility. /


air-to-surface |adjective| directed from a flying aircraft to a point on the ground


air traffic |noun| aircraft operating in the air or on the airport surface / Students who exercise circuit flying need to keep a very careful lookout especially at times when there is a lot of air traffic. /


air traffic control |noun| a service that oversees and guides the movements of aircraft and provides for the safe and efficient flow of air traffic / Controllers in the tower provide an air traffic control service for aircraft in the air around the airfield. / Abbreviation: ATC (NOTE: Air Traffic Control’s main function is to maintain separation between aircraft operating within Instrument Flight Rules (IFR), but it also provides a service to aircraft using Visual Flight Rules (VFR). Ground control is for aircraft taxiing to and from runways. The tower controls aircraft around an airport, clearing them for take-off or landing. Departure and approach controls monitor and control aircraft around the airport, and en route centers control traffic between airports).


air traffic controller |noun| a person who works in air traffic control and whose main task is to ensure correct separation of aircraft in all phases of flight / The air traffic controller approved the emergency landing. / Abbreviation: ATC controller


air traffic movements |plural noun| the number of aircraft taking off and landing / an increase in air traffic movements /


airway |noun| an area of the sky, usually rectangular in cross-section, along which civil aircraft fly from place to place / Airways provide a high degree of safety by ensuring adequate separation between aircraft. Aircraft inside an airway are controlled by ATC. / (NOTE: Airways are usually 10 nautical miles wide with a center line joining navigational beacons.)


Airways |noun| a commercial company operating flights (NOTE: Usually used in the names of companies, e.g. British Airways, South African Airways)


airworthiness |noun| the state of an aircraft with regard to whether it can fly safely, as determined by a national certifying authority


airworthiness directive |noun| a regulation issued by an aviation authority when a problem has been identified with a particular aircraft part. Abbreviation: AD


airworthy |adjective| meeting the standards of a national certifying authority / It is the pilot’s responsibility to ensure that the aircraft is airworthy. /


AIS |abbreviation| aeronautical information services


aisle |noun| a long passageway between the seats in the passenger cabin of an airliner - aisle seat > a seat which is by an aisle, as opposed to a window seat


AlAr |abbreviation| Approach and Landing Accident Reduction


alarm |noun|  1. fear or worry / If the ammeter shows a high level of charge after start-up, it is quite normal and no cause for alarm. /  2. a warning sound or light / In the event of fire or overheat, the control unit will produce an alarm. / |verb| to frighten or worry / Severe turbulence may alarm passengers. /


alert |adjective| fully awake, watchful and ready to deal with any situation / The crew must be alert at all times to the possibility of hijacking, bombs and stowaways. / |noun| a signal, warning everyone to be alert - to be on the alert > to be watchful and ready for anything that may happen - |verb| to warn / It is the cabin staff ’s responsibility to alert the flight crew if they see smoke coming from an engine. /


alight |adjective| on fire / Although the passenger thought he had extinguished his cigarette, it was still alight when he threw it into the waste disposal bin. / - |verb| (formal)  1. (of people) to leave or get off an aeroplane / At some airports, passengers alight onto the apron when they leave the aircraft. /  2. (of aircraft) to land / An aeroplane may not fly over a city below such a height as would allow it to alight in the event of an engine failure. /


align |verb|  1. to position along an axis or line / The nose wheel must be aligned in a fore and aft direction during retraction.2. to set in a correct position in relation to something else / Aligned white marks on the wheel and tire indicate that there is no creep. /


alignment |noun|  1. position in relation to an axis or a line - to check the alignment of something > to make sure it is in the correct position relative to an axis or line - to maintain alignment with the runway > to keep the aircraft on the imaginary extended center line of the runway  2. correct position in relation to something else - out of alignment > not aligned as it should be


alkaline |noun| a substance with a pH value of more than 7


alleviate |verb| to reduce or lessen the harmful effect of something / Anti-icing additives are available to alleviate the problem of icing. /


alleviation |noun| a reduction or lessening of the harmful effect of something / Deep, regular breathing may provide some alleviation from stress. /


allocate |verb| to provide something particular for a given purpose / Special seats are allocated to mothers with small children. /


allocation |noun| the provision of something particular for a given purpose / At the check-in desk, airline staff are responsible for the allocation of seats to passengers. / - frequency allocation > the frequency or range of radio frequencies set aside for a particular use / The frequency allocation for VOR is 108–117.975 MHz. /


allow |verb| to enable, to permit or to authorize / An engine should be run at low rpm after flight to allow engine components to cool. Additional fuel is carried to allow for holding en route. Passengers are not allowed to smoke on some airplanes. /


allowable |adjective| permitted or authorized / maximum allowable weight, maximum allowable tire pressure /


allowance |noun|  1. consideration for possibilities or changing circumstances - to make allowances for > to take into account / When estimating flight duration, make allowances for taxiing time. /  2. something such as money given at regular intervals or for a specific purpose / a travel allowance to cover hotel and restaurant bills. /  3. the amount of something that somebody is allowed to have ‘…with many four and six seat aircraft, it is not possible to fill all the seats, use the maximum baggage allowance, fill all the fuel tanks and remain within the approved center of gravity limits’ [Civil Aviation Authority, General Aviation Safety Sense Leaflet]


alloy |noun| a mixture of metals / an alloy of aluminum and lithium /


aloft |adjective| up in the air


alter |verb| to change, modify or adjust / If there is a risk of collision, alter course to the right. If the rate of descent is too low, alter the throttle setting accordingly. The rudder linkage was altered to comply with certification requirements. /


alteration |noun|  1. a change, modification or adjustment / It was discovered that alterations had been made to the log book. As a result of the accident, alterations were made to the design of the carburetor heat system. /  2. the act of making changes, modifications or adjustments - heading alteration > the act of making of heading corrections


alternate |adjective|  1. every other / A, c, e, and g are alternate letters, as are b, d, f, h, etc. / - alternate days > every other day / There are outward flights on alternate days, i.e. on Mondays, Wednesdays and Fridays. /  2. US same as alternative - |noun| an aerodrome of second choice to be used if the aircraft cannot be landed at the aerodrome of first choice because of bad weather, etc. / The point of no return is calculated before departure to cover the chance that both the terminal airfield and its alternate become unavailable during flight. / - |verb| to happen in turns - Captain Smith and Captain Jones alternate as CFI on a daily rota > each captain has one day on duty as CFI followed by a day off, on which the other captain acts as CFI


alternating current |noun| an electric current which reverses its direction at regular intervals / Resistance to alternating current remains almost constant and is independent of frequency. / Abbreviation: AC


alternative |adjective| referring to another or a second possibility / A turbine bypass, in the form of an alternative exhaust duct is fitted with a valve. / - an alternative means of doing something > another or different way of doing something - |noun| another choice or possibility / In some emergency situations the pilot may have no alternative but to force-land the aircraft as soon as possible. /


alternator |noun| a type of generator designed to produce AC power


altimeter |noun| a radio instrument for measuring vertical distance or altitude - altimeter check > a routine check to ensure that the altimeter pressure setting is correct - altimeter display > the display of altitude information, which can be given in analogue or digital form (pointer) - altimeter setting > standard pressure altitude with reference to sea level (QNH) or local pressure altitude at the airport elevation (QFE) set by the crew on their altimeter and critical, especially during descent and approach


altitude |noun| the vertical distance between an aircraft, or a point or a level, and mean sea-level - to lose altitude > to descend from higher to lower altitude - cabin altitude > the artificial altitude created in the cabin by pressurization


altitude restriction |noun| an obligation for the crew to not fly above or below a certain altitude at a given point or in a given area


alto- |prefix| at a moderate or high altitude


alto-cumulus |noun| small white cumulus clouds which form as a layer at moderate altitude, usually meaning fair weather.


alto-stratus |noun| a uniform layer cloud at moderate altitude


aluminium |noun| a strong, light metal used in the construction of aircraft (NOTE: The US English is aluminum.)


aluminum |noun| US same as aluminium


AMA |abbreviation| approach monitoring aid


amber |adjective| an orange or yellow color / An amber light flashes on the instrument panel. / (NOTE: Amber is often used to describe the color of the yellow light in traffic signals.)


amber transit lights |noun| the amber lights neat the landing gear lever which are illuminated when the landing gear is moving between its extended and retracted positions and vice versa


ambient |adjective| referring to the surrounding atmospheric conditions / Fresh ambient air is routed into the cabin. / - ambient temperature > the temperature outside the aircraft


ambient lighting |noun| the general lighting of the cockpit provided by the dome light


ambient pressure |noun| the pressure outside the aircraft


ambiguity |noun| something heard or seen which can be understood in more than one way, thus resulting in possible confusion - to avoid ambiguity > to avoid misunderstanding or confusion / Correct use of R/T phraseology avoids ambiguity. /


ambiguous |adjective| able to be understood in more than one way / It is important that R/T transmissions are not ambiguous. /


AMD |abbreviation| amendment


amend |verb| to change, update, improve or correct something - he amended the entry in his log book > he corrected or changed the entry in his log book


amendment |noun| a change, updating, improvement or correction made, e.g., to a document or procedure / When a terminal aerodrome forecast requires amendment, the amended forecast is indicated by inserting AMD after TAF. /


ammeter |noun| an instrument for measuring amperes in order to give the strength of an electric current / The center-zero ammeter tells the pilot the status of the aircraft battery. /


amp |abbreviation| ampere


amperage |noun| the strength of an electric current expressed in amperes / Measuring the amperage of a motor can give a rough estimate of the load on the motor. /


ampere |noun| a unit of electric current equal to one volt flowing through an impedance of one ohm / Current flow is measured in amperes. / Abbreviation: amp - ampere hours > number of amperes per hour / Battery capacity is rated in ampere hours. /


ample |adjective| plenty of / During the course you will have ample opportunity to demonstrate your skill. / - ample time > plenty of time


amplification |noun| the act of increasing the strength of an electrical signal / Amplification of the signal increases the volume. /


amplifier |noun| an electronic device for increasing the strength of an electrical signal / If the power supply from the amplifier to the gauge fails, the needle slowly falls to zero. /


amplify |verb| to increase the strength of an electrical signal / An electric current is amplified and then transmitted. / (NOTE: amplifies – amplifying – amplified)


amplitude |noun| the maximum variation of a vibration or oscillation from the position of equilibrium / to calculate fuel required, multiply the duration of the flight by the consumption of the engine at the required power /


AMS |abbreviation| aeronautical mobile service


AMSL |abbreviation| above mean sea level


AMSS |abbreviation| automatic message switching system


anabatic |adjective| referring to a warm flow of air traveling up a hillside or mountainside.


anabatic wind |noun| a wind current, caused by solar heating of the land, that rises up a south-facing mountainside / South-facing slopes are most suitable for the anabatic wind. /


analog |adjective| same as analogue


analogous |adjective| similar or comparable to / Isobars are analogous to contour lines. /


analogue |adjective| 1. representing a quantity or signal that varies continuously by means of a physical apparatus such as a dial and pointer / The electronic centralized aircraft monitor (ECAM) does not have analogue presentation of engine information. /  2. - analogue display (on a clock) > a traditional hands and face display on a clock or dial.


analyze |verb| to break down into parts and study very closely - to analyze fuel > to separate fuel into its different parts to find out what it consists of - to analyze a chart > to examine a chart in detail


analysis |noun| breaking down a substance into its parts in order to study them closely / At a crash site, samples of materials are removed for analysis. / (NOTE: The plural form is analyses.) - chart analysis > careful study of charts


anchor |noun| a device connected to and dropped from a boat in order to prevent the boat from moving in the water - |verb| to drop an anchor > to prevent the boat from moving


anemograph |noun| an instrument which maintains a continuous recording of wind direction and speed on a graph / The anemograph gives a continuous recording of wind velocity which is displayed on a chart and reveals gusts, squalls and lulls. /


anemometer |noun| an instrument, usually attached to a building, with three or four ‘cups’ which rotate with the wind thus providing wind-speed information / The strength of the wind can be seen by the speed with which the anemometer rotates. /


aneroid |adjective| not containing or using liquid


aneroid barometer |noun| a barometer which uses an aneroid capsule to sense atmospheric pressure changes


aneroid capsule |noun| a thin flexible cylindrical box, usually made of metal, which has most of the air removed from it and which expands and contracts with changes in atmospheric pressure / The aneroid capsule in the barometer is connected to a system of levers which operate a pointer. /


aneroid switch |noun| a switch operated by an aneroid capsule


angle |noun| the difference in direction between two lines or surfaces measured in degrees


angled exit / turn-off |noun| exit designed to facilitate aircraft vacating the runway at speed, hence the term high-speed turnoff, and performing a rolling start for take-off


angle of attack |noun| the angle formed between the relative airflow and the chord line of the airfoil (NOTE: The angle of attack is related to the flight path of the aircraft, not to the angle the wing makes with the horizontal. If the angle of attack becomes too great, the smooth airflow over the upper surface of the wing will break down. If no corrective action is taken by the pilot, there will be a sudden loss of lift and the aircraft will stall).


angle of incidence |noun| the angle formed between the chord-line of the main-plane and the horizontal when the aircraft is in the rigging position


angle of inclination |noun| the angle formed between a sloping path or surface and a reference point or line which is either horizontal or vertical / Between any two meridians there is an angle of inclination one to the other which varies with latitude. /


angular |adjective| referring to or forming an angle / The angular difference between the direction of magnetic north and compass north is called variation. /


anneal |verb| to heat and allow to cool slowly in order to strengthen / Sheet and plate magnesium are annealed at the rolling mill. /


annotate |verb| to add notes to an existing document, book, chart, etc. / He annotated his report after he was asked to give the exact time of the incident. Variation is annotated east or west according to the direction of change. /


annotation |noun| the act of adding notes to a document, book, chart, etc., or the notes added


announce |verb| to state something publicly or officially / British Airways announce the departure of flight BA152 to New York. /


announcement |noun| a public statement / The captain made a public address (PA) system announcement asking passengers to remain seated. /


annual |adjective|  1. happening once a year - annual inspection > an inspection that happens once a year  2. over a period of one year / Overload operations should not exceed 5% of annual departures. /


annular |adjective| shaped like a ring


annunciation |noun| an announcement or indication on the annunciator panel - failure annunciation > signals on the annunciator panel indicating the failure of a system


annunciator |noun| a device which gives off a sound or light to indicate which of several electrical circuits is active / An annunciator panel may contain a precise warning. /


anode |noun| a positive pole or electrode / The positive connector of a battery is usually called the anode and is indicated by the sign +. /


anodize |verb| to coat or cover by using electrolysis / Anti-corrosion treatment includes the anodizing of aluminum parts. /


anomalous |adjective| referring to something unusual, unexpected or otherwise departing from what is the normal order or range - an anomalous instrument reading > an unusual instrument reading which may require further investigation


anomaly |noun| something unusual, unexpected or otherwise not within the normal order or range / Any anomalies in the localiser will be detected during calibration. /


anoxia |noun| a state in which no oxygen reaches the body tissues, resulting in death.


ANSP |abbreviation| Air Navigation Service Provider


antenna |noun| US same as aerial


anti- |prefix| against, opposing /anti-icing, anticlockwise, anti-corrosion/


anticipate |verb| to realize what is likely happen and do what is necessary in readiness - during takeoffs, pilots should anticipate an engine failure > pilots should think ahead and be ready to act immediately if an engine fails during take-off


anticipation |noun| a state in which you realize what is likely to happen and do what is necessary in readiness


anticipation of landmarks |noun| the action of watching out for landmarks, which you know from flight planning should be visible at a particular stage of a flight


anticlockwise |adjective|,|adverb| referring to a circular movement in the opposite direction to the hands of a clock / Turn the nut anticlockwise to loosen it. / Opposite: clockwise


anti-collision |adjective| helping to prevent collisions


anti-collision light |noun| a flashing white/red light on an aircraft


anti-corrosion |adjective| protecting against corrosion, especially rust / an anti-corrosion treatment /


anticyclone |noun| an area of high atmospheric pressure, usually associated with fine dry weather in summer and fog in winter / Winds circulate round an anticyclone clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. /


anti-icing |adjective| all the pneumatic systems which prevent the accumulation of ice on the wing leading edges and engine air intakes / wing anti-ice, engine anti-ice /


anti-icing fluid |noun| a fluid which prevents icing


anti-skid |adjective| designed to prevent skidding


Antonov |noun| Russian aircraft manufacturer / The Antonov 124 and 225 are currently among the world’s largest cargo aircraft. The Antonov 225 has a maximum take-off weight of approximately 600 tonnes. /


anvil |noun| a metal block which ends in a point, has a rounded bottom and a flat top, and on which horseshoes, etc., are made / A cumulonimbus cloud has a characteristic anvil shape. /


anvil cloud |noun| a cloud, usually a large dark thundercloud, which has the shape of an anvil


A/P |abbreviation|  1. airport  2. autopilot


apart |adverb| separated from one another / The jets were only 200 feet apart, vertically. /


aperture |noun| an opening / Any aperture or cut-out in the fuselage structure must be specially strengthened./


APHAZ |abbreviation| aircraft proximity hazard


APP |abbreviation|  1. approach  2. approach control


apparent |adjective|  1. obvious, clear / It became apparent that carbon monoxide was entering the cabin. / - from the above, it will be apparent that … > from the above, it will be clear that …  2. seeming or appearing to be / The ILS showed an apparent deflection to the right. /


appear |verb|  1. to come into view / Another aircraft appeared on the radar screen. /  2. to seem to be / Although air may appear to be still, it is in fact, moving. /


appearance |noun|  1. an instance of being seen or coming into view / The appearance of the passenger on the flight deck surprised the crew. /  2. the way something looks / It may be difficult to recognize a particular stretch of coast in an area simply by its appearance. /


appendix |noun| a section containing additional information, often found at the end of a book, etc. / Charts are reproduced as an appendix to the map section. / (NOTE: The plural form is appendices.)


applicable |adjective|  1. relevant or appropriate - rule 24 is not applicable in this case > rule 24 cannot be used in this case  2. suitable, necessary, appropriate / Emergency systems are checked when applicable. /


application |noun|  1. a formal request, often on paper, for employment - application form > a form to be filled out by a person looking for a job, and sent back to the organization offering the job  2. the act of putting a substance onto something - the application of a coat of paint > the covering of something with a coat of paint  3. the act of using something, e.g. an ability, to carry out a task / When an accident occurs, the application of knowledge and skills is important. /


apply |verb|  1. to apply for a job > to formally ask for employment / He applied for the post of chief engineer but was not successful. /  2. to put on / Apply a plaster to the skin. /  3. to use something to carry out a task / Apply the same method as in the example. /  4. to be relevant or relate to / The rules which apply to the measurement of wind velocities on isobaric charts apply equally to contour charts. / (NOTE: applying – applied)


appreciable |adjective|  1. possible to measure / Appreciable weakening may be permitted without risk of failure. /  2. considerable, large in size or amount - there is an appreciable difference between statute miles and nautical miles > there is a big difference between statute miles and nautical miles


appreciate |verb|  1. to understand or recognize the importance or significance of something / The map reader is in a position to appreciate the relative values of the features seen on the ground. /  2. to increase in value / The value of the building has appreciated by 100% in 10 years. / Opposite: depreciate  3. to be thankful or grateful for something / The student appreciated the extra help given by the instructor. /


appreciation |noun|  1. understanding / It is essential to have an appreciation of the basic gas laws. /  2. an increase in value / There has been an appreciation of 100% in the value of the building in 10 years. / Opposite: depreciation  3. thankfulness, gratitude / After gaining her private pilot’s license, the newly-qualified pilot showed her appreciation by sending a letter of thanks to her instructor. /


approach |noun|  1. a path towards something / The approach to the terminal was blocked by an overturned lorry. /  2. the descent of an aircraft towards the place where it intends to land. Abbreviation: APP  3. a way of achieving or doing something - to take a different approach to a situation > to deal with or to manage a situation in a different way - |verb|  1. to move nearer in place or time to something / The aircraft is approaching a danger area. / - nightfall is approaching > it will soon be dark  2. to have a particular mental attitude towards something / He approaches his studies with great enthusiasm. /  3. to speak to or get in touch with somebody / You must approach the chief flying instructor regarding your request for a week’s holiday. /


approach charts |plural noun| instrument approach charts show holding procedures, instrument approach procedures and missed approach procedures. In addition to the plan and profile views of various instrument procedures, the charts provide a wealth of other information: obstacle location and clearance height (OCH); ground speeds versus rates of descent; VOR-DME, LOC, G/S, IAF identifiers and frequencies; transition altitudes and levels; airfield elevation in feet and meters; Tower, Approach, Ground and ATIS radio frequencies; the location of outer, middle and inner markers, fixes and missed approach point; ILS minimum; minimum safe /descent altitudes; final approach course; decision height / altitude; threshold crossing heights (TCH); missed approach procedure etc.


approach control |noun| a control station in an air traffic control center that guides an aircraft while it is making its approach


Approach Control frequency |noun|  the frequency used by the Approach controllers at a given airport as distinct from the Tower or Ground frequencies


approach gate |noun| an imaginary point used as a basis for vectoring the aircraft to the final approach course. The gate will be established along the final approach course 1 mile from the final approach fix on the side away from the airport and will be no closer than 5 miles from the landing threshold.


approach monitoring aid |noun| an instrument or system that helps an air traffic controller to track the position and movements of an aircraft during its approach. Abbreviation: AMA


approach path |noun| the course taken by the aircraft in preparation for landing


approach plate |noun| a document issued by an aviation authority which provides detailed information about how to land at a given airport in very poor visibility


approach segments |plural noun| the parts of an instrument approach: arrival, initial approach, intermediate approach, final approach and missed approach segments


approach to land |noun| the final stage of the flight when the aircraft is maneuvered into position, relative to the landing area, in preparation for landing / on the approach to land, the aircraft reduces speed and height /


appropriate |adjective| suitable or needed - appropriate action > the action that is needed to deal with the situation


appropriately |adverb| in a way that it is suitable or necessary - to adjust the mixture appropriately > to adjust the mixture to suit the conditions


approval |noun| permission or agreement - with the captain’s approval > with the permission of the captain - to meet with the approval > to be approved by / The management’s plans for restructuring the airline met with the approval of the shareholders. /


approve |verb|  1. to allow or agree to something / The air traffic controller approved the emergency landing. /  2. to approve of > to believe something to be right or good / Nearly everybody approved of the new color scheme for the furnishings. / - he doesn’t approve of women being airline pilots > he believes that it is wrong for women to be airline pilots


approx |adjective| same as approximate, approximately


approximate |adjective| not exact, around or about - an approximate distance of 60 nautical miles > about 60 nautical miles - |verb| to be close to, to be around  (NOTE: Approximate can be shortened to approx or APRX (ICAO).)


approximately |adverb| not exactly, around or about / Approximately 2,000 people work in the airport. /


approximation |noun| a calculation which is not exact but near enough, a rough estimate - an approximation of aircraft height > a rough estimate of aircraft height


apron |noun| an area of tarmac, concrete, etc., outside a hangar for parking aircraft (NOTE: The US term is ramp.)


APRX |abbreviation| (ICAO)  1. approximate  2. approximately


APU |abbreviation| auxiliary power unit


aquaplaning |noun| sliding in an uncontrolled way over a thin layer of water on the runway / Aquaplaning is caused by a layer of water between the tire and the runway. /


arbitrary |adjective| decided by chance rather than by careful logical thought, happening without planning or at random / The statute mile is an arbitrary unit of measurement. /


arc |noun| part of the circumference of a circle / A nautical mile is the length of an arc on the Earth’s surface subtended by an angle of one minute at the center of the Earth. / - |verb| to jump across a gap / The spark arcs from one electrode to another. /


Arctic |adjective| referring to the area around the North Pole - cold Arctic air > cold air from the Arctic - the Arctic Circle > a parallel running round the Earth at latitude 66°32N, to the north of which lies the Arctic region - |noun| the Arctic > the area of the Earth’s surface around the North Pole, north of the Arctic Circle / The aircraft flew over the Arctic. /


area |noun|  1. a defined part of a surface  2. a region - area forecasts > a weather forecast for a region rather than, e.g., an aerodrome


area control service |noun| a unit that provides air traffic control services to flights within the area for which it is responsible


area navigation |noun| a method of navigation that permits aircraft to operate on any desired flight path within the area covered by ground-based navigational aids, self-contained navigational aids or a combination of the two. Abbreviation: RNAV


argument |noun|  1. a factor / QNH is the pressure at station level reduced to sea level using arguments of station height and an international standard atmosphere. /  2. a verbal disagreement - to have an argument > to disagree openly and verbally with somebody / The investigation revealed that there had been an argument between the commander and the copilot about the advisability of continuing with the final approach to land. /  3. a reason / One of the arguments in favor of building the new terminal is the increase in opportunities of employment for the local residents. /


arid |adjective| very dry - arid terrain > desert - an arid, sub-tropical climate > a hot, dry climate


arise |verb| to come into being, to happen, to show up or to appear / Should any problems arise, report back to me immediately. / (NOTE: arising – arose – arisen)


arm |noun|  1. a device similar in function to a human arm, operating as a lever  2. the horizontal distance from a reference point to the center of gravity / The principle of the arm is used in weight and balance calculations for an aircraft. / |verb| to make ready for action or use / Door-mounted escape slides are armed before flight. /


armature |noun| the rotating coils of an electric motor or dynamo / Secondary windings are wound over the primary windings and the whole assembly is known as an armature. /


ARR |abbreviation| arrival


arrange |verb|  1. to organize, to plan and prepare  2. to put in special position / Charts should be numbered and arranged in order of use. A series of dipoles are arranged in a circle. /


arrangement |noun|  1. a plan / The arrangements for the VIPs are being handled by the public relations department. /  2. the relative positions of a number of different parts / The diagram shows a simple arrangement of pistons, cylinders and pipes. /


array |noun| an arrangement of antennas / The localiser antenna array is very wide. /


arrest |verb|  1. to stop or to prevent something from happening - to arrest the spread of a fire > to stop the fire spreading  2. to hold somebody for breaking the law / He was arrested at the airport. / |noun| the act of holding somebody for breaking the law / His arrest was unexpected. /


arrester |noun| a device or substance which prevents or stops something from happening


arrival |noun| the act of reaching somewhere. Abbreviation: ARR - Gulf Air announce the arrival of flight GF147 from Abu Dhabi > flight GF147 from Abu Dhabi has just landed


arrivals |noun| the part of an airport that deals with passengers who are arriving


arrive |verb| to reach somewhere - the flight from Tokyo arrived at 8.30 > the flight from Tokyo landed at 8.30


arrow |noun| a painted or printed sign which points to something / Non-return valves are marked with an arrow which shows the direction of flow. /


arrow convention |noun| an agreed method of using arrows when drawing wind triangles


article |noun| an object, an item - loose articles > things which may move during flight and cause problems


artificial |adjective| not natural, made by humans / The small needle indicates cabin altitude or the artificial altitude created by the pressurization system. /


artificial horizon |noun| an instrument that displays the degree of pitch or bank of an aircraft relative to the horizon


asap |abbreviation| as soon as possible: immediately, very quickly


ascend |verb| to rise, to go or move upwards / Hot air ascends. / - in ascending order > in order of number or rank with the smallest or less important at the bottom and the largest or more important at the top. Opposite: descend


ascent |noun| a rise, a slow upward movement / In a stable atmosphere where the ascent of air is forced, precipitation is mostly light and occasionally moderate. /


ascertain |verb| to find out, to make certain / During pre-flight checks, control surfaces should be moved by hand to ascertain that they have full and free movement. /


ASDE |abbreviation| airport surface detection equipment


ASI |abbreviation| airspeed indicator


ASMI |abbreviation| aerodrome surface movement indicator


aspect |noun|  1. a part of a problem or subject / Vertical motion is an important aspect of meteorology. / - safety aspects > matters related to safety  2. the view from a particular position / The aspect of the runway on final approach helps the pilot to judge height and progress. /


aspect ratio |noun| the ratio of the length of an aircraft’s wing to the average distance between the front and back edge of the wing (NOTE: Aircraft that operate at low speeds, for example gliders, need a high aspect ratio and have long narrow wings. Supersonic aircraft need a low aspect ratio, which is created by swinging the wings back.)


asphyxiation |noun| unconsciousness or death caused by lack of oxygen / Fire may result in the cabin being filled by smoke causing asphyxiation. /


ASR |abbreviation|  1. airport surveillance radar   2. altimeter setting region


assemble |verb|  1. to put a number of parts together / The parts are made in different countries but the plane is assembled in France. /  2. to gather together / Passengers should assemble in the departure lounge where an airline representative will meet them. /


assembly |noun|  1. something that is made up of smaller parts  2. the act of putting parts together to make a whole / Final assembly of the A320 takes place in France. /


assess |verb| to check, estimate or find out / Cabin crew must assess if their exits are usable. / - to assess a situation > to consider all aspects of a situation


assessment |noun| a judgement on a situation based on careful thought / The captain’s assessment of factors such as aircraft damage, passenger-load, fire, etc., will affect the decision on whether to evacuate the aircraft or not. /


assign |verb| to set apart beforehand or allocate for a specific purpose - assigned seats > seats selected beforehand for particular people / Crew sit in their assigned seats. Individual carriers assign codes to aircraft. / - assigned level > the flight level to which a flight has been cleared by ATC


assist |verb| to help / If you have any difficulty, cabin staff will assist you. When evacuating the aircraft, hand signals by cabin staff assist in directing passengers to the exits. / 


assistance |noun| help - to require assistance > to need help / If a pilot requires assistance, they should contact ATC. / - to provide assistance > to give help


associate |verb| to come with or be linked to something else / Turbulence is often associated with strong winds. The airport authority has to overcome a lot of problems associated with its plans to build a new terminal.  /


association |noun|  1. a group of people who organize themselves into an official body with common objectives and a code of conduct / British Air Line Pilots Association. /  2. - in association with > together with / Rain-ice occurs only rarely over the British Isles and is usually found in association with warm fronts. /


assume |verb|  1. to take as true before there is proof / I assume that she’s ill because she’s not at work today – but I may be wrong. /  2. to suppose - for our studies we will assume that the earth is a perfect sphere > we know that the Earth is not a perfect sphere but it helps if we accept, for the time being, that it is - assuming (that) > accepting or supposing that / Assuming that the return flight from the point of no return to A is made on three engines, calculate the distance from D to the point of no return. /  3. to take on, to undertake the duties of somebody / The copilot assumed control of the aircraft after the captain was taken ill during the flight. /  4. to take a particular bodily position / The correct technique of using the escape slides is to assume a sitting position. /


assumption |noun| an understanding or belief / The one-in-sixty rule is based on the assumption that one nautical mile subtends an angle of one (at a distance of 60 nautical miles). /


ASU |abbreviation| Air Start Unit


asymmetric, asymmetrical |adjective| not identical or equal on each side of an imaginary central dividing line. Opposite: symmetric


asymmetric flight |noun| a condition in which one engine, displaced from the aircraft’s center line is not working


asymmetric power |noun| power on one side of the aircraft’s center line only


asynchronous |adjective|  1. not happening at the same time or rate / An asynchronous orbit is a 24-hour orbit which enables a satellite to remain overhead one part of the Earth’s surface. /  2. not in frequency or phase


asynchronous computer |noun| a computer which does not process information according to the internal clock


at time |preposition| mentioned prior to a given time to avoid confusion with any other value. / request descent at time 45 /


ATA |abbreviation| actual time of arrival


ATC |abbreviation|  1. air traffic control  2. air traffic controller


ATCC |abbreviation| air traffic control center


ATCRU |abbreviation| air traffic control radar unit


ATD |abbreviation| actual time of departure


ATFM |abbreviation| air traffic flow management


ATIS |abbreviation| Automatic Terminal Information Service


ATM |abbreviation| air traffic management


atmosphere |noun|  1. a mixture of gases in a mass surrounding the earth / The surrounding atmosphere moves with the earth. /  2. a unit of measurement of pressure (NOTE: The main gases found in the atmosphere are nitrogen and oxygen. The atmosphere contains less than 1% carbon dioxide and argon, and also traces of hydrogen, helium, krypton, neon, ozone and xenon.)


atmospheric |adjective| referring to the atmosphere / atmospheric density /


atmospheric attenuation |noun| the weakening of a radio signal as it passes through the air


atmospheric pollution |noun| same as air pollution / Solid particles in the air include dust, sand, volcanic ash and atmospheric pollution. /


atmospheric pressure |noun| normal air pressure on the surface of the earth


atmospheric refraction |noun| change in direction of waves due to variations in temperature, pressure and humidity, particularly at lower altitudes


atom |noun| the smallest amount of a substance which can take part in a chemical reaction / An atom consists of a nucleus and electrons. /


atomic |adjective| referring to atoms - atomic structure of matter > the structure of materials and substances at their smallest level


atomization |noun| the reduction of liquids to a fine spray / The fuel achieves fine atomization under pressure. /


atomize |verb| to reduce liquids to a fine spray / The fuel must be atomized or vaporized to combine with the air to permit combustion. /


ATPL |abbreviation| Airline Transport Pilot’s License


ATR |abbreviation| a twin-engine turboprop regional transport manufactured by a consortium of Alenia Aeronautica and EADS. There are two versions: the ATR 42 and larger ATR 72.


ATHR |abbreviation| auto-throttle


ATS |abbreviation| air traffic services


ATSU |abbreviation| air traffic service unit


attach |verb| to join or fix something to something / The ice detector is attached to the fuselage. /


attachment |noun|  1. the act of joining or fixing something to something / The attachment of winglets improved the handling characteristics of the airplane. /  2. an accessory which can be attached / The video camera is sold with a number of attachments including a carrying strap and a battery pack. /


attachment point |noun| a place on the airframe where something such as an engine is attached by means of bolts / Additional strength is required for the power plant attachment points. /


attain |verb| to reach, to achieve something, often with difficulty / In order to attain a fuller understanding of gas turbines, it is essential to know something about basic gas laws. /


attempt |noun| a try / Any attempt to increase range by applying more power is of little or no benefit. / |verb| to try / He attempted to land despite the poor visibility but then decided to divert to another airfield where he landed safely. /


attendant |adjective| accompanying something else / Fuel spillage and attendant fire risk must be minimized. / - attendant problems > associated problems - |noun| a person employed to help members of the public


attention |noun| the ability or power to concentrate on something / The crew’s attention is alerted by an automatic display. / - attention please > listen carefully to what will be said - pay attention > listen to the speaker and concentrate on what is being said


attenuate |verb| to lose power or strength / A wave becomes attenuated or loses strength as range increases./


attenuation |noun| loss of strength / Atmospheric attenuation is negligible until the upper end of the UHF band when it increases rapidly to limit the highest usable frequency to about 10 GHz. /


attenuative |adjective| becoming weaker / Rain has an attenuative effect. /


attitude |noun|  1. the position of the aircraft in the air in relation to the horizon / Angle of attack will vary with changes in engine speed and aircraft attitude. / - nose down attitude > the attitude of the aircraft when the nose is at a lower level than the tail  2. a way of thinking and feeling about or of behaving towards something or somebody - he has an excellent attitude towards his training program > he is positive and motivated in his training program


attitude heading reference system |noun| full form of AHRS


attitude indicator |noun| a flight instrument that gives the pilot information about the position of the aircraft in the air in relation to the horizon / In light aircraft, the attitude indicator is situated on the instrument panel, directly in front of the pilot. / (NOTE: The attitude indicator is sometimes referred to as the ‘artificial horizon’. In instrument flight training, the attitude indicator is the primary reference instrument. It is positioned on the instrument panel directly in front of the pilot.)


attract |verb|  1. to cause to draw near / If two magnets, with unlike poles are brought together, they will attract each other. / - to attract attention > to behave in such a way that people will notice you  2. to cause people to want to have or do something


attraction |noun|  1. a force that draws things towards something / The strength of the magnetic force will depend, amongst other things, on the magnitude of attraction at the magnetic source. /  2. a quality that causes people to want to have or do something / The attraction of flying was the factor which made him decide to train as a pilot. /


attractive |adjective|  1. referring to something you feel you would like to have / After long talks, the prospective buyer made a financially attractive offer for the aircraft. /  2. nice to look at


ATZ |abbreviation| aerodrome traffic zone


audible |adjective| possible to hear / The fire detection system should contain an audible warning device. /


audio |noun| an audible sound or sound signal / The diagram shows an amplitude modulation case where the lower frequency of the audio is about 300 Hertz. /


audio warning |noun| a standardized sound (repetitive chime, single stroke chime, clacker, cavalry charge, woofer) which draws the crew’s attention to an anomaly. / The ENG 1 red fire warning light came on accompanied by the repetitive chime audio warning. /


augment |verb| to make larger by adding something / The sea breeze may augment the up-slope motion of an anabatic wind. /


aural |adjective| referring to hearing / The aural and visual alerts will continue until the crew take action to cancel them. /


authorize |verb| to allow officially, to give permission / A signature is required to authorize the repair. /


authorized |adjective| officially allowed, permitted / Aircraft with a maximum authorized weight of 12,500 lb or less. / - an authorized person > a person who has been given power to act and perform particular tasks or duties


authoritative |adjective| in the manner of somebody with authority, in a commanding way - crew must act in an authoritative manner > crew must give firm instructions or orders


authority |noun|  1. complete control or power over something / While boarding, the captain has the authority to ask an unruly passenger to leave the aircraft. /  2. an official or government body with the power to make decisions


auto- |prefix| automatic or automated


auto-brake |noun| a computer-assisted system which controls and monitors landing gear brake applications in order to achieve maximum braking efficiency. / The PF selects an auto-brake MIN, MED or MAX setting according to the runway conditions. /


auto-flight system |noun| the combination of autopilot, auto-throttle / auto-thrust, flight director, auto-land systems etc. used to control the flight through the Flight Management System (FMS). Abbreviation: AFS


auto-giro |noun| an aircraft that uses a propeller to produce forward motion and has an non-powered horizontal rotor for lift and stability


auto-land |abbreviation| automatic landing


automate |verb| to make e.g. a device or procedure automatic - automated systems > systems which have been made less dependent on direct human control or management


automatic |adjective|  1. done without needing to think / In the early stages of training, student pilots have to think about the use of the flying controls, but after a while these actions become automatic. /  2. which works by itself without the need of an operator / The normal activation method is automatic. /


automatic dependent surveillance |noun| - an electronic surveillance system that uses data that aircraft provide automatically via a data link and is able to identify and track the aircraft


automatic direction finder |noun| a radio navigation instrument that receives signals from non-directional radio beacons / The needle on the ADF indicator points toward the selected radio signal. / Abbreviation: ADF


automatic landing |noun| automatic flight control system capable of landing an aircraft ‘hands-off.’ Abbreviation: auto-land / ILS installations now often support fully automatic “hands-off” auto-land approaches to below 50 feet above the runway threshold in visibility, or Runway Visual Ranges (RVR) as low as 200 meters or less. /


automatic mixture control |noun| a subsystem in a piston engine which adjusts the flow of fuel to balance changes in air density


automatic pilot |noun| full form of autopilot


Automatic Terminal Information Service |noun| a recording of information played continuously on a specified radio frequency which gives pilots the current weather, runway in use, etc. / Students listen to the ATIS to practice their language skills. / Abbreviation: ATIS


automation |noun| the automatic operation or automatic control of a piece of equipment, a process, or a system / Automation has expedited the process of baggage handling. Automation of throttle control has removed the need for pilots to monitor airspeed so closely. It is possible that the alternate source might provide a reduced level of automation. /


autopilot |noun| a system which automatically stabilizes an aircraft about its three axes, restores the original flight path following an upset and, in some systems, causes the aircraft to follow a preselected airspeed, altitude or heading. Full form: automatic pilot. Abbreviation: A/P


auto-throttle |noun| an automatic engine power control system. Abbreviation: ATHR / When using the auto-throttle during auto-land, position command speed to VREF +5 knots. /


auto-thrust |noun| computerized system which provides the engines with orders. / The auto-thrust was disconnected by the PF to prevent another over-speed condition. /


auxiliary |adjective| secondary, which is used when necessary to help or substitute for something else


auxiliary gearbox |noun| a gear box which allows main engine power to be used for secondary systems


auxiliary power unit |noun| a small jet engine used to generate electrical power for air-conditioning, etc., when the aircraft is parked on the ground. Abbreviation: APU


auxiliary rotor |noun| the tail rotor of a helicopter


availability |noun| the fact of being available / The status of an airport is determined by the availability of suitable navigation aids. /


available |adjective| ready for immediate use / On a multi-engine aircraft, all the fuel must be available for use by any engine. /


average |adjective| referring to an average / For load sheet purposes, an average weight of the passengers and crew members may be used. / |noun| the total divided by the number of items added / The average of 1, 5, 9, 10 and 15 is 8 (1+5+9+10+15 = 40 ÷ 5 = 8). / |verb| to reach a particular figure as an average / Brake temperatures average around 500°C during normal operations. /


avert |verb| to avoid / To avert a collision, he changed direction. /


AVGAS |abbreviation| aviation gasoline


aviation |noun| flying an aircraft / Wind speeds in aviation are usually given in knots. /


aviation English |noun| Aviation English is broader than ICAO standard phraseology, but it is the language used by pilots and controllers in an operational context. In the ICAO context, fuel prices, low-cost airlines, aerobatics or the four forces of flight are not Aviation English. Non-aviation English would also include vocabulary from completely unrelated fields, idiomatic language, slang, etc.


aviation gasoline |noun| fuel used in piston-engined aircraft. Abbreviation: AVGAS


aviation law |noun| the laws relating to flying


aviation routine weather report |noun| a weather report issued regularly at intervals of an hour or half an hour describing weather conditions at an airport. Abbreviation: METAR


aviator |noun| a person who flies aircraft


avionics |noun| electronic communication, navigation, and flight-control equipment of an aircraft / The trainee engineer is doing an avionics course. / Full form: aviation electronics - avionics bay > the under-floor avionics compartment where computers and other electronic equipment are located (Airbus). Boeing call this compartment the main equipment center.


avoid |verb|  1. to prevent something from happening / She just managed to avoid an accident. /  2. to keep away from something / Avoid flying close to any person or vessel. Cumulonimbus clouds and thunderstorms should be avoided by as great a distance as possible. /


avoidance |noun| an act of avoiding something - avoidance of thunderstorms is recommended > it is recommended to keep away from thunderstorms


avoiding action |noun| an announcement by the controller to alert the crews that they must modify their flightpath to avoid coming into conflict with other traffic


await |verb| to wait for / Await instructions from the flight deck. /


aware |adjective| knowing and being conscious of something / The pilot should be aware of the positions of all other aircraft in the circuit. /


awareness |noun| the state of being aware or conscious of something - safety awareness > the state of being familiar with and prepared for any situation in which safety is important


AWR |abbreviation| airborne weather radar


axial |adjective| referring to an axis


axial flow compressor |noun| a compressor in which the flow of air is along the longitudinal axis of the engine / In spite of the adoption of the axial flow type compressor, some engine retain the centrifugal type. /


axis |noun|  1. an imaginary line around which a body rotates / The Earth rotates around its own axis. An aircraft moves around three axes – vertical, longitudinal and lateral. /  2. a horizontal or vertical scale on a graph, often referred to as the X axis, the horizontal axis, and the Y axis, the vertical axis / The plot shows the effect of airspeed on lift with airspeed shown on the horizontal axis and lift on the vertical axis. / (NOTE: The plural form is axes.)


axle |noun| a shaft on which a wheel is mounted / Unequal tire-pressures, where two wheels are mounted on the same axle, will result in one tire carrying a greater share of the load than the other. / (NOTE:The wheel either turns round the axle or is fixed to the axle.)


azimuth |noun| the horizontal angle or direction of a compass bearing / Where precision approach radar is installed, the controller can inform the pilot if they depart from either the extended center-line in azimuth or height or both. /


Azimuth Guidance for Nose-In Stand |noun| one of the most popular forms of stand guidance, i.e. ways of guiding a plane to its correct position in the stand

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | XYZ
UTC | Zulu Time
Copyright © 2012 Roger. All rights reserved. | Sitemap
Make a Free Website with Yola.