航空缩略语（A-gt；E）
A
AAC-Army Air Corps
AAIB-Air Accident Investigation Branch of the Department of the Environment，Transport and the Regions。
aae-above aerodrome elevation。Also see aal。
aal-above aerodrome level。Also see aae。
ab initio-elementary flying training，literally‘from the beginning’，。
abm abeam-an aircraft is abeam a point when that point is at ninety degrees left or right of the aircraft‘s track，but term usually used to indicate a general position rather than a specific point。
a/c-aircraft。
ACARS-Aircraft Communication Adressing and Reporting System。
AC-alternating current。
ACC-Area Control Centre。And ACZ Aerodrome Control Zone。See ATZbelow。
ACMS-aircraft condition monitoring system。
ACR-aerodrome control radar。
accelerate-stop distance-calculated distance required for an aircraft to accelerate to V1（which see），reject take-off and brake safely to a halt。
A/D-aerodrome。
AD-Airworthiness Directive，issued by airworthiness authorities to correct a defect found in an aircraft type after certification。Compliance is mandatory and may be required immediately and before further flight，within a specified period of time or number of flying hours，or when next due for routine maintenance。
ADA-Advisory aispace-Advisory Area or Advisory Route。
ADC-air data computer。
ADELT-automatically deployable emergency locator transmitter。
ADF-automatic direction finder/finding。Radio compass which gives a relative bearing to the non-directional radio beacon to which it is tuned。
ADI-attitude deviation indicator。An advanced type of artificial horizon，part of a flight director system providing pitch and roll information and commands。
ADIZ-Air Defence Identification Zone。An area of airspace extending upwards from the surface，usually along a national boundary，within which identification of all aircraft is required in the interests of national security。
ADR-Accident Data Recorder。
ADS-Automatic Dependence Surveillance。
ADT-Approved Departure Time。
AEF-Aerodromes Environmental Federation。
AEW-Airborne early warning
Aerad-UK-published flight guide and navigational chart system。
aerodrome/airport elevation-highest point of an aerodrome’s usable runway（s）expressed in feet above mean sea level（amsl）。
AFB-air force base，usually U。S。or Canadian。
AFCS-automatic flight control system，an advanced autopilot。Also IFCS，integrated flight control system。
AFDS-Autopilot and flight director system。
AFI-assistant flying instructor。Also AFIC，assistant flying instructor course，FIC，flying instructor course。
AFIS-Aerodrome Flight Information Service，providing information to，but not control of，aircraft using that aerodrome。
AFIS（O）-Aerodrome Flight Information Service（Officer）
AFS-Aerodrome Fire Service。
AFS-Aeronautical Fixed Service-telephone/teleprinter network，includes AFTN。
AFS-auto flight system。
AFTN-Aeronautical Fixed Telecommunications Network。Aground-based teleprinter network transmitting flight plans，weather information etc。
AGO-air-to-ground operator
A/G-air-to-ground。
agl-above ground level。
AHRS-attitude-heading reference system。Asensor deriving aircraft attitude and heading information from gyros and accelerometers。
AIAA-area of intense aerial activity，usually military。
AIC-Aeronautical Information Circular。Bulletins issued at intervals by the CAArelating to matters of airworthiness，administration，operating procedures，safety etc。AICs are colour-coded according to subject，e.g.safety circulars are pink，thus‘Pink12’issued in December1990。
AIDS-Airborne integrated data system。
AIP-Aeronautical Information Publication。The UK Air Pilot，statutory bible of aeronautical information published by the CAA。
Airep-form for reporting position and Met conditions in flight。
Airmet-CAA‘s telephone aviation weather service，covering Southern，Northern and Scottish regions of the UK。Also Metdial and Metplan，privately-operated aviation weather services。For full details see Pilot，February1991。
AIS-Aeronautical Information Service。CAAunit based at London-Heathrow Airport，providing flight-planning services and information for pilots。Publishes AICs，above。
AIZ-Aerodrome Information Zone。See ATZbelow。
ALERFA-alert phase of search-and-rescue procedure。
alt-altitude。Height above sea level。
alternate-aerodrome specified on a flight plan to which an aircraft chooses to divert if a landing at its intended destination is not possible（for reasons of poor weather，for example）。
altimeter setting-barometric pressure reading in millibars，hectopascals or（in USA）inches of mercury（Hg）used to set a pressure altimeter’s sub-scale to QFEor QNH。
AM-Amplitude modulation。
AME-authorized medical examiner。Adoctor approved by the CAA（or foreign licensing authority）to conduct examinations for the issue or renewal of aircrew medical certificates。
amsl-above mean sea level（sometimes asl in USA）。
anhedral-sloping down from root to tip。Opposite：dihedral。
ANO-Air Navigation Order。Statutory legal instrument defining the laws of air navigation，pilot licensing etc，in the UK。Other aviation legislation includes the Rules of the Air and Air Traffic regulations and the Air Navigation（General）Regulations
AoA-angle of attack。Also alpha，thus‘high alpha’，high angle of attack。
AOA-Airport Operators‘Association。
AOC-Air Operator’s Certificate，issued by the CAAand required by aircraft operators flying scheduled or charter public transport flights，including cargo，air-taxi and pleasure-flying work。Also Air Officer Commanding in RAFparlance。
AoE-airport of entry（usually in USA）。
AOG-aircraft on ground，a term used to denote urgency when requesting spares or service from suppliers or manufacturers，meaning that the aircraft cannot fly again until the parts have been supplied。
AOPA-Aircraft Owners and Pilots Association。
A/P-airport or autopilot。
A&P-Airframe and Powerplant Mechanic（USA）。
APA-Aerodromes Protection Agency，the federation of associations for the advancement of British general aviation facilities。
APHAZ-Aircraft Proximity Hazards Assessment Panel，which investigates near-miss reports filed by air traffic controllers（see also JAWG）。
APP-Approach（control）。
APU-auxiliary power unit。Large transport aircraft and some business jets have an APU，typically a small turbine，to provide power for engine-starting and for running systems when on the ground，obviating the need for external power or ground power unit，GPU。
ARB-Airworthiness Review Board。
ARCAL-aircraft radio control of aerodrome lighting。
Aresti-key shorthand notation system devised by Spaniard JoséL Aresti whereby aerobatic display routines or competition sequences can be drawn up on paper like a musical score。Now largely superseded by the simpler FAI Aerobatic Catalogue system。
ARINC-Aeronautical Radio Incorporated。Anon-profit corporation owned by airlines to set standards for airline avionics and provide communications services。
ARP-aerodrome reference point。
articulated rotor-blades can flap，drag and feather。
ARV-air recreational vehicle。
ASDA-accelerate-stop distance available。
ASI-airspeed indicator，a flight instrument which measures the speed of an aircraft through the air。
ASR-altimeter setting region，a geographical area for which the lowest value of QNHis forecast hourly and relayed by air traffic control centres。Also airport surveillance radar and air-sea rescue。
ASTOVL-advanced short take-off and vertical landing。
ATA-actual time of arrival。Also Air Training Association。
ATC-air traffic control。
ATCA-air traffic control assistant
ATC（C）-air traffic control centre；
ATCO-air traffic control officer。
ATIS-automatic terminal information service，a continuous recorded broadcast of routine non-control airport information，usually at large airports。
ATPL-Air Transport Pilot‘s Licence，needed to act as pilot-in-command of a commercial air transport aircraft exceeding20，000kg all-up weight。
ATO-assisted take-off e.g。J（et）or（R）ocket assisted。
ATS-air traffic service。Also ATSU，ATS Unit。
ATSORA-air traffic services outside regulated airspace。
ATC（U）-air traffic control unit。
ATZ-Aerodrome Traffic Zone。An area of protected airspace surrounding an aerodrome bounded by a circle of2nm or2.5nm radius（depending on runway length）centred on the mid-point of the longest runway。Permission is required for entry into and movement in an ATZ。
AUW-all-up weight，a term for the total loaded weight of an aircraft，made up of empty weight plus useful load；maximum auw is the maximum allowable weight，including fuel and payload，specified in an aircraft’s Certificate of Airworthiness。Sometimes referred to（in USAespecially）as gross weight and maximum gross weight respectively。Also MTWA，maximum total weight authorised；BOW Basic operating weight，the weight of an aircraft with all equipment，lubricants，fuel and operating crew，but without payload；MLW，maximum landing weight，above which fuel must be burned off or jettisoned before landing or there may be risk of structural damage。
avgas-aviation gasoline，usually followed by the octane rating。Used by piston-engined aircraft。Also LL，low lead。
avtur-aviation turbine fuel（kerosene）。Used by turboprops and jets。
AWR-airborne weather radar。
Awy-airway。
B
BA-British Airways
BAA-British Airports Authority。
BAeA-British Aerobatic Association。
BALPA-British Airline Pilots Association。
base leg-The crosswind segment of an aerodrome circuit bringing the aircraft from the downwind leg to final approach
BAUA-Business Aircraft Users Association。
BCAR-British Civil Air Requirements。Airworthiness standards laid down by the CAAfor certification of aircraft on the UK Civil Aircraft Register。
BCP-break cloud procedure。
BCPL-Basic Commercial Pilot‘s Licence，the minimum qualification necessary in the UKto receive payment for acting as a pilot。Also CPL，Commercial Pilot’s Licence，and SCPL，Senior Commercial Pilot‘s Licence（no longer issued）。
beta mode-manually-controlled mode for CSpropellers on turboprop aircraft enabling reverse pitch to be selected for braking or to aid ground manoeuvring。
BFR-Biennial Flight Review（USA）。Holders of U。S。FAA Private Pilot Licences must undergo a flight check with an FAA-approved examiner every two years。No UKequivalent。
BGA-British Gliding Association。
BHAB-British Helicopter Advisory Board。
bhp-brake horsepower。
BHPA-British Hang-Gliding and Paragliding Association。
Bleed air-Hot compressed air taken from turbine engines。
BMAA-British Microlight Aircraft Association。
Bottlang-Loose-leaf Euopean airfields manual for VFRoperations。
BRG-bearing，the horizontal direction to or from any point expressed in degrees of the compass。
BWPA-British Women Pilots Association。
C
C-Celsius（temperature）or compass。
CAA-Civil Aviation Authority。
CAD/CAM-computer-aided design/manufacture。
CAAFU-Civil Aviation Authority Flying Unit，based at Stansted Airport，which performs such tasks as navaid checking and calibration and also examines candidates for instrument ratings and commercial pilot’s licences。
CANP-Civil Aviation Notification Procedure。Avoluntary system whereby civil operators notify their intention to fly at low level（at or below1，000feet agl，when crop-spraying or powerline inspecting for example），aimed at avoiding conflict with low-flying military aircraft。
CAP-Civil Air Publication。Information booklets issued by the CAA，e.g。CAP53The Private Pilot Licence。
CAS-calibrated airspeed--indicated airspeed corrected for air density and compressibility。
casevac-casualty evacuation。
CAT-clear-air turbulence。Also CATegory when referring to certain instrument landing systems which require special aircraft instrumentation，certification and pilot qualification beyond those needed for standard instrument approaches（e.g.a CAT IIIC ILSpermits operation down to the surface of the runway without external visual reference，true zero-zero operation）。
CAVOK-pronounced CAV-okay（ceiling and visibility OK），visibility at least ten kilometres，with no cloud below5，000feet，with no Cbs，precipitation，thunderstorms，shallow fog or low drifting snow。
CAVU-ceiling and visibility unlimited。Cloudless（or scattered cloud）conditions with visibility in excess of ten kilometres。
CCF-Combined Cadet Force
CDI-course deviation indicator。The vertical needle of a VORindicator which shows the aircraft‘s position relative to the selected VORradial。
CDU-control display unit。
ceiling-height above ground or water of the base of the lowest layer of cloud below20，000feet which covers more than half of the sky。An aircraft’s service ceiling is the density altitude at which its maximum rate of climb is no greater than100feet per minute。Its absolute ceiling is the highest altitude at which it can maintain level flight。
CFI-chief flying instructor（certified flying instructor in USA）。
CFS-Central Flying School（RAF）
CG-centre of gravity
CH-compass heading。
Check‘A’-a thorough pre-flight inspection-the first of the day。
CHIRP-Confidential Human Factors Incident Reporting system，whereby professional pilots and ATCstaff may report in confidence incidents arising from human errors for analysis by the CHIRP Charitable Trust at Farnborough。
CHT-cylinder head temperature（gauge）。Adevice which，by means of a probe（s）gives a cockpit readout of the temperature of one or more of an aircraft engine‘s cylinder heads。
circuit-pattern around which aircraft fly when arriving at an airfield，usually rectangular in UKbut not necessarily elsewhere。The circuit（known as the pattern in USA）is aligned with the active runway and may be either left-or right-handed。Dead side is the opposite side of the circuit pattern in operation from which arriving aircraft join for landing。See also final（s）。
C/L-centre-line（of a runway，for example）。
clamped-colloquialism referring to an airport closed to air traffic by bad weather
clean-flaps，slats and undercarriage retracted and on military aircraft no external missiles etc。
clearance-authorization from air traffic control to proceed as requested or instructed。Used for ground and air manoeuvring，thus“cleared for take-off”，“cleared flight-planned route”，“cleared to descend”etc。
Clouds-commonly-used abbreviations for cloud types:
AC=altocumulus
AS=altostratus
CB=cumulonimbus
CC=cirrocumulus
CI=cirrus
CS=cirrostratus
CU=cumulus
NS=nimbo stratus
SC=stratocumulus
ST=stratus
Cof A-Certificate of Airworthiness issued by the CAAindicating that an aircraft meets the Authority’s airworthiness standards。Cs of Aare issued to individual aircraft，and also to generic aircraft types（Type Certification in the USA）when the first example of a type is registered。Cs of Aon individual aircraft are granted in several categories，e.g。Private，Public Transport，Aerial Work etc.and much be renewed at intervals。Permits to Fly are authorisations granted to specialist aircraft and are accordingly restricted in the kinds of operation for which they may be used。
Cof E-Certificate of Experience，valid for private pilot licence holders for thirteen months，and renewed by flight test or evidence of completing the minimum required flying experience in the preceding thirteen-month period。Also Cof T，certificate of test。
Cof G-centre of gravity。The point on an aircraft through which the entire aircraft‘s weight may be assumed to act（i.e.around which the aircraft，if suspended，would balance）。Cof Glimits are the most forward and rearward positions of the Cof Gpermitted for safe operation。An aircraft loaded outside its Cof Glimits can be difficult or impossible to control。
Cof P-centre of pressure，the point through which the total effect of lift may be said to act on an aeroplane。
Com（m）（s）-communication（s）
CPL-Commercial Pilot’s Licence
CRor C/R-counter-rotating。Usually in general aviation referring to twin-engined aircraft with‘handed’engines whose propellers turn in opposite directions to eliminate propeller torque effect。
CRM-cockpit resources management
crosswind（leg）-portion of an aerodrome circuit flown before downwind
CRP-compulsory reporting point。
CRT-cathode ray tube（like a television）。Used in flight deck displays of new-generation airliners，business aircraft and military jets instead of conventional instruments。See also EFIS，。
critical altitude-the highest density altitude at which it is possible to maintain the maximum continuous rated power or manifold pressure of an aero engine。
critical engine-the engine on a multi-engined aircraft whose failure would most seriously effect performance or handling of the aircraft，through asymmetric effects or loss of power to systems such as hydraulics。
CRScourse-the intended direction of flight in the horizontal plane expressed in degrees of the compass。
c/s-call sign。
CS-constant-speed（propeller）。Avariable-pitch propeller which maintains constant rpm by automatically changing blade angle。Also CSU，constant-speed unit。
CTA-Control Area。An area of controlled airspace extending upwards from specified limit agl。
CTR-Control Zone。An area of controlled airspace extending upwards from ground level to a specified upper limit。
CVR-cockpit voice recorder。Atape recorder installed on the flight decks of commercial transport aircraft and helicopters and some business aeroplanes to record crew conversation，RTtransmissions and cockpit background noises（e.g.trim-wheel operation，flap motor running）in case required for incident or accident investigation。
CW-carrier wave or continuous wave。
CWR-colour weather radar。
CZ-Control Zone（USA）。
CZI-compressor zone inspection。
D
DA-Danger Area。
DAAIS-Danger Area Activity Information Service。
DACS-Danger Area Crossing Service。
DADC-Digital air data computer（DADS-/system）。
D&D-Distress&Diversion Cells at Air Traffic Control Centres。RAFunits which provide a24-hour listening watch on VHFand UHFemergency frequencies and can locate and assist pilots who are lost or in emergency situations。
dB-decibel（s）-a unit of sound
DC-direct current
DCT-direct
dead side-opposite side of an airfield circuit pattern from which aircraft join for landing
deadstick-descent and landing with engine（s）shut down and propeller（s）stopped。
Decca-hyperbolic area navigation system，originally developed for maritime use，based on signals received from a chain of master and slave ground stations located in northern Europe。
DEEC-digital electronic engine control
density altitude-pressure altitude corrected for air temperature。
derated-engine‘s potential power deliberately limited，lengthening likely life。
DETRESFA-distress phase of search-and-rescue operation。
DF-direction-finding。A DFbearing can be provided by airfields or other facilities such as D&Dcells（above）having suitable direction-finding equipment to locate an aircraft。
DG-Directional gyro
DGAC-Direction Généralàl’Aviation Civile
DH-decision height。The height on a precision approach at which a pilot must have the runway approach lights in sight to continue the descent，or if not，must initiate a go-around。
DHFS-UK Defence Helicopter Flying School at RAF Shawbury
DI-direction indicator。Agyro instrument which indicates the magnetic heading of an aircraft。The DI，also known as the directional gyro（DG），is free of the turning errors associated with magnetic compasses but is prone to precession（wander）and must be reset against the magnetic compass at intervals。ALSO-
DI-is also used to refer to the daily inspection--a thorough pre-flight check of an aircraft prior to the first flight of the day。
dihedral-sloping up from root to tip。Opposite：anhedral。
DIN（S）-digital interial navigation（system）。
DME-distance-measuring equipment。Acombination of ground and airborne equipment which gives a continuous slant range distance-from-station readout by measuring time-lapse of a signal transmitted by the aircraft to the station and responded back。DMEs can also provide groundspeed and time-to-station readouts by differentiation。
Doppler-Doppler effect（or shift）is the change in frequency of light，radio or sound waves when source and receiver are in relative motion。
DoT-Department of Transport。
downwind-The segment of an aerodrome circuit paralleling the active runway and flown on a reciprocal heading
DP-dew point
DR-dead（deduced）reckoning。Plotting position by calculating the effect of speed，course，time and wind against last known position。
dry-when referring to aircraft hire charges means‘without fuel’，as opposed to wet，with fuel。
DZ-dropping zone，for parachuting etc。
E
EAA-Experimental Aircraft Association，the American homebuilders‘organisation。
EADI-electronic attitude director indicator。An ADIwith CRTcockpit display forming part of an EFIS，below。
EAS-equivalent airspeed。
EAT-estimated（or expected）approach time。
EBAA-European Business Aircraft Association。
ECAC-European Civil Aviation Conference。
ECOGAS-European Council of General Aviation Support。
ECU-environmental control unit。
ED-emergency distance。
EET-estimated elapsed time。
EFAS-electronic flash approach light system。
EFATO-engine failure at（or after）take-off。
EFIS-electronic flight instrument system，in which multi-function CRTdisplays replace traditional instruments for providing flight，navigation and aircraft systems information，forming a so-called’glass cockpit‘。Now common in commercial transports，corporate aircraft and helicopters，military fighters and some GApiston singles and twins。
EGT-exhaust gas temperature（gauge）。Adevice which provides a cockpit readout of the exhaust gas temperature of an aircraft’s（piston）engine（s），enabling the pilot to lean the mixture for maximum fuel efficiency。
EHSI-electronic horizontal situation indicator。CRT-based HSIforming part of an EFIS。
EICAS-engine indication and crew alerting system。CRTdisplay which monitors engine performance and alerts the crew to system or airframe failure。Found in new-generation transports and business jets。
EICMS-engine in-flight monitoring system
ELT-emergency locator transmitter。Asmall radio transmitter fixed to an aircraft‘s structure which is automatically activated by impact or water immersion and transmits a code on emergency frequencies enabling SARsatellites or search units equipped with DFto locate the crash or ditching site。Carriage mandatory in the USA，but not in UK。Sometimes styled ADELT，automatically deployable ELT，or ELB，emergency locator beacon。
empty weight-weight of the basic aeroplane including all fixed equipment，plus unusable fuel，oil，hydraulic and other fluids。
encoding altimeter-an altimeter which gives a digital output to the transponder（which see）for automatic transmission of the aircraft’s pressure altitude to ATC。
EOBT-estimated off-blocks time。
EP-Elementary pilot rating of the British Hang Gliding and Paragliding Association
EPNdB-effective perceived noise decibel。Unit of measurement of aircraft noise levels。
ER-extended range。
eshp-equivalent shaft horsepower。
ETA-estimated time of arrival。Also；
ETD-estimated time of departure
ETE-estimated time en route。
ETOPS-extended-range twin operations，usually long over-water flights by airliners。
ETPS-Empire Test Pilots School，based at the Aircraft&Armament Experimental Establishment，Boscombe Down。
Eurocontrol-organisation，headquartered in The Netherlands，comprising Belgium，France，Germany，Ireland，Luxembourg，Netherlands and UKfor coordinating en route air traffic control in Europe。