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Aviation jargon is sometimes a confusing and frustrating language and contains three, four or more letter acronyms which can catch out even the knowledgeable! Sometimes the picture is further confused by a single acronym having a number of meanings depending on the context in which it is used. Take for example the acronym IFE, it has several meanings depending on the area of aviation it relates to; it can mean 'In-Flight Emergency', 'In-Flight Entertainment' or 'International Flight Engineers'. Confused? Hopefully the following list will be of help.

Of course the list is not exhaustive. If you would like to benefit others by adding (or taking away from) this list please contact ifalpa@ifalpa.org

Acronym

A-VDGS		Advanced-Visual Docking Guidance System
A/A		Air to air
A/G		Air/Ground
A&F		IFALPA Administration & Finance Committee
A&P		Airframe & Powerplant (US FAA)
AAA		Aesean Airline Association
AAC		Airline Administrative Communication
AACC		Airport Associations Co-coordinating Council
AACO		Arab Air Carriers Organization
AAIB		Air Accidents Investigation Branch (UK)
AALPBH		Association of Airline Pilots in Bosnia & Herzegovina
AAM		Airbus Asset Management
AAME		Association of Aviation Medical Examiners
AAP		IFALPA Accident Analysis & Prevention Committee
AAPA		Association of Asia Pacific Airlines
AASA		Air Lines Association of Southern Africa
AASC		Airport Authorities Steering Committee
AATF		Airworthiness Assurance Task Force
ABET		Airspace Behavioral Engineering Technology
ABM		Abeam
ABV		Above
AC		Altocumulus
ACA		Austrian Cockpit Association
ACAC		Arab Civil Aviation Council
ACAMS		Aircraft Condition Analysis and Management System
ACARS		Aircraft Communications, Addressing, and Reporting System
ACARS		MU Aircraft Communications and Reporting Systems Management Unit
ACAS		Airborne Collision Avoidance System
ACCC		Australian Competition and Consumer Commission
ACCS		Air Command and Control System
ACDAC		Asociacion Colombiana de Aviadores Civiles (Columbia)
ACG		ATN/CNS Consultancy Group
ACH		Air traffic control Flight Plan Change
ACI		Airports Council International
ACIPLA		Asociacian Civil de Pilotos de Lineas Aereas (Uruquay)
ACK		Acknowledge
ACL		Air Traffic Control Clearance (Service)
ACM		Acceptable Means of Compliance
ACNZ		Airways Corporation of New Zealand
ACRPWG		Aircraft Crash Recovery Procedures Working Group
AD		Aerodrome
ADEP		Aerodrome of Departure
ADES		Aerodrome of Destination
ADIRS		Air Data Inertial Reference System
ADIS		Automatic dependent surveillance and Data Link Interim System
ADISP		Automated Data Interchange Systems Panel
ADIZ		Air Defence Identification Zone
ADM		Aeronautical Decision Making
ADO		IFALPA Aircraft Design & Operation Committee
ADREP		Aircraft Accident/Incident Data Reporting System (ICAO)
ADS		Automatic Dependent Surveillance
ADS-B		Automatic Data Surveillance Broadcast
ADS-C		Automatic Data Surveillance Contract
ADSP		Automatic Dependent Surveillance Panel (ICAO)
AEA		Association of European Airlines
AEEC		Airlines Electronic Engineering Committee
AEROSAT		Aeronautical Satellite Council
AFA		Association of Flight Attendants
AFC		Air Traffic Control Frequency Change (Service)
AFCAC		African Civil Aviation Commission
AFCS		Automatic Flight Control System
AFIS		Aerodrome Flight Information Service
AFM		Aeroplane Flight Manual
AFN		Air traffic Services Facilities Notification
AFP		Area Forecast Panel
AFRAA		African Airlines Association
AFS		Aeronautical Fixed Service
AFTN		Aeronautical Fixed Telecommunications Network
AGA		Aerodromes, Air Routes and Ground Aids
AGAS		European Action Group for ATM Safety
AGE		IFALPA Aerodrome & Ground Environment Committee
AGL		Above Ground Level
AI		Application Interface
AIC		Aeronautical Information Circular
AIDC		Air traffic control Inter-Facility Ground/Ground Data Communications
AIDC		ATS Interfacility Data Communication
AIDS		Airborne Integrated Data Systems
AIG		Accident Investigation & Prevention (ICAO Divisional)
AIM		Aeronautical Information Management
AIM-FANS		Airbus Interoperable Modular FANS
AIMS		Aircraft Information Management System
AIP		Aeronautical Information Publication
Air		Report (message designator)
AIRAC		Aeronautical Information Regulation & Control
AIRC		Aeronautical Information & Control
AIRCOM		Air Communications
AIREP		Plain language form of Air Report
Airspace		and Traffic Management
AIRSTRM		Assuring the Implementation of Regulations for the Safe Transport of Radio-active Materials
AIS		Aeronautical Information Services
AIXM		Aeronautical Information eXchange Model
AL		Approach Lights
ALPA		Asociacion de Pilotos de Lineas Aereas (Argentina)
ALPA		Japan Air Line Pilots' Association of Japan
ALPA-A		Air Line Pilots' Association of Armenia
ALPA-E		Air Line Pilots' Association of Ethiopia
ALPA-FYROM		Air Line Pilots' Association of The Former Yugoslav Republic of Macedonia
ALPA-Int		Air Line Pilots' Association - International
ALPA-K		Air Line Pilots' Association of Korea
ALPA-M		Airline Pilots' Association - Malta
ALPA-S		Air Line Pilots' Association - Singapore
ALPA-SA		Air Line Pilots' Association - South Africa
ALPA-SL		Air Line Pilots' Association of Slovenia
ALPAP		Air Line Pilots' Association of the Philippines
ALPL		Association Luxembourgeoise des Pilotes de Ligne
ALR		IFALPA's Airport Liaison Representative Program
ALRS		Approach Lighting System
ALT		Altitude (above mean sea level)
ALTN		Alternate aerodrome
AMA		Area Minimum Altitude
AMC		Air Traffic Control Microphone Check
AMCP		Aeronautical Mobile Communications Panel
AMDA		Airlines Medical Directors Association
AMOSA		Association of Aviation Maintenance Organisations of Southern Africa
AMPL		Association Marocaine de Pilots de Ligne
AMSL		Above Mean Sea Level
AMSS		Aeronautical Mobile Satellite System
AMSSP		Aeronautical Mobile Satellite Service Panel
ANC		Air Navigation Commission
ANConf		Air Navigation Conference
ANPAC		Associazione Nazionale Piloti Aviazione Commerciale (Italy)
ANPP		Air Navigation Plan Publication
ANSPs		Air Navigation Service Providers
ANT		Air Navigation Team (Eurocontrol)
AO		Aircraft Operator
AOA		Aircrew Officers Association
AOAS		Advanced Oceanic Automation System
AOC		Airline Operational Control
AOCI		Airport Operators Council International
AOPG		Aerodrome Operations Planning Group
APA		Allied Pilots Association
APA(CV)		Air Line Pilots Association (Cape Verde)
APANPIRG		Asia/Pacific Air Navigation Planning and Implementation Regional Group APATSI Airport/air traffic system interface
APDSG		Airspace Planning & Development Sub-Group
APEC		Aircraft Performance Evaluation & Certification
APG		Asosiasi Pilot Garuda
APGSL		Air Line Pilots' Guild of Sri Lanka
API		Advanced Passenger Information
APIRG		African Planning and Implementation Regional Planning Group
APLRIM		Association des Pilotes de Lignes de Mauritanie
APM		Accident Prevention Manual
APN		Apron
APP		Approach Control
APPA		Asociacion Profesional de Pilotos Aviadores de Costa Rica
APPLA		Associacao Pilotos Portugueses Linha Aerea (Portugal)
APU		Auxiliary Power Unit
APV		Approach with Vertical Guidance
AQM		Aircom Quality Performance
AR		Administrative Recommendation
ARAC		Aviation Rulemaking Advisory Committee (FAA)
ARASCNAC		Air traffic services Routes for Aircraft with Self-contained Navigational Capabilities
ARC		Area Chart
ARCP		Aerodrome Reference Code Panel
ARINC		Aeronautical Radio INCorporated
ARITRM		Assessment of the Radiological Impact from the Transport of Radioactive Materials
ARM		Airspace Risk Model
ARO		Air traffic services reporting office
ARP		Aerodrome Reference Point
ARQ		Automatic error correction
ARST		Arresting (part of an aircraft arresting system)
AS		Altostratus
ASA		Airservices Australia
ASAP		Aviation Safety Action Programme
ASC		Aviation Safety Council Ascend to or ascending
ASD		Air Situation Display
ASDA		Accelerate Stop Distance Available
ASE		Altimetry System Error
ASECNA		Agence pour la Securité de la Navigation en Afrique et à Madagascar (Agency for Security and Navigation for Africa and Madagascar)
ASIP		AVPAC (Aviation VHF-Very High Frequency- Packet Communication) Simple Interface Protocol
ASM		Air Space Management
AsMA		Aerospace Medical Association
ASP		AIRCOM Service Processor
ASPA		Asociacian Sindical de Pilots Aviadores de Mexico
ASPENN RPG		Aeronautical Fixed Service Planning Study EUR/NAM/NAT Regional Planning Group
ASPH		Asphalt
ASPLAB		Asociacion Sindical de Pilotos del Lloyd Aereo (Bolivia)
ASPP		Aeronautical Fixed Service Systems Planning for Data Interchange Panel
ASTERIX		All Purpose Structured EUROCONTROL Radar Information Exchange
ASTOR		Aircraft Simulation for Traffic Operations Research
ATA		Air Transport Association of America
ATAFG		African Air Traffic Analysis and Forecasting Group
ATAG		Air Transport Action Group
ATC		Air Traffic Control
ATCA		Air Traffic Controllers Association (USA)
ATFM		Air Traffic Flow Management
ATIS		Aerodrome Terminal Information Service
ATIS-B		Automatic Terminal Information Service - Broadcast
ATK		Air Traffic Controller Acknowledgement (service)
ATLA		Air Transport Licensing Authority
ATM		Air Transport Management
ATMCP		Air Traffic Management Operational Concept Panel
ATMG		Airspace and Traffic Management Group
ATMRPP		ATM Requirements and Performance Panel
ATN		Aeronautical Telecommunications Network
ATNP		Aeronautical Telecommunications Network Panel
ATPL		Air Transport Pilot Licence
ATS		Air Traffic Services
ATS		Air Traffic Services
ATSB		Air Transportation Stabilisation Board Australian Transport Safety Bureau
ATSU		Air Traffic Services Unit
ATTCS		Automatic Takeoff Thrust Control Systems
ATV		Associazione Tecnici di Volo Aviazione Civile (Italy Flight Engineers)
ATZ		Aerodrome Traffic Zone
AUS-ALPA		Australian Air Line Pilots Association
AUSEP		Australian RNAV Separation Standards
AVLC		Aviation VHR Link Control
AVMED		Aviation Medicine
AVPAC		Aviation VHF (Very High Frequency) Packet Communication
AVSEC		Aviation Security
AWO JAA		All Weather Operations
AWOP		All Weather Operations Panel
AWPA		Australian Women Pilots' Association
AWY		Airway
BA		Braking Action
Bahamas ALPA		Bahamas Airline Pilots' Association
BALPA		British Air Line Pilots' Association
BAPA		Bangladesh Airline Pilots' Association
BCC		Battery Charge Controller
BeCA		Belgium Cockpit Association
BORG		Basic Operational Requirements Group
BSP		Aircraft Parameter Downlink (service)
BUL-ALPA		Bulgarian Air Line Pilots' Association
C-ATSU		Current Air Traffic Services Unit
CAA NZ		Civil Aviation Authority of New Zealand
CAA PNG		Civil Aviation Authority of Papua New Guinea
CAA SI		Civil Aviation Authority of Solomon Islands
CAAC		Civil Aviation Administration of China
CAAF		Civil Aviation Authority of Fiji
CAAS		Certification of Aeroplane Automatic Systems
CAASA		Commercial Aviation Association of Southern Africa
CACRC		Commercial Aircraft Composite Repair Committee
CAEE		Committee of Aircraft Engine Emissions
CAeM		Commission for Aeronautical Meteorology
CAEP		Committee on Aviation Environmental Protection (ICAO)
CALPA		China Airline Pilots' Association
CAMA		Civil Aviation Medical Association
CAN		Committee on Aircraft Noise
CANDI		Civil Aviation Network Data Interchange
CANSO		Civil Air Navigation Services Organisation
CAP		Study Group on Continuing Airworthiness Problems
CAPA		Cayman Airline Pilots' Association
CAPS		Computer Automated Profiling Systems
CARATS		Collaborative Actions for Renovation of Air Traffic Systems
CAS		Calibrated Air Speed
CASA		Computer Assisted Slot Allocation
CASA		Civil Aviation Safety Authority (Australia)
CASS		Corporate Aviation Safety Seminar
CAVOK		Ceiling and Visibility OK / Clouds and Visibility OK
CAVU		Ceiling and Visibility Unlimited
CAWU		Civil Aviations Workers Union
CCAA		Chinese Civil Aviation Association
CCIF		International Telephone Consultative Committee
CCIR		International Radio Consultative Committee
CCITT		International Telegraph and Telephone Consultative Committee
CCQ		Cross Cockpit Qualification
CCS		Cabin Communications System
CD		Candela
CDA		Continuous Descent Approach
CDFA		Constant Descent Final Approach
CDN		Coordination (message designator)
CDR		Conditional Route
CDS		Cabin Distribution System
CDTI		Cockpit Display of Traffic Information
CDTI		Cockpit Display Traffic Information
CEAC		Committee of European Airspace Co-ordination
CEFA		Committee for Environmentally Friendly Aviation (ERA)
CEI		Cabin Equipment Interfaces
CFDIU		Central Fault Display Interface Unit
CFDS		Centralised Fault Display System
CFIT		Controlled Flight Into Terrain
CFMU		Central Flow Management Unit
CG		Centre of Gravity
CGL		Circling Guidance Lights
CHG		Modification (message designator)
CIDIN		Common ICAO Data Interchange Network
CIE		International Commission on Illumination
CIMO		Committee for Instruments and Methods of Observation
CIP		Convergence and Implementation Programme
CIR		Cockpit Image Recorders
CIRM		International Radio Maritime Committee
CLOP		Criminal Liability of Pilots
CMIC		Civil/Military Interface Committee
CNS		Communication, Navigation and Surveillance
COCESNA		Central American Corporation for Air Navigation Services
CODA		Central Office of Delay Analysis
COSCAP		Cooperative Development of Operational Safety and Airworthiness Activities
CPAR		Cockpit Personnel Association of Russia
CPC		Circulo de Pilotos de Chile
CPDLC		Controller Pilot Data Link Communications
CPL		Commercial Pilot Licence
CPU		Core Processing Unit
CRAM		Conditional Route Availability Message
CRCO		Central Route Charges Office
CRM		Collision Risk Methodology
CRO-ALPA		Croatian Air Line Pilots' Association
CRP		Co-ordinated Research Programme
CSI		Criticality Safety Index
CSM		Consultant Services Meeting
CTAM		Climb to and maintain
CTO		Calculated Time Over
CTOL		Conventional Take-Off & Landing
CTU		Cabin Telecommunications Unit
CUI		Committee on Unlawful Interference
CVR		Cockpit Voice Recorder
CW		Carrier Wave
CWP		Controller Working Position
CZ-ALPA		Czech Air Line Pilots' Association
D-ATSU		A Downstream Air Traffic Services Unit
D-GPS		Differential Global Positioning System
DALPA		Danish Air Line Pilots' Association
DANT		Danish NEAN Project Team
DAP		Download of Aircraft Parameter
DARP(S)		Dynamic Airborne Route Planning (System)
DATAC		Digital Autonomous Terminal Access Communication
DCAA		Danish Civil Aviation Administration (SLV)
DCD		Double Channel Duplex
DCPC		Direct Controller-Pilot Communications
DCS		Double Channel Simplex
DED		Directorate of European Air Traffic Control Harmonisation and Integration Programme Development
DEFAMM		Demonstration Facilities for Airport Movement Management
DES		Descend to/descending
DFTI		Distance From Touchdown Indicator
DG		IFALPA Dangerous Goods Committee
DGAC		Direction Générale de l'Aviation Civile (France)
DGB		Dangerous Goods Board
DGCA		Director-Generals of Civil Aviation
DGELG		Dangerous Goods European Advisory Group
DGP		ICAO Dangerous Goods Panel
DGP		DLEC Dangerous Goods Panel - Department for Liaison with the European Community
DGRs		Dangerous Goods Regulations
DGVII		Directorate General VII
DH		Decision Height
DITS		Digital Information Transfer System
DL		Downlink Message
DLAP		Down Linked Aircraft Parameters
DLASD		Data Link Application and System Document
DLH		Deutsche Lufthansa
DLSG		Data Link Sub Group (Eurocontrol)
DME		Distance Measuring Equipment
DOTS		Dynamic Ocean Tracking System
DP		Dew Point Temperature
DR		Dead Reckoning Navigation
DSB		Double Side Band
DSCN		Direct Speech Circuit Networks
DTU		Data Terminating Unit
DTW		Dual Tandem Wheels
DW		Dual wheels
DZ		Drizzle
EAD		Emergency Airworthiness Directive
EAMG		European Air (Traffic Flow Management) Group
EANPG		European Air Navigation Planning Group
EAPTU		Air Line Pilots Trade Union (Estonia)
EARC		Elimination of Ambiguity in Radiotelephony Call Signs
EASA		European Aviation Safety Agency
EASS		European Aviation Safety Seminar
EATCHIP		European Air Traffic Control Harmonisation and Integration Programme
EATMS		European Air Traffic Management System
EBAA		European Business Aviation Association
EBU		Engine Build Unit
EC		Executive Controller (also known as 'Radar Controller')
ECA		European Cockpit Association
ECAC		European Civil Aviation Conference
ECAM		Electronic Centralised Aircraft Monitoring (airborne display)
ECAR		European Civil Aviation Requirement
ECASS		European Committee on Aircrew Scheduling and Safety
ECMT		European Conference of Ministers of Transport
EDD		Electronic Data Display
EEC		EUROCONTROL Experimental Centre
EFB		Electronic Flight Bag
EFC		Expect Further Clearance
EGALPA		Egyptian Air Line Pilots Association
EGNOSS		European Geostationary Navigation System Overlay
EGPWS		Enhanced Ground Proximity Warning System
EHEST		European Helicopter Safety Team
EHF		Extremely High Frequency (30,000 to 300,000 Mhz)
EHSAT		European Helicopter Safety Analysis Team
EIM		Enosis Iptamenon Michanikon (Greece Flight Engineers)
ELBA		Emergency Locator Beacon Aircraft
ELS		Electronic Library Systems
EMARSSH		Europe, Middle East, Asia Route Structure of the Himalayas
EMAS		Engineered Materials Arresting System
EPCU		Electrical Power Control Unit
ERA		European Regions Airlines Association
EROC		Study Group on En-Route Obstacle Clearance Criteria
ERP		Emergency Response Plan
ESA		European Space Agency
ETA		Estimated Time of Arrival
ETD		Estimated Time of Departure
ETFMS		Enhanced Tactical Flow Management Systems (Eurocontrol)
ETO		Estimated Time Over
ETOPs		Extended Range Twin-Engine Operations
ETOT		Estimated Take Off-Time
ETSI		European Telecommunications Standards Institute
EU		European Union
EU-FCL		EASA Flight Crew Licensing
EU-OPS		EASA Operations Regulations
EUR		Region European Region
EUR /TFG		European Traffic Forecasting Group
EURO RAN		European Regional Air Navigation (Meeting)
EUROCAE		European Organisation for Civil Aviation Equipment
EUROCONTROL		European Organisation for the Safety of Air Navigation
EUROPILOTE		European Organisation or Airline Pilots Association
EVS		Enhanced Visual System
FAA		Federal Aviation Administration (USA)
FADEC		Full Authority Digital Engine Control
FAF		Final Approach Fix
FAL		Final Assembly Line
FALPA		Fiji Air Line Pilots Association
FANS		Future Air Navigation System
FAP		Final Approach Point
FAR		Federation Aviation Regulations (US FAA)
FARAWAY		Fusion of Radar and ADS data through two WAY data link
FCL		Flight Crew Licensing
FCM		Flight Confirmation Message
FCT		Friction Coefficient
FDA		Flight Data Analysis
FDFM		Flight Data and Flow Management Group
FDM		Flight Data Message
FDP		Flight Data Processing
FDPS		Flight Data Processing System
FDR		Flight Data Record
FEATS		Future European Air (Traffic Services) System Concept Group
FENA		Flight Engineers and Navigators Association
FHA		Functional Hazard Analysis
FIA		Icelandic Air Line Pilots Association
FIC		Finance Committee
FIM		Fault Isolation Manual
FIR		Flight Information Region
FIS-B		Flight Information Services Broadcast
FISA		Flight Information Service (Automatic)
FIXM		Flight Information eXchange Model
FKFE		Forum Komunikasi Flight Engineers (Indonesia)
FL		Flight Level
FLAS		Flight Level Allocation Scheme
FLIREC		Flight Recorders
FLOE/FLOEast		Informal Flow Control (Europe East)
FLOW/FLOWest		Informal Flow Control (Europe West)
FLT		Flight
FMC		Flight Management Computer
FMDB		Fault Message Database
FMG		Frequency Management Group
FMI		Frequency Management Issues
FMPG		Air Traffic Flow Management Planning Group
FMS		Flight Management System
FMU		Flow Management Unit
FNPT		Flight & Navigation Procedures Trainer
FO		Flight Object
FOD		Foreign Object Debris
FOQA		Flight Operations Quality Assurance
FPA		Finnish Pilots' Association
FPL		Filed Flight Plan
FREER		Free-Route Experimental Encounter Resolution
FRP		Fares and Rates Panel
FSF		Flight Safety Foundation
FSF IAS		Flight Safety Foundation International Aviation Safety
FSG		Flight Study Group
FTPC		Flight Technical Professional Committee
FUA		Flexible Use of Airspace
FZDZ		Freezing Drizzle
FZFG		Freezing Fog
FZL		Freezing Level
FZRA		Freezing Rain
G/A		Ground to Air
GA		Go-around
GALPA		Ghanaian Air Line Pilots' Association
GANP		Global Air Navigation Plan
GAPAN		Guild of Air Pilots & Navigators
GASAG		Global Aviation Security Action Group
GAT		General Air Traffic
GBAS		Ground Based Augmentation System (ie GLS)
GCU		Generator Control Unit
Georgian ALPA		Georgian Air Line Pilots' Association
GERT		German NEAN Project Team
GES		Ground Earth Station (satellite)
GIS		Geographic Information System
GIVD		Gravity Induced Vestibular Dysfunction
GLOC		Gravity Induced Loss of Consciousness
GLONASS		Global Orbiting Navigation Satellite System (Russia)
GLS		Global Landing System
GNLU		GNSS Navigation and Landing Unit
GNSS		Global Navigation Satellite System
GP		Glidepath
GPS		Global Positioning System
GPWS		Ground Proximity Warning System
GRACYAS		Caribbean/ South American African Regional Planning Group
GSIF		Ground Station Identification Frames
GTPAPC		Grupo Tecnico de Pilotos Aviadores Profesionales de Cuba
GUI		Graphical User Interface
HALPA		Hellenic Air Line Pilots Association (Greece)
HAPI		Helicopter Approach Path Indicator
HARA		Helicopter Airborne Radar Approaches Study Group
HASA		Helicopter Association of Southern Africa
HAWOP		Helicopter All-Weather Operations Study Group
HBT		Human Behavioural Technology
HDF		High Frequency Direction-finding station
HEL		IFALPA Helicopter Committee
HELIOPS		Helicopter Operations Panel
HEMS		Helicopter Emergency Medical Services
HF		High Frequency
HIRO		High Intensity Runway Operations
HIS		Horizontal Situation Indicator
HKALPA		Hong Kong Air Line Pilots Association
HKAOA		Hong Kong Aircrew Officers Association
HMI		Human Machine Interface
HUD		Head-Up Display
HUGs		Head-Up Guidance Systems
HUMS		Health & Usage Monitoring Systems
HUNALPA		Hungarian Air Line Pilots' Association
HUPER		IFALPA Human Performance Committee
IAAC		International Agricultural Aviation Centre
IAARC		International Administrative Aeronautical Radio Conference
IAASM		International Academy of Aviation and Space Medicine
IABA		International Association of Aircraft Brokers and Agents
IAC		International Advisory Committee
IACA		International Air Carrier Association
IACSC		Improved Airworthiness Communications Steering Committee
IAEA		International Atomic Energy Agency
IALPA		Irish Air Line Pilots Association
IAM		Informal (South Pacific Air Traffic Services Co-ordinating Group) Application Manual
IANC		International Airline Navigators Council
IAOPA		International Aircraft Owners and Pilots Associations
IAP		Instrument Approach Plate
IAPA		International Airline Passengers Association
IAS		Indicated Air Speed
IASA		International Air Safety Association
IASS		International Air Safety Seminar
IATA		International Air Transport Association
ICAO		International Civil Aviation Organisation
ICASM		International Congress of Aviation and Space Medicine
ICD		Interface Control Document
IFA		International Federation of Airworthiness
IFALPA		International Federation of Air Line Pilots' Associations
IFATCA		International Federation of Air Traffic Controllers' Associations
IFATSEA		International Federation of Air Traffic Safety Electronic Associations
IFE		In-flight Emergency
IFEA		Indian Flight Engineers Association
IFEO		International Flight Engineers Organisation
IFFAS		International Fund for Aviation Safety
IFHO		International Federation of Helicopter Operators
IFP		Integrated Flight Plan System
IFPP		Instrument Flight Procedures Panel (ICAO)
IFPS		Integrated Initial Flight Plan Processing System
IFPZ		Integrated Initial Flight Plan Processing System Zone
IFR		Instrument Flight Rules
IHST		International Helicopter Safety Team
ILO		International Labour Organisation
ILS		Instrument Landing System
IMA		Integrated Modular Avionics
IND		IFALPA Industrial Committee
INS		Inertial Navigation System
INSTRAT		Institutional Strategy for Air Traffic Management
INTERPOL		International Criminal Police Organisation
IOCS		Interim Oceanic Control System (Interim datalink system for the Auckland Flight Information Region)
IOSA		IATA Operational Safety Audit
IP		Internet Protocol
IPACG		Informal Pacific ATS (Air Traffic Services) Co-ordinating Group
IPG		Indian Pilots' Guild
IPV		Instrument Approach with Vertical guidance
IR		Ice on Runway
IRS		Inertial Reference System
ISAD		ICAO's Incorporating Security into Aircraft Design () Working Group
ISASI		International Society of Air Safety Investigators
ISO		International Standards Organisation
ISPACG		Informal South Pacific ATS (Air Traffic Services) Co-ordinating Group
ISR-ALPA		Israel Air Line Pilots Association
Israel FE		Israel Flight Engineers
ITA		Institute of Air Transport
ITF		International Transport Workers Federation
ITP		In Trail Procedure (for climb or descent)
ITU		International Telecommunications Union
IUAI		International Union of Aviation Insurers
JALPA		Jamaica Air Line Pilots Association
JCCA		Joint Committee for Civil Aviation
JSSI		Joint Safety Strategy Initiative
JTSO		Joint Technical Standard Order
KAEPA		Kuwait Aircraft Engineers and Pilots Association
KAL		Korean Airlines
KALPA		Kenya Air Line Pilots Association
LAAS		Local Area Augmentation System
LACAC		Latin American Civil Aviation Commission
LAHSO		Land and Hold Short Operations
LAN		Local Area Network
LDG		Landing
LDM		Low dispersible material
LIALPA		Leeward Islands Air Line Pilots Association
LIT-ALPA		Lithuanian Airline Pilots' Association
LOA		Letter of Agreement
LOSA		Line Orientated Safety Audit
LPA		Lebanese Pilots Association
LRM		Line Replacement Modules
LRNS		Long Range Navigation System
LROPS		Long Range Operations
LRU		Line Replacement Unit
LSA		Low specific activity materials
MADAP		Maastricht Automatic Data Processing and Display System
MALPA		Mauritius Air Line Pilots' Association
MAN		Metropolitan Area Network
MAPA		Malaysian Airline Pilots' Association
MAPE		Mean Absolute Percentage Errors (traffic forecasting)
MAPT		Missed Approach Point
MASPS		Minimum Aviation Systems Performance Standards
MAT		Maintenance Access Terminal
MATSE		Meeting on the Air Traffic System in Europe
MAUW		Maximum All Up Weight
MBA		Microburst Alert
MCC		Multi Crew Coordination
MCDU		Multifunction Control Display Unit
MDA		Minimum Descent Altitude
MEA		Minimum En-route Altitude
MECACON		Middle East Civil Aviation Conference
MEL		Minimum Equipment List
MET		Meteorological
METAG		MET Advisory Group
METAR		Meteorological Aerodrome Report
METODA		Meteorological Observations and Information Distribution Arrangements for Local Aeronautical Users
MIL		Military
MLS		Microwave Landing Systems
MLW		Maximum Landing Weight
MM		Middle Marker
MMEL		Master Minimum Equipment List
MMU		Memory Management Unit
MNOP		Maximum Normal Operating Pressure
MNPS		Minimum Navigation Performance Specifications
MNPSA		Minimum Navigation Performance Specification Airspace
MOA		Memorandum of Understanding
MOPS		Minimum Operation Performance Standards
MOTNE		Meteorological Operational Telecommunication Network in Europe
MPL		Multi-crew Pilot Licence
MRVA		Minimum Radar Vector Altitude
MSL		Mean Sea Level
MTBF		Mean Time Between Failure
MTOW		Maximum Take-Off Weight
MU		Management Unit
N1		Gas generator speed
N2		Second stage turbine speed
NAAN		North Atlantic ADS-B Network
NAAPE		National Association of Aircraft Pilots and Engineers (Nigeria)
NAPA		Namibia Air Line Pilots' Association
NARG		Navigation Aids and Area Navigation Group
NAS		National Airspace System
NASA		National Aeronautics and Space Administration
NATO		North Atlantic Treaty Organisation
NATS		National Air Traffic Services (UK)
NATSPG or NAT/SPG		North Atlantic Systems Planning Group
NAV		Navigation
NAVSEP or NAV/S		Panel Experts on Navigation and Separation
ND		Navigation Display
NDA		Next Data Authority
NDB		Non Directional radio Beacon
NEAN		North European ADS-B Network
NEAP		North European CNS/ATM Application Project
NEG		Negative, No, No permission, that is not correct
NextGen		Next Generation Air Transportation System
NF		Norwegian Air Line Pilots Association
NFPA		National Fire Protection Association
NLA		New Large Aircraft
NM		Nautical Miles
NMB		National Mediation Board
NOSIG		No Significant change
NOTAM		Notice to AirMen
NP		Propeller speed
NPA		Notice of Proposed Amendments
NPRM		Notice of Proposed Rulemaking (US FAA)
NPS		Navigation Performance Scales
NSSG		Navigation & Separation Sub-Group
NTSB		National Transportation Safety Board
NUP		NEAN Update Programme
NVG		Night Vision Goggles
NZ-ALPA		New Zealand Air Line Pilots Association
OAT		Outside Air Temperature
OBS		Omni Bearing Selector
OBST		Obstacle
OCS		Oceanic Control System
OCU		OMT (Onboard Maintenance Terminal) Controller Unit
ODETE		On-Line Data Exchange Terminal
ODIAC-TF		Operational Development of Initial A/g data Communications Task Force
ODID		Operational Input and Display System
ODL		Oceanic Data Link (Datalink system for the Oakland Flight Information Region)
ODT		OMT (Onboard Maintenance Terminal) Display Unit
OFZ		Obstacle Free Zone
OGP		Oil and Gas Producers Aviation Sub Committee
OIP		Organization Iberoamericana de Pilotos
OLDI		On-Line Data Interchange
OM		Outer Marker
OMT		Onboard Maintenance Terminal
OP		Operational (issues)
OPAC		Operations of Aircraft
OPR		Air Traffic Management Operational Requirements
OPS		Operations
OPS/AIR		Operations/Airworthiness
OPSP		Operational Panel
ORCAM		Originating Region Code Assignment Method
OSI		Open Systems Interconnection
OUR		Operational Users Requirements
PAAST		Pan American Aviation Safety Team
PACOTS		Pacific Organised Track System
PAK		Pilot Acknowledgement (service)
PALPA		Pakistan Air Line Pilots Association
PALPU		Pancyprian Airline Pilots Union
PAMC		Provisional Acceptable Means of Compliance
PANS		Procedures for Air Navigational Services
PANS-OPS		Procedures for Air Navigational Services - Aircraft Operations
PAPI		Precision Approach Path Indicator
PAR		Precision Approach Radar
PASYI		Pan-Cyprian Airline Pilots' Union (PASYPI)
PATRAM		Packaging and Transport of Radio-Active Materials
PBS		Preferential Bidding System
PCA		Propulsion Controlled Aircraft
PCATD		Personal Computer based Aviation Training Device
PCM		Post Crash Management
PEC		Pan European Conference
PED		Passenger Electronic Devices
PEL/TRG		Personnel Licensing and Training
PETAL		Preliminary EUROCONTROL Test of Air/Ground Data Link
PF		Pilot Flying
PFA		Pilot Friendly Airport
PFCS		Primary Flight Computer System
PFD		Planned Flight Data
PIC		Pilot In Command
PID		Pilot Information Downlink (service)
PIRG		Planning and Implementation Regional Group
PIs		Performance Indicators
PLC		Planning Controller (also known as Co-ordinator)
PMC		Project Management Cell (Eurocontrol)
PMS		Pavement Management System
PNF		Pilot Not Flying
PNGAPA		Papua New Guinea Air Pilots' Association
POH		Pilot Operating Handbook
POL STAT		IFALPA Policy Statement
POLALPA		Stowarzyszenie Polskich Pilotow Komunikacyjnych (Poland)
PRC		Performance Review Commission
PRICE		ICAO Proficiency Requirements in Common English Study Group
PRL		Pilot Request Level (service)
PROMET		Provision of Meteorological Information
PRQ		Pilot Request (service)
PRR		Pilot Request, Route (service)
PRU		Performance Review Unit
PTOT		Provisional Take-Off Time
PTT		Press To Talk
PTUK		Pilots' Trade Union Kazakhstan
PTUL		Pilots Trade Union of Latvia
Q PROCEDURE		Procedure to identify replacement flight plans
QDM		Magnetic zero wind heading
QDR		Magnetic bearing
QFA		Qantas
QFE		Altimeter setting to give height above aerodrome
QNH		Altimeter setting to give height above sea level
QOS		Quality of Service
R-ATSU		The Receiving Air Traffic Services Unit
RA		Resolution Advisory
RAA		Regional Airline Association (USA)
RAAS		Runway Aural Awareness System
RAC		Rules of the Air and Air Traffic Services
RAeS		Royal Aeronautical Society
RAIM		Receiver Autonomous Integrity Monitoring
RAN		Regional Air Navigation
RAPNET		Regional ATC Packet switched Network
RASP		Radar Application Specialist Panel
RCL		Runway Centreline Lighting
RDPS		Radar Data Processing System
REG		Regulatory (issues)
REL		Runway Entrance Light(s)
RESA		Runway End Safety Area
RESMA		Requirements for Emergency and Safety Airborne Equipment
RET		Airborne & Ground Retrofit (issues)
RFC		Request For Change
RFF		Rescue and Fire Fighting
RFL		Requested Flight Level
RGCSP		Review of General Concept of Separation Panel
RGS		Remote Ground Station
RIMS		Runway Incursion Monitoring System
RMCDE		Radar Message Conversion and Distribution Equipment
RMP		Radio Management Panel
RNAV		Area Navigation
RNDSG		Route Network and Development Sub-Group
RNMP		Replacement of the Nautical Mile Panel
RNP		Required Navigation Performance
RO-ALPU		Romanian Air Line Pilot's Union
RPF		Rapid Prototyping Facility
RPG		Regional Planning Group
RPL		Repetitive Flight Plan
RPP		Radiation Protection Programme
RPR		Re-Routing Proposal Message
RSC		Runway Service Conditions
RTA		Required Time of Arrival
RTCA		Radio Technical Commission for Aeronautics
RTCA		Requirements and Technical Concepts for Aeronautics
RTCM SC		Radio Technical Commission for Maritime Services Special Committee
RTD		Research and Technical Development
RTF		Radiotelephony
RTO		Rejected Take Off
RVR		Runway Visual Range
RVSM		Reduced Vertical Separation Minima
RWSL		Runway Status Lights
SAAFEA		South African Airways Flight Engineers Association
SAAM		System for Assignment and Analysis at a Macroscopic level
SACAA		Southern African Civil Aviation Authority
SAE		Society of Automotive Engineers
SAGSTRAM		Standing Advisory Group on the Safe Transport of Radioactive Material
SALPA		Sudan Air Line Pilots Association
SAPA		Swazi Air Line Pilots Association
SAR		Search And Rescue
SARPs		Standards and Recommended Practices (ICAO)
SAS		Scandinavian Airline Systems
SASP		ICAO Separation and Airspace Safety Panel
SATCOM		Satellite Communication
SATSAR		Satellite-aided Search And Rescue
SBAS		Space Based Augmentation System (ie WAAS)
SC		Steering Committee
SCA		Serbian Cockpit Association
SCAA		Swedish Civil Aviation Administration (LFV)
SCAT-1		Special Category One
SCP		Spacecraft Control Processors
SDR		Service Difficulty Report
SDS		Sub Domain Server
SEAC		Service d'Etat de l'Aviation Civile (French Polynesia)
SEC		IFALPA Security Committee
SEIFR		Single-Engine Instrument Flight Rules
SEOTV		Sindicato Espanol de Oficiales Tecnicos de Vuelo (Spain Flight Engineers)
SEP		Safety Equipment and Procedures
SEPLA		Sindicato Espanol de Pilotos de Lineas Aereas (Spain)
SES		Single European Sky
SESAR		Single European Sky ATM Research
SESMA		Special Event Trend Analysis
SETP		Society of Experimental Test Pilots
SF		Special Freighter
SGCAS		Study Group on Certification of Automatic Systems
SGTOAA		Study Group on Take-off Accountability Areas
SICASP		SSR Improvements and Collision Avoidance Systems Panel
SID		Standard Instrument Departure
SIPAC		Sindicato Panameno de Aviadores Comerciales (Panama)
SIPACIP		Sindicato de Pilotos Aviadores Civiles del Paraguay
SISG		Safety Indicators Study Group (ICAO)
SITA		Société Internationale de Télécommunications Aéronautiques
SITNA		Service Technique de la Navigation Aérienne (French technical service)
SLOP		Strategic Lateral Offset Procedure
SLOVALPA		Slovak Air Line Pilots' Association (Slovakia)
SMGCS		Surface Movement Guidance and Control Systems
SMI		Special Message Identifier
SMR		Surface Movement Radar Study Group
SMS		Safety Management System
SNA		Sindicato Nacional dos Aeronautas (Brazil)
SNOMAC		Syndicat National des Officiers Mecaniciens de l'Aviation Civile (France Flight Engineers)
SNOWTAM		Special NOTAM notifying the presence or removal of snow, ice, and slush or associated melt water from the manoeuvring areas of and aerodrome
SNPL		Syndicat National des Pilotes de Ligne (France)
SOIR		Simultaneous Operations on Intersecting Runways
SOIR		Simultaneous Operations on Parallel or Near-Parallel Instrument Runways
SPA		Suriname Pilots' Association
SPACDAR		Specialist Panel on Automatic Conflict Detection and Resolution
SPAS		Safety Performance Analysis System
SPF		Svensk Pilot Forening (Sweden)
SPLA		Syndicat des Pilotes de Ligna Algeriens (Algeria)
SPNT		Syndicat Personnel Navigant Technique de Tunisia
SR&O		System Requirements and Objectives
SRC		Safety Regulation Commission
SRG		Safety Regulation Group
SSA		System Safety Approach
SSR		Secondary Surveillance Radar
SSR Mode S WG		Secondary Surveillance Radar Mode Selective WG
STA		Scheduled Time of Arrival
STAP		(International Civil Aviation Organisation) Statistics Panel
STAR		Standard Terminal Arrival Route
STCA		Short Term Conflict Alert
STDMA		Self-organising Time Division Multiple Access
STVAC		Sindicato dos Tecnicos de Voo da Aviacao Civil (Portugal Flight Engineers)
SWET		Swedish NEAN Project Team
SWIM		System Wide information Management
Swissalpa		Swiss Air Line Pilots' Association
T-VASIS T		Visual Approach Slope Indicator System
TA		Traffic Advisory
TAAATS		The Australian Advanced Air Traffic Services System
TALPA		Turk Hava Yallair Pilotlari Dernegi (Turkey)
TARA		Terminal Area R-NAV Applications Sub-Group
TARMAC		Taxi and Ramp Management and Control
TARTAR		International Civil Aviation Organisation Meetings on Transit Air Traffic Services Routes through the Airspace of the Russian Federation
TBC		The Boeing Company
TCAA		Transatlantic Common Aviation Area
TCAS		Traffic Collision Avoidance System
TCP		Transmission Control Protocol
TDI		Track Deviation Instrument
TDM		Track Definition Message
TDZ		Touchdown Zone
TEMPO		Temporary or temporarily
TEN-T		Trans- European Network - Transport
TFG		Traffic Forecasting Group
TFTS		Terrestrial Flight Telephone System
TGS		Taxi Guidance System
ThaiPA		Thai Pilots' Association
TIS-B		Traffic Information service - Broadcast
TIS-B		Traffic Information System - Broadcast
TMA		Terminal Area
TMC		Traffic Management Coordinator
TMU		Traffic Management Unit
TOPM		Take-Off Performance Monitors
TOR		Terms Of Reference
TOS		Traffic Orientation Scheme
TPA		Tanzania Pilots Association
TRANSSAC		Transport Safety Standards Advisory Committee
TRL		Transition Level
TRNSG		Testing of Radio Navaids Study Group (ICAO)
TROP		Tropopause
TSA		Temporary Segregated Area
TSD		Time Sequence Diagram
TSO		Technical Standards Order
TTALPA		Trinidad & Tobago Airline Pilots Association
TUI		Trade Unions International of Transport Workers
TWR		Air Traffic Control Tower
TWS		Terrain Awareness and Warning System
UAC		Upper Area Control Centre
UAL		United Airlines
UAT		Universal Access Transceiver
UAV		Unmanned Aerial Vehicles
UHF		Ultra High Frequency
UIR		Upper Information Region
UL		Uplink message
ULR		Ultra Long Range
UN		United Nations
UNCOE		United Nations Committee of Experts
UPA		Uganda Pilots' Association
UPU		Universal Postal Union
USOAP		Universal Safety Oversight Audit Program (ICAO)
UTC		Universal Time Coordinated (equivalent to GMT & Zulu )
VAAC		Volcanic Ash Advisory Centre
VAC		Visual Approach Chart
VAP		Visual Aids Panel (ICAO)
VAR		Magnetic Variation
VASI		Visual Approach Slope Indicator
VAW		Volcanic Ash Warnings
VC		Vereinigung Cockpit (German Air Line Pilots' Association)
VCS		Voice Communications System
VDL VHF		(Very High Frequency) Data Link
VDP		Visual Descent Point
VDR VHF		(Very High Frequency) Digital Radio
VFOP		Visual Flight Rules Operations Panel
VFR		Visual Flight Rules
VFRG		Visual Flight Rules Group
VHF		Very High Frequency
VIVO		Visualisation des Vols Océaniques (situation display & datalink system for the Tahiti Flight Information Region)
VKB KLM		Flight Engineers Association
VLDM		Very low dispersible material
VMP		Vertical Measurement Panel
VNV		Vereniging van Nederlandse Verkeersvliegers (Dutch Air Line Pilots' Association)
VSCF		Variable Speed Constant Frequency
VSSG		Vertical Separation Study Group
VTOL		Vertical Take-Off & Landing
WAAS		Wide Area Augmentation System
WAFS		World Area Forecast System Study Group
WAN		Wide Area Network
WEAA		Western European Airports Association
WEAAP		Western European Association for Aviation Psychology
WFTU		World Federation of Trade Unions
WG		Working Group
WGS 84		World Geodetic System 1984
WHO		World Health Organisation
WIAS		Weather Information Automated System
WIST		Study Group on Low Level Wind Shear Turbulence (ICAO)
WMO		World Meteorological Organisation
WOCL		Window of Circadian Low
WP		Work Package
WXXM		Weather eXchange Model
XPDR		Transponder
YOYO		Only Y Available
Zulu or z		Equivalent to Greenwich Mean Time or UTC