ICAO - Indicates International Civil Aviation Organization usage. International messages should use these.
METAR/TAF - Indicates ICAO weather usage.
A
Contraction
Definition
Usage
+FC
tornado/water spout
METAR
A
absolute (temperature)
NWS
A
Alaskan Standard Time (time groups only)
NWS
A
Amber
GEN
A
arctic (air mass)
NWS
A/A
air to air
ATC
A/C
approach control
ATC
A/G
air to ground
ICAO
A/H
already had
ATC
AAC
Alaskan Air Command
GEN
AAD
Assigned altitude deviation
ICAO
AADC
approach and departure control
ATC
AAF
Army Air Field
GEN
AAITVL
arrival aircraft interval
ATC
AAL
Above aerodrome level
ICAO
AAL
Alaskan Region, FAA
GEN
AAP
Advise if able to proceed
ATC
AAR
airport arrival rate
ATC
AARTE
airport acceptance rate
ATC
AATM
at all times
GEN
AAWF
Auxiliary Aviation Weather Facility
NWS
AAWTA
Advise at what time able
ICAO
AB
Airborne
ATC
ABBR
Abbreviate
GEN
ABCST
automatic broadcast
GEN
ABD
Aboard
GEN
ABI
Advance boundary information
ICAO
ABLCHG
airborne launching
ATC
ABM
abeam
ICAO
ABN
aerodrome beacon
ICAO
ABND
abandon
GEN
ABNDT
abundant
GEN
ABNML
abnormal
GEN
ABT
about
GEN
ABV
above
ICAO
AC
Advisory Circular
GEN
AC
altocumulus
NWS
AC
assistant chief
GEN
ACA
artic control area
ATC
ACARS
Aircraft communication addressing and reporting system
ICAO
ACAS
airborne collision avoidance system
ICAO
ACC
area control center
ATC
ACC
altocumulus castellanus
NWS
ACCID
notification of aircraft accident
ATC
ACCT
account
GEN
ACCUM
accumulate
GEN
ACDNT
accident
GEN
ACDO
Air Carrier District Office
GEN
ACE
Central Region, FAA
GEN
ACES
access
GEN
ACFT
aircraft
ICAO
ACID
aircraft identification
ATC
ACK
acknowledge
GEN
ACL
altimeter check location
ATC
ACLD
above clouds
GEN
ACLS
automatic carrier landing system
GEN
ACLT
accelerate
GEN
ACM
air combat maneuvers
ATC
ACN
aircraft classification number
ICAO
ACN
all concerned notified
GEN
ACNOT
accident notice
GEN
ACP
acceptance (message type designator)
ICAO
ACP
area command post
GEN
ACPT
accept
GEN
ACPY
accompany
GEN
ACR
air carrier
GEN
ACRBT
acrobatic
ATC
ACRS
across
GEN
ACSL
standing lenticular altocumulus
NWS
ACT
active or activated or activity
ICAO
ACT
air combat training
ATC
ACT
Technical Center, FAA
GEN
ACTG
acting
GEN
ACTV
active
GEN
ACTVT
activate
GEN
ACW
aircraft control and warning
GEN
ACYC
Anticyclonic
NWS
AD
Aerodrome
ICAO
ADA
advisory area
ATC
ADAP
Airport Development Aid Program
GEN
ADC
Aerodrome chart
ICAO
ADCF
Air Defense Control Facility
GEN
ADCON
advise or issue instructions to all concerned
GEN
ADCUS
advise customs
GEN
ADDN
addition
GEN
ADE
Air Defense Emergency
GEN
ADF
automatic direction finder
GEN
ADFAP
automatic direction finder approach
ATC
ADIZ
air defense identification zone
GEN
ADJ
adjacent
ICAO
ADL
aggregate demand list
ATC
ADLO
Air Defense Liaison Officer
GEN
ADLY
arrival delay
ATC
ADMAP
advise by air mail as soon as possible
GEN
ADMIN
administration
GEN
ADMIR
administrator
GEN
ADMIS
aircraft departing at (number of minutes) intervals
ATC
ADMIV
administrative
GEN
ADNL
additional
GEN
ADNL TFC
additional traffic is
ATC
ADNOK
advise if not correct
ATC
ADO
Aerodrome office (specify service)
ICAO
ADO
Airport District Office
GEN
ADP
automatic data processing
GEN
ADPE
automatic data processing equipment
GEN
ADPS
automatic data processing systems
GEN
ADQT
adequate
GEN
ADR
airport departure rate
ATC
ADR
advisory route
ATC
ADRDE
advise reason for delay
ATC
ADRNDCK
adirondack
NWS
ADRT
alternate departure route
ATC
ADS
address
GEN
ADS
Air Defense Sector
GEN
ADS
automatic dependent surveillance
ICAO
ADS-B
Automatic Dependent Surveillance-B
ICAO
ADSPN
advise disposition
GEN
ADSU
automatic dependent surveillance unit
ICAO
ADV
advise
NWS
ADVALT
allotment advice
GEN
ADVC
advice
GEN
ADVCTN
advection
NWS
ADVN
advance
GEN
ADVY
advisory
NWS
ADVZY
advisory
ATC
ADW
air defense warning
GEN
ADZ
advise
ICAO
ADZAR
advise arrival
ATC
ADZI
advise intentions
ATC
ADZOF
advise this office
GEN
ADZY
advisory
ATC
ADZY
advisory
GEN
AEA
Eastern Region, FAA
GEN
AEM
aircraft and engine mechanic
GEN
AENG
airways engineer
GEN
AER
approach end runway
GEN
AERO
aeronautical
GEN
AES
aircraft earth station
ICAO
AEU
Europe, Africa, and Middle East Office, FAA
GEN
AEVAC
air evacuation
ATC
AEW
airborne early warning
GEN
AFB
Air Force Base
GEN
AFC
area forecast center
NWS
AFCT
affect
GEN
AFDK
after dark
NWS
AFIL
filed flight plan in the air
GEN
AFIO
authorization for interceptor operations
ATC
AFIRM
affirmative
GEN
AFIS
aerodrome flight information service
ICAO
AFJ
Air Force Jet
ATC
AFM
affirmative
ICAO
AFNEA
Air Force NOTAM Exchange Area
GEN
AFNEO
Air Force NOTAM Exchange Office
GEN
AFOVRN
Air Force overrun 1000-ft standard approach lighting system
MIL
AFRCC
Air Force Rescue Coordination Center
GEN
AFREP
Air Force Representative to the FAA
GEN
AFRT
air freight
GEN
AFS
aeronautical fixed service
GEN
AFT
after
GEN
AFTN
Aeronautical Fixed Telecommunications Network
GEN
AFTN
afternoon
GEN
AG
air ground
ATC
AGA
aerodromes, air routes and ground aids
ICAO
AGACS
automatic ground air/ground communication system
GEN
A-GEAR
arresting gear
GEN
AGL
above ground level
ICAO
AGL
Great Lakes Region, FAA
GEN
AGN
again
GEN
AGR
agree
GEN
AGRMT
agreement
GEN
AHD
ahead
GEN
AI
arrival approved request for IFR flight
ATC
AIA
advise if able
ATC
AIATSC
all international air traffic switching centers
GEN
AIC
Aeronautical Information Circular
GEN
AID
airport information desk
GEN
AIDC
Air traffic services inter-facility data communication
ICAO
AIFP
activate IFR flight plan
ATC
AILS
automatic instrument landing system
GEN
AIM
Airman's Information Manual
GEN
AIP
Aeronautical Information Publication
ATC
AIP
aeronautical information publications (In General)
GEN
AIRAC
aeronautical information regulation and control
GEN
AIRCOMNET
Air Force Communications Network
GEN
AIREP
air report
GEN
AIRFL
air refueling
ATC
AIRMET
Airmen's Meteorological Information
GEN
AIROPNET
air operations network
GEN
AIS
aeronautical information service
GEN
AIS
aeronautical information specialist
GEN
AIS
airport in sight
GEN
AL
all (when used as prefix)
GEN
AL
annual leave
GEN
AL/(---)
at least (altitude)
ATC
ALA
alighting area
GEN
ALACFO
all air carrier field offices
GEN
ALADLO
all air defense liaison officers in service area
GEN
ALAFFO
all technical operations
GEN
ALANO
all accident notice offices
GEN
ALARTC
all air route traffic control centers in service area
GEN
ALAT
all air traffic service personnel in service area
GEN
ALATAS
all air traffic (area) supervisors in service area
GEN
ALATF
all air traffic field facilities
GEN
ALATFO
all air traffic field offices
GEN
ALCKT
all offices having send-receive teletypewriter service on circuit
GEN
ALCS/C
all air traffic combined station/centers in service area
GEN
ALCS/T
All air traffic combined station/towers in service area
GEN
ALCT
attempt to locate
GEN
ALDA
Air Line Dispatchers Association
GEN
ALERFA
alert phase code (alerting service)
ATC
ALF
aloft
NWS
ALFAA
all FAA field offices and personnel
GEN
ALFAB
all FAA offices on NADIN
GEN
ALFSFO
all flight standards field offices
GEN
ALFSS
all flight service stations in service area
GEN
ALG
along
GEN
ALGHNY
Allegheny
NWS
ALIATSC
all international aeronautical telecommunication switching centers
GEN
ALIFO
all international field offices
GEN
ALIFSS
all international flight service stations in service area
GEN
ALNMT
alignment
GEN
ALNOT
alert notice
GEN
ALP
airport layout plan
GEN
ALPA
Air Line Pilots Association
GEN
ALQDS
all quadrants
NWS
ALR
alerting
ICAO
ALRAFAC
all radar ATC facilities in service area
GEN
ALRGN
all regional/service area offices
GEN
ALS
approach light system
ICAO
ALSEC
all sectors
NWS
ALSF-1
standard 2400' high-intensity approach lighting system with sequenced flashers (Category I configuration)
GEN
ALSF-2
standard 2400' high-intensity approach lighting system with sequenced flashers (Category II configuration)
GEN
ALSTG
altimeter setting
GEN
ALT
altitude
ICAO
ALTA
Alberta
NWS
ALTM
altimeter
GEN
ALTN
alternate or alternating
ICAO
ALTN
alternate (aerodrome)
ICAO
ALTPT
alternate airport
GEN
ALTRV
altitude reservation
GEN
ALTWR
all ATC towers in service area
GEN
ALUTN
Aleutian
NWS
ALWF
actual wind factor
NWS
AM
ante meridiem
NWS
AMA
area minimum altitude
ICAO
AMB
ambiguity
GEN
AMC
Air Mobility Command
ATC
AMC
Mike Monroney Aeronautical Center, FAA
GEN
AMCL
amended clearance
ATC
AMD
amend / amended forecast
GEN/
AMDT
amendment
ICAO
AMECH
account mechanical
GEN
AMGR
airport manager
GEN
AMIS
aircraft movement information services
GEN
AMOS
Automatic Meteorological Observing System
GEN
AMP
Amplifier or amplify
GEN
AMPLTD
amplitude
NWS
AMRF
amended route of flight
ATC
AMS
aeronautical mobile service
GEN
AMS
air mass
NWS
AMS
American Meteorological Society
NWS
AMSL
above mean sea level
GEN
AMSS
aeronautical mobile satellite service
ICAO
AMT
Amount
GEN
AMVER
Automated Mutual-Assistance Vessel Rescue System
ATC
ANC
Aeronautical chart 1:500 000 (followed by name/title)
ICAO
ANCPT
anticipate
GEN
ANCS
Aeronautical navigation chart small scale (followed by name/title scale)
ICAO
ANE
New England Region, FAA
GEN
ANF
air navigation facility
GEN
ANG
Air National Guard
GEN
ANLYS
Analysis
NWS
ANM
Northwest Mountain Region, FAA
GEN
ANMS
Automatic Network Management System
GEN
ANNC
announce
GEN
ANR
Advanced Navigation Routes
ATC
ANRA
air navigation radio aids
GEN
ANS
answer
GEN
ANT
antenna
GEN
AO1
ASOS automated observation without precipitation discriminator (rain/snow)
METAR
AO2
ASOS automated observation with precipitation discriminator (rain/snow)
NWS
AOA
at or above
ATC
AOAF
at or after
ATC
AOB
at or below
ATC
AOBF
at or before
ATC
AOC
aerodrome obstacle chart (followed by type & name/title)
ICAO
AOC
airport operating certificate
GEN
AOCP
aircraft out of commission for parts
GEN
AOE
airport of entry
GEN
AOPA
Aircraft Owners and Pilots Association
GEN
AP
airport
ICAO
AP
anomalous propagation
ATC
APAP
approach path alignment panel
GEN
APAPI
Abbreviated precision approach path indicator
ICAO
APC
area positive control
ATC
APCH
approach
ICAO
APDC
Aircraft parking/docking chart (followed by name/title)
ICAO
APL
airport lights
GEN
APLCN
Appalachian
NWS
APN
Apron
ICAO
APNT
appoint
GEN
APP
approach control or approach control office
ICAO
APPA
advise present position and altitude
ATC
APPR
appear
GEN
APR
airports program report
GEN
APREQ
approval request
GEN
APRNT
apparent
GEN
APROP
appropriate
GEN
APRX
approximate
GEN
APS
airborne pulse search radar
GEN
APSG
after passing
ICAO
APV
approve
GEN
APVL
approval
GEN
AR
Atlantic Route
ATC
ARAC
area airports checked
ATC
ARAC
Army Radar Approach Control facility (US Army)
GEN
ARAD
altitude radial
ATC
ARB
Air Reserve Base
GEN
ARC
Area chart
ICAO
ARCP
air refueling control point
ATC
AREP
air refueling egress point
ATC
AREX
air refueling exit
ATC
ARFF
aircraft rescue and fire fighting
ATC
ARFFOK
airport rescue and fire fighting alarm checked
ATC
ARFOR
area forecast
GEN
ARINC
Aeronautical Radio, Incorporated
GEN
ARIP
air refueling initial point
ATC
ARL
Aerial
ATC
ARLO
Army Liaison Officer
GEN
ARMET
forecast upper wind and temperature at specified points
GEN
ARML
Airmail
GEN
ARND
Around
GEN
ARNG
Arrange
GEN
ARNOT
area notice
GEN
ARO
air traffic services reporting office
GEN
ARO
Airport Reservations Office
GEN
ARP
aerodrome reference point
ICAO
ARP
airport reference point
GEN
ARP
airport reservation position
GEN
ARP
air-report
GEN
ARPT
Airport
GEN
ARQ
automatic error correction equipment
GEN
ARR
arrive or arrival
ICAO
ARS
Air Rescue Service (USAF)
GEN
ARS
special air-report
GEN
ARSA
airport radar service area
ATC
ARSR
air route surveillance radar
GEN
ARST
arrest
GEN
ARST
arresting
ICAO
ARTC
air route traffic control
GEN
ARTCC
Air Route Traffic Control Center
GEN
ARTS
Automated Radar Terminal Systems
GEN
ARU
Airborne Radar Unit
GEN
ARU
Airspace Reservation Unit (Canadian)
GEN
ARUNK
arrival unknown
ATC
AS
altostratus
NWS
AS/R
automatic send/receive
GEN
ASAP
as soon as possible
GEN
ASC
ascent to
GEN
ASCU
automatic scanning control unit
GEN
ASD
airspace docket
GEN
ASDA
accelerate-stop distance available
ICAO
ASDE
airport surface detection equipment
GEN
ASE
Altimetry system error
ICAO
ASGN
assign
GEN
ASHTAM
Volcanic Ash Advisory
ICAO
ASI
altimeter setting indicator
GEN
ASIP
airspace flight inspection pilot
GEN
ASL
above sea level
GEN
ASMD
assumed
ATC
ASND
ascend
GEN
ASO
Southern Region, FAA
GEN
ASOS
automated surface observing system
NWS
ASP
airport system plan
GEN
ASP
airspace
GEN
ASPH
asphalt
ICAO
ASR
airport surveillance radar
GEN
ASSOC
associate
GEN
ASST
assistant
GEN
ASW
Southwest Region, FAA
GEN
ATA
actual time of arrival
ATC
ATA
Air Transport Association of America
GEN
ATAM
at and maintain
ATC
ATAR
above transmitted as received
GEN
ATC
air traffic control
ICAO
ATCA
Air Traffic Control Association
GEN
ATCA
ATC advises
ATC
ATCAA
ATC assigned airspace
ATC
ATCBI
ATC beacon interrogator
GEN
ATCC
ATC clears
ATC
ATCF
ATC facility
GEN
ATCH
attach
GEN
ATCOR
ATC operations representative
GEN
ATCR
ATC requests
ATC
ATCRBS
ATC radar beacon system
GEN
ATCS
ATC specialist
GEN
ATCSCC
David J. Hurley ATC System Command Center
GEN
ATCT
Airport Traffic Control Tower
GEN
ATD
actual time of departure
ATC
ATFC
account traffic
GEN
ATFM
air traffic flow management
ICAO
ATIS
automatic terminal information service
ICAO
ATLC
Atlantic
NWS
ATM
air traffic management
ICAO
ATM
air traffic manager
ATC
ATM
authentication maneuver
ATC
ATMT
attempt
GEN
ATMTC
attempt to contact
ATC
ATN
Aeronautical Telecommunications Network
ICAO
ATND
attend
GEN
ATO
aeronautical telecommunications operator
GEN
ATO
Air Traffic Organization
GEN
ATOG
allowable take-off gross weight
GEN
ATP
actual time of penetration
ATC
ATP
air traffic procedures
GEN
ATPAC
Air Traffic Procedures Advisory Committee
GEN
ATR
air transport rating
GEN
ATREP
air traffic representative
GEN
ATRLS
actual time of release
ATC
ATSCCP
Air Traffic Service Contingency Command Post
GEN
ATT
American Telephone and Telegraph Company
GEN
ATTM
at this time
GEN
ATTN
attention
GEN
AT-VASIS
Abbreviated T visual approach slope indicator system
ICAO
ATZ
aerodrome traffic zone
ICAO
AUGRA
authority granted
GEN
AURBO
Aurora Borealis
NWS
AUREQ
authority is requested
GEN
AUTH
authority
GEN
AUTH
authorized or authorization
ICAO
AUTO
automatic
ICAO
AUTOB
automatic weather reporting system
GEN
AUW
all up weight (gross weight)
GEN
AUX
auxiliary
GEN
AUZ
authorize
GEN
AVANA
altitude reservation void for aircraft not airborne by ---
ATC
AVBL
available or availability
ICAO
AVFP
activate VFR flight plan
ATC
AVFPNO
pilot failed to activate VFR/DVFR flight plan
ATC
AVG
average
GEN
AVGAS
aviation gasoline
ICAO
AVN
aviation
GEN
AWA
advise when able
ATC
AWANS
Aviation Weather and NOTAM System
GEN
AWBE
automatic weather broadcast equipment
GEN
AWE
advise when established
ATC
AWL
all weather landing
ATC
AWOS
automatic weather observing/reporting system
GEN
AWP
aviation weather processors
NWS
AWP
Western-Pacific Region, FAA
GEN
AWS
air weather service (USAF)
GEN
AWT
await or awaiting
GEN
AWX
account weather
GEN
AWY
airway
ICAO
AXPS
air express
GEN
AZM
azimuth
ICAO
AZRAN
azimuth and range data
ATC
,
B
Contraction
Definition
Usage
B
base leg
ATC
B
beginning of precipitation (time in minutes) (weather reports only)
NWS
B
Bering Standard Time (time groups only)
NWS
B
blue
GEN
B
center clearance delivered
ATC
BA
braking action
freezing rain information not available (weather reports only)