JO 7340.2 ContractionsJO 7340.2P · Change 3 · Effective 7/9/2026

Chapter 2. United States of America Aeronautical Contractions · Section 1

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2-1-1 A

EXPLANATION OF CODES

GEN - Indicates general aeronautical usage.

NWS - Indicates National Weather Service and aeronautical weather usage.

ATC - Indicates Air Traffic Control usage.

ICAO - Indicates International Civil Aviation Organization usage. International messages should use these.

METAR/TAF - Indicates ICAO weather usage.

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	adapted arrival route	GEN
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
ADAR	adapted departure arrival route	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	adapted departure route	GEN
ADR	advisory route	ATC
ADR	airport departure rate	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-Broadcast	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	arrival or arrive	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	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
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

2-1-2 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	ICAO
BAC	below all clouds	ATC
BACLIN	baroclinic or baroclinic prognosis	NWS
BAFVC	bids accepted for the following vacancies	GEN
BAL	balance	GEN
BASE	cloud base	GEN
BASOPS	Base Operations Office	GEN
BATROP	barotropic or barotropic prognosis	NWS
BC	back course	GEN
BC	beginning climb	ATC
BC	British Columbia	NWS
BC	patches	METAR
BCFG	fog patches	NWS
BCH	beach	NWS
BCKG	backing	NWS
BCM	back course marker	GEN
BCM	become	GEN
BCN	beacon	ICAO
BCREQ	broadcast requested	ATC
BCST	broadcast	ICAO
BCSTN	broadcast station	GEN
BDA	Bermuda	NWS
BDAT	beacon data (digitized)	ATC
BDR	border	GEN
BDRY	boundary	ICAO
BDSLD	bids solicited	GEN
BECMG	becoming (expected between 2 digit beginning hour and 2 digit ending hour)	TAF
BFDK	before dark	NWS
BFR	before	GEN
BGN	began or begin	GEN
BGND	begin or beginning descent	ATC
BHND	behind	GEN
BIFR	before encountering IFR conditions	ATC
BINOVC	breaks in overcast	NWS
BKN	broken	METAR
BL	blowing	METAR
BLD	build	NWS
BLDG	building	ICAO
BLDU	blowing dust	METAR
BLDUP	buildup	NWS
BLKHLS	Black Hills	NWS
BLKT	blanket	NWS
BLN	balloon	GEN
BLO	below	GEN
BLO	below clouds	ICAO
BLSA	blowing sand	METAR
BLSN	blowing snow	METAR
BLW	below	ICAO
BLX	block	ATC
BLZD	blizzard	NWS
BMBR	bomber	GEN
BMS	basic meteorological services	NWS
BND	bound	GEN
BNDRY	boundary	NWS
BNTH	beneath	GEN
BOMB	bombing	GEN
BOVC	base of overcast	NWS
BPOC	before proceeding on course	ATC
BPS	bytes per second	GEN
BPT	beginning procedure turn	ATC
BR	Bahama Route	ATC
BR	branch	GEN
BR	mist	METAR
BRAG	braking action good	GEN
BRAM	braking action medium	GEN
BRAN	braking action nil	GEN
BRAP	braking action poor	GEN
BRF	brief	NWS
BRG	bearing	GEN
BRGT	bright	GEN
BRITE	bright radar indicator tower equipment	GEN
BRK	break	NWS
BRKG	braking	ICAO
BRKHIC	breaks in higher overcast	NWS
BRKSHR	Berkshire	NWS
BRM	barometer	NWS
BS	commercial broadcasting station	ICAO
BSAF	bids solicited as follows	GEN
BSC	bird sweep completed	ATC
BSHP	beginning standard holding procedure	ATC
BSIAP	beginning straight‐in approach	ATC
BSRAP	beginning standard range approach	ATC
BSRO	begin standard refuel orbit	ATC
BT	back taxiing	ATC
BTL	between layers	ICAO
BTN	between	ICAO
BTR	better	GEN
BTWN	between	NWS
BUEC	backup emergency communication	GEN
BUIC	backup interceptor control	ATC
BUL	bulletin	GEN
BUR	bureau	GEN
BUS	business	GEN
BY	blowing spray (weather reports only)	METAR
BYD	beyond	GEN
BZR	buzzer (radar)	GEN

2-1-3 C

Contraction	Definition	Usage
C	celsius	GEN
C	Central Standard Time (time groups only)	NWS
C	centre (runway ID)	ICAO
C	circling (approach and landing charts)	ATC
C	continental (air mass)	NWS
C/A	Coarse/Acquisition	ATC
CA	clear above (PIREP only)	ATC
CAAS	Class A Airspace	ATC
CAC	change to approach control or changing to approach control	ATC
CAC	contact approach control	ATC
CACT	civil air carrier turbojet	GEN
CADO	Chief, Airport District Office	GEN
CAM	Canadian Armed Forces Transport Command	GEN
CAN	Canada	NWS
CANFORCE	Canadian Armed Force	GEN
CANO	catalogue number	GEN
CANOT	Canadian NOTAM	GEN
CANR	Canadian NORAD Region	GEN
CAO	change of appointing office	GEN
CAP	Civil Air Patrol	GEN
CAP/IS	combined approach control/international station	GEN
CAPD	climb at pilot's discretion	ATC
CAPT	captain	GEN
CARA	check area airports	GEN
CARF	central altitude reservation function	GEN
CARIB	Caribbean	NWS
CARU	Canadian Airspace Reservation Unit	GEN
CAS	calibrated airspeed	ATC
CAS	collision avoidance system	GEN
CASCDS	cascades	NWS
CAT	category	ICAO
CAT	clear air turbulence	GEN
CATX	climb and cross	ATC
CAUFN	caution advised until further notice	GEN
CAVOK	cloud and visibility OK	NWS
CAVU	clear or scattered clouds and visibility greater than ten miles	NWS
CAWS	common aviation weather subsystem	NWS
CB	cumulonimbus	NWS
CBAS	Class B airspace	ATC
CBMAM	cumulonimbus mamma	NWS
CBSA	Class B surface area	ATC
CC	carbon copy	GEN
CC	cirrocumulus	NWS
CCA	continental control area	GEN
CCAS	Class C airspace	ATC
CCC	Central Computer Complex	GEN
CCC	Regional Communications Control Center	GEN
CCD	City (or County) Civil Defense Director at____	GEN
CCF	Combined Control Facility	GEN
CCFP	collaborative convective forecast product	ATC
CCLDS	clear of clouds	ATC
CCLKOB	counterclockwise orbit	ATC
CCLKWS	counterclockwise	NWS
CCRU	complete crew	GEN
CCRZ	climb and cruise	ATC
CCSA	Class C surface area	ATC
CCSL	standing lenticular cirrocumulus	NWS
CCTLR	chief controller	GEN
CCUS	cleared Customs	GEN
CD	candela	ICAO
CD	civil defense	GEN
CD	clearance delivery	GEN
CDAS	Class D airspace	ATC
CDC	computer display channel	GEN
CDFNT	cold front	NWS
CDM	collaborative decision making	ATC
CDN	coordination	ICAO
CDO	communications duty officer	GEN
CDSA	Class D surface area	ATC
CE	communications equipment	GEN
CEAS	Class E airspace	ATC
CELNAV	celestial navigation	GEN
CENGR	civil engineer	GEN
CENPAC	Central North Pacific	ATC
CER	climb en route	ATC
CERT	certificate	GEN
CERTIF	certification	GEN
CESA	Class E surface area	ATC
CF	change frequency to	ICAO
CFA	controlled firing area	ATC
CFAD	composite flight data processing	GEN
CFADC	Canadian Forces Air Defense Command	GEN
CFAP	cleared for approach	ATC
CFM	confirm	GEN
CFM	Confirm or I confirm	ICAO
CFN	confine	GEN
CFP	cold front passage	NWS
CFPL	carryover from previous log	ATC
CFR	Code of Federal Regulations	GEN
CFWSU	central flow weather service unit	GEN
CFY	clarify	GEN
CG	Coast Guard	GEN
CGAS	Class G airspace	ATC
CGAS	Coast Guard Air Station	GEN
CGL	circling guidance light	ICAO
CGLS	Coast Guard LORAN Station	GEN
CGSTN	congestion	GEN
CH	channel	ICAO
CH	This is a channel‐continuity‐check of transmission to permit comparison of your record of channel‐ sequence numbers of messages received on the channel	ICAO
CHAP	chapter	GEN
CHARC	characteristic	GEN
CHC	chance	NWS
CHG	change	GEN
CHGO	changing over	ATC
CHM	chemicals	GEN
CHNL	channel	GEN
CHOK	check okay	GEN
CHOV	changeover	ATC
CHRG	charge	GEN
CHSPK	Chesapeake	NWS
CHTR	charter	GEN
CI	cirrus	NWS
CIC	controller in charge	GEN
CIDIN	common ICAO data interchange network	ICAO
CIFP	cancel IFR flight plan	ATC
CIFR	cancel IFR clearance previously given	ATC
CIFRR	Common IFR Room	GEN
CIG	ceiling	NWS
CINCNORAD	Commander in Chief, North American Aerospace Defense Command	GEN
CIRNAV	circumnavigate	ATC
CIRNOT	circuit notice	GEN
CIRVIS	communications instructions for reporting vital intelligence sightings	ATC
CIT	near or over large towns	ICAO
CIV	civil	ICAO
CK	check	ICAO
CKT	circuit	GEN
CL	centre line	ICAO
CL	closing station	GEN
CL	course line	ATC
CLA	clear type of ice formation	ICAO
CLB	climb	ATC
CLBI	climb immediately	ATC
CLBN	crash locator beacon	GEN
CLBR	calibration	ICAO
CLD	cloud	NWS
CLG	calling	ICAO
CLKOB	clockwise orbit	ATC
CLKWS	clockwise	GEN
CLN	colon	GEN
CLNC	clearance	GEN
CLODA	closing date	GEN
CLOTO	close this office	GEN
CLR	clears, or cleared to, or clearance	ICAO
CLRAP	cleared as planned	ATC
CLRS	clear and smooth	NWS
CLSD	closed	ICAO
CLST	celestial	ATC
CLU	circuit line up	GEN
CM	centimeter	ICAO
CMA	comma	GEN
CMB	climb to or climbing to	ICAO
CMNC	commence	GEN
CMPCT	compact	GEN
CMPL	complete or completed or completion	ICAO
CMPLT	complete	GEN
CMPLX	complex	GEN
CMPSN	composition	GEN
CMPT	component	GEN
CMS	construction maintenance supervisor	GEN
CMSN	commission	GEN
CNCL	cancel	NWS
CNCNT	concurrently	GEN
CNCT	connect	GEN
CNDN	Canadian	NWS
CNL	cancel	GEN
CNLFP	cancel flight plan	ATC
CNS	communications, navigation and surveillance	ICAO
CNS	Consolidated NOTAM System	ATC
CNSTNT	consistent	GEN
CNTR	center	GEN
CNTRL	central	GEN
CNTRLN	centerline	GEN
CNVG	converge	GEN
CNVRT	convert	GEN
CNVSN	conversion	GEN
CNVTV	convective	NWS
CO	company	GEN
CO	county	GEN
COB	close of business	GEN
COC	climb on course	ATC
COLL	collect	GEN
COM	communication	ICAO
COMB	combine	GEN
COML	commercial	GEN
COMLO	compass locator	GEN
COMPR	compare	GEN
COMPRT	compartment	GEN
CONC	concrete	ICAO
CONCA	continue calling until	ATC
COND	condition	ICAO
CONF	confidential	GEN
CONFDC	confidence	NWS
CONFIG	configuration	ATC
CONFIGN	configuration	GEN
CONR	Continental NORAD Region	GEN
CONS	continuous	ICAO
CONSO	CONSOLAN Facility	GEN
CONSOL	consol beacon	GEN
CONSOLAN	low or medium frequency long range navigational aid	GEN
CONST	construction	ICAO
CONT	continue(s) or continued	ICAO
CONTDVD	Continental Divide	NWS
CONTH	continue to hold	ATC
CONTR	contract	GEN
CONTRAILS	condensation trails	NWS
COORD	coordinate	GEN
COORD	Coordinates	ICAO
COP	changeover point	GEN
COPCOM	Controllers' Operations and Procedures Committee	GEN
COPT	completed procedure turn	ATC
COR	correct or corrected or correction	GEN
CORAS	corridor assignment	ATC
COREQ	confirming requisition follows	GEN
COT	at the coast	ICAO
COV	cover	ICAO
CP	circular polarization	GEN
CPA	crash phone activated	GEN
CPBL	capable	GEN
CPD	coupled	GEN
CPDLC	Controller‐pilot data link communications	ICAO
CPF	complete power failure	GEN
CPL	current flight plan	ICAO
CPME	Calibration performance monitoring equipment	GEN
CPN	air transport pulse radar navigation aid	GEN
CPS	air transport pulse radar search	GEN
CPTY	capacity	GEN
CRAD	composite radar data processing	GEN
CRAF	civil reserve air fleet	GEN
CRC	circle	GEN
CRC	Cyclic redundancy check	ICAO
CRCHF	crew chief	GEN
CRLC	circulate	GEN
CRS	course	GEN
CRT	cathode ray tube	GEN
CRTFY	certify	GEN
CRYPTO	cryptographic	GEN
CRZ	cruise	ICAO
CRZAM	cruise and maintain	ATC
CRZWTR	cruise well to right	ATC
CS	Call sign	ICAO
CS	cirrostratus	NWS
CS/C	combined station/center	GEN
CS/T	combined station/tower	GEN
CSATR	climb so as to reach	ATC
CSATX	climb so as to cross	ATC
CSDR	consider	GEN
CSDRBL	considerable	GEN
CSLDT	consolidate	GEN
CST	coast	NWS
CTA	control area	ICAO
CTAF	common traffic advisory frequency	ATC
CTAM	climb to and maintain	ATC
CTAS	controlled airspace	ATC
CTAX	climb to and cross	ATC
CTC	contact	ICAO
CTCC	change to center control or changing to center control	ATC
CTCC	contact center control	ATC
CTCEN	contact center	ATC
CTGY	category	NWS
CTL	control	ICAO
CTLA	control area	GEN
CTLB	control boundary	GEN
CTLR	controller	GEN
CTLZ	control zone	GEN
CTN	caution	GEN
CTR	control zone	ICAO
CTRAC	common terminal radar approach control	GEN
CTSKLS	Catskills	NWS
CU	cumulus	NWS
CUF	cumuliform	ICAO
CUFRA	cumulus fractus	NWS
CUSNO	customs has been notified	GEN
CUST	customs	ICAO
CVFP	cancel VFR flight plan	ATC
CVINO	clearance void if not off	ATC
CVN	convene	GEN
CVR	Cockpit voice recorder	ICAO
CVR	cover	GEN
CVRS	computerized voice reservation system	ATC
CW	continuous wave	ICAO
CWM	change weight manifest	GEN
CWRC	climb well to right of course	ATC
CWSU	center weather service unit	GEN
CWTR	climb well to right	ATC
CWY	clearway	ICAO
CXA	cancel approved arrival	ATC
CXD	cancel approved departure	ATC
CYC	cyclonic	NWS
CYCLGN	cyclogenesis	NWS
CYL	cylinder	GEN
CZM	coastal zone management	GEN

2-1-4 D

Contraction	Definition	Usage
D	danger area	ICAO
DA	decision altitude	ICAO
DA	departure approved	ATC
DAAR	deviation approved as requested	ATC
DABRK	daybreak	NWS
DAE	district airport engineer	GEN
DAIRE	direct altitude and identification readout equipment	GEN
DALGT	daylight	GEN
DAP	do all possible	GEN
DAPD	descend at pilot's discretion	ATC
DASI	digital altimeter setting indicator	GEN
D‐ATIS	Data link Automatic Terminal Information Service	ICAO
D‐ATIS	Digital-Automatic Terminal Information Service	ATC
DB	decibel	GEN
DB	describe	GEN
DBA	doing business as	GEN
DBASI	digital barometer altimeter setting indicator	GEN
DBL	double	GEN
DBTF	doubtful	GEN
DC	direct current	GEN
DCA	Defense Communications Agency	GEN
DCAVU	clear or scattered clouds and visibility greater than ten, remainder of report missing (weather reports only)	NWS
DCD	double channel duplex	ICAO
DCF	deputy chief	GEN
DCKG	docking	ICAO
DCLRT	decelerate	ATC
DCM	defense combat maneuvers	ATC
DCMSN	decommission	GEN
DCMT	document	GEN
DCPC	Direct controller‐pilot communications	ICAO
DCR	decrease	GEN
DCRZ	descend to and cruise	ATC
DCS	defense communications system	GEN
DCS	double channel simplex	GEN
DCT	direct	ICAO
DDM	difference in depth of modulation	GEN
DE	From (used to precede the call sign of the calling station)	ICAO
DECCO	Defense Commercial Communications Office	GEN
DEF	defense	GEN
DEFCON	Defense Readiness Conditions	GEN
DEG	degree	ICAO
DELPHO	deliver by telephone	GEN
DEMOL	demolition	GEN
DENEB	fog dispersal operations	ICAO
DEP	depart	ATC
DEP	departure	ICAO
DEPT	department	GEN
DER	departure end of runway	ICAO
DES	descend to or descending to	ICAO
DESTN	destination	GEN
DETRESFA	Distress Phase Code (Alerting Service)	ATC
DEV	deviation	ATC
DEW	distant early warning	GEN
DEWIZ	distant early warning identification zone	GEN
DFCLT	difficult	GEN
DFDR	Digital flight data recorder	ICAO
DFL	daily flight log	GEN
DFNT	definite	GEN
DFRS	differs	GEN
DFTI	distance from touchdown indicator	GEN
DFUS	diffuse	GEN
DGCGO	dangerous cargo	GEN
DGNL	diagonal	GEN
DGR	danger	GEN
DH	decision height	ICAO
DI	delay indefinite	ATC
DI	departure approval request for IFR flight	ATC
DIAM	diameter	GEN
DIF	diffuse	ICAO
DIR	director	GEN
DISABLD	disabled	GEN
DISC	discontinue	GEN
DISEM	disseminate	GEN
DIST	distance	ICAO
DIST	district	GEN
DISTR	distribute	GEN
DIV	divert	ICAO
DIV	division	GEN
DKTS	Dakotas	NWS
DLA	delay or delayed	ICAO
DLAC	delay account of	ATC
DLAT	delay time	ATC
DLC	delay clearance or delayed clearance	ATC
DLIC	Data link initiation capability	ICAO
DLT	delete	GEN
DLVR	deliver	GEN
DLVY	delivery	GEN
DLY	daily	GEN
DLY	Daily	ICAO
DMAAC	Defense Mapping Agency Aerospace Center	GEN
DMAHC	Defense Mapping Agency Hydrographic Center	GEN
DME	distance measuring equipment	ICAO
DMEG	DME‐collocated with glide slope	GEN
DMEL	DME‐collocated with localizer	GEN
DMER	DME‐tactical air navigation with DME only commissioned	GEN
DMEV	DME‐collocated with VOR	GEN
DMG	damage	GEN
DMNT	dominant	GEN
DMO	Directives Management Officer, FAA	GEN
DMSH	diminish	NWS
DMSTN	demonstration	GEN
DNA	Defense Nuclear Agency	GEN
DNG	danger	ICAO
DNS	dense	NWS
DNSLP	downslope	NWS
DNSTRM	downstream	NWS
DNWND	downwind	ATC
DO	Deputy Commander for Operations	GEN
DO	ditto	GEN
DOB	date of birth	GEN
DOC	Department of Commerce	GEN
DOD	Department of Defense	GEN
DOE	Department of Energy	GEN
DOLLY	data link	GEN
DOM	domestic	ICAO
DOT	Department of Transportation	GEN
DOT‐1	Transport One‐Secretary of Transportation	ATC
DOT‐2	Transport Two‐Deputy Secretary of Transportation	ATC
DP	deep	NWS
DP	dew point temperature	ICAO
DPCR	departure procedure	ATC
DPNG	deepening	NWS
DPT	depth	ICAO
DPTH	depth	NWS
DR	dead reckoning	ATC
DR	direct route	GEN
DR	low drifting	METAR
DRCT	direct	GEN
DRCTN	direction	GEN
DRDU	low drifting dust	METAR
DRFT	drift	NWS
DRG	during	ICAO
DRIR	direct readout infrared	GEN
DRMS	Distance Root Mean Square	ATC
DRR	Deployment Readiness Review	ATC
DRSA	low drifting sand	METAR
DRSN	low drifting snow	METAR
DRZL	drizzle	NWS
DS	domestic services (island operations)	GEN
DS	dust storm	METAR
DSATR	descend so as to reach	ATC
DSATX	descend so as to cross	ATC
DSB	double sideband	ICAO
DSCNT	descent	ATC
DSGND	designated	GEN
DSIPT	dissipate	NWS
DSN	Defense Switching Network	GEN
DSND	descend	ATC
DSNDI	descend immediately	ATC
DSNT	distant	GEN
DSPL	display	GEN
DSPLC	displace	GEN
DSPN	disposition	GEN
DSPRL	dispersal	GEN
DSR	desire	GEN
DSRGD	disregard	GEN
DST	distort	GEN
DSTC	distance	GEN
DSTND	destined	ATC
DTAM	descend to and maintain	ATC
DTAX	descend to and cross	ATC
DTE	data terminal equipment	GEN
DTF	data transmission feature	GEN
DTG	date time group	GEN
DTHR	Displaced runway threshold	ICAO
DTL	detail	GEN
DTLN	international dateline	NWS
DTR	data transmission request	GEN
DTRM	determine	GEN
DTRT	deteriorate	NWS
DTS	Diplomatic Telecommunications Service	GEN
DTW	dual tandem wheels	ICAO
DU	widespread dust	METAR
DUATS	direct user access terminal system	GEN
DUC	dense upper cloud	ICAO
DUPE	duplicate	GEN
DUPE	This is a duplicate message (to be used in AFS as a procedure signal)	ICAO
DUR	duration	ICAO
DURC	during climb	ATC
DURD	during descent	ATC
DURG	during	GEN
DURN	duration	GEN
DV	distinguished visitors	GEN
DVFR	defense VFR	GEN
DVLP	develop	GEN
D‐VOLMET	Data link VOLMET	ICAO
DVOR	doppler VHF omni‐directional radio range	ICAO
DVRG	diverge	GEN
DVRSN	diversion	GEN
DVV	downward vertical velocity	NWS
DW	dual wheels	ICAO
DWG	drawing	GEN
DWNDFTS	downdrafts	NWS
DWPNT	dew point	NWS
DWRC	descend well to right of course	ATC
DWTR	descend well to right	ATC
DX	duplex	GEN
DZ	drizzle	ICAO

2-1-5 E

Contraction	Definition	Usage
E	east or eastern longitude	ICAO
E	Eastern Standard Time (time groups only)	NWS
E	ending of precipitation (time in minutes) (weather reports only)	NWS
E	equatorial (air mass)	NWS
E/G	engine‐generator	GEN
E/R	exchange and repair	GEN
EACLN	expect approach clearance	ATC
EACNL	expect approach clearance not later than	ATC
EADIZ	entering air defense identification zone	ATC
EARTS	en route automated radar tracking system	GEN
EAS	equivalent airspeed	ATC
EAT	expected approach time	ATC
EB	eastbound	ICAO
EBND	eastbound	GEN
ECA	enter control area	ATC
ECAS	enter controlled airspace	ATC
ECD	except change departure to read	ATC
ECM	electronic counter measures	GEN
ECMSN	electronic counter measure mission	ATC
ECOM	en route communications	GEN
ECR	except change route to read	ATC
ECSP	electronic specialist	GEN
EDA	early departure authorized	GEN
EDC	expect departure clearance at	ATC
EDCT	estimated departure clearance (time)	ATC
EDR	expect departure release at	ATC
EEE	Error (to be used in AFS as a procedure signal)	ICAO
EEM	electronic equipment modification	GEN
EENGR	electrical engineer	GEN
EEP	end exercise point	GEN
EET	estimated elapsed time	ICAO
EFA	entire field available	GEN
EFC	expect further clearance at	ATC
EFCT	effect	GEN
EFF	effective	GEN
EFR	expect further routing	ATC
EFTO	encrypt for transmission only	GEN
EG	emergency gear	GEN
EGECON	electronic geographic coordinator navigation system	GEN
EHA	expect higher altitude	ATC
EHF	extremely high frequency (30000 to 300000 MHz)	ICAO
EIT	electronic installation technician	GEN
ELAT	estimated latitude	GEN
ELBA	emergency location beacon ‐ aircraft	ICAO
ELEC	electric	GEN
ELECN	electrician	GEN
ELEV	elevate or elevation	ICAO
ELIP	elliptical	GEN
ELMT	electronic mechanic technician	GEN
ELNGT	elongate	NWS
ELONG	estimated longitude	GEN
ELR	extra long range	ICAO
ELSW	elsewhere	GEN
ELT	emergency locator transmitter	GEN
EM	emission	ICAO
EMBD	embedded (in cloud layer)	ICAO
EMBDD	embedded	NWS
EMDO	Engineering and Manufacturing District Office	GEN
EMERG	emergency	ICAO
EMI	electronic maintenance inspector	GEN
EMSU	environment meteorological support unit	NWS
EMT	electronic maintenance technician	GEN
ENCTR	encounter	GEN
END	stop‐end (related to RVR)	ICAO
ENDCE	endurance	GEN
ENDG	ending	GEN
ENE	east‐north east	ICAO
ENERN	east‐northeastern (weather reports only)	NWS
ENEWD	east‐northeastward (weather reports only)	NWS
ENG	engine	ICAO
ENGR	engineer	GEN
ENHNCD	enhanced	GEN
ENHNCMNT	enhancement	GEN
ENR	en‐route	ICAO
ENRC	En‐route chart (followed by name/title)	ICAO
ENRT	en route	GEN
ENTR	entire	GEN
EOBT	estimated off‐block time	ICAO
EOD	entered on duty	GEN
EOF	expected operations forecast	NWS
EP	en route penetration	ATC
EPI	expanded position indicator	ATC
EQCRT	equipment certified	GEN
EQPT	equipment	ICAO
EQUIP	equipment	GEN
ER	here	ICAO
ERAD	en route radar (broadband)	GEN
ERMG	en route metering	ATC
ERT	embedded route text	GEN
ERSP	en route spacing program	ATC
ERY	early	GEN
ESCAT	emergency security control of air traffic	GEN
ESE	east‐south east	ICAO
ESEC	en route secondary radar beacon (broadband)	GEN
ESERN	east‐southeastern (weather reports only)	NWS
ESEWD	east‐southeastward (weather reports only)	NWS
ESNTL	essential	GEN
ESP	en route sequencing program	ATC
EST	estimate or estimation	ICAO
ESTAB	establish	GEN
ESV	expanded service volume	GEN
ET	electronic technician	GEN
ETA	estimated time of arrival	GEN
ETARS	en route tracking automatic radar service	ATC
ETC	et cetera	GEN
ETD	estimated time of departure	GEN
ETE	estimated time en route	GEN
ETFL	each thousand foot level	ATC
ETI	estimated information	ATC
ETIM	elapsed time	ATC
ETO	estimated time over significant point	ICAO
ETOV	estimated time over	ATC
ETP	estimated time of penetration	ATC
ETR	eastern test range	ATC
EU	electronic unit	GEN
EUO	emergency use only	GEN
EV	every	ICAO
EVAC	evacuation	GEN
EVAL	evaluate or evaluation	GEN
EVE	evening	GEN
EVS	electronic voice switching system	GEN
EVT	expect vector to	ATC
EXAM	examination	GEN
EXC	except	ICAO
EXCH	exchange	GEN
EXCLD	exclude	GEN
EXCLV	exclusive	GEN
EXCP	except	GEN
EXCT	execute	GEN
EXDLVY	expedite delivery	GEN
EXEC	executive	GEN
EXEC‐1	President on board civil aircraft	GEN
EXEC‐1F	President's family is aboard aircraft	GEN
EXEC‐2	Vice President is aboard civil aircraft	GEN
EXEC‐2F	Vice President's family is aboard aircraft	GEN
EXER	exercise	ICAO
EXP	expect	ICAO
EXPC	expect	GEN
EXPED	expedite	GEN
EXPHO	expedite delivery by telephone	GEN
EXPS	express	GEN
EXQF	expanded quota flow	ATC
EXREP	expedite mail reply	GEN
EXSEC	extra section	GEN
EXSHI	expedite shipment	GEN
EXTD	extend	GEN
EXTN	extension	GEN
EXTRAP	extrapolate	NWS
EXTRM	extreme	NWS
EXTSV	extensive	GEN

2-1-6 F

Contraction	Definition	Usage
F	Cleared to fix	ATC
F	fahrenheit	GEN
F	flight inspection	GEN
FA	area forecast	NWS
FA	fuel advisory	ATC
FA	final approach	ATC
FA CENTER	Aviation Area Forecast Center	GEN
FAA	Federal Aviation Administration	GEN
FAA	for an approach to	ATC
FAA‐1	SafeAir One‐Federal Aviation Administration Administrator	ATC
FAA‐2	SafeAir Two‐Federal Aviation Administration Deputy Administrator	ATC
FAAP	federal aid to airports program	GEN
FAAR	FAA requirements	GEN
FAC	facilities	ICAO
FAC	facility	GEN
FACF	facility chief	GEN
FACSFAC	Fleet Area Controlled and Surveillance Facility	ATC
FAD	fuel advisory departure	GEN
FAF	final approach fix	ICAO
FAFAB	FSS assumes flight‐plan area and Service B	GEN
FAH	fahrenheit	NWS
FAL	facilitation of international air transport	ICAO
FAM	familiar or familiarization	GEN
FAMAE	following amendment authorized effective	GEN
FAP	final approach point	ICAO
FAR	Federal Aviation Regulations	GEN
FATFL	FSS assumes control of tower frequencies and lights	GEN
FAX	facsimile	GEN
FBO	fixed‐base operator	GEN
FC	funnel cloud	METAR
FCA	frequency change approved	ATC
FCC	Federal Communications Commission	GEN
FCFSS	FAA Contract Flight Service Station	GEN
FCO	facility coordination officer	GEN
FCRP	field condition report	ATC
FCST	forecast	GEN
FCTA	flow control time of arrival	ATC
FCWOS	FAA Contract Weather Observing Station	GEN
FDAT	flight data	GEN
FDC	Flight Data Center	GEN
FDDL	frequency division data link	GEN
FDEP	flight data entry and printout	ATC
FDI	Fault Detection and Isolation	ATC
FDIO	flight data input/output	ATC
FDIOR	flight data input/output repeater	ATC
FDPS	Flight data processing system	ICAO
FE	flight engineer	GEN
FENKN	fuel supply unknown	ATC
FENTL	fuel supply until	ATC
FEW	1 or 2 octas (eighths) cloud coverage	METAR
FEXHA	fuel supply exhausted	ATC
FFC	for further clearance	ATC
FFLT	familiarization flight	GEN
FFMN	fixed federal monitoring network	GEN
FG	fog	METAR
FGSB	FSS guarding Service B	GEN
FI/P	flight information (permanent)	GEN
FI/T	flight information (temporary)	GEN
FIBI	filed but impracticable to transmit	NWS
FIC	Flight Information Center	GEN
FICON	field condition	GEN
FIDO	Flight Inspection District Office	GEN
FIFO	Flight Inspection Field Office	GEN
FIFO‐H	Flight Inspection Field Office ‐ High Altitude	GEN
FIFP	filed IFR flight plan	ATC
FIG	figure	GEN
FIG	flight inspection group	GEN
FIL	filament	GEN
FILG	filling	NWS
FILS	florescan instrument landing system	GEN
FINO	weather report will not be filed for transmission	NWS
FIR	Flight Information Region	GEN
FIRAV	first available	GEN
FIRB	Flight Information Region Boundary	GEN
FIRG	firing	GEN
FIRIV	arrival report will be filed with	ATC
FIS	flight information service	GEN
FISA	automated flight information service	ICAO
FL	flash advisory	NWS
FL	flight level	GEN
FLCTN	fluctuation	GEN
FLD	field	ICAO
FLDST	flood stage	NWS
FLG	falling	NWS
FLG	flashing	ICAO
FLIDAP	flight data position	GEN
FLIP	flight information publication	GEN
FLORL	fluorescent runway lighting (floodlight system)	GEN
FLR	flares	ICAO
FLRY	flurry	NWS
FLT	flight	ICAO
FLTCK	flight check	ICAO
FLTO	flight orders	GEN
FLTWO	flight watch outlet	GEN
FLUC	fluctuating	ICAO
FLW	follow	GEN
FLWIS	flood warning issued	NWS
FM	fan marker	GEN
FM	from	ICAO
FMAP	fan marker approach	ATC
FMH	fan marker located with radio beacon	GEN
FMO	frequency management officer	GEN
FMS	Flight management system	ICAO
FMT	format	GEN
FMU	flow management unit	ICAO
FNA	final approach	ICAO
FNCTN	function	GEN
FNT	Front	NWS
FNTGNS	frontogenesis	NWS
FNTLYS	frontolysis	NWS
FOB	fuel on board	GEN
FOD	foreign object debris	GEN
FONE	telephone	GEN
FORNN	forenoon	NWS
FP	flight plan	GEN
FPA	flight plan area	ATC
FPB	flight progress board	ATC
FPDI	flight path deviation indicator	GEN
FPL	filed flight plan	ICAO
FPL	full performance level	ATC
FPM	feet per minute	GEN
FPN	fixed pulse radar navigation aid	GEN
FPNO	flight plan not received	GEN
FPP	from present position	ATC
FPR	flight plan route	GEN
FPRC	for possible reclearance	ATC
FPWA	further particulars when available	ATC
FQT	frequent	GEN
FR	fuel remaining	GEN
FRC	full route clearance	GEN
FRD	fix‐radial‐distance	ATC
FREQ	frequency	ICAO
FRFAB	FSS returns flight‐plan area and Service B	GEN
FRI	Friday	ICAO
FRH	fly runway heading	ATC
FRM	form	GEN
FRMG	forming	NWS
FRMN	formation	GEN
FRNG	firing	ICAO
FROPA	frontal passage	NWS
FROSFC	frontal surface	NWS
FRQ	frequent	ICAO
FRSB	FSS returns Service B	GEN
FRST	frost	NWS
FRTFL	FSS returns control of tower frequencies and lights	GEN
FRWF	forecast wind factor	NWS
FRZ	freeze	NWS
FRZLVL	freezing level	NWS
FRZN	frozen	NWS
FSDO	Flight Standards District Office	GEN
FSL	full stop landing	ICAO
FSM	flight schedule monitor	ATC
FSNFO	Flight Standards National Field Office	GEN
FSP	flight strip printer	GEN
FSS	Flight Service Station	ICAO
FST	first	ICAO
FT	feet	ICAO
FT	filing time	GEN
FT	foot	GEN
FTAR	following transmitted as received (message handling)	GEN
FTHR	farther or further	GEN
FTHRD	feathered	ATC
FTS	Federal Telecommunications System	GEN
FU	smoke	METAR
FURN	furnish	GEN
FV	forward visibility (miles)	ATC
FVFP	filed VFR flight plan	ATC
FW/SIFR	fixed wing special IFR	GEN
FW/SVFR	fixed wing special VFR	GEN
FWA	flight watch area	GEN
FWC	Fleet Weather Central	NWS
FWCS	flight watch control station	GEN
FWD	forward	GEN
FWDC	forward collect	GEN
FWP	flight watch point	GEN
FWRNG	fire warning	GEN
FWS	flight watch specialist	GEN
FWU	flight watch unit	GEN
FYI	for your information	GEN
FZ	supercooled/freezing	METAR
FZDZ	freezing drizzle	METAR
FZFG	freezing fog	METAR
FZRA	freezing rain	METAR
FZRANO	freezing rain sensor not available	METAR

2-1-7 G

Contraction	Definition	Usage
G	Green	ICAO
G	gusts reaching (knots) (weather reports only)	NWS
G/A	ground to air	ICAO
G/A/G	ground to air and air to ground	ICAO
GA	general aviation	ICAO
GA	glide angle	GEN
GA	Go ahead, resume sending (to be used in AFS as a procedure signal)	ICAO
GADO	General Aviation District Office	GEN
GALS	gallons	ATC
GBA	give better address	GEN
GBAS	ground-based augmentation system	ICAO
GBL	government bill of lading	GEN
GBR	give better reference	GEN
GC	ground control	GEN
GCA	ground control approach	ICAO
GCI	ground control intercept	GEN
GCO	ground communication outlet	ATC
GDP	ground delay program	ATC
GDPGM	Ground Delay Program	ATC
GEN	general	GEN
GENOT	general notice	GEN
GEO	geographic	GEN
GEOREF	geographical reference	GEN
GES	ground earth station	ICAO
GHZ	gigahertz	GEN
GIC	GPS Integrity Channel	ATC
GICG	glaze icing	NWS
GLD	glider	ICAO
GLDR	glider	GEN
GLFALSK	Gulf of Alaska	NWS
GLFCAL	Gulf of California	NWS
GLFSTLAWR	Gulf of St. Lawrence	NWS
GLONASS	global navigation satellite system	ICAO
GLONASS	Global orbiting navigation satellite system	ICAO
GLS	GBAS Landing System	ICAO
GMC	Ground movement chart (followed by name/title)	ICAO
GMT	Greenwich Mean Time	GEN
GND	ground	ICAO
GNDCK	ground check	ICAO
GNDFG	ground fog	NWS
GNSS	global navigation satellite system (in general)	ICAO
GNTR	generator	GEN
GOV	Governor	GEN
GOVT	government	GEN
GP	glide path	ICAO
GPA	glide path angle	ICAO
GPI	ground point of intercept	ATC
GPS	global positioning system	ICAO
GQA	get quick answer	GEN
GR	hail (greater than 3/4”)	METAR
GRAD	gradient	NWS
GRADU	gradual	ICAO
GRASS	grass landing area	ICAO
GRBL	garble	GEN
GRBNKS	Grand Banks	NWS
GRDL	gradual	NWS
GRID	grid point values of processed meteorological data	ICAO
GRTLKS	Great Lakes	NWS
GRVL	gravel	ICAO
GS	glide slope	GEN
GS	Ground stop	ATC
GS	Ground speed	ATC
GS	snow pellets/small hail (less than 1/4”)	METAR
GSA	General Services Administration	GEN
GSDO	General Safety District Office	GEN
GSI	General safety inspector	GEN
GSTS	Gusts	NWS
GSTY	gusty	NWS
GTC	gain time control	ATC
GTCL	Great Circle	GEN
GTR	greater	GEN
GUND	Geoid undulation	ICAO
GV	ground visibility	NWS
GVG	giving	GEN
GVH	government vehicle	GEN
GWT	gross weight	GEN

2-1-8 H

Contraction	Definition	Usage
H24	continuous 24‐hour service	ICAO
HAA	height above airport	GEN
HADA	Hawaiian Defense Area	GEN
HADD	Hawaiian Air Defense Division	GEN
HADIZ	Hawaiian Air Defense Identification Zone	GEN
HAL	height above landing	GEN
HANG	Hawaiian Air National Guard	GEN
HAPI	holding as previously instructed	ATC
HARS	hazardous area reporting service	ATC
HAT	height above touchdown	GEN
HAZ	hazard	GEN
HAZMAT	hazardous material	ICAO
HB	homing beacon	ATC
HBN	hazard beacon	ICAO
HCVIS	high clouds visible	NWS
HDATZ	high density traffic zones	ATC
HDF	high frequency direction finding station	ICAO
HDFRZ	hard freeze	NWS
HDG	heading	ICAO
HDOP	Horizontal Dilution of Precision	ATC
HDSVLY	Hudson Valley	NWS
HDTA	high density traffic airport	GEN
HDWND	headwind	ATC
HEAD	Head of State status	ICAO
HEL	helicopter	ICAO
HELI	heliport	GEN
HF	high frequency	GEN
HFR	hold for release	ATC
HGT	height	ICAO
HHE	household effects	GEN
HI	high	NWS
HIALS	high intensity approach light system	GEN
HIBAL	high altitude balloon	GEN
HIEAT	highest temperature equaled for all time	NWS
HIEFM	highest temperature equaled for the month	NWS
HIESE	highest temperature equaled so early	NWS
HIESL	highest temperature equaled so late	NWS
HIFOR	high level forecast	NWS
HIRIV	how will arrival report be filed concerning	ATC
HIRL	high intensity runway lights	GEN
HITMP	highest temperature	NWS
HIWAS	hazardous inflight weather advisory service	GEN
HIXAT	highest temperature exceeded for all time	NWS
HIXFM	highest temperature exceeded for the month	NWS
HIXSE	highest temperature exceeded so early	NWS
HIXSL	highest temperature exceeded so late	NWS
HJ	sunrise to sunset	ICAO
HLDG	holding	ICAO
HLF	half	GEN
HLP	heliport	ICAO
HLSTO	hailstones	NWS
HLTP	hilltop	NWS
HN	sunset to sunrise	ICAO
HND	hundred	GEN
HNGR	hangar	GEN
HO	service available to meet operational requirements	ICAO
HOL	holiday	GEN
HOP	handoff point	ATC
HOP	helicopter operations	GEN
HOSP	hospital aircraft	ICAO
HOW	handover word	ATC
HP	holding pattern	GEN
HPA	hectopascal	ICAO
HQ	headquarters	GEN
HR	here	GEN
HR	hour	ICAO
HRZN	horizon	GEN
HS	service available during scheduled operations	ICAO
HTN	heterodyne	GEN
HTR	heater	GEN
HUM	humanitarian mission	ICAO
HURCN	hurricane	ICAO
HUREP	hurricane report	NWS
HV	high voltage	GEN
HVDF	high and very high frequency direction finding stations	ICAO
HVY	heavy	ICAO
HWVR	however	GEN
HWY	highway	GEN
HX	high index	NWS
HX	no specific working hours	ICAO
HYD	hydraulic	GEN
HYDRO	hydrographic	GEN
HYR	higher	ICAO
HZ	haze	METAR
Hz	hertz	GEN

2-1-9 I

Contraction	Definition	Usage
I/IFR	intermittent instruments	ATC
IAARC	International Administrative Aeronautical Radio Conference	GEN
IAATCD	if authorized by ATC, DME may be used	ATC
IAC	instrument approach chart (followed by name/title)	ICAO
IAF	initial approach fix	ICAO
IAO	in and out of clouds	ICAO
IAP	instrument approach procedure	ICAO
IAR	intersection of air routes	ICAO
IAS	indicated air speed	ATC
IATA	International Air Transport Association	GEN
IATSC	International Aeronautical Telecommunications Switching Center	GEN
IAW	in accordance with	GEN
IBASF	intervals between aircraft in stream type formation	ATC
IBN	identification beacon	ICAO
IBND	inbound	ATC
IC	ice crystals (weather reports only)	METAR
IC	icing (PIREP only)	ATC
ICAO	International Civil Aviation Organization	GEN
ICD	Interface Control Document	ATC
ICG	icing	NWS
ICGIC	icing in clouds	NWS
ICGICIP	icing in clouds and precipitation	NWS
ICGIP	icing in precipitation	NWS
ID	identify or identifier	ICAO
IDAT	interfacility data	GEN
IDENT	identification	ICAO
IDP	individual development plan	GEN
IF	intermediate approach fix	ICAO
IF	intermediate fix	GEN
IFAMP	if approach missed proceed	ATC
IFF	identification friend/foe	ICAO
IFHOL	if holding	ATC
IFIM	International Flight Information Manual	GEN
IFINS	if instrument conditions encountered	ATC
IFO	International Field Office	GEN
IFO	interphone	GEN
IFONO	interphone (service F) not operative	GEN
IFORO	interphone (service F) resumed operation	GEN
IFPFP	individual flight plans from this point	ATC
IFR	instrument flight rules	ICAO
IFSS	International Flight Service Station	GEN
IFUN	if unable	GEN
IFVLS	if flight visibility becomes less than	ATC
IFVR	if visibility remains	ATC
IGA	international general aviation	ICAO
IGIA	Interagency Group on International Aviation	GEN
IIA	if incorrect advise	GEN
IISD	if incorrect service direct	GEN
ILAS	instrument low approach	ATC
ILS	instrument landing system	ICAO
ILSP	ILS‐partial	GEN
IM	inner marker	ICAO
IMAP	immediately after passing	ATC
IMC	instrument meteorological conditions	GEN
IMDT	immediate	NWS
IMF	interrogation sign	GEN
IMG	immigration	ICAO
IMI	Intensity unknown (weather reports only)	ICAO
IMP	impracticable	GEN
IMPL	impulse	GEN
IMPR	improve	ICAO
IMPT	important	GEN
IMT	immediate or immediately	GEN
IN	inch	ICAO
INA	initial approach	ICAO
INADQT	inadequate	GEN
INATS	interruption of air traffic services	GEN
INBD	inbound	ICAO
INC	in clouds	ICAO
INC	incorporated	GEN
INCERFA	uncertainty phase code (alerting service)	ATC
INCL	include	GEN
INCLV	inclusive	GEN
INCOMP	incomplete	GEN
INCOR	incorrect	GEN
INCR	increase	GEN
INDC	indicate	GEN
INDEF	indefinite	GEN
INDUS	industrial	GEN
INF	inland navigation facility	GEN
INFO	information	ICAO
INIT	initial training	GEN
INLD	inland	NWS
INOF	if not off	GEN
INOP	inoperative	ICAO
INP	if not possible	GEN
INPR	in progress	ICAO
INREQ	information request	GEN
INS	inertial navigation system	ICAO
INSP	inspect	GEN
INST	instrument	GEN
INSTA	instruments authorized	ATC
INSTA	interstate	GEN
INSTBY	instability	NWS
INSTL	install	GEN
INSTR	instruct	GEN
INSTR	instrument	ICAO
INSUF	insufficient scheduled time available	GEN
INSUF	unable to finish	GEN
INT	intersection	ICAO
INTCNTL	intercontinental	GEN
INTCP	intercept	GEN
INTD	intend	GEN
INTER	intermittent	ICAO
INTFC	interference	GEN
INTL	international	ICAO
INTMD	intermediate	GEN
INTMT	intermittent	GEN
INTNS	intentions	GEN
INTR	interior	NWS
INTRG	interrogator	ICAO
INTRMTRGN	Inter‐Mountain Region	NWS
INTRP	interrupt	GEN
INTS	intense	NWS
INTSF	intensify or intensifying	ICAO
INTSFY	intensify	NWS
INTST	intensity	ICAO
INTVL	interval	GEN
INTXN	intersection	GEN
INVES	investigate	GEN
INVOF	in the vicinity of	ATC
INVRN	inversion	NWS
INVSTAR	investigate and report	GEN
IOVC	in overcast	NWS
IP	initial point	ATC
IP	instructor pilot	GEN
IP/HHCL	initial point/H‐hour control line	ATC
IPV	improve	GEN
IR	ice on runway	NWS
IR	IFR military training route	GEN
IRAC	Interdepartmental Radio Advisory Committee	GEN
IRAD	inbound radial	ATC
IREG	irregular	GEN
IRN	Interface Revision Notices	ATC
IS	island	GEN
ISA	international standard atmosphere	ICAO
ISB	independent sideband	ICAO
ISMGR	Island Manager	GEN
ISMLS	interim standard microwave landing system	GEN
ISOL	isolate	GEN
ITCK	issue time check	ATC
ITNRNT	itinerant	GEN
ITRY	itinerary	GEN
ITU	International Telecommunications Union	GEN
IVFRC	in VFR conditions	ATC

2-1-10 J

Contraction	Definition	Usage
JAL	jet approach landing charts	GEN
JATO	jet assisted take‐off	ATC
JAWYS	join airways	ATC
J‐BAR	jet runway barrier	ATC
JCTN	junction	GEN
JOUR	journeyman	GEN
JP	jet penetration	ATC
JPAP	jet penetration approach	ATC
JTST	jet stream	ICAO
JTSTR	jet stream	NWS

2-1-11 K

Contraction	Definition	Usage
K	Cold (air mass)	NWS
KC	kilocycles	GEN
KEPOA	keep this office advised	GEN
KFRST	killing frost	NWS
KG	kilogram	GEN
KHZ	kilohertz	GEN
KIAS	knots indicated airspeed	GEN
KM	kilometers	GEN
KMH	kilometers per hour	ICAO
KPA	kilopascal	ICAO
KT	knots	ICAO
KW	kilowatt	GEN

2-1-12 L

Contraction	Definition	Usage
L	Left	ICAO
L	Locator	ICAO
L	Logistics	GEN
L/MF	low/medium frequency	GEN
LA	low approach	ATC
LAA	local airport advisory	GEN
LAADR	low altitude arrival/departure routing	ATC
LAAS	Local Area Augmentation System	ATC
LAB	laboratory	GEN
LABRDR	labrador	NWS
LABS	leased Service A/B system	ATC
LABS	low altitude bombing system	GEN
LADP	local airport deicing plan	ATC
LAM	logical acknowledgement	ICAO
LAN	inland	ICAO
LARCT	last radio contact	ATC
LAT	latitude	ICAO
LAWRS	Limited Aviation Weather Reporting Station	GEN
LB	left base	ATC
LB	pounds (weight)	GEN
LC	local control	GEN
LCA	locally	ICAO
LCL	local or locally	GEN
LCT	locate	GEN
LCTMP	little change in temperature	NWS
LD	long distance	GEN
LDA	landing distance available	ICAO
LDA	localizer type directional aid	ATC
LDG	landing	ICAO
LDI	landing direction indicator	ICAO
LDIN	lead in lighting system	GEN
LEN	length	ICAO
LETFO	letter follows	GEN
LF	low frequency	GEN
LFC	laminar flow control	GEN
LFNT	low frequency intersection	GEN
LFR	low frequency radio range	GEN
LFT	lift	NWS
LGRNG	long range	NWS
LGT	light or lighting	ICAO
LGTD	lighted	ICAO
LGWV	long wave	GEN
LICOF	land lines communications facilities	GEN
LIFR	low IFR (weather reports only)	NWS
LIH	light intensity high	ICAO
LIL	light intensity low	ICAO
LIM	light intensity medium	ICAO
LIN	linearity	GEN
LIRL	low intensity runway edge lights	GEN
LK	lake	NWS
LKLY	likely	GEN
LKTYP	like type	ATC
LL	landline	GEN
LLWAS	low level wind shear alert system	GEN
LLWS	low level wind shear	GEN
LLZ	localizer (not associated with ILS)	ICAO
LM	locator middle	ICAO
LMM	compass locator at ILS middle marker	GEN
LMT	limit	GEN
LMT	Local Mean Time	ICAO
LN	line	GEN
LNAV	lateral navigation (from TERPS‐A1)	GEN
LND	Land	GEN
LNDG	landing	GEN
LO	liaison officer	GEN
LO	outer locator	ICAO
LOA	letter of agreement	GEN
LOC	localizer	ICAO
LOCOR	local coordinator	GEN
LODISNAV	long distance navigation	GEN
LOEAT	lowest temperature equaled for all time	NWS
LOEFM	lowest temperature equaled for the month	NWS
LOESE	lowest temperature equaled so early	NWS
LOESL	lowest temperature equaled so late	NWS
LOM	compass locator at ILS outer marker	GEN
LONG	longitude	ICAO
LONGL	longitudinal	GEN
LOP	line of position	GEN
LORAC	long range accuracy	GEN
LORAN	long range air navigation system	GEN
LOTMP	lowest temperature	NWS
LOXAT	lowest temperature exceeded for all time	NWS
LOXFM	lowest temperature exceeded for the month	NWS
LOXSE	lowest temperature exceeded so early	NWS
LOXSL	lowest temperature exceeded so late	NWS
LP	left traffic pattern	ATC
LP	linear polarization	ATC
LP	liquid propane	GEN
LP	localizer performance without vertical guidance	GEN
LPV	localizer performance with vertical guidance	ICAO
LR	The last message received by me was ….	ICAO
LRA	landing rights airport	GEN
LRCOM	long range VHF/UHF communications	GEN
LRG	large	GEN
LRG	long range	GEN
LRS	lake reporting service	GEN
LS	left side	ATC
LS	The last message sent by me was …or last message was …	ICAO
LSQ	line squall	ICAO
LSR	loose snow on runway	NWS
LST	Local Standard Time	GEN
LT	turn left after take‐off	ATC
LTAV	light and variable	GEN
LTD	limited	ICAO
LTF	local training flight	ATC
LTFC	landing traffic	ATC
LTGCA	lightning cloud‐to‐air	NWS
LTGCC	lightning cloud‐to‐cloud	NWS
LTGCCCG	lightning cloud‐to‐cloud, cloud to ground	NWS
LTGCG	lightning cloud‐to‐ground	NWS
LTGCW	lightning cloud‐to‐water	NWS
LTGIC	lightning in clouds	NWS
LTL	little	GEN
LTLCG	little change	NWS
LTNG	lightning	NWS
LTR	later	GEN
LTR	letter	GEN
LTT	landline teletypewriter	ICAO
LTTR	latter	GEN
LV	leaving	GEN
LV	light and variable	ICAO
LVE	leave or leaving	ICAO
LVG	leaving	ATC
LVL	level	ATC
LVO	low visibility operations	GEN
LVLOF	level off	ATC
LWR	lower	GEN
LX	low index	NWS
LYR	layer or layered or layers	NWS

2-1-13 M

Contraction	Definition	Usage
M	in RVR indicates visibility less than lowest reportable sensor value (e.g. M600)	METAR
M	in temperature field means “minus” or below zero	METAR
M	Mach number	GEN
M	maritime (air mass)	NWS
M	metres (preceded by figures)	ICAO
M	missing (weather reports only)	NWS
M	Mountain Standard Time (time groups only)	NWS
MA	map analysis	NWS
MAA	maximum authorized (IFR) altitude	GEN
MAC	Military Airlift Command	GEN
MACH	MACH Number (speed ratio to speed of sound)	ATC
MACKAY	Mackay Radio and Telegraph Company	GEN
MACVFR	make altitude changes VFR	ATC
MAFAP	minimum altitude over facility on final approach course	ATC
MAG	magnetic	GEN
MAGSI	minimum altitude at glide slope intersection inbound	GEN
MAINT	maintenance	ICAO
MAL	maintain at least (altitude)	ATC
MALS	medium intensity approach lighting system	GEN
MALSF	medium intensity approach lighting system with sequenced flashers	GEN
MALSR	medium intensity approach lighting system with runway alignment indicator lights	GEN
MAM	maintenance assumes monitor	GEN
MAN	Manitoba	NWS
MAN	manual	GEN
MANAM	manual amendment	GEN
MANOP	manual of operations	GEN
MAP	aeronautical maps and charts	ICAO
MAP	missed approach point	GEN
MAPS	Meteorological Aeronautical Presentation System	GEN
MAPT	missed approach point	ICAO
MAR	at sea	ICAO
MARPT	municipal airport	GEN
MARSA	military assumes responsibility for separation of aircraft	GEN
MAS	manual A1 simplex	ICAO
MAS	military alert system	GEN
MAX	maximum	GEN
MB	marker beacon	GEN
MB	millibars	GEN
MBST	microburst	ICAO
MCA	minimum crossing altitude	ICAO
MCAS	Marine Corps Air Station	GEN
MCAS(H)	Marine Corps Air Station (Helicopter)	GEN
MCK	maintenance check	GEN
MCS	Master Control Station	ATC
MCW	modulated continuous wave	ICAO
MCZNE	minimum when control zone effective	GEN
MDA	minimum descent altitude	ICAO
MDF	medium frequency direction finding station	ICAO
MDFR	make descent from	ATC
MDFY	modify	GEN
MDH	minimum descent height	ICAO
MDT	moderate	GEN
MDZ	modernize	GEN
MDZN	modernization	GEN
MEA	minimum en route altitude	ICAO
MECH	mechanic	GEN
MED	medical	GEN
MED	medium	GEN
MEDEVAC	medical emergency evacuation	ICAO
MEGG	merging	NWS
MEHT	minimum eye height over threshold	ICAO
MEML	memorial	GEN
MET	meteorological	GEN
METAR	aviation routine weather report	ICAO
METOF	meteorological officer	GEN
METRO	metropolitan	GEN
MEX	Mexico	NWS
MF	medium frequency	GEN
MFL	maintain flight level	ATC
MFOB	minimum fuel on board	ATC
MFPOF	master flight plan on file	ATC
MFS	military flight service	GEN
MFV	forward visibility more than (miles)	ATC
MFXT	meter fix time	ATC
MGAT	make good a track of (degrees)	ATC
MGMT	make good a magnetic track of (degrees)	ATC
MGMT	management	GEN
MGR	manager	GEN
MHA	minimum holding altitude	GEN
MHDF	medium and high frequency direction‐finding station (same location)	ICAO
MHDG	magnetic heading	GEN
MHFR	military height finder radar	GEN
MHKVLY	Mohawk Valley	NWS
MHVDF	medium high and very high frequency direction‐finding station (same location)	ICAO
MHZ	megahertz	ICAO
MI	manufacturing inspector	GEN
MI	mile	GEN
MI	shallow	METAR
MID	middle	GEN
MID	mid‐point (related to RVR)	ICAO
MID/ASIA	ICAO Middle East/Asia Region	ATC
MIDIZ	Mid‐Canada Identification Zone	GEN
MIDN	midnight	NWS
MIDPT	midpoint	GEN
MIFG	patches of shallow fog not deeper than two meters	NWS
MIFG	shallow fog	METAR
MIJI	meaconing, intrusion, jamming, interference	ATC
MIL	military	ICAO
MIMNO	mimeographic notice	GEN
MIN	minute	ICAO
MINIT	minutes in trail	ATC
MIREQ	minimum requirements specified	GEN
MIRL	medium intensity runway edge lights	GEN
MIS	Missing …(transmission identification)	ICAO
MISC	miscellaneous	GEN
MISG	missing	GEN
MISL	missile	GEN
MIT	miles in trail	ATC
MITO	minimum interval take‐off	ATC
MKCT	make check turn	ATC
MKD	marked	GEN
MKR	marker	GEN
MKR	marker radio beacon	ICAO
MLS	microwave landing system	GEN
MLTLVL	melting level	NWS
MM	middle marker	ICAO
MM	millimeter	GEN
MMACH	maintain Mach	ATC
MMO	main meteorological office	NWS
MNLD	mainland	NWS
MNLY	mainly	GEN
MNM	minimum	ICAO
MNPS	minimum navigation performance specification	ATC
MNPSA	minimum navigation performance specification airspace	ATC
MNT	monitor, monitored, or monitoring	ICAO
MNTN	maintain	ICAO
MNVR	maneuver	GEN
MOA	memorandum of agreement	GEN
MOA	military operations area	ICAO
MOC	minimum obstacle clearance (required)	ICAO
MOCA	minimum obstruction clearance altitude	ICAO
MOD	moderate	GEN
MOD	modulate or modulation or modulator	GEN
MOGR	moderate or greater	NWS
MON	above mountains	ICAO
MON	Monday	ICAO
MONOK	monitor resumed normal operation	GEN
MONOS	monitor out of service	GEN
MONTR	monitor	NWS
MOPS	Minimum operational performance standards	ICAO
MOPTAR	multi‐object phase tracking and ranging	GEN
MOREPS	monitor station reports	GEN
MOT	Ministry of Transport (Canada)	GEN
MOTNE	Meteorological Operational Telecommunications Network Europe	ICAO
MOV	Move, or moving, or movement	ICAO
MPH	miles per hour	GEN
MPP	Merit Promotion Program	GEN
MPS	meters per second	ICAO
MPVA	maintain a position VFR and advise	ATC
MRA	minimum reception altitude	GEN
MRG	medium range	GEN
MRGL	marginal	NWS
MRKG	marking	GEN
MRM	maintenance returns monitor	GEN
MRNG	morning	NWS
MRP	ATS/MET reporting point	ICAO
MRR	mechanical reliability report	GEN
MRTM	maritime	NWS
MRU	Military Radar Unit	GEN
MS	minus	NWS
MSA	minimum safe/sector altitude	GEN
MSAW	minimum safe altitude warning	GEN
MSG	message	ICAO
MSGCTR	message center	GEN
MSL	mean sea level	ICAO
MSR	Message …(transmission identification) has been misrouted	ICAO
MSSR	Monopulse secondary surveillance radar	ICAO
MSTLY	mostly	NWS
MSTR	moisture	NWS
MT	mountain	ICAO
MTCA	minimum terrain clearance altitude	GEN
MTI	moving target indicator	ATC
MTN	mountain	NWS
MTR	military training route	GEN
MTRL	material	GEN
MTRY	momentary	GEN
MTU	metric units	ICAO
MTW	mountain wave	ICAO
MU	designate a friction value representing runway surface conditions (Greek letter)	GEN
MUA	maximum usable altitude	GEN
MUF	maximum usable frequency	GEN
MULT	multiple	GEN
MUNI	municipal	GEN
MV	millivolt	GEN
MVA	minimum vector altitude	GEN
MVDF	medium and very high frequency direction‐finding station (same location)	ICAO
MVFR	maintain VFR	ATC
MVFR	marginal VFR	NWS
MVSP	maintain visual separation	ATC
MWO	Meteorological Watch Office	ICAO
MWRC	maintain well to right of course	ATC
MWTCS	modernized weather teletypewriter communications system	GEN
MXD	mixed	NWS

2-1-14 N

Contraction	Definition	Usage
N	north or northern latitude	ICAO
N/A	not applicable	GEN
NA	not authorized	GEN
NAAS	Naval Auxiliary Air Station	GEN
NAATS	National Association of Air Traffic Control Specialists	GEN
NAB	not above	GEN
NACOS	national communications schedule	GEN
NADIN	National Airspace Data Interchange Network	GEN
NAF	Naval Air Facility	GEN
NAFEC	National Aviation Facilities Experimental Center	GEN
NANAC	National Aircraft Noise Abatement Council	GEN
NAP	not at present	GEN
NAPRS	National Airspace Performance Reporting System	ATC
NAR	North American Route	GEN
NAR	not according to routine	GEN
NAS	National Airspace System	GEN
NAS	Naval Air Station	GEN
NASA	National Aeronautics and Space Administration	GEN
NASC	National AIS system centre	ICAO
NASEO	National Airways System Engineering office	GEN
NASP	National Airport System Plan	GEN
NAT	North Atlantic	GEN
NAT	not ARTS tracked	ATC
NATCA	National Air Traffic Controllers Association	ATC
NATCAS	Navigation, ATC, and Collision Avoidance System	GEN
NATCC	National Air Transport Coordinating Committee	GEN
NATCOM	National Communications Center	GEN
NATL	national	GEN
NATR	no additional traffic reported	ATC
NATS	noise abatement test system	GEN
NAV	navigation	ICAO
NAVAID	navigational aid	GEN
NAVLO	Navy Liaison Officer	GEN
NAVREP	Navy Representative to the FAA	GEN
NB	New Brunswick	NWS
NB	northbound	ICAO
NBCAP	national beacon code allocation plan	GEN
NBFR	not before	ICAO
NBND	northbound	GEN
NBRHD	neighborhood	GEN
NC	no change	GEN
NCDC	National Climatic Data Center	GEN
NCE	no change in estimates	ATC
NCS	National Communications System	GEN
NCWX	no change in weather	NWS
NDB	nondirectional radio beacon	ICAO
NDB/DME	NDB and DME (collocated)	GEN
NDBLO	not to descend below	ATC
NE	north‐east	ICAO
NEB	north‐eastbound	ICAO
NEC	necessary	GEN
NEF	no further clearance required	ATC
NEG	negative	GEN
NELY	northeasterly (weather reports only)	NWS
NERN	northeastern	NWS
NESS	national environmental satellite service	GEN
NETR	no essential traffic reported	ATC
NEW ENG	New England	NWS
NFDD	National Flight Data Digest	GEN
NFLD	Newfoundland	NWS
NFQ	night frequency	GEN
NFT	no filing time	GEN
NFU	not for us	GEN
NG	National Guard	GEN
NGT	night	ICAO
NHD	not heard	ATC
NICS	National Airspace System Interfacility Communications System	GEN
NIL	none	GEN
NIL	unable to transmit	GEN
NIS	not in system	GEN
NL	no layers	NWS
NLT	not later than	GEN
NM	nautical mile	ICAO
NMBR	number	NWS
NMC	National Meteorological Center	GEN
NML	normal	GEN
NMN	no middle name	GEN
NMR	nautical mile radius	GEN
NMRS	numerous	GEN
NMS	NOTAM Management Service	GEN
NNE	north‐north east	ICAO
NNERN	north‐northeastern (weather reports only)	NWS
NNEWD	north‐northeastward (weather reports only)	NWS
NNW	north‐north west	ICAO
NNWRN	north‐northwestern (weather reports only)	NWS
NNWWD	north‐westward (weather reports only)	NWS
NO	No (negative)	ICAO
NO	not available	METAR
NOAA	National Oceanic and Atmospheric Administration	GEN
NOAC	no action necessary	GEN
NOF	NOTAM Office	GEN
NOFIN	no further information	GEN
NOHOL	not holding	ATC
NOIFN	no information	GEN
NOLF	Naval Outlying Landing Field	GEN
NOMAD	Naval Oceanographic Meteorological Automatic Device	GEN
NONEG	negative replies not required	GEN
NONRVSM	non-RVSM capable flight	ICAO
NOPAC	North Pacific	ATC
NOPAR	do not pass to Air Defense radar	ATC
NOPT	no procedure turn required	GEN
NORAC	no radio contact	ATC
NORAD	North American Aerospace Defense Command	GEN
NORDO	no radio	GEN
NOREC	no record	GEN
NOREP	no report	GEN
NORIV	no arrival report	ATC
NORPI	no pilot balloon observation will be filed next collection unless weather changes significantly	NWS
NORR	no reply received	GEN
NORST	no restrictions	GEN
NOS	National Ocean Service	GEN
NOSI	now simultaneous	GEN
NOSIG	no significant change	ICAO
NOSPL	no special observations taken (weather reports only)	NWS
NOSUM	NOTAM Summary	GEN
NOTAM	Notice to Airmen	ICAO
NOZ	normal operating zone	GEN
NOZ	Normal operating zone	ICAO
NPI	nonprecision instrument	GEN
NPRL	no parallel traffic	ATC
NPRM	Notice of Proposed Rulemaking	ATC
NPRS	nonpersistent	NWS
NR	near	GEN
NR	number	GEN
NRAB	Naval Reserve Air Base	GEN
NRD	no record of destination	GEN
NRH	no reply heard	ICAO
NRP	North American route program	ATC
NRV	nonrevenue	GEN
NRW	narrow	GEN
NS	nimbostratus	NWS
NS	Nova Scotia	NWS
NSC	no significant cloud	ICAO
NSC	Nonstandard C/A Code	ATC
NSCSWD	no small craft or storm warning are being displayed	NWS
NSP	nonstandard holding pattern	GEN
NSSFC	National Severe Storm Forecast Center	GEN
NSTD	non-standard	GEN
NSTP	nonstop	GEN
NSW	no significant weather	METAR
NTAP	National Track Analysis Program	ATC
NTE	not to exceed	GEN
NTFD	notified	GEN
NTFND	no trouble found	GEN
NTFY	notify	GEN
NTL	National	ICAO
NTO	name to	GEN
NTRP	no traffic reported	ATC
NTSB	National Transportation Safety Board	GEN
NTZ	no transgression zone	ATC
NTZ	No transgression zone	ICAO
NUDET	nuclear detonation	GEN
NVA	negative vorticity advection	NWS
NW	north‐west	ICAO
NWB	north‐westbound	ICAO
NWLY	northwesterly (weather reports only)	NWS
NWRN	northwestern (weather reports only)	NWS
NWS	National Weather Service	GEN
NWSO	Naval Weather Service Office	GEN
NXT	next	GEN

2-1-15 O

Contraction	Definition	Usage
O/F	on file	GEN
O/R	on request	GEN
O/T	overtime	GEN
OA	overhead approach	ATC
OAC	oceanic area control	GEN
OAG	Official Airline Guide	GEN
OANDR	operation and regulation	GEN
OAOI	on and off instruments	ATC
OARTS	oceanic air route tracking system	GEN
OAS	obstacle assessment surface	ICAO
OAT	outside air temperature	GEN
OB	on board	GEN
OBL	obliterate	GEN
OBND	outbound	ATC
OBS	observe, observed, or observation	ICAO
OBSC	obscure, obscured, or obscuring	ICAO
OBST	obstacle	ICAO
OBST	obstruct	GEN
OBSTN	obstruction	GEN
OC	obstruction chart	GEN
OC	on course	ATC
OCA	obstacle clearance altitude	ICAO
OCA	oceanic control area	ICAO
OCAC	oceanic ATC	GEN
OCAS	out of controlled airspace	ATC
OCFNT	occluded front	NWS
OCH	obstacle clearance height	ICAO
OCL	obstacle clearance limit	ICAO
OCLD	occlude	NWS
OCLN	occlusion	NWS
OCNL	occasional	GEN
OCR	occur	GEN
OCS	obstacle clearance surface	ICAO
OCTLA	out of control area	ATC
ODALS	omnidirectional approach lighting system	GEN
ODAPS	Oceanic Display and Planning System	ATC
OFAS	overseas flight assistance service	GEN
OFC	office	GEN
OFFL	official	GEN
OFM	out for maintenance	GEN
OFP	occluded frontal passage	NWS
OFP	original flight plan	GEN
OFSHR	offshore	NWS
OFW	off watch	GEN
OFXT	outer fix time	ATC
OFZ	Obstacle free zone	ICAO
OG	on ground	ATC
OGN	Originate	ICAO
OHD	overhead	ICAO
OI	on instruments	ATC
OINT	omni intersection	GEN
OIS	operational information system	ATC
OJT	on‐the‐job training	GEN
OK	operating normally	GEN
OK	We agree or it is correct	ICAO
OLDI	On line data interchange	ICAO
OLS	optical landing system	ATC
OM	outer marker	ICAO
OMSG	our message	GEN
OMTNS	over mountains	NWS
ONER	oceanic navigational error report	ATC
ONSHR	on shore	NWS
ONT	Ontario	NWS
ONW	on watch	GEN
OOT	out of tolerance	GEN
OPA	opaque, white type of ice formation	ICAO
OPC	operational control	ICAO
OPDT	opposite direction traffic	GEN
OPER	operate	GEN
OPMET	operational meteorological (information)	ICAO
OPN	open	ICAO
OPN	operation	GEN
OPNML	operations normal	GEN
OPR	operate, operator, operational	ICAO
OPS	operations	ICAO
OPSNET	operations network	ATC
ORD	order, indication of	ICAO
ORGPHC	orographic	NWS
ORIG	original	GEN
ORL	overrun lights	GEN
ORS	over range station	ATC
OSV	ocean station vessel	NWS
OT	on time	ATC
OTAS	on top and smooth	NWS
OTFC	overflight traffic	GEN
OTLK	outlook	NWS
OTP	on top	ATC
OTR	other	GEN
OTRW	otherwise	GEN
OTS	organized track system	GEN
OTS	out of service	GEN
OUBD	outbound	ICAO
OV	location (PIREP only)	ATC
OVC	overcast	NWS
OVD	overdue	GEN
OVHD	overhead	GEN
OVLA	overlay	GEN
OVNGT	overnight	GEN
OVR	over	GEN
OVRN	overrun	GEN
OVSEA	overseas	GEN
OVTK	overtake	GEN
OW	one way	GEN
OWF	optimum working frequency	GEN
OXY	oxygen	GEN

2-1-16 P

Contraction	Definition	Usage
P	in RVR indicates visibility greater than highest reportable sensor value (e.g. P600FT)	METAR
P	Pacific Standard Time (time group only)	NWS
P	polar (air mass)	NWS
P	prohibited area	ICAO
P/CG	pilot controller glossary	GEN
P6SM	visibility greater than 6 SM (TAF only)	METAR
PA	precision approach	GEN
PA	pressure altitude	GEN
PAC	Pacific	NWS
PACF	parent FSS assumes control of part‐time FSS	GEN
PADRA	pass to air defense radar	ATC
PAEW	personnel and equipment working	GEN
PAJA	parachute jumping activities	GEN
PALS	precision approach lighting system	ICAO
PALT	present altitude	ATC
PANS	procedures for air navigation services	ICAO
PAPI	precision approach path indicator	ICAO
PAR	precision approach radar	ICAO
PARA	paragraph	GEN
PAREN	parenthesis	GEN
PARL	parallel	ICAO
PARROT	Transponder	GEN
PARROT	Position adjustable range reference orientation transponder	ATC
PAT	pattern	GEN
PATC	Precision approach terrain chart	ICAO
PATWAS	pilots automatic telephone weather answering service	GEN
PAU	present address unknown	GEN
PAX	passenger	ICAO
PBCT	proposed boundary crossing time	GEN
PBL	probable	NWS
PBS	public buildings service	GEN
PCA	positive control area	GEN
PCD	proceed	ICAO
PCK	pilot check	ATC
PCL	pilot controlled lighting	GEN
PCL	Pilot controlled lighting	ICAO
PCN	pavement classification number	ICAO
PCPN	precipitation	NWS
PCS	permanent change of station	GEN
PCT	percent	ICAO
PD	period	GEN
PDAR	preferential arrival/departure route (Stage A)	GEN
PDC	Pre‐departure clearance	ICAO
PDDC	proceed directly on course	ATC
PDMT	predominant	NWS
PDMT	predominate	NWS
PDOP	Position Dilution of Precision	ATC
PDR	preferential departure route (Stage A)	GEN
PDW	priority delayed weather	NWS
PEN	peninsula	NWS
PENT	penetrate or penetration	ATC
PER	performance	ICAO
PERCOM	peripheral communications	GEN
PERF	perforator	GEN
PERI	perimeter	GEN
PERM	permanent	ICAO
PFSV	pilot to forecaster service	GEN
PGTSND	Puget Sound	NWS
PHYS	physical	GEN
PIB	Pre‐flight information bulletin	ICAO
PIBAL	pilot balloon observation	NWS
PIC	pilot in command	GEN
PIR	precision instrument runway	GEN
PIREP	pilot weather report	GEN
PIRFC	pilot requests forecast	GEN
PISE	no pilot balloon observation due to unfavorable sea conditions	NWS
PISO	no pilot balloon observation due to snow	NWS
PIT	pilot instructor training	GEN
PIWI	no pilot balloon observation due to high, or gusty, surface wind	NWS
PJE	parachute jumping exercise	ICAO
PK WND	peak wind (weather reports only)	NWS
PL	ice pellets	METAR
PLA	practice low approach	ICAO
PLASI	pulsating visual approach slope indicators	ATC
PLAT	present latitude	ATC
PLF	private line telephone	GEN
PLINE	Power line	GEN
PLN	flight plan	ICAO
PLOB	place of birth	GEN
PLONG	present longitude	ATC
PLS	please	GEN
PLT	private line teletypewriter	GEN
PLVL	present level	ICAO
PLW	plow (snow)	NWS
PM	post meridiem	GEN
PMSN	permission	GEN
PMT	permit	GEN
PN	prior notice required	ICAO
PNHDL	panhandle	NWS
PNR	point of no return	ATC
PO	dust devils	METAR
PO	post office	GEN
PO	purchase order	GEN
POA	privately owned aircraft	GEN
POB	persons on board	ICAO
POC	proceed or proceeding on course	ATC
POS	positive	GEN
POSS	possible	ICAO
POV	privately owned vehicle	GEN
PP	pay period (number)	GEN
PPI	plan position indicator	ICAO
PPINA	radar weather report not available (or omitted for a reason different than those otherwise stated)	NWS
PPINE	radar weather report no echoes observed	NWS
PPINO	radar weather report equipment inoperative due to breakdown	NWS
PPIOK	radar weather report equipment operation resumed	NWS
PPIOM	radar weather report equipment inoperative due to maintenance	NWS
PPR	prior permission required	ICAO
PPS	propose	GEN
PPSN	present position	ATC
PR	partial	METAR
PR	photo reconnaissance	GEN
PRBL	probable	GEN
PRBLTY	probability	NWS
PRBO	position relief briefing observed	ATC
PRCF	parent FSS returns control of part‐time FSS	GEN
PRCHT	parachute	GEN
PRCTN	precaution	GEN
PRECD	precede	GEN
PREF	preferred	ATC
PRES	pressure	GEN
PRESFR	pressure falling rapidly	NWS
PRESRR	pressure rising rapidly	NWS
PREV	previous	GEN
PRFG	fog partial	METAR
PRI	primary	ICAO
PRIM	primary	GEN
PRIN	principal	GEN
PRIND	present indications are	GEN
PRIRA	primary radar	GEN
PRJMP	pressure jump (weather reports only)	NWS
PRKG	parking	ICAO
PRN	pseudo random noise	GEN
PROB	probability	ICAO
PROB30	slight chance	METAR
PROB40	probability 40 percent	METAR
PROC	procedure	ICAO
PROCD	proceed	GEN
PROG	prognosis or prognostic	NWS
PROG	progress	GEN
PROP	propeller	GEN
PROPA	propagation	GEN
PROSIG	procedure signal	GEN
PROV	provisional	ICAO
PRP	prepare	GEN
PRSNT	present	NWS
PRST	persist	GEN
PRVD	provide	GEN
PS	passenger service	GEN
PS	plus	NWS
PSBL	possible	GEN
PSBT	pilot self‐briefing terminal	GEN
PSG	passage	NWS
PSG	passing	NWS
PSGR	passenger	GEN
PSN	position	ICAO
PSNAL	personal	GEN
PSNL	personnel	GEN
PSNRP	position report	ATC
PSP	pierced steel planking	ICAO
PSR	packed snow on runway	NWS
PSR	Primary surveillance radar	ICAO
PSRI	position subject to return of incumbent	GEN
PSRS	position subject to rotating shifts	GEN
PST	Pacific Standard Time	GEN
PT	procedure turn	GEN
PTC	plan to clear	ATC
PTC	positive target control	ATC
PTCHY	patchy	NWS
PTCP	participate	GEN
PTLY	partly	NWS
PTN	portion	GEN
PTN	procedure turn	ICAO
PTP	point‐to‐point	ATC
PTR	printer	GEN
PTS	polar track structure	ICAO
PUB	public	GEN
PUBL	publish	GEN
PUP	pickup	GEN
PVA	positive vorticity advection	NWS
PVASI	pulsating/steady visual approach slope indicator	GEN
PVL	prevail	GEN
PVLT	prevalent	GEN
PVT	private	GEN
PWB	pilot weather briefing	GEN
PWI	proximity warning indicator	ATC
PWINO	precipitation identifier information not available (weather reports only)	NWS
PWR	power	GEN
PWRNO	power failure	GEN
PWROK	power restored	GEN
PY	spray	METAR

2-1-17 Q

Contraction	Definition	Usage
QDL	Do you intend to ask me for a series of bearings? Or I intend to ask you for a series of bearings	ICAO
QDM	magnetic heading	ICAO
QDR	magnetic bearing	ICAO
QFE	atmospheric pressure at airport elevation	ICAO
QFLOW	quota flow control procedures	GEN
QFU	magnetic orientation of runway	ICAO
QGE	What is my distance to your station or Tour distance to my station is …	ICAO
QJH	Shall I run my test tape/a test sentence	ICAO
QLFY	qualify	GEN
QLTY	quality	GEN
QN	question	GEN
QNH	altimeter sub‐scale setting to obtain elevation when on the ground	ICAO
QNTY	quantity	GEN
QSP	Will you relay to …free of charge or I will relay to…free of charge	ICAO
QSTNRY	quasistationary	NWS
QTA	Shall I cancel telegram number …? Or cancel telegram number …	ICAO
QTE	true bearing	ICAO
QTF	Will you give me the position of my station according to the bearings taken by the D/F station which you control or the position of your station according to the bearings taken by the D/F stations that I control was …latiude…longitude (or other indication of position), class ....at....hours	ICAO
QTR	quarter	GEN
QUAD	quadrant	GEN
QUE	Quebec	NWS
QUJ	Will you indicate the TRUE track to reach you or the TRUE track to reach me is …degrees at …hours	ICAO

2-1-18 R

Contraction	Definition	Usage
R	Acknowledgement of receipt (message handling)	GEN
R	Received (acknowledgement of receipt)	ICAO
R	restricted area (followed by identification)	ICAO
R	right (runway identification)	ICAO
R	runway (used in RVR measurement)	METAR
R/O	receive only	GEN
R/OC	receive, only centers	GEN
RA	rain	METAR
RAA	Remote Airport Advisory	ATC
RAAF	Royal Australian Air Force	GEN
RABA	no RAWIN obs., no balloons available	NWS
RABAL	radiosonde balloon wind data	NWS
RABAR	radiosonde balloon release	NWS
RAC	request altitude change	ATC
RAC	rules of the air and air traffic services	ICAO
RACE	request altitude changes en route	ATC
RACFI	radio and communication facilities inoperative	GEN
RACO	no RAWIN obs., communications out	NWS
RACON	radar responder beacon	GEN
RADAT	radiosonde observation data	NWS
RADEP	radar departure	ATC
RADNO	report missing account radio failure	NWS
RADON	radar beacon	GEN
RADU	weather radar analysis and development unit	GEN
RAF	Royal Air Force	GEN
RAFC	regional area forecast center	ICAO
RAFI	radiosonde observation not filed	NWS
RAFRZ	radiosonde observation freezing levels	NWS
RAG	ragged	ICAO
RAG	runway arresting gear	ICAO
RAGF	remote air‐ground facility	GEN
RAHE	no RAWIN obs., no gas available	NWS
RAI	runway alignment indicator	ICAO
RAICG	radiosonde observation icing at	NWS
RAIL	runway alignment indicator lights	GEN
RAIM	Receiver Autonomous Integrity Monitoring	ATC
RAIM	Receiver autonomous integrity monitoring	ICAO
RAJAM	radar jamming	ATC
RALT	regardless of altitude	ATC
RAM	returned account mechanical	GEN
RAOB	radiosonde observation	NWS
RAPCON	Radar Approach Control facility (USAF, USN and USMC)	GEN
RAPI	radiosonde report already sent in PIBAL collection	GEN
RARAD	radar advisory	GEN
RAREP	radar weather report	NWS
RASC	Regional AIS system centre	ICAO
RASH	rain showers	ICAO
RASN	rain and snow or showers of rain and snow	METAR
RATCF	Radar Air Traffic Control Facility (USN and USMC)	GEN
RAVU	radiosonde analysis and verification unit	NWS
RAWE	no RAWIN obs., unfavorable weather	NWS
RAWI	no RAWIN obs., high and gusty winds	NWS
RAWIN	upper winds obs. (by radio methods)	NWS
RAWX	returned account weather	GEN
RB	rescue boat	ICAO
RB	right base	ATC
RBDE	radar bright display equipment	GEN
RBN	radio beacon	GEN
RBOC	report back on course	ATC
RBOF	report back on frequency	ATC
RBS	radar bomb scoring	GEN
RBS PP(RBS+++)	ration by schedule plus compression	ATC
RC	reverse course	ATC
RC	road reconnaissance	GEN
RCA	reach cruising altitude	ICAO
RCADV	reverse course and advise	ATC
RCAG	remote center air/ground facility	GEN
RCALT	reach cruising altitude	ATC
RCC	Rescue Coordination Center	GEN
RCD	radar cloud detection report	NWS
RCDNA	radar cloud detection report not available	NWS
RCDNE	radar cloud detection report no echoes observed	NWS
RCDNO	radar cloud detector inoperative due to breakdown until	NWS
RCDOM	radar cloud detector inoperative due to maintenance until	NWS
RCF	radio communication failure	ICAO
RCF	radiocommunication failure	ICAO
RCF	remain on company frequency	ATC
RCH	reach	GEN
RCH	reach ‐ call sign for U.S. AirForce, Air Mobility Command (USAFAMC)	MIL
RCK	radio check	ATC
RCKY	Rockies (mountains)	NWS
RCL	runway center line	ICAO
RCLL	runway center line lights	ICAO
RCLM	runway centerline marking	GEN
RCLR	radio communications link repeater	GEN
RCLS	runway centerline light system	GEN
RCLT	radio communications link terminal	GEN
RCMD	recommend	GEN
RCN	Royal Canadian Navy	GEN
RCO	remote communication outlet	GEN
RCOM	en route communications	GEN
RCON	reconfiguration	ATC
RCPT	receipt	GEN
RCR	runway condition reading	GEN
RCRD	record	GEN
RCS	Rehost Computer System	ATC
RCV	receive	GEN
RCVNO	receiving capability out	GEN
RDARA	regional and domestic air route area	GEN
RDAT	radar data (digitized)	GEN
RDC	reduce	GEN
RDG	ridge	NWS
RDH	reference datum height (ILS)	ICAO
RDL	radial	ICAO
RDO	radio	ICAO
RDS	radius	GEN
RDSP	redispatch	GEN
RDSPA	redispatch accepted	GEN
RDWND	radar dome wind	NWS
RE	regard	GEN
REBAT	reference BATCS report	GEN
REC	receive or receiver	ICAO
RECLR	recleared	ICAO
RECON	reconnaissance	GEN
RECON	reference conversation	GEN
REDL	runway edge light	ICAO
REF	reference	ICAO
REFONE	reference our telephone conversation	GEN
REFORM	reference form	GEN
REG	registration	ICAO
REG	regulation	GEN
REGAL	range and elevation guidance for approach and landing	ATC
REIB	report established in block	ATC
REIL	runway end identifier lights	GEN
REINV	reference invoice	GEN
RELBL	reliable	GEN
RELCT	relocate	GEN
RELET	reference letter	GEN
REMES	reference message	GEN
REMT	relief electronic maintenance technician	GEN
RENL	runway end light	ICAO
RENOT	regional office notice	GEN
REOC	report when established on course	ATC
REP	report or reporting point	ICAO
REP	represent or representative	GEN
REP	research project	GEN
REPAML	reply by airmail	GEN
REPBS	reference PBS message	GEN
REPERF	reperforator	GEN
REPMES	reply by message	GEN
REPML	reply by mail	GEN
REPTWX	reply by TWX	GEN
REQ	request	GEN
REQID	request if desired	GEN
REQON	request consideration	GEN
REQRCM	request your recommendation	GEN
REQSTD	requested	GEN
RERTE	reroute	ICAO
RES	reserve	GEN
RES	resident	GEN
RESA	Runway end safety area	ICAO
RESP	response	GEN
RESTR	restrict	NWS
REWRC	report when established well to right of course	ATC
RF	radio frequency	GEN
RF	reception fair (radio logs only)	ATC
RFA	request further airways	ATC
RFI	radio frequency interference	GEN
RFI	ready for issue	GEN
RFL	refuel	GEN
RFS	refuse	GEN
RFTO	ready for take‐off	ATC
RG	range (lights)	ICAO
RG	reception good (radio logs only)	ATC
RGD	ragged	NWS
RGLR	regular	GEN
RGN	region	GEN
RH	relative humidity	NWS
RHC	Right‐hand circuit	ICAO
RHI	range height indicator	GEN
RHINO	radar echo height information not available	NWS
RHINO	radar range height indicator not operating on scan	NWS
RIF	reclearance in flight	ICAO
RIF	reduction in force	GEN
RIMAT	must ride company material	GEN
RIOGD	Rio Grande	NWS
RIS	reports identification symbol	GEN
RITC	Request in Trail Climb	ATC
RITD	Request in Trail Descent	ATC
RITE	right (direction of turn)	ICAO
RL	report immediately upon leaving	ATC
RL	report leaving	ICAO
RLA	relay to	ICAO
RLANO	relay equipment out of operation	GEN
RLAOK	relay equipment resumed operation	GEN
RLBG	relative bearing	GEN
RLC	report landing completed	ATC
RLCE	request level change en route	ICAO
RLETFL	report leaving each thousand foot level	ATC
RLLS	runway lead‐in lighting system	ICAO
RLNA	request level not available	ICAO
RLRD	railroad	GEN
RLS	release	GEN
RLSTN	relay station	GEN
RLTK	rhumbline track	ATC
RLTV	relative	GEN
RLV	relieve	GEN
RLVL	report level	GEN
RM	remarks (PIREP only)	ATC
RMK	remark	ICAO
RMLR	radar microwave link repeater	GEN
RMLT	radar microwave link terminal	GEN
RMN	remain	GEN
RMPCK	ramp check	ATC
RMRK	remark	GEN
RN	reception nil (radio logs only)	ATC
RNAV	area navigation	ICAO
RNFL	rainfall	NWS
RNG	Army National Guard	GEN
RNG	radio range	ICAO
RNLS	resume normal speed	ATC
RNP	required navigation performance	ICAO
RO	regional office	GEN
RO	regulated output	GEN
ROBEPS	radar operating below prescribed standard	NWS
ROBEX	regional OPMET bulletin exchange	ICAO
ROC	rate of climb	ICAO
ROCC	NORAD Region Operations Control Center	GEN
ROD	rate of descent	ICAO
RODA	regardless of destination airport	ATC
ROFOR	route forecast	ICAO
ROLET	reference letter from our office	GEN
ROMEMO	reference our memorandum	GEN
ROMES	reference message from our office	GEN
RON	remaining overnight	GEN
ROPBS	reference PBS message from our office	GEN
RORQN	reference requisition from our office	GEN
RORU	rest of route unchanged	ATC
ROT	rotate	GEN
ROTEL	reference telegram from our office	GEN
ROTG	rotating	GEN
ROTWX	reference our TWX	GEN
ROV	report over	ATC
RP	reception poor (radio logs only)	ATC
RP	right traffic pattern	ATC
RPA	request present altitude	ATC
RPD	rapid	NWS
RPFOD	reported for duty	GEN
RPI	Radar position indicator	ICAO
RPL	repetitive flight plan	ICAO
RPLC	replace	GEN
RPM	rotation per minute	GEN
RPOC	report proceeding on course	ATC
RPR	repair	GEN
RPRT	report	GEN
RPS	radar position symbol	ICAO
RPSG	report passing	ATC
RPT	repeat	GEN
RPT	Repeat or I repeat	ICAO
RQ	Indication of a request	ICAO
RQ	request	GEN
RQCL	request clearance	ATC
RQDCZ	request clearance to depart VFR and leave control zone at	ATC
RQECZ	request clearance to enter control zone VFR at	ATC
RQMNTS	requirements	ICAO
RQN	requisition	GEN
RQOF	request on file	ATC
RQP	request flight plan	ICAO
RQP	request permission	GEN
RQPP	request present position	ATC
RQR	require	GEN
RQRP	request reply	GEN
RQS	request supplementary flight plan	ICAO
RQTAO	request time and altitude over	ATC
RR	low or medium frequency radio range stations	GEN
RR	radar range station	GEN
RR	report immediately upon reaching	ATC
RR	report reaching	ICAO
RRBN	round robin	ATC
RRCVR	remote receiver	GEN
RRL	runway remaining lights	GEN
RRP	runway reference point	GEN
RRPD	runway reference point downwind	GEN
RRPU	runway reference point upwind	GEN
RRS	remainder of same route	ATC
RRTE	reroute	ATC
RS	receiver station	GEN
RS	record special observation (weather reports only)	NWS
RS	right side	ATC
RSC	rescue sub‐center	ICAO
RSCD	runway surface condition	ICAO
RSCU	rescue	GEN
RSG	rising	NWS
RSN	reason	GEN
RSOPN	resumed operation	GEN
RSP	responder beacon	ICAO
RSR	en route surveillance radar	ICAO
RSTR	restrict	GEN
RSU	runway supervisory unit	GEN
RSVN	reservation	GEN
RT	right turn after take‐off	ATC
RT	round trip	GEN
RTB	return to base	ATC
RTD	delayed	ICAO
RTE	route	GEN
RTF	radiotelephone	GEN
RTG	radiotelegraph	GEN
RTHL	runway threshold light	ICAO
RTMTR	remote transmitter	GEN
RTN	return	ICAO
RTND	retained	GEN
RTNE	routine	GEN
RTO	report time over	ATC
RTR	remote transmitter/receiver	ATC
RTR	returning to ramp	ATC
RTRD	retard	GEN
RTRN	return	GEN
RTS	return to service	ICAO
RTT	radioteletypewriter	GEN
RTX	report time crossing	ATC
RTZL	runway touchdown zone light	ICAO
RUF	rough	NWS
RUFORM	reference your form	GEN
RULET	reference letter from your office	GEN
RUMEMO	reference your memorandum	GEN
RUMES	reference message from your office	GEN
RURQN	reference requisition from your office	GEN
RUT	standard regional route transmitting frequencies	ICAO
RUTEL	reference telegram from your office	GEN
RUTWX	reference your TWX	GEN
RV	radar vector	ATC
RV	rescue vessel	ICAO
RVO	runway visibility by observer	GEN
RVR	runway visual range	ICAO
RVRA	RVR ten minute average	GEN
RVRANO	RVR ten minute average not available	GEN
RVRENO	RVR ten minute extremes not available	GEN
RVRM	RVR midpoint	GEN
RVRMNO	RVR midpoint not available	GEN
RVRNO	RVR not available	GEN
RVRR	RVR rollout	GEN
RVRRNO	RVR rollout not available	GEN
RVRT	RVR touchdown	GEN
RVRTNO	RVR touchdown not available	GEN
RVS	revise	GEN
RVSM	Reduced Vertical Separation Minimum	ICAO
RVV	runway visibility value	GEN
RVVNO	RVV not available	GEN
RWRC	remain well to right of course	ATC
RWY	runway	ICAO
RY	runway	GEN

2-1-19 S

Contraction	Definition	Usage
S	South or southern latitude	ICAO
S/A	semi‐annual	GEN
S/RC	send/receive center	GEN
SA	duststorm, sandstorm, rising dust or sand	METAR
SA	record observation (weather reports only)	NWS
SA	sand, sandstorm, or dusting	ICAO
SA	surveillance approach	GEN
SABH	simultaneous automatic broadcast homer	GEN
SADT	same direction traffic	GEN
SAFI	semi‐automatic flight inspection	GEN
SAFI	semi‐automatic flight inspection aircraft	GEN
SALS	short approach lighting system	GEN
SALS	simple approach lighting system	ICAO
SALSF	short approach lighting system with sequenced flashing lights	GEN
SAN	sanitary	ICAO
SAO	surface aviation observation	NWS
SAP	as soon as possible	ICAO
SAPD	speed at pilots discretion	GEN
SAR	search and rescue	ICAO
SARPS	standards and recommended practices	ICAO
SASK	Saskatchewan	NWS
SAT	Saturday	ICAO
SATCOM	satellite communication	ICAO
SATFY	satisfy or satisfactory	GEN
SATR	so as to reach	ATC
SATR	special air traffic rules	GEN
SAVASI	simplified abbreviated visual approach slope indicator	GEN
SAWRS	supplementary aviation weather reporting station	GEN
SAYTA	say time able	ATC
SB	southbound	ICAO
SBAS	satellite-based augmentation system	ICAO
SBFC	standby for further clearance	ATC
SBND	southbound	ATC
SBSD	subside	NWS
SC	stratocumulus	NWS
SCAN	self‐correcting automatic navigation	GEN
SCANO	automatic scanning unit out of service	GEN
SCAOK	automatic scanning unit returned to service	GEN
SCAT	security control of air traffic	GEN
SCATANA	security control of air traffic and air navigation aids	GEN
SCC	System Command Center	GEN
SCLN	semicolon	GEN
SCND	second (in line)	GEN
SCS	single channel simplex	GEN
SCSL	standing lenticular stratocumulus	NWS
SCT	scattered	NWS
SCTR	sector	GEN
SCTY	security	GEN
SDB	scheduled data base	GEN
SDBY	standby	GEN
SDF	simplified directional facility	GEN
SE	south‐east	ICAO
SE	system engineer	GEN
SEADRM	seadrome	GEN
SEB	south‐eastbound	ICAO
SEC	second (time)	GEN
SECMR	sector manager	GEN
SECRA	secondary radar	GEN
SECT	sector	ICAO
SEL	space environment laboratory	GEN
SELCAL	selective calling	ATC
SELS	severe local storms	NWS
SELY	southeasterly (weather reports only)	NWS
SENS	sensitivity	GEN
SEPN	separation	GEN
SEQ	sequence	GEN
SER	service	ICAO
SERN	southeastern (weather reports only)	NWS
SES	supervisory electronics specialist	GEN
SESC	space environment service center	GEN
SET	stack entry time	ATC
SEV	severe	ICAO
SF	standard form	GEN
SFA	single frequency approach	GEN
SFC	surface	ICAO
SFERICS	atmospherics	NWS
SFL	sequence flashing lights	GEN
SFO	sector field office	GEN
SFO	simulated flame out	ATC
SFPP	stored flight plan program	ATC
SFRA	special flight rules area	GEN
SFU	sector field unit	GEN
SG	snow grains (weather reports only)	METAR
SGD	signed	GEN
SGD	solar‐geophysical data	NWS
SGFNT	significant	GEN
SGL	signal	GEN
SH	showers	METAR
SHF	super high frequency	GEN
SHFT	shift (weather reports only)	NWS
SHGR	hail showers	METAR
SHGS	hail showers (small)	METAR
SHLW	shallow	NWS
SHORN	short range navigation system	GEN
SHP	standard holding procedure	GEN
SHPL	ice pellet showers	METAR
SHRA	rain showers	METAR
SHRT	short	GEN
SHRTLY	shortly	NWS
SHRTWV	shortwave	GEN
SHSN	snow showers	METAR
SHTDN	shutdown	GEN
SHUD	should	ATC
SHWR	shower	NWS
SI	straight‐in approach	GEN
SIA	standard instrument approach	GEN
SIAP	standard instrument approach procedure	GEN
SID	standard instrument departure	ICAO
SIERNEV	Sierra Nevada	NWS
SIF	selective identification feature	ICAO
SIG	signature	GEN
SIGMET	significant meteorological information	GEN
SIGWX	significant weather	ICAO
SIM	simulated approach	ATC
SIMUL	simultaneous/ly	ICAO
SIR	snow and ice on runway	NWS
SIWL	single isolated wheel load	ICAO
SJP	standard jet penetration	GEN
SK	sky condition (PIREP only)	ATC
SKC	sky clear	METAR
SKED	schedule	ICAO
SL	sea level	GEN
SL	sick leave	GEN
SLCT	select	GEN
SLD	solid	NWS
SLGT	slight	GEN
SLMM	simultaneous compass locator at middle marker	GEN
SLO	slow	GEN
SLOM	simultaneous compass locator at outer marker	GEN
SLP	sea level pressure	METAR
SLP	slope	GEN
SLP	speed limiting point	ICAO
SLR	slush on runway	NWS
SLRAP	standard low frequency range approach	GEN
SLS	side lobe suppression	GEN
SLT	sleet	NWS
SLW	slow	ICAO
SM	statute mile	GEN
SMC	squawk mode code	GEN
SMC	surface movement control	ICAO
SMGCS	surface movement guidance and control system	GEN
SML	small	GEN
SMR	statute mile radius	GEN
SMR	surface movement radar	ICAO
SMRY	summary	GEN
SMS	synchronous meteorological satellite	GEN
SMS	systems maintenance sector	GEN
SMT	submit	GEN
SMTH	smooth	NWS
SMTM	sometime	GEN
SMWHT	somewhat	GEN
SN	snow	ICAO
SN	strategic navigation	GEN
SN	systems navigation	GEN
SNBNK	snowbank	NWS
SND	sand or sanded or sanding	GEN
SNFLK	snowflake	NWS
SNGL	single	GEN
SNOINCR	snow depth increase in past hour	NWS
SNOWTAM	NOTAM reporting the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush or ice on the movement area	ICAO
SNSH	snow showers	ICAO
SNW	snow	NWS
SNWFL	snowfall	NWS
SOAP	spectrometric oil analysis program	ATC
SOB	souls on board	ATC
SOCC	NORAD Sector Operations Control Center	GEN
SOMSG	see our message	GEN
SOP	standard operating procedure	GEN
SORAP	standard omni range approach	GEN
SP	standard holding pattern	GEN
SP	station pressure	NWS
SPAN	stored program for alpha numerics	GEN
SPB	seaplane base	GEN
SPCLY	especially	GEN
SPD	speed	GEN
SPEC	specification	GEN
SPECI	aviation selected special weather report	METAR
SPKL	sprinkle	NWS
SPL	special	GEN
SPL	supplementary flight plan	ICAO
SPLNS	south plains	NWS
SPO	strategic plan of operation	ATC
SPOT	spot wind	ICAO
SPRD	spread	NWS
SPRL	spiral	GEN
SPS	Standard Positioning Service	ATC
SPT	strategic planning team	ATC
SQ	squall	METAR
SQDN	squadron	GEN
SQK	squawk	ATC
SQLN	squall line	NWS
SR	standard range approach	GEN
SR	sunrise	ICAO
SRA	surveillance radar approach	ICAO
SRCH	search	GEN
SRE	surveillance radar element of precision approach radar system	ICAO
SRG	short range	ICAO
SRND	surround	GEN
SRPN	special requisition priority number	GEN
SRR	search and rescue region	ICAO
SRY	secondary	ICAO
SS	sandstorm	METAR
SS	sunset	ICAO
SSALF	simplified short approach lighting system with sequenced flashers	GEN
SSALR	simplified short approach lighting system with runway alignment indicator lights	GEN
SSALS	simplified short approach lighting system	GEN
SSB	single sideband	ICAO
SSE	south‐south east	ICAO
SSERN	south‐southeastern (weather reports only)	NWS
SSEWD	south‐southeastward (weather reports only)	NWS
SSNO	request no SIDs or STARs	ATC
SSR	secondary surveillance radar	ICAO
SST	supersonic transport	ICAO
SSW	south‐south west	ICAO
SSWRN	south‐southwestern (weather reports only)	NWS
SSWWD	south‐southwestward (weather reports only)	NWS
ST	saint	GEN
ST	stratus	NWS
STA	straight in approach	ICAO
STADMR	station administrator	GEN
STAGN	stagnation	NWS
STALO	stabilized local oscillator	GEN
STAR	standard instrument arrival	ICAO
STAR	standard terminal arrival	GEN
STATE	military, customs, or police services	ICAO
STBL	stable	GEN
STBY	standby	ICAO
STCLB	start climb	ATC
STD	standard	ICAO
STDST	start descent	ATC
STDY	steady	GEN
STF	stratiform	ICAO
STFRA	stratus fractus	NWS
STFRM	stratiform	NWS
STG	strong	NWS
STLT	satellite	GEN
STM	storm	NWS
STMGR	station manager	GEN
STMP	special traffic management program	ATC
STN	station	GEN
STNR	stationary	ICAO
STNRY	stationary	NWS
STOL	short take‐off and landing	GEN
STR	subject terminal control release	ATC
STRB	strobe	GEN
STRO	stereo routes	GEN
STS	status	ICAO
STWL	stopway light	ICAO
STWY	stopway	GEN
SUA	special use airspace	GEN
SUB	substitute	GEN
SUBFIX	subject to correction	GEN
SUBJ	subject to	ICAO
SUF	sufficient	GEN
SUG	suggest	GEN
SUN	Sunday	ICAO
SUP	supply	GEN
SUPCHG	supercharge	GEN
SUPPL	supplement	GEN
SUPPS	regional supplementary procedures	ICAO
SUPR	superior	GEN
SUPSD	supersede	GEN
SUPT	superintendent	GEN
SUPVR	supervisor	GEN
SURPIC	surface picture	ATC
SUSP	suspend	GEN
SVC	service	GEN
SVCBL	serviceable	ICAO
SVFR	special VFR	GEN
SVG	serving	GEN
SVN	space vehicle number	GEN
SVR	severe	GEN
SVRL	several	GEN
SW	south‐west	ICAO
SWAP	severe weather avoidance plan	GEN
SWB	scheduled weather broadcast	GEN
SWB	south‐westbound	ICAO
SWLG	swelling	NWS
SWLY	southwesterly (weather reports only)	NWS
SWRN	southwestern (weather reports only)	NWS
SWSL	supplemental weather service location	ATC
SWY	stopway	ICAO
SX	stability index	NWS
SXN	section	NWS
SYD	release subject your discretion	GEN
SYNOP	synoptic	NWS
SYNS	synopsis	NWS
SYS	see your service	GEN
SYS	system	GEN

2-1-20 T

Contraction	Definition	Usage
T	Temperature	ICAO
T	trace (weather reports only)	NWS
T	training	GEN
T	tropical (air mass)	NWS
T	true (bearing)	GEN
T/R	transportation request	GEN
TA	temperature (PIREP only)	ATC
TA	total aboard	GEN
TA	transition altitude	ICAO
TAC	terminal area chart	GEN
TACAN	tactical air navigational aid	ICAO
TACLO	tactical air command liaison officer	GEN
TACR	tactical air navigation	GEN
TAD	ATC tower, approach and departure control facility	ATC
TAF	aerodrome forecast	ICAO
TAF	terminal forecast	METAR
TAIL	tail wind	ICAO
TAND	tandem	GEN
TANDA	time and attendance report	GEN
TAO	TACAN only	ATC
TAO	time and altitude over	ATC
TAPER	temporary appointment pending establishment of a register	GEN
TAR	terminal area surveillance radar	ICAO
TARND	turn around	ATC
TARS	terminal automated radar services	GEN
TARS	Tethered Aerostat Radar System	GEN
TAS	true air speed	GEN
TASR	terminal area surveillance radar	GEN
TAWOG	travel arrangements without government expense	GEN
TAX	taxi or taxiing	ICAO
TB	turbulence (PIREP only)	ATC
TBJT	turbojet	GEN
TC	time check	ATC
TC	tropical cyclone	ICAO
TCA	terminal control area	GEN
TCA	tactical customer advocate	ATC
TCAS	traffic alert and collision avoidance system	GEN
TCF	Traffic Flow Management Convective Forecast Product	ATC
TCH	threshold crossing height	ICAO
TCHD	threshold crossing height downwind	GEN
TCHU	threshold crossing height upwind	GEN
TCNTL	trans‐continental	GEN
TCOM	terminal communications	GEN
TCP	transfer of control point	ATC
TCU	towering cumulus	NWS
TD	Touchdown	ATC
TD	transmitter distributor	GEN
TDA	Today	GEN
TDEL	time delay	GEN
TDLS	Terminal Data Link System	GEN
TDO	Tornado	ICAO
TDOP	Time Dilution of Precision	ATC
TDWR	Terminal Doppler Weather Radar	ATC
TDY	temporary duty	GEN
TDZ	touchdown zone	ICAO
TDZE	touchdown zone elevation	ATC
TDZL	touchdown zone light (system)	GEN
TEC	tower en route control	ATC
TECA	tower en route control area	ATC
TECR	technical reason	ICAO
TEL	telecommunications	GEN
TEL	Telephone	ICAO
TELAU	Teleautograph	GEN
TELCO	telephone company	GEN
TELCON	telephone conference	GEN
TELEX	telephone exchange	GEN
TELRY	telegraph reply	GEN
TEMP	Temperature	GEN
TEMPO	temporary	ICAO
TEND	Trend	ICAO
TERPS	terminal instrument procedures	GEN
TET	Tetrahedron	GEN
TF	terrain following	GEN
TFC	traffic	ICAO
TFMS	traffic flow management system	ATC
TFR	temporary flight restriction	GEN
TFRCD	traffic received	ATC
TFZ	traffic zone	GEN
TGL	touch and go landing	ICAO
TGS	taxiing guidance system	ICAO
THD	Thunderhead	NWS
THDR	Thunder	NWS
THK	Thick	NWS
THLD	Threshold	GEN
THN	Thin	NWS
THR	threshold	ICAO
THRFTR	Thereafter	GEN
THRU	through	ICAO
THRUT	Throughout	GEN
THSD	Thousand	GEN
THTN	threaten	GEN
THU	Thursday	ICAO
TIBA	Traffic information broadcast by aircraft	ICAO
TIL	until	GEN
TINOP	transponder inoperative	ATC
TIP	until past	ATC
TIPS	terminal information processing system	GEN
TKOF	take‐off	ICAO
TLM	Telemetry	ATC
TLRNC	tolerance	GEN
TLTP	too long to print	GEN
TLWD	tailwind	ATC
TM	time (PIREP only)	ATC
TM	traffic management	ATC
TMA	terminal control area	ICAO
TMPA	traffic management program alert	ATC
TMPRY	temporary	GEN
TMT	transmit	GEN
TMW	tomorrow	GEN
TNA	turn altitude	ICAO
TNDCY	tendency	GEN
TNGT	tonight	GEN
TNH	turn height	ICAO
TNTV	tentative	GEN
TO	travel order	GEN
TOC	to be continued	GEN
TOC	top of climb	ICAO
TOD	time of delivery	GEN
TODA	take‐off distance available	ICAO
TOG	take‐off gross weight	GEN
TOP	cloud top	NWS
TOR	time of receipt	GEN
TOR	traffic on request	ATC
TORA	take‐off run available	ICAO
TOT	time of transmission	GEN
TOVC	top of overcast	NWS
TP	turning point	ICAO
TP	type aircraft (PIREP only)	ATC
TPA	traffic pattern altitude	ATC
TPG	topping	NWS
TR	track	ICAO
TR	VFR low altitude training routes	GEN
TRA	temporary reserved airspace	ICAO
TRACAB	terminal radar approach control in tower cab	GEN
TRACON	terminal radar approach control facility	GEN
TRAD	terminal radar	GEN
TRAN	transient	ATC
TRANS	transmit or transmitter	ICAO
TRBL	trouble	GEN
TRCV	tri‐color visual approach slope indicator	GEN
TRG	training	ICAO
TRIB	tributary	NWS
TRK	track	GEN
TRLVL	transition level	ICAO
TRML	terminal	GEN
TRMT	terminate	GEN
TRNG	Training	GEN
TRNSP	Transport	GEN
TROF	Trough	NWS
TROP	Tropopause	NWS
TRPCD	tropical continental (air mass)	NWS
TRPCL	Tropical	NWS
TRPLYR	trapping layer	NWS
TRRN	Terrain	GEN
TRSA	terminal radar service area	GEN
TRSN	Transition	GEN
TRTD	Treated	GEN
TS	team supervisor	GEN
TS	Thunderstorm	METAR
TS	transmitter station	GEN
TSA	Transportation Security Administration	GEN
TSATLC	Trans‐Atlantic	GEN
TSEC	terminal secondary radar beacon	GEN
TSFR	Transfer	GEN
TSGR	thunderstorm with hail	METAR
TSGS	thunderstorm with small hail	METAR
TSMNO	transmitting capability out of service	GEN
TSMOK	transmitting capability returned to service	GEN
TSNO	thunderstorm information not available	METAR
TSNT	Transient	GEN
TSO	technical standard order	GEN
TSPAC	Trans‐Pacific	GEN
TSPL	thunderstorm with ice pellets	METAR
TSRA	thunderstorm with rain	METAR
TSSA	thunderstorm with duststorm or sandstorm	METAR
TSSN	thunderstorm with snow	METAR
TSTM	thunderstorm	NWS
TT	teletypewriter	GEN
TTS	teletype switching facilities	GEN
TTY	teletypewriter station	GEN
TUE	Tuesday	ICAO
TURB	turbulence	ICAO
TURBC	turbulence	NWS
TURBT	turbulent	NWS
T‐VASIS	T visual approach slope indicator system	ICAO
TVL	travel	GEN
TVOR	terminal VOR	ICAO
TWD	toward	GEN
TWEB	transcribed weather broadcast	GEN
TWI	twilight	GEN
TWR	aerodrome control tower	ICAO
TWR	tower	GEN
TWRG	towering	NWS
TWS	radar track while scan	ATC
TWX	teletypewriter exchange service	GEN
TWY	taxiway	ICAO
TWYL	taxiway link	ICAO
TXG	taxiing	ATC
TXL	taxilane	ICAO
TXT	Text	ICAO
TYP	type aircraft	ICAO
TYPH	typhoon	ICAO
TYPNO	teletypewriter communications out of service	GEN
TYPOK	teletypewriter communications returned to service	GEN

2-1-21 U

Contraction	Definition	Usage
U	Intensity unknown (weather reports only)	NWS
U/S	unserviceable	ICAO
UA	routine PIREP	ATC
UA	unable to approve arrival for the time specified	ATC
UAB	until advised by	ATC
UAC	upper area control center	ICAO
UAG	upper atmosphere geophysics	NWS
UAR	upper air route	ICAO
UAS	unmanned aircraft system	ICAO
UAT	until advised by the tower	ATC
UCDWN	until cleared down	ATC
UCLT	until cleared to land by the tower	ATC
UD	unable to approve departure for the time specified	ATC
UDDF	up and down drafts	NWS
UDF	ultra high frequency direction finding station	ICAO
UERE	User Equivalent Range Error	ATC
UFA	until further advised	GEN
UFN	until further notice	GEN
UFO	unidentified flying object	GEN
UHA	unable higher altitude	ATC
UHDODT	unable higher due opposite direction traffic	ATC
UHDSDT	unable higher due same direction traffic	ATC
UHDT	unable higher due traffic	ICAO
UHDT	unable higher due traffic	ICAO
UHF	ultra high frequency	ICAO
UIC	upper information center	ICAO
UIR	upper flight information region	ICAO
ULDT	unable lower due traffic	ATC
ULR	ultra long range	ICAO
UM	unable to maintain	ATC
UN	Unable	GEN
UNA	Unable	ICAO
UNAP	unable to approve	ICAO
UNAPV	unable to approve	GEN
UNAR	unable to approve altitude requested	ATC
UNATNDD	unattended	GEN
UNAVBL	unavailable	GEN
UNCC	unable to contact company radio	ATC
UNCHG	unchanged	GEN
UNDLD	undelivered	GEN
UNEC	unnecessary	GEN
UNHRD	unheard	GEN
UNID	unidentified	GEN
UNKN	unknown	GEN
UNL	unlimited	ICAO
UNLGTD	unlighted	GEN
UNMON	unable to monitor	GEN
UNMON	unmonitored	ATC
UNOFFL	unofficial	GEN
UNRDBL	unreadable	GEN
UNREL	unreliable	ICAO
UNRELBL	unreliable	GEN
UNRR	unable to approve route requested	ATC
UNRSTD	unrestricted	GEN
UNSATFY	unsatisfactory	GEN
UNSBL	unseasonable	NWS
UNSKED	unscheduled	GEN
UNSTBL	unstable	NWS
UNSTDY	unsteady	NWS
UNSTL	unsettle	NWS
UNTC	unable to establish contact	ATC
UNUSBL	unusable	GEN
UP	unknown precipitation	METAR
UPDFTS	up drafts	NWS
UPDT	update	NWS
UPR	upper	NWS
UPSLP	upslope	NWS
UPSTRM	upstream	NWS
UQOT	unquote	GEN
URAUZ	you are authorized	GEN
URG	urgent	GEN
URIZR	your recommendation is requested	GEN
USA	U.S. Army	GEN
USAF	U.S. Air Force	GEN
USAFIB	U.S. Army Aviation Flight Information	GEN
USBL	usable	GEN
USCG	U.S. Coast Guard	GEN
USMC	U.S. Marine Corps	GEN
USN	U.S. Navy	GEN
USNO	United States Naval Observatory	ATC
USNOF	United States NOTAM Office	GEN
USP	urgent special observation (weather reports only)	NWS
UTA	upper control area	ICAO
UTC	Coordinated Universal Time	ICAO
UTCOK	Coordinated Universal Time Coordinate Check Completed	GEN
UUA	urgent PIREP	ATC
UVV	upward vertical velocity	NWS
UW	upwind	ATC
UWNDS	upper winds	NWS

2-1-22 V

Contraction	Definition	Usage
V	Variable (weather reports only)	NWS
VA	victor airways	ATC
VA	volcanic ash	METAR
VAC	visual approach chart	ICAO
VAC	Visual approach chart (followed by name/title)	ICAO
VACAPES	Virginia Capes	ATC
VADA	VFR arrival delay advisory	ATC
VAL	in valleys	ICAO
VAN	runway control van	ICAO
VAPS	V/STOL approach system	GEN
VAR	magnetic variation	ICAO
VAR	visual‐aural radio range	ICAO
VARN	Variation	GEN
VASI	visual approach slope indicator	GEN
VASIS	visual approach slope indicator system	ICAO
VC	Vicinity	METAR/TAF
VC	Vicinity	METAR
VCFG	fog in vicinity	METAR
VCNTY	vicinity	GEN
VCOT	VFR conditions on top	ATC
VCTR	Vector	ATC
VCY	vicinity	ICAO
VDF	very high frequency direction‐ finding station	ICAO
VDOP	Vertical Dilution of Precision	ATC
VDP	visual descent point	GEN
VER	Vertical	ICAO
VF	maintaining visual flight (Special VFR)	ATC
VFLT	visual flight	GEN
VFPR	via flight planned route	ATC
VFR	visual flight rules	ICAO
VFRSA	VFR restrictions still apply	ATC
VFY	Verify	GEN
VHF	very high frequency	ICAO
VIA	by way of	GEN
VIP	very important person	ICAO
VIP	visual integrated presentation	GEN
VIS	visibility	ICAO
VLCTY	Velocity	NWS
VLF	very low frequency	GEN
VLFD	via low frequency direct	ATC
VLNT	Violent	NWS
VLR	very long range	ICAO
VLY	Valley	NWS
VM	voice modulation	GEN
VMC	visual meteorological conditions	ICAO
VNAV	vertical navigation (from TERPS‐A1)	GEN
VOD	via omni direct	ATC
VOL	Volume	GEN
VOLMET	meteorological information for aircraft in flight	ICAO
VOPR	voice operated relay	GEN
VOR	VHF omni‐directional radio range	ICAO
VOR/DME	VOR and DME (collocated)	GEN
VORTAC	VOR and TACAN (collocated)	ICAO
VOT	VOR airborne equipment test facility	ICAO
VOT	VOR test signal	GEN
VOT	vorticity	GEN
VOU	voucher	GEN
VR	veer	NWS
VR	VFR military training routes	GEN
VRB	variable	ICAO
VRBL	variable	GEN
VRG	visual reference gate	GEN
VRISL	Vancouver Island, BC	NWS
VRT MOTN	vertical motion	NWS
VSA	by visual reference to the ground	ICAO
VSB	visible	GEN
VSBY	visibility	NWS
VSBYDR	visibility decreasing rapidly	NWS
VSBYIR	visibility increasing rapidly	NWS
VSL	vessel	GEN
VSP	vertical speed	ICAO
VSPI	visual glide path indicator	GEN
VSTOL	vertical/short take‐off and landing	GEN
VTOL	vertical take‐off and landing	ICAO
VV	vertical visibility (indefinite ceiling)	METAR

2-1-23 W

Contraction	Definition	Usage
W	warm (air mass)	NWS
W	west or western longitude	ICAO
W	White	ICAO
WA	AIRMET	NWS
WAAS	Wide Area Augmentation System	ICAO
WAC	World aeronautical chart ‐ ICAO 1:1 000 000(followed by name/title)	ICAO
WAFC	world area forecast center	ICAO
WAIOP	will accept, if offered, the position	GEN
WB	Westbound	ICAO
WBAR	wing bar lights	ICAO
WBND	Westbound	ATC
WBRBN	will be reported by NOTAM	GEN
WBRH	Weather Bureau Regional Headquar- ters	GEN
WBTS	Whereabouts	GEN
WCLC	Watch check list completed	GEN
WDC‐1	World Data Centers in Western Europe	NWS
WDC‐2	World Data Centers throughout rest of world	NWS
WDI	wind direction indicator	ICAO
WDLY	Widely	NWS
WDSPR	Widespread	GEN
WDSPRD	Widespread	NWS
WEA	Weather	NWS
WED	Wednesday	ICAO
WEF	With effect from, or effective from	ICAO
WFO	Weather Forecast Office	GEN
WFP	Warm front passage	NWS
WG	Working group	GEN
WGS	World Geodetic System	ATC
WGS‐84	World geodetic system 1984	ICAO
WI	within	ICAO
WIBIS	will be issued	GEN
WICA	while in control area	ATC
WICZ	while in control zone	ATC
WID	width or wide	ICAO
WIE	with immediate effect or effective immediately	ICAO
WILCO	will comply	GEN
WINT	winter	NWS
WINTEM	forecast upper wind and temperature for aviation	ICAO
WIP	work in progress	ICAO
WK	weak	GEN
WKDAY	weekday	GEN
WKEND	weekend	GEN
WKN	weaken	GEN
WL	will	GEN
WLAV	will advise	GEN
WMO	World Meteorological Organization	GEN
WMSC	Weather Message Switching Center	GEN
WND	wind	NWS
WNW	west‐north west	ICAO
WNWRN	west‐northwestern (weather reports only)	NWS
WNWWD	west‐northwestward (weather reports only)	NWS
WO	Washington Office	GEN
WO	without	GEN
WP	waypoint	GEN
WPLTO	western plateau	NWS
WPM	words per minute	GEN
WPRT	waypoint report	ATC
WPT	waypoint	ICAO
WR	wet runway	NWS
WRA	Weather Reconnaissance Area	GEN
WRC	well to right of course	ATC
WRM	warm	NWS
WRMFNT	warm front	NWS
WRNG	warning	NWS
WRS	worse	GEN
WS	SIGMET	NWS
WS	weak signals	ATC
WS	wind shear	ICAO
WSCMO	Weather Service Contract Meteorological Observatory	GEN
WSHFT	wind shift	NWS
WSO	Weather Service Office	GEN
WSOM	weather service operations manual	NWS
WSP	weather system processor (replacement for LLWAS)	GEN
WSR	wet snow on runway	NWS
WSSF	National Weather Service Support Facility	GEN
WSSU	National Weather Service Support Unit	GEN
WSTCH	wasatch range	NWS
WSW	west‐south west	ICAO
WSWRN	west‐southwestern (weather reports only)	NWS
WSWWD	west‐southwestward (weather reports only)	NWS
WT	Weight	GEN
WTR	Water	NWS
WTR	well to right	ATC
WTSPT	waterspout	NWS
WU	Western Union Telegraph Company	GEN
WV	Wave	NWS
WV	wind at altitude (PIREP only)	ATC
WW	severe weather forecast	NWS
WWW	World wide web	ICAO
WX	weather	ICAO
WX	weather at altitude (PIREP only)	ATC
WXCON	weather reconnaissance flight pilot report	NWS
WYAIO	will you accept, if offered, the position of	GEN

2-1-24 X

Contraction	Definition	Usage
X	Cross	ICAO
X	Obscured sky condition	NWS
XBAR	Crossbar	ICAO
XCP	Except	NWS
XFSS	Auxiliary Flight Service Station	ATC
XH	special handling service for aircraft	GEN
XNG	Crossing	ICAO
XPC	expect	NWS
XPLOS	explosive	GEN
XREP	auxiliary report	GEN
XS	atmospherics	ICAO
XTAL	crystal	GEN
XTLK	cross talk	ATC
XW	crosswind	ATC
XX	heavy (to qualify weather phenomena, e.g. XXRA ‐ heavy rain)	ICAO

2-1-25 Y

Contraction	Definition	Usage
Y	Yukon Standard Time (time groups only)	NWS
YCZ	yellow caution zone (runway lighting)	ICAO
YD	Yards	ICAO
YDA	Yesterday	GEN
YES	Yes (affirmative)	ICAO
YKN	Yukon	NWS
YL	approach light lane	ATC
YLSTN	Yellowstone	NWS
YMSG	your message	GEN
YMSGD	your message date	GEN
YR	Your	ICAO

2-1-26 Z

Contraction	Definition	Usage
Z	Greenwich Mean Time	GEN
Z	jet terminal area	ATC
ZI	zonal index	NWS
ZI	zone of interior	NWS
ZM	Z marker (VHF station location marker)	GEN
ZRNO	freezing rain information not available (weather reports only)	NWS