Aeronautical Information ManualChange 3 · Effective 7/9/2026
Appendix 3
Abbreviations/Acronyms
As used in this manual, the following abbreviations/acronyms have the meanings indicated.
| Abbreviation/Acronym | Meaning |
|---|---|
| AAWU | Alaskan Aviation Weather Unit |
| AAS | Airport Advisory Service |
| AAM | Advanced Air Mobility |
| ABRR | Airborne Reroutes |
| AC | Advisory Circular |
| ACAR | Aircraft Communications Addressing and Reporting System |
| ACL | Aircraft List |
| ADCUS | Advise Customs |
| ADDS | Aviation Digital Data Service |
| ADF | Automatic Direction Finder |
| ADIZ | Air Defense Identification Zone |
| ADS-B | Automatic Dependent Surveillance-Broadcast |
| AFB | Air Force Base |
| AFCS | Automatic Flight Control System |
| AFIS | Automatic Flight Information Service |
| AFM | Aircraft Flight Manual |
| AGL | Above Ground Level |
| AHRS | Attitude Heading Reference System |
| AIM | Aeronautical Information Manual |
| AIRMET | Airmen's Meteorological Information |
| AIS | Aeronautical Information Services |
| ALD | Available Landing Distance |
| ALDARS | Automated Lightning Detection and Reporting System |
| ALS | Approach Light Systems |
| AMSL | Above Mean Sea Level |
| ANP | Actual Navigation Performance |
| AOCC | Airline Operations Control Center |
| AP | Autopilot System |
| APV | Approach with Vertical Guidance |
| AR | Authorization Required |
| ARENA | Areas Noted for Attention |
| ARFF IC | Aircraft Rescue and Fire Fighting Incident Commander |
| ARINC | Aeronautical Radio Incorporated |
| ARO | Airport Reservations Office |
| ARSA | Airport Radar Service Area |
| ARSR | Air Route Surveillance Radar |
| ARTCC | Air Route Traffic Control Center |
| AS | Altimeter Setting |
| ASDE-X | Airport Surface Detection Equipment - Model X |
| ASOS | Automated Surface Observing System |
| ASR | Airport Surveillance Radar |
| ASRS | Aviation Safety Reporting System |
| ASSC | Airport Surface Surveillance Capability |
| ATC | Air Traffic Control |
| ATCRBS | Air Traffic Control Radar Beacon System |
| ATCSCC | Air Traffic Control System Command Center |
| ATCT | Airport Traffic Control Tower |
| ATD | Along-Track Distance |
| ATIS | Automatic Terminal Information Service |
| ATO | Air Traffic Organization |
| ATT | Attitude Retention System |
| AWC | Aviation Weather Center |
| AWOS | Automated Weather Observing System |
| AWTT | Aviation Weather Technology Transfer |
| AWW | Severe Weather Forecast Alert |
| BAASS | Bigelow Aerospace Advanced Space Studies |
| BBS | Bulletin Board System |
| BC | Back Course |
| BECMG | Becoming group |
| BVLOS | Beyond Visual Line of Sight |
| C/A | Coarse Acquisition |
| CAA | Confirm Assigned Altitude |
| CAT | Clear Air Turbulence |
| CBO | Community-Based Organization |
| CCF | Combined Control Facility |
| CD | Controller Display |
| CDI | Course Deviation Indicator |
| CDR | Coded Departure Route |
| CFA | Controlled Firing Area |
| CFIT | Controlled Flight into Terrain |
| CFR | Code of Federal Regulations |
| COA | Certificate of Waiver or Authorization |
| CPDLC | Controller Pilot Data Link Communications |
| CTAF | Common Traffic Advisory Frequency |
| CVFP | Charted Visual Flight Procedure |
| CVRS | Computerized Voice Reservation System |
| CWA | Center Weather Advisory |
| CWSU | Center Weather Service Unit |
| DA | Decision Altitude |
| DCA | Ronald Reagan Washington National Airport |
| DCP | Data Collection Package |
| DER | Departure End of Runway |
| DH | Decision Height |
| DME | Distance Measuring Equipment |
| DME/N | Standard DME |
| DME/P | Precision DME |
| DoD | Department of Defense |
| DP | Instrument Departure Procedure |
| DPU | Data Processor Unit |
| DRT | Diversion Recovery Tool |
| DRVSM | Domestic Reduced Vertical Separation Minimum |
| DVA | Diverse Vector Area |
| DVFR | Defense Visual Flight Rules |
| DVRSN | Diversion |
| EDCT | Expect Departure Clearance Time |
| EFAS | En Route Flight Advisory Service |
| EFV | Enhanced Flight Visibility |
| EFVS | Enhanced Flight Vision System |
| ELT | Emergency Locator Transmitter |
| EMAS | Engineered Materials Arresting System |
| EPE | Estimate of Position Error |
| ESV | Expanded Service Volume |
| ETA | Estimated Time of Arrival |
| ETD | Estimated Time of Departure |
| ETE | Estimated Time En Route |
| EWINS | Enhanced Weather Information System |
| EWR | Newark International Airport |
| FA | Area Forecast |
| FAA | Federal Aviation Administration |
| FAF | Final Approach Fix |
| FAWP | Final Approach Waypoint |
| FB | Fly-by |
| FCC | Federal Communications Commission |
| FD | Flight Director System |
| FDB | Full Data Block |
| FDC | Flight Data Center |
| FDE | Fault Detection and Exclusion |
| FIR | Flight Information Region |
| FIS | Flight Information Service |
| FISDL | Flight Information Services Data Link |
| FLIP | Flight Information Publication |
| FMS | Flight Management System |
| FO | Fly-over |
| FPA | Flight Path Angle |
| FPV | Flight Path Vector |
| FPNM | Feet Per Nautical Mile |
| FRIA | FAA-Recognized Identification Area |
| FSDO | Flight Standards District Office |
| FSS | Flight Service Station |
| GBAS | Ground Based Augmentation System |
| GEO | Geostationary Satellite |
| GLS | GBAS Landing System |
| GNSS | Global Navigation Satellite System |
| GNSSP | Global Navigation Satellite System Panel |
| GPS | Global Positioning System |
| GRI | Group Repetition Interval |
| GSD | Geographical Situation Display |
| GUS | Ground Uplink Station |
| HAT | Height Above Touchdown |
| HAZMAT | Hazardous Material |
| HDTA | High Density Traffic Airports |
| HEMS | Helicopter Emergency Medical Services |
| HIRL | High Intensity Runway Lights |
| HRR | Helicopter Rapid Refueling Procedures |
| HUD | Head-Up Display |
| Hz | Hertz |
| IAF | Initial Approach Fix |
| IAP | Instrument Approach Procedure |
| IAS | Indicated Air Speed |
| IAWP | Initial Approach Waypoint |
| IC | Initial Contact |
| ICAO | International Civil Aviation Organization |
| IF | Intermediate Fix |
| IFR | Instrument Flight Rules |
| ILS | Instrument Landing System |
| ILS/PRM | Instrument Landing System/Precision Runway Monitor |
| IM | Inner Marker |
| IMC | Instrument Meteorological Conditions |
| InFO | Information For Operators |
| INS | Inertial Navigation System |
| IOC | Initial Operational Capability |
| IR | IFR Military Training Route |
| IRU | Inertial Reference Unit |
| ITWS | Integrated Terminal Weather System |
| JFK | John F. Kennedy International Airport |
| kHz | Kilohertz |
| LAA | Local Airport Advisory |
| LAANC | Low Altitude Authorization and Notification Capability |
| LAAS | Local Area Augmentation System |
| LAHSO | Land and Hold Short Operations |
| LAWRS | Limited Aviation Weather Reporting Station |
| LDA | Localizer Type Directional Aid |
| LDA/PRM | Localizer Type Directional Aid/Precision Runway Monitor |
| LGA | LaGuardia Airport |
| LIRL | Low Intensity Runway Lights |
| LLWAS | Low Level Wind Shear Alert System |
| LLWAS NE | Low Level Wind Shear Alert System Network Expansion |
| LLWAS-RS | Low Level Wind Shear Alert System Relocation/Sustainment |
| LNAV | Lateral Navigation |
| LOC | Localizer |
| LOP | Line-of-position |
| LORAN | Long Range Navigation System |
| LP | Localizer Performance |
| LPV | Localizer Performance with Vertical Guidance |
| LUAW | Line Up and Wait |
| LZ | Landing Zone |
| MAHWP | Missed Approach Holding Waypoint |
| MAP | Missed Approach Point |
| MAWP | Missed Approach Waypoint |
| MDA | Minimum Descent Altitude |
| MEA | Minimum En Route Altitude |
| MEARTS | Micro En Route Automated Radar Tracking System |
| METAR | Aviation Routine Weather Report |
| MGOW | Maximum Gross Operating Weight |
| MHz | Megahertz |
| MIRL | Medium Intensity Runway Lights |
| MM | Middle Marker |
| MOA | Military Operations Area |
| MOCA | Minimum Obstruction Clearance Altitude |
| MRA | Minimum Reception Altitude |
| MRB | Magnetic Reference Bearing |
| MSA | Minimum Safe Altitude |
| MSAW | Minimum Safe Altitude Warning |
| MSL | Mean Sea Level |
| MTI | Moving Target Indicator |
| MTOS | Mountain Obscuration |
| MTR | Military Training Route |
| MVA | Minimum Vectoring Altitude |
| MWA | Mountain Wave Activity |
| MWO | Meteorological Watch Office |
| NAS | National Airspace System |
| NASA | National Aeronautics and Space Administration |
| NAVAID | Navigational Aid |
| NAVCEN | Coast Guard Navigation Center |
| NCWF | National Convective Weather Forecast |
| NDB | Nondirectional Radio Beacon |
| NEXRAD | Next Generation Weather Radar |
| NGA | National Geospatial-Intelligence Agency |
| NM | Nautical Mile |
| NMAC | Near Midair Collision |
| NOAA | National Oceanic and Atmospheric Administration |
| NOPAC | North Pacific |
| NoPT | No Procedure Turn Required |
| NPA | Nonprecision Approach |
| NRS | Navigation Reference System |
| NSA | National Security Area |
| NSW | No Significant Weather |
| NTSB | National Transportation Safety Board |
| NTZ | No Transgression Zone |
| NWS | National Weather Service |
| OAT | Outside Air Temperature |
| OBS | Omni-bearing Selector |
| ODP | Obstacle Departure Procedure |
| OIS | Operational Information System |
| OIS | Obstacle Identification Surface |
| OM | Outer Marker |
| OOP | Operations Over People |
| ORD | Chicago O'Hare International Airport |
| P/CG | Pilot/Controller Glossary |
| PA | Precision Approach |
| PAO | Public Aircraft Operation |
| PAPI | Precision Approach Path Indicator |
| PAR | Precision Approach Radar |
| PAR | Preferred Arrival Route |
| PC | Personal Computer |
| PDC | Pre-departure Clearance |
| PFD | Personal Flotation Device |
| PIC | Pilot-in-Command |
| PinS | Point-in-Space |
| PIREP | Pilot Weather Report |
| POB | Persons on Board |
| POFZ | Precision Obstacle Free Zone |
| POI | Principal Operations Inspector |
| PPS | Precise Positioning Service |
| PRM | Precision Runway Monitor |
| PT | Procedure Turn |
| QICP | Qualified Internet Communications Provider |
| RA | Resolution Advisory |
| RAA | Remote Advisory Airport |
| RAIM | Receiver Autonomous Integrity Monitoring |
| RAIS | Remote Airport Information Service |
| RBDT | Ribbon Display Terminals |
| RC | Radio-Controlled |
| RCAG | Remote Center Air/Ground |
| RCC | Rescue Coordination Center |
| RCLS | Runway Centerline Lighting System |
| RCO | Remote Communications Outlet |
| RID | Remote Identification |
| RPIC | Remote Pilot-in-Command |
| TAF | Aerodrome Forecast |
| RD | Rotor Diameter |
| REIL | Runway End Identifier Lights |
| REL | Runway Entrance Lights |
| RFM | Rotorcraft Flight Manual |
| RLIM | Runway Light Intensity Monitor |
| RMI | Radio Magnetic Indicator |
| RNAV | Area Navigation |
| RNP | Required Navigation Performance |
| ROC | Required Obstacle Clearance |
| RPAT | RNP Parallel Approach Runway Transitions |
| RVR | Runway Visual Range |
| RVSM | Reduced Vertical Separation Minimum |
| RWSL | Runway Status Light |
| SAA | Sense and Avoid |
| SAFO | Safety Alerts For Operators |
| SAM | System Area Monitor |
| SAR | Search and Rescue |
| SAS | Stability Augmentation System |
| SATR | Special Air Traffic Rules |
| SBAS | Satellite-based Augmentation System |
| SDF | Simplified Directional Facility |
| SFL | Sequenced Flashing Lights |
| SFR | Special Flight Rules |
| SFRA | Special Flight Rules Area |
| SGI | Special Government Interest |
| SIAP | Standard Instrument Approach Procedure |
| SID | Standard Instrument Departure |
| SIGMET | Significant Meteorological Information |
| SM | Statute Mile |
| SMGCS | Surface Movement Guidance Control System |
| SNR | Signal-to-noise Ratio |
| SOIA | Simultaneous Offset Instrument Approaches |
| SOP | Standard Operating Procedure |
| SPC | Storm Prediction Center |
| SPS | Standard Positioning Service |
| STAR | Standard Terminal Arrival |
| STARS | Standard Terminal Automation Replacement System |
| STMP | Special Traffic Management Program |
| sUAS | Small UAS |
| TA | Traffic Advisory |
| TAA | Terminal Arrival Area |
| TAC | Terminal Area Chart |
| TACAN | Tactical Air Navigation |
| TAS | True Air Speed |
| TCAS | Traffic Alert and Collision Avoidance System |
| TCH | Threshold Crossing Height |
| TD | Time Difference |
| TDLS | Tower Data Link System |
| TDWR | Terminal Doppler Weather Radar |
| TDZ | Touchdown Zone |
| TDZE | Touchdown Zone Elevation |
| TDZL | Touchdown Zone Lights |
| TEC | Tower En Route Control |
| THL | Takeoff Hold Lights |
| TIS | Traffic Information Service |
| TIS-B | Traffic Information Service-Broadcast |
| TLS | Transponder Landing System |
| TOC | Transfer of Communications |
| TPP | Terminal Procedures Publications |
| TRSA | Terminal Radar Service Area |
| TRUST | The Recreational UAS Safety Test |
| TSO | Technical Standard Order |
| TWIB | Terminal Weather Information for Pilots System |
| U.S. | United States |
| UA | Unmanned Aircraft |
| UAM | Urban Air Mobility |
| UAS | Unmanned Aircraft System |
| UASFM | UAS Facility Map |
| UAV | Unmanned Aerial Vehicle |
| UFO | Unidentified Flying Object |
| UHF | Ultrahigh Frequency |
| USCG | United States Coast Guard |
| UTC | Coordinated Universal Time |
| UTM | UAS Traffic Management |
| UWS | Urgent Weather SIGMET |
| UWS | Urgent Weather SIGMET |
| VAR | Volcanic Activity Reporting |
| VASI | Visual Approach Slope Indicator |
| VCOA | Visual Climb Over the Airport |
| VDA | Vertical Descent Angle |
| VDP | Visual Descent Point |
| VFR | Visual Flight Rules |
| VGSI | Visual Glide Slope Indicator |
| VHF | Very High Frequency |
| VIP | Video Integrator Processor |
| VLOS | Visual Line of Sight |
| VMC | Visual Meteorological Conditions |
| VMINI | Instrument flight minimum speed, utilized in complying with minimum limit speed requirements for instrument flight |
| VNAV | Vertical Navigation |
| VNE | Never exceed speed |
| VNEI | Instrument flight never exceed speed, utilized instead of VNE for compliance with maximum limit speed requirements for instrument flight |
| VO | Visual Observer |
| VOR | Very High Frequency Omni-directional Range |
| VORTAC | VHF Omni-directional Range/Tactical Air Navigation |
| VOT | VOR Test Facility |
| VR | VFR Military Training Route |
| VREF | The reference landing approach speed, usually about 1.3 times Vso plus 50 percent of the wind gust speed in excess of the mean wind speed. |
| VSO | The stalling speed or the minimum steady flight speed in the landing configuration at maximum weight. |
| VTF | Vector to Final |
| VV | Vertical Visibility |
| VVI | Vertical Velocity Indicator |
| VY | Speed for best rate of climb |
| VYI | Instrument climb speed, utilized instead of VY for compliance with the climb requirements for instrument flight |
| WA | AIRMET |
| WAAS | Wide Area Augmentation System |
| WFO | Weather Forecast Office |
| WGS-84 | World Geodetic System of 1984 |
| WMO | World Meteorological Organization |
| WMS | Wide-Area Master Station |
| WMSC | Weather Message Switching Center |
| WMSCR | Weather Message Switching Center Replacement |
| WP | Waypoint |
| WRA | Weather Reconnaissance Area |
| WRS | Wide-Area Ground Reference Station |
| WS | SIGMET |
| WSO | Weather Service Office |
| WSP | Weather Systems Processor |
| WST | Convective Significant Meteorological Information |
| WW | Severe Weather Watch Bulletin |