Aviation Acronyms from A to Z

This list of aviation acronyms is a good starting point those new to aviation, although it far from comprehensive – aviation weather has its own codes and aircraft manufacturers have an acronym for every part and component.

• 99s - The Ninety-Nines, Inc. International Organization of Women Pilots
• A - Designator for Airbus aircraft, such as A-321
• AC - Advisory Circulars, FAA memos, documents, and booklets, all free
• ACS - Airman Certification Standards, FAA document
• ADM - Aeronautical Decision-Making
• ADS-B - Automatic Dependent Surveillance - Broadcast satellite tracking system; flight tracking apps use this data
• AFM - Aircraft Flight Manual
• AGI – Advanced Ground Instructor certificate
• AGL - Above Ground Level
• AIM - Aeronautical Information Manual
• AME - [FAA-designated] Aviation Medical Examiner, the doctor to see for a medical certificate
• AOPA - Aircraft Owners & Pilots Association 
• ASEL - Airplane Single-Engine Land rating
• ASI - Aviation Safety Inspector, FAA pilot representative responsible for supervising pilots & flight schools
• ATC - Air Traffic Control or Controller
• ATIS - Automatic Terminal Information Service, a recording of current weather and runways in use at larger airports
• ATP - Airline Transport Pilot certificate (also the name of a string of flight schools) (see also: R-ATP)
• AWOS - Automated Weather Observation System
• B - Designator for Boeing aircraft, such as B-737
• BE - Designator for Beechcraft aircraft, such as BE-200
• C - Designator for Cessna aircraft, such as C-172
• CAP - Civil Air Patrol, pronounced 'see-ay-pee', not 'cap'
• CFI - Certificated Flight Instructor 
• CFII - Certificated Flight Instructor - Instrument
• CG - Center of Gravity, for aircraft loading and weight and balance
• CPL - Commercial Pilot License (but it’s really a certificate)
• CRJ - Informal designator for Canadair regional jet, such as CRJ-700 which is actually a CL-65
• CRM - Crew Resource Management
• CTAF - Common Traffic Advisory [radio] Frequency, for pilots to announce position and intentions at airports without control towers
• DPE - [FAA-] Designated Pilot Examiner who can conduct flight checks to issue pilot certificates and ratings
• E6B - Circular slide rule for computing flight speed/time/fuel/distance/wind correction; the name is the original parts number from the U.S. Army Air Corps in the 1930s
• EAA - Experimental Aircraft Association
• EFB - Electronic Flight Bag, often an iPad
• ELT - Emergency Locator Transmitter
• EMB - Designator for Embraer aircraft, such as EMB-175
• ETA - Estimated Time of Arrival
• F/A - Flight Attendant
• FAA - Federal Aviation Administration
• FAR - Federal Aviation Regulation(s)
• FBO - Fixed-Base Operator, airport business that sells fuel, rent planes, offers flight instruction and charters
• FO - First Officer in airline operations (co-pilot, informally) (see also: SIC)
• FSDO - Flight Standards District Office, your local FAA office
• G - Designator for Gulfstream aircraft, such as G-V, pronounced 'gee five' and written G-V, not G-5
• GA - General Aviation, all of aviation that is not military or airline
• GPS - Global Positioning System using satellites
• HIMS - Human Motivational Intervention Study, the recovery / monitoring program for pilots and air traffic controllers with substance abuse or dependence; also denotes AMEs specially trained in these and other mental health and cognitive issues (see also: AME)
• IACRA - Integrated Airman Certification and Rating Application, the FAA online form
• ICAO - International Civil Aviation Organization, a UN agency
• IFR - Instrument Flight Rules (see also: VFR)
• ILS - Instrument Landing System with precision vertical and lateral guidance to a runway
• IMC - Instrument Meteorological Conditions (see also: VMC)
• IOE - Initial Operating Experience, flights at a new company made under the supervision of a check pilot 
• IR - Instrument Rating
• K - International designator for U.S. airports when four letters are used, such as KLAX for LAX
• LPA - Latino Pilots Association 
• LTA - Lighter-Than-Air (balloons)
• ME - Multi-Engine rating or flight time
• MEI - Multi-Engine Flight Instructor
• MEL - Minimum Equipment List to determine if aircraft can be dispatched with inoperative items
• MX - Maintenance
• N - International designator for U.S.-registered aircraft, informally called N-number or tail number, such as aircraft registration N123AB
• NGPA - National Gay Pilots Association
• NORDO - No radio aircraft
• NOTAMs - Notices to Air Missions, alerts about temporary runway closures, for example
• NTSB - National Transportation Safety Board 
• NWS - National Weather Service, source of official aviation weather reports and forecasts 
• OBAP - Organization of Black Aerospace Professionals 
• PA - Designator for Piper aircraft, such as PA-28)
• PAPA - Professional Asian Pilots Association
• PAPI – Precision Approach Path Indicator next to some runways to assist pilot on landing (see also: VASI)
• PAX - Passenger(s)
• PIC - Pilot-in-Command (Captain in airline operations) (see also: SIC)
• PIREP - Pilot Report, a weather observation
• POH - Pilot’s Operating Handbook
• PPL - Private Pilot License (but it’s really a certificate)
• PTT - Push-To-Talk switch to transmit on radio
• R-ATP - Restricted-privileges Airline Transport Pilot certificate (see also: ATP)
• RNAV - Area Radio Navigation
• SAR - Search And Rescue operations
• SE - Single-Engine rating or flight time
• SIC - Second-in-Command (First Officer in airline operations, and co-pilot informally) (see also: PIC)
• SIGMET - Significant Meteorological Information, a bad weather alert
• SOPs - Standard Operating Procedures
• SOS - Sisters of the Skies
• STOL - Short Take-Off and Landing
• TAF - Terminal Area Forecast, weather forecast for an airport
• TFR - Temporary Flight Restriction, restricted airspace for events such as when the President flies into town or for aerial firefighting operations
• TT - Total Time of flight hours logged by a pilot
• UAS - Unmanned Aerial Systems, or drones
• UNICOM - Universal Communication radio frequency to communicate with FBOs
• UTC - Universal Coordinated Time
• V - Velocity or speed, such as Vx best-angle-of-climb speed
• VASI - Visual Approach Slope Indicator next to some runways to assist pilot on landing (see also: PAPI)
• VFR - Visual Flight Rules (see also: IFR)
• VMC - Visual Meteorological Conditions (see also: IMC)
• VOR - VHF Omni Range radio navigation aid
• VTOL - Vertical Take-Off & Landing (helicopters)
• WAI - Women in Aviation, International
• WX - Weather
• Z - UTC was previously called Zulu time (see: UTC)