A quick-reference glossary for the acronyms you'll hear on frequency and in training — plain-English definitions, no jargon explaining jargon.
Altitude measured from the terrain directly below the aircraft, not sea level.
The FAA's guide to airspace, procedures, and standard radio phraseology — the basis for most of the calls in this app.
An automated weather-reporting station, often broadcast on its own discrete frequency near the field.
The service that directs and separates aircraft, on the ground and in the air.
A looping recorded broadcast of an airport's current weather, active runway, and advisories, tagged with a phonetic letter ("Information Bravo") that changes each update.
Same idea as ASOS — an automated weather broadcast, common at smaller non-towered airports.
A pilot certificated by the FAA to teach other pilots.
Airspace around the busiest major airports. An explicit ATC clearance is required to enter.
Airspace around busy mid-size airports. Two-way radio contact must be established before entering.
Airspace around smaller towered airports. Two-way radio contact is required before entering.
Controlled airspace with no radio-contact requirement for VFR flight.
Uncontrolled airspace — no ATC involvement at all.
The shared frequency pilots use to self-announce position and intentions at a non-towered airport.
The altitude on a precision approach where the pilot must decide to land or go around.
Pressure altitude corrected for non-standard temperature — the altitude the aircraft actually "feels" like it is performing at.
Tells a pilot their aircraft's slant-range distance to a ground navigation station.
The predicted clock time an aircraft will reach its destination.
The predicted duration of a flight or flight leg.
The U.S. government agency that regulates civil aviation.
The point where the final descent segment of an instrument approach begins.
A specific U.S. aviation rule, also cited as "14 CFR" (Code of Federal Regulations, Title 14).
The business at an airport providing fuel, parking, and other services to visiting aircraft.
An optional ATC traffic-advisory service for VFR aircraft — not mandatory, provided workload permitting.
A facility that provides pilot weather briefings, flight-plan filing, and en route advisories — not ATC separation.
Abandoning a landing or approach and climbing back out instead of touching down.
When a controller transfers an aircraft to the next facility or frequency.
An instruction to stop before a specified point — a runway or taxiway — and not cross it without further clearance.
The point where an aircraft begins a published instrument approach procedure.
The UN body that sets international aviation standards, including its own phraseology conventions used outside the U.S.
A transponder button a pilot presses on ATC request so their radar return highlights momentarily for the controller.
Flying primarily by reference to instruments, under ATC control, used when weather is below VFR minimums.
A precision approach system using radio beams to guide an aircraft's course and glidepath to a runway in low visibility.
Weather actually too poor to fly VFR — requires IFR.
An instruction to taxi onto the runway and hold there — not yet cleared for takeoff.
The lowest altitude allowed on a non-precision approach before the pilot must see the runway or go around.
A routine hourly (or special) surface weather report in a standard coded format.
The published procedure a pilot flies after a go-around on an instrument approach.
Airspace where military training activity occurs. VFR flight through it is permitted but caution is advised.
Altitude measured from average sea level — what most altimeters read.
An older ground radio beacon that aircraft home in on with an ADF receiver.
A time-critical notice about a hazard, closure, or change — e.g. a closed runway — not yet reflected on charts.
A light system on the runway showing whether an aircraft is above, on, or below the glidepath.
The pilot who is legally responsible for, and has final authority over, the flight.
The aircraft-specific manual with performance data, limitations, and procedures.
The certificate most pilots earn first, allowing non-commercial flight. (The FAA's formal term is "Private Pilot Certificate.")
The current barometric pressure setting dialed into an altimeter so it reads altitude above sea level.
GPS/computer-based navigation that lets an aircraft fly a direct or defined path without relying on ground stations.
"Message received and understood" — does not by itself mean agreement or compliance.
A request to repeat the last transmission.
A published, charted departure procedure for IFR flights out of an airport.
The four-digit transponder code ATC assigns an aircraft so it can be identified on radar.
"Wait — I'll get back to you," used by either a pilot or a controller.
A published, charted arrival procedure for IFR flights into an airport.
A coded weather forecast for an airport, typically valid 24–30 hours out.
A temporary no-fly or restricted area — for example over a wildfire, a stadium, or a VIP movement.
A non-ATC radio service, often FBO staff, at many non-towered airports that can pass advisories like wind and traffic; frequently shares the CTAF.
An older-style version of the same above/on/below glidepath light system as PAPI.
Flying by visual reference to the ground and horizon, in weather clear enough to see and avoid other traffic.
Weather actually good enough to fly VFR.
A ground navigation beacon that broadcasts bearings a pilot's instruments use to fly to or from a fixed point.
"Will comply" — the pilot acknowledges an instruction AND will follow it (more than just "Roger").
The onboard radio that reports an aircraft's squawk code (and altitude) to ATC radar.