ATIS explained: understanding and following automatic airport information

Shortly before a crew speaks to the approach or ground controller for the first time, it has already listened for a minute: to a calm, often synthetic-sounding voice reciting runway, wind, clouds and air pressure and then starting over from the beginning. This endless loop is the ATIS. If you understand it, you know within seconds how an airport is currently operating – and that is exactly what makes it so valuable for spotters. This guide shows you what is in an ATIS, how to decode the jargon and how to work out from the broadcast where you should stand today.

ATIS: the short answer

ATIS stands for Automatic Terminal Information Service. It is an automatically repeated broadcast that bundles all routine information for an airport: which runways are in use, which approach procedure to expect, what wind, visibility, weather and clouds look like, plus temperature, dew point, air pressure and operational notes. The broadcast runs on a frequency of its own, sometimes also over the voice channel of a radio beacon.

The idea behind it is simple: in the past the controller had to read this information out to each crew individually. At a large airport that eats up an enormous amount of radio time. With the ATIS, every crew listens to the information itself, and the actual working frequency keeps room for clearances. The procedure was developed in the 1960s in the USA; today it is regulated internationally through ICAO, which sets out content and procedure in its standards.

The information letter: Information Alpha to Zulu

Every version of the ATIS carries an information letter, spoken in the ICAO phonetic alphabet. The first issue is called, say, “Information Alpha,” the next “Bravo,” then “Charlie” and so on. After Zulu the cycle starts again at Alpha.

The letter has a clear function: on first contact with air traffic control, the crew reports which version it has heard – for example with “information Kilo received” or simply “with Kilo.” If the letter matches the current issue, the controller doesn’t have to repeat anything. If the crew names an outdated letter, he passes on the changes or sends them to listen again. Especially at changes, the controller often announces on his frequency that new information is valid.

For you as a listener, the letter is a handy indicator. If it moves on outside the usual rhythm, something has changed that was important enough for a new issue – very often the runway direction in use, deteriorating visibility or a thunderstorm nearby.

What’s in an ATIS – and in what order

ICAO prescribes a fixed order. Not every ATIS contains every element, but the basic framework is the same everywhere. If you know it, you can find your way around even a rapidly spoken broadcast.

Element	Example in the broadcast	What it means	Use for spotters
Airport and type	“Hamburg Information …”	Name of the airport, possibly separate for arrival or departure	confirms you have the right frequency
Information letter	“… Kilo”	current version	a change points to changes
Observation time	“time 1420”	time of the weather observation in UTC	shows how fresh the data is
Approach and runways	“expect ILS approach runway 23, departure runway 33”	expected procedure, runways in use	decisive for choosing a spot
Operational notes	runway condition, construction work, transition level	information for the crew	hints at closures and special operations
Wind	“wind 240 degrees, 12 knots, gusts 25”	direction (magnetic) and strength	announce gusts and crosswind
Visibility and weather	“visibility 10 kilometers, light rain”	visual range, possibly runway visual range, current weather	haze, fog, precipitation
Clouds	“broken 1800 feet”	coverage and base	Are approaches visible below the deck?
Temperature, dew point	“temperature 14, dew point 11”	values in degrees Celsius	fog risk, condensation on the wings
Air pressure	“QNH 1009”	altimeter setting	irrelevant for you, mandatory for pilots
Trend and additions	“no significant change,” wind shear	short-term forecast and warnings	weather change in the next hours

At the end there is usually a request like “advise on initial contact you have information Kilo.” After that the loop starts over.

An example step by step

This is what an ATIS can sound like. The following broadcast is a constructed example for Hamburg Airport and not a real recording, but it matches the typical structure:

Hamburg Information Kilo, time one four two zero. Expect ILS approach runway two three. Departure runway three three. Transition level seven zero. Wind two four zero degrees, one two knots, gusts two five knots. Visibility one zero kilometers, light rain. Broken one thousand eight hundred feet. Temperature one four, dew point one one. QNH one zero zero niner. No significant change. Advise on initial contact you have information Kilo.

Translated, that means:

• Information Kilo, 14:20 UTC – the current version, weather observed at 14:20 universal time. In summer time that corresponds to 4:20 p.m. local time.
• ILS approach runway 23 – landing is on runway 23 using the instrument landing system. How the ILS works is explained in the guide to the ILS approach.
• Departure runway 33 – takeoffs are on a different runway. Separate landing and takeoff runways are common at airports with crossing runways.
• Transition level 70 – from flight level 70 upward you fly with the standard altimeter setting of 1013.25 hPa, below the transition altitude with QNH. The value depends on the current air pressure.
• Wind 240 degrees, 12 knots, gusts 25 – the wind comes almost exactly against landing direction 23 but is gusty. Expect bumpy approaches.
• 10 kilometers visibility, light rain, broken clouds (5 to 7 eighths) at 1,800 feet – aircraft emerge from the cloud at around 550 meters above ground.
• 14 degrees, dew point 11 – temperature and dew point are close together; in humid air, condensation trails like to form on wings and flaps.
• QNH 1009 – air pressure in hectopascals, reduced to sea level.

Numbers are spoken digit by digit on aviation radio, and the nine sounds like “niner.” You can find more on pronunciation and standard phrases under Radio phraseology.

The most important abbreviations and terms

You already know many terms from the ATIS if you can read METAR and TAF. Some, however, appear mainly in the voice broadcast:

• CAVOK (“cav-o-kay”): visibility at least 10 kilometers, no clouds below the operationally relevant altitude, no thunderstorm clouds, no significant weather. For spotters usually a very good day.
• RVR (runway visual range): the measured runway visual range, given in poor visibility. If it shows up, it is foggy or hazy.
• Low visibility procedures: procedures for very poor visibility. The airport then operates with larger spacing and fewer movements.
• Transition level: the lowest flight level at which flying is done with standard pressure.
• Braking action / runway condition: braking effect and runway state, especially in winter with snow and ice.
• Wind shear: wind shear in the approach or departure area, a warning of sudden wind changes.
• Bird activity / work in progress: bird strike risk or construction work at the airport.

Separate ATIS and the text variant D-ATIS

At large hubs there are sometimes separate broadcasts for arrivals and departures. That keeps each individual loop short and gives each crew only what it needs. The landing crew hears approach procedure and landing runway, the departing one the departure runway.

Alongside that exists the D-ATIS (data link ATIS). It transmits the same information as text over a data connection such as ACARS. The crew retrieves the current version and reads it on a screen in the cockpit instead of taking notes over headphones. That saves time and avoids mishearing. How you can receive and decode ACARS data link yourself is shown in the article Receiving ACARS messages.

How often the ATIS changes

A new version comes about for two reasons:

1. Routinely with the weather report. At German airports the METAR usually appears every half hour, and with it a new ATIS. If you listen regularly, you quickly notice that the letters advance in a fixed rhythm.
2. Unscheduled for important changes. If the runway direction in use changes, the wind shifts markedly, visibility drops, a thunderstorm approaches or a runway is closed, a new issue with the next letter comes out immediately.

The second case in particular is exciting for you. An unscheduled change of the information letter can mean that aircraft are about to land on the other side of the airport. When and why airports change direction is explained in the guide Understanding runway direction in use at airports.

How to use the ATIS as a spotter

The ATIS answers the three questions that decide every spotting day: where do aircraft land, where do they take off, and is the weather worth it? The procedure is the same at every airport.

An example from practice: at Hamburg Airport there are spots for different runways, such as the Affenfelsen or the observation deck. Which one is the right one today, the ATIS tells you even before you leave – you can find more spots in the guide Plane spotting in Hamburg. Similarly at Frankfurt Airport: whether approaches pass over the Zeppelinheim viewing platform depends on the current runway direction in use.

The ATIS is also useful for videographers: gusty winds across the runway announce spectacular approaches. What happens then is explained in the article on crosswind landings.

Where you can receive the ATIS

The ATIS usually transmits on a frequency of its own in the aviation radio band between 118 and 137 MHz, at some airports also on the frequency of a radio beacon. The respective frequency is listed in the official aeronautical information publications and on the airport’s approach charts. How aviation radio frequencies are structured and why some channels have odd decimal places is explained in the articles Understanding aviation radio frequencies and 8.33 kHz channel spacing.

You can receive the broadcast in several ways:

• Scanner or handheld receiver with the aviation band – what to look for when buying is in the guide Buying an aviation radio scanner.
• SDR stick on a computer – the cheap DIY solution, described under Receiving aviation radio with SDR.
• Online streams provided by community members – more on this in the article Listening to aviation radio online.

Because the ATIS is usually broadcast fairly close to the airport, it can often be heard well in the surrounding area. Before you start, though, find out what is allowed in your country: the rules on listening to aviation radio are not the same everywhere. An overview is offered by the article Is listening to aviation radio legal?.

ATIS, METAR and controller radio compared

The ATIS is one of several sources from which you can read the state of an airport. Each has its strengths.

Source	Form	Content	Strength for spotters
ATIS	voice loop, as D-ATIS also text	runways, procedures, weather, notes	runway direction in use straight from the airport
METAR	coded text report	current weather	easy to retrieve online, also retroactively
TAF	coded forecast	expected weather for many hours	planning for the next day
Controller frequencies	live radio	clearances, instructions, special cases	shows which aircraft is coming next

If you want to tell tower, ground and approach apart, you’ll find the explanation in the article Delivery, ground, tower, approach, center. The ATIS is the calm counterpart: no hurry, no queries, just the state of affairs.

What to keep in mind

• Times are UTC. The observation time in the ATIS is universal time. In Germany you need to add one hour in winter and two hours in summer.
• Altitudes are in feet, visibility in meters or kilometers. Cloud bases are given in feet above ground; one foot is a little over 30 centimeters.
• The ATIS is a snapshot. Between two versions the situation can change. For short-term changes, controller radio is faster; for planning ahead, weather maps like Windy help.
• Not every airfield has an ATIS. Mainly larger airports with instrument flight operations broadcast one. Small airfields often give information directly on the airfield frequency.
• English is the standard. At international airports the ATIS usually runs in English, at some airfields additionally in the national language. More on this in the article English or German on aviation radio.

Conclusion

The ATIS is an airport’s calling card on the radio: short, always structured the same way and constantly up to date. For pilots it is required reading before the first call, for spotters the quickest answer to the question of where aircraft land today. If you can pick out the information letter, runways, wind and clouds, you plan your spot more precisely and notice early from the letter change when the situation turns.