Atis - general🧭

Automatic terminal information service, or ATIS, is an automated broadcast on most major and some minor airports to inform aviators about important airport conditions.

A lot of information:🧭

“Rotterdam Information Kilo. Time 1450 Zulu. Runway in use 24 for departures and arrivals. ILS approach runway 24 in operation. Wind 230 degrees at 10 knots. Visibility 10 kilometers. Few clouds at 1,500 feet, broken at 3,500 feet. Temperature 18, dew point 12. QNH 1016. Transition level 50. Work in progress near taxiway Bravo. Advise on initial contact you have Information Kilo.”

This might seem a bit overwhelming at first but the good thing is that the structure is standardized. Lets break it down.

Rotterdam information Kilo is the letter assigned to the current weather report. As described above this letter rotates when there is a new weather report.

The letter🧭

Every ATIS report starts with a letter of the alphabet for example A (Alpha). This letter changes during the day to ensure weather reports are accurate and that pilots can inform the airport delivery that they received the weather information. Even between delivery clearance and takeoff the weather could change. In that case ATC will instruct you with the new information

For example, when requesting clearance on Rotterdam Airport (EHRD) to fly (in this example) IFR to Brussels (EBBR) the pilot says the following : "Rotterdam Delivery, KLM1234 request, IFR clearance to Brussels International with information alpha."

The controller knows that I received the weather information and can grant me clearance to my destination.

The time🧭

Next is the time, 1450 Zulu means 1450 in UTC (Coordinated Universal Time). In the Netherlands at time of writing that would mean 16:50 UTC+2. In aviation all date-times are in Zulu, so when filing a flight plan the departure and arrival time are in Zulu time. The only thing to keep in mind is to use the time zone when informing the passengers about the arrival time.

Runways🧭

Runway in use 24 for departures and arrivals tells the pilots which runways are in use and if they are used for departing or arriving traffic. After the flight plan is filled it could be that the runway is changed due to a change of the weather. If the wind would have turned it could be that we should use 06 instead of 24.

ILS (Instrument Landing System) in operation means the the ILS is functional and ready for interception. This is useful when listening to the ATIS on arrival. And yes, before the approach starts the pilots ensure they get the latest information as-well.

Wind🧭

Wind is an important factor in aviation. Arriving traffic prefers to land with headwind as-well departing traffic. This has to do with lift and also useful to reduce speed.

Wind 230 degrees at 10 knots tells the pilots that the wind is coming the southwest at 10 knots.

• 230° is measured clockwise from north.

• North = 360°

• East = 090°

• South = 180°

• West = 270°

So:

• 230° sits between 180° (south) and 270° (west)

• That means the wind is from the southwest

• It blows toward the northeast

10 knots tells the speed of the wind in this case, light wind.

1. Light wind🧭

0–10 knots

• Minimal effect on takeoff/landing

• Small corrections needed

• Smooth approaches

• Often “calm” or “light and variable”

2. Moderate wind🧭

11–20 knots

• Noticeable crosswind corrections

• Slight airspeed fluctuations

• Normal operations for airliners

3. Strong wind🧭

21–30 knots

• Significant crosswind

• Gusts can destabilize approach

• Autothrust works harder

• Pilots may add gust correction to VAPP

4. Heavy wind🧭

30+ knots

• Turbulence and wind shear more likely

• Crosswind limits become relevant

• Some runways may be closed

• Approaches require high attention

5. Gale / Storm conditions🧭

40+ knots

• Operational limits reached

• ATC may suspend operations

• Severe turbulence and wind shear

Visibility🧭

Visibility 10km is very good. It means that all operations are possible and there is no limitation for the visibility on this airport. When flying IFR (Instrument Flight Rules) the visibility is less of importance, because you can decent on your instruments like (PFD) Primary Flight Display. When flying VFR (Visual Flight Rules) the weather must be good because you MUST see the runway and potential traffic nearby.

1. Excellent visibility🧭

10 km or more

• Clear horizon

• Terrain and runway easily visible

• Perfect for VFR and IFR

• No operational limitations

• Typical on sunny days or post‑rain air

2. Good visibility🧭

5–10 km

• Still fully safe

• Slight haze possible

• All approach lights visible early

• Normal operations

3. Moderate visibility🧭

1,500 m – 5 km

• Haze, mist, or light fog

• Approach lights visible later

• Pilots rely more on instruments

• Still safe for IFR

4. Poor visibility🧭

800 m – 1,500 m

• Significant haze or fog

• Runway may only be visible close to minima

• Autoland often used

• ATC spacing increases

5. Very poor / low visibility🧭

Below 800 m

• LVP (Low Visibility Procedures) activated

• Taxiing becomes slow and controlled

• CAT II / CAT III approaches required

• Ground radar used for aircraft movement

6. Extremely low visibility🧭

Below 300 m

• Only CAT III capable aircraft can land

• Pilots may not see runway until touchdown

• Airport capacity drops sharply

Clouds🧭

Clouds are important in flying. Pilots will mostly try to fly under or above clouds.

1. FEW clouds🧭

• Coverage: 1–2 oktas (very small portion of the sky)

• Meaning: A few scattered clouds, no operational impact

• At 1,500 ft, this is a low cloud layer, but very thin

2. BROKEN clouds🧭

• Coverage: 5–7 oktas (most of the sky covered)

• Meaning: This is considered a ceiling

• At 3,500 ft, this is the main cloud layer you care about for IFR

Temperature🧭

Every ATIS report includes a temperature and dew point value. The dew point is the temperature at which the air becomes fully saturated, meaning moisture in the air begins to condense into mist, fog, or clouds. This value helps pilots understand how close the atmosphere is to forming visibility‑reducing weather.

For example, when the ATIS at Rotterdam Airport (EHRD) reports: “Temperature 18, dew point 12”, it means the air is still dry enough that fog is unlikely. However, when the temperature and dew point move closer together (for example 12/11), the risk of fog, mist, or low visibility increases significantly.

Transition level 🧭

Every ATIS report includes a transition level, which is the altitude where aircraft change their altimeter setting from the local QNH to the standard pressure setting of 1013 hPa. This is important because aircraft flying higher in controlled airspace must all use the same pressure reference to maintain safe vertical separation. Below the transition level, pilots use QNH to ensure their altitude matches the airport elevation; above it, they use standard pressure to align with other aircraft.

For example, when the ATIS at Rotterdam Airport (EHRD) reports: “Transition level 50”, it means that aircraft climbing out of Rotterdam must switch their altimeter from QNH to standard 1013 hPa once passing FL50. This ensures that all aircraft cruising above that level use the same pressure reference.

Below transition level ATC instructions are in FEET instead of a flightlevel.

Other information🧭

Next to the standard information there can be additional information like the work in progress near bravo but it could also contain information about birds in the area. Therefore it's always a good idea to listen to the entire ATIS information and if there is any unclarity you should request the delivery to clarify a message.