ATIS stands for Automatic Terminal Information Service, a recorded broadcast that gives pilots the latest routine airport information. It matters because it lets many pilots receive the same weather, runway, and operational details without tying up the air traffic control frequency. Student pilots use ATIS before contacting ground, tower, approach, or departure control.
The broadcast repeats on a loop and is identified by a phonetic alphabet letter such as Information Alpha or Information Bravo.
Understanding Aviation: The ATIS
An ATIS recording is built from several sources of airport data. Wind comes from sensors near the runway. Visibility may come from an automated weather station or an observer.
Cloud reports tell crews how much of the sky is covered and the height of important cloud layers above the ground. The temperature and dew point help pilots judge the chance of fog, frost, icing, or low cloud. When temperature and dew point are close together, the air is nearly saturated.
Conditions can then change quickly, especially near sunrise or after rain. The altimeter setting is equally important.
Pilots set it on their instruments so the displayed altitude matches local pressure conditions. A wrong setting can make an aircraft appear higher or lower than it really is.
Runway and approach information tells pilots how the airport is operating at that moment. Aircraft usually take off and land into the wind because this reduces the ground speed needed for flight. A runway can still have a crosswind, which pushes the aircraft sideways and requires careful control.
Students can break a wind into two useful parts. The headwind component equals wind speed times the cosine of the angle between the wind and runway. The crosswind component equals wind speed times the sine of that angle.
A wind directly along the runway gives the greatest headwind or tailwind. A wind at right angles gives the greatest crosswind. These estimates help a pilot compare the conditions with aircraft limits and personal training limits.
The recording may include notices that change the normal plan. A taxiway may be closed. Construction vehicles may be working near movement areas.
Birds may have been reported close to a runway. Some lights or navigation equipment may be out of service. A notice can sound minor, yet it may affect where an aircraft taxies, which approach is available, or how much runway remains usable.
Pilots should not treat the recording as background noise. They write down the parts that affect their flight, then compare them with charts, airport signs, and instructions from controllers.
The code letter is a simple way for controllers to check that a pilot has current information. On the first call, the pilot states the letter received. This tells the controller that routine details do not need to be repeated.
If the wind shifts, visibility falls, a runway changes, or a major notice appears, a new recording is issued with the next letter. A pilot who heard an older version must listen again before acting on outdated details. In training, it helps to use a fixed note order.
Record wind, visibility, cloud, temperature and dew point, altimeter, runway, approach, then notices. This reduces missed items when the broadcast is fast or hard to hear. Listening carefully is part of situational awareness, not just a radio procedure.
Key Facts
- ATIS = Automatic Terminal Information Service.
- Pilots listen to ATIS before first contact with ATC at airports that provide it.
- Each ATIS update is assigned a phonetic code letter, such as Information Charlie.
- Typical ATIS content includes time, wind, visibility, clouds, temperature, dew point, altimeter, runways in use, approaches, and notices.
- Headwind component = wind speed x cos(angle between wind and runway).
- Crosswind component = wind speed x sin(angle between wind and runway).
Vocabulary
- ATIS
- Automatic Terminal Information Service is a recorded airport broadcast that gives current weather and operational information to pilots.
- Information Code
- An information code is the phonetic alphabet letter assigned to the current ATIS recording so controllers know which version a pilot has received.
- Altimeter Setting
- The altimeter setting is the local pressure value pilots enter into the altimeter so it reads the correct airport elevation when on the ground.
- Runway in Use
- The runway in use is the runway selected for takeoffs and landings based on wind, traffic flow, and airport operations.
- NOTAM
- A NOTAM is a notice to air missions that alerts pilots to temporary or important changes such as closed taxiways, equipment outages, or construction.
Common Mistakes to Avoid
- Calling ATC without the current ATIS code is a mistake because the controller may need to repeat information that was already broadcast.
- Assuming the ATIS is unchanged is a mistake because weather, runway use, and airport notices can update quickly.
- Ignoring the altimeter setting is a mistake because an incorrect pressure setting can make the indicated altitude wrong.
- Reading back the ATIS letter without understanding the content is a mistake because pilots must apply the runway, weather, and notice information to safe decision making.
Practice Questions
- 1 A pilot hears wind 270 at 12 knots and plans to use runway 27. Using headwind component = wind speed x cos(angle), what is the headwind component?
- 2 A pilot hears wind 240 at 20 knots and plans to use runway 27, whose heading is about 270 degrees. Using crosswind component = wind speed x sin(angle), estimate the crosswind component.
- 3 A pilot listened to Information Bravo 15 minutes ago, but the tower now says Information Charlie is current. Explain why the pilot should get the new ATIS before taxi or takeoff.