Automatic Terminal Information Service (ATIS) in Aviation

Departing aircraft or those approaching a landing area require a good amount of information to make sure they can actually take off or land safely. Things such as a busy runway, bad weather conditions, and air traffic congestion can be critical for safety.

In the past, this information was provided by the air traffic controllers to the pilots. And this was OK for most airports at the beginning since they did not have much traffic. In 1964, the FAA began testing a kind of service to give pilots timely airport information without burdening air traffic controllers.

However, for busy airports such as the US airports of the present, this would make air traffic control spend most of the time repeating the same information, and no air traffic controller would be able to cover the rest of the duties.

Also, air traffic control radio frequencies would always be congested, thus making it impossible to have fluent and smooth communication, a vital aspect of the aviation industry.

So, ATIS broadcasts have taken the role now. Let’s see the details on how they do it.

What is an ATIS in aviation?

An ATIS is an Automatic Terminal Information Service. This involves pre-compiled messages broadcasting on an airwave frequency at international airports. Pilots typically listen to the ATIS broadcast before contacting the air traffic control unit to get the essential information first.

ATIS broadcasts include essential information for aircraft going out or announcing their appearance at an airport. ATIS information includes weather conditions and runway use, approach type, and approachable style. The ATIS system was developed to reduce the working load of air traffic controllers and reduce congestion of the radio frequency, especially the one used by the control tower.

How is the Automatic Terminal Information Service (ATIS) used?

There are two different types or formats of ATIS worldwide, and they have slight differences in the way they are used. Let’s see them closely.

Voice ATIS

This was the first type created and probably the most common one around the world. With the voice ATIS, pilots listen to the voice transmitted in the cockpit and take notes. When conducting ATIS broadcasts, a VHF transmission should be carried out using a separate frequency at every possible moment to avoid interference with other GPS devices and important frequencies like frequency 121.5 MHz.

Suppose a discrete VHF frequency is not available. In that case, the signal can be transmitted on the voice channel of the most suitable terminal navigation aid, preferably via a Very High-Frequency Omni-Directional Range (VOR) system, providing the range and readiness.

Voice ATIS updates every hour, usually ten minutes before the current hour ends, but some airports update it every 30 minutes. ATIS messages are identified with a code, a letter of the ICAO spelling alphabet that goes Alpha, Bravo, Charlie, Delta, etc. until the last letter is Zulu. This way, on check-in, the pilot can confirm whether the ATIS information received is correct or needs an update from the air traffic controller.

When weather conditions or airport conditions show significant change before a new ATIS broadcast is due, a new ATIS message will be recorded immediately with the word “special” added immediately after the Zulu time. This alerts pilots about significant changes in the conditions that must be considered.

D-ATIS

This is the other type of ATIS broadcast found in busy airports. D-ATIS stands for Data Link-Automatic Terminal Information Service. This Automatic Terminal Information Service (ATIS) comes as an improvement of the voice ATIS.

While voice ATIS was very convenient in the 60s and the 70s, larger airports in the present world and the technological developments we have now have made voice ATIS feel inefficient and even obsolete.

D-ATIS is a digital version that provides the ATIS information directly on the cockpit screens for the pilots to access quickly. This results in two clear benefits: reduced human error from misunderstanding human voice and improved efficiency as taking notes is not needed anymore.

D-ATIS information can be easily printed for the pilot’s records since the system has been part of the Flight Management System (FMS). Therefore, the pilot can have the D-ATIS information before initial contact with control to confirm it more quickly.

Of course, D-ATIS is more expensive, so we only see this version in some larger airports.

ATIS broadcast

As mentioned above, ATIS broadcasts contain essential operational information, especially about present weather conditions like wind direction and speed. But together with weather information, an ATIS broadcast includes precise ATIS instructions with functional significance. Those detailed ATIS instructions are summarized in the following list:

• Departure information includes the name of the airport, indicator, and active runway, among other information found in departure messages.
• Weather observation, including surface wind direction and speed, and any significant variations in the present weather. This is usually possible when surface wind sensors are in place. If surface wind sensors are not available, then this information is taken from other weather observation systems.
• Significant runway surface conditions.
• Significant meteorological phenomena with operational significance for take-off, climb out, or any other flight stage.
• Temperature (Dew point) and air temperature.
• Cloud conditions under current weather.
• Transitional altitude and transitional level, which refer to the highest minimum sector altitude.
• Altimeter setting.
• Vertical visibility.
• Comments and any other relevant information

There is a significant amount of essential operational information. And the pilot needs to digest it all before it can acknowledge receipt during initial contact. This is why data link ATIS (D-ATIS) is used to make the work more efficient.

The ATIS frequency can be increased with the D-ATIS format to ensure the current ATIS is always updated. A departure ATIS with updated ATIS content is critical for safety.

What is the ATIS altimeter?

In a voice or digital ATIS, altimeter setting refers to the value of the atmospheric pressure used to adjust the sub-scale of a pressure altimeter to indicate the height of an aircraft above a known reference surface. This reference can be the mean sea level pressure (QNH), the pressure at the nearby surface airport (QFE), or the pressure level of 1,013.25 hectopascals (29.92 inches of mercury) which gives pressure altitude and is used to maintain one of the standard flight levels.

To set it properly, both the transitional altitude and transition flight level must be known. This will help the pilot to control the altitude during climbing and descent.

ATIS, pilots, and air traffic controllers

Automatic Terminal Information Services (ATIS) provides a continuous stream of archiving aeronautical data in busier airports.

Therefore, it is clear that pilots and air traffic controllers deal with a significant amount of information, which is why current ATIS systems have made their life easier. At this point, it is essential to highlight that pilots can easily find the tower frequency or data link information in airport diagrams and approach charts. When recorded, they are available in English and any other language that may be relevant to the airport’s location.

Also, it is relevant to point out that one of the biggest concerns for airports and airlines is the safety of their passengers. Having things like significant runway surface conditions, significant meteorological phenomena like dew point, surface wind direction, and air temperature easy to read, and identifying and communicating any significant variations in the readings helps their purpose.

However, having and communicating the information on time can be difficult in busy airports. Think about Dallas/Fort Worth International Airport in the US or even a more minor but busy London Stansted Airport. With millions of passengers a year, controlling all their operations, including ATIS, can be a very challenging task.

Final words about ATIS

Airports are complex ecosystems with sophisticated operations that ensure a smooth travel experience for passengers. To achieve the best results, airport management must have a comprehensive understanding of the many aspects required to process passengers transiting through an airport.

And this applies to all airports. The only difference is the scale of the operation. Obviously, the higher the number of passengers, departures, and arrivals, the more challenging it will be.

There is also the legislation that airports must adhere to with a particular emphasis on safety management. This is essential knowledge to make the smartest decisions in the most complex situations.

In short, a career in airport operations management can be very rewarding, but it requires being up-to-date with constant preparation and training.

Fortunately, if you are interested in learning more about airport operations to understand better the interaction between the airport operator and the stakeholders, understand the legislation which airports and stakeholders must adhere to, understand the flow process that will safely allow passengers either leave by aircraft or by transport to use the airport facilities and have a significant appreciation of the various departments and how decision making can affect processes, Aeroclass.org has the right course for you.