Automatic Terminal information System (ATIS)

Automatic terminal information service, or ATIS, is a continuous broadcast of recorded aeronautical information in busier terminal areas containing essential information, such as current weather information, active runways, available approaches, and any other information required by the pilots who usually listen to an available ATIS broadcast before contacting the local control unit, reducing the controllers’ workload and relieves frequency congestion.

The recording is updated in fixed intervals or when there is a significant change in the information,

e.g. a change in the active runway.

It is given a letter designation (e.g. Zulu) from the ICAO spelling alphabet. The letter progresses through the alphabet with every update and starts at alpha after a break in service of 12 hours or more.

When contacting the local control unit, pilots indicate their

information <letter>

-where, <letter> is the ATIS identification letter of the ATIS transmission the pilot received.

This helps the ATC controller verify that the pilot has all current information.

Many airports also employ the use of Data-link ATIS (D-ATIS), a text-based, digitally transmitted version of the ATIS audio broadcast accessed via a data link service such as the ACARS and displayed on an electronic display in the aircraft.