1. Many controlled airports have a separate frequency that is only used to broadcast the ATIS. ATIS is a continuously looping recorded message, updated whenever the weather changes significantly, and at some airports every hour. Sometimes it uses a computer voice, but the information is provided by a human. Some uncontrolled airports have a computer generated broadcast called an AWOS, derived from automated observations.

    As AIP RAC 1.3 says: "its purpose is to improve controller and flight service specialist effectiveness and to reliece frequency congestion by automating the repetitive transmission of essential but routine information."
  1. If you want weather information, always contact the FSS. The ATIS only tells you the conditions at the airport. It usually won't mention the cumulonimbus clouds 6 miles to the east.
  2. The ATIS broadcast spares the controller from having to tell every arriving pilot the winds, active runway, and other special information.
  3. If the weather is changing rapidly, the ATIS will probably be out of date. The controller will give you any new information when you call, so listen carefully.
  4. The ATIS continues to be broadcast even if the weather is so bad that even the IFR traffic can't fly. At some airports there is a telephone number that connects to the ATIS, and on bad weather days that ATIS line continuously rings busy, as everyone keeps calling to see if they can go flying yet