The control of air traffic on, or in the vicinity of an aerodrome, is provided by the control tower. In most cases the tower is located on top of terminal building. The aerodrome controller, who is located in the tower cab, provides separation between aircraft arriving and departing, and also controls aircraft and vehicles manoeuvring on the manoeuvring area.
The tower’s ‘tools’ include a number of radio transmitters and receivers used to communicate with pilots. The tower’s radio equipment may be used with microphone and loudspeakers or with a headset. There is a wind speed indicator and a wind direction indicator at each controller console. A further instrument is the altimeter setting indicator. It is from this instrument that the controller advises the current altimeter setting which the pilot sets on his aircraft altimeter.
At some busy airports an Automatic Terminal Information Service (ATIS) is available to pilots of departing and arriving aircraft. This service consists of a continuous radio broadcast on a special frequency of recorded and periodically updated noncontrol information. Included is information regarding ceiling, visibility, wind direction and speed, altimeter settings, and runway-in-use. Where ATIS is not available, the tower provides this information.