air traffic data systems The Copperchase METSYS operates in a similar manner to an Automated Weather Observing System (AWOS) at an airfield. It consists of a set of airfield meteorological sensors located at appropriate points on the airfield, data gathering processor running METSYS software and a number of distributed MET The sensors send raw or averaged meteorological data at periodic intervals of, typically, 30 seconds. The data gateway processor reads the incoming data and stores it in a database for later distribution to MET Displays and/or other systems. The information collected and displayed by the METSYS will be used by ATC staff, meteorologists, pilots and flight dispatchers to prepare and monitor weather forecasts, plan flight routes, and provide necessary information for correct takeoffs and landings. The METSYS makes available the actual and averaged readings from airfield instruments to: - A number of dedicated MET Displays for Controllers in the Visual Control Room (VCR) and the Radar/Approach Room. Assist the Meteorological Observer staff at the airfield to create the Surface Actual (SA) METAR and SPECI (Met Reports) for the airfield. The Automated Terminal Information Service (ATIS) The airfield sensors measure weather parameters such as wind speed and direction, barometer pressure, temperature and dew point, visibility, cloud heights and precipitation. The METSYS can accept data from any combination of sensors using the manufacturers proprietary telemetry interface for each sensor. The METSYS will not predict weather, current information to weather offices where forecasts are produced. Typically, the METSYS will record (subject to the • Airport identifier • Zulu time • Wind Speed & Variation • Wind Direction & Variation • Present Weather • Recent Weather Transition Level Transition Altitude • Cloud Base ICAO Requirements The ICAO document Annex 3, Chapter 4 describes the requirements for automatic meteorological systems for the acquisition, processing, dissemination and display in real-time of the meteorological parameters affecting landing and take-off operations at an airfield. The Copperchase METSYS adheres to the recommendations and practices described in Annex 3. METSYS generates alarms or warnings for the generation of SPECI (special) reports according to the criteria defined in Annex 3 for changes in each of the meteorological parameters. UK Civil Aviation Authority Requirements METSYS follows the requirements and recommendation of the appropriate CAA document "CAP 746: Requirements for Meteorological Observations at