Sunday, December 18, 2005

A question from Caz......

Caz has posted the following question:

Hello its Caz again! A quick question, what does it mean when pilots say 'We are a Boeing 777 (understand that bit!) with information Lima? or Romeo? or Papa?' It always seems to be a different letter but i just don't understand what that bit means & i can't find it anywhere in my books!

This relates to the continuous weather broadcast given out on a dedicated frequency at airports. Remember my post regarding Gatwick frequencies mentions the 'ATIS' frequency of 136.525? ATIS stand for 'automatic terminal information service' - it is a continuous broadcast of the current weather conditions at that airport and it is typically updated every 20 to 30 minutes. This is just an example, but say the weather broadcast at 8am in the morning is known as 'information alpha' when it is next updated at say, 8.30am it becomes 'information bravo' and so it goes on throughout the day until the update becomes 'information zulu' and it then starts all over again at 'information alpha'. When an aircraft calls approach control and advises his aircraft type along with 'information alpha' for example, the controller immediately knows which weather broadcast the pilot has listened in to on the ATIS frequency. If there has been a further update with any changes in weather conditions this will be reported to the pilot.

I hope I have explained this clearly enough? If there are still any queries please let me know.

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