Meteorological information takes different forms of presentation according to the importance of the station and the means that are used: by word of mouth, by phone or by answering machine. Let's describe the best case: the station having a forecasting service. We can obtain a file. It includes a verbal explanation, which describes the general situation and includes an analysis of the flux in altitude and a description of conditions foreseen for the flight. It is therefore indispensable to specify the journey as well as timetables of departure and arrival. But it includes others information: