on time so the time of de-icing will be shortened and the departure time will not be in joepardy. After the de-icing the captain will report that the aircraft is fully ready within his TSAT window so he can get the start up approval to taxi to the runway.

The last couple of months Amsterdam Schiphol Airport has been confronted with high levels of mixed weather conditions. One of these conditions which is fog has a major influence on Airport operations. The fog we are talking about occurs when the temperature and dew point are equal or within a degree and the air becomes saturated. The dew point is the temperature at which the air becomes 100 % saturated. At that point the air condenses into water droplets which we see as fog. At the airport we have 4 visibility phases. A / B / C / D

AT PHASE ALPHA: The horizontal visibility is more than 550m and less then 1500m with a cloud base of 200 / 300 FT. AT PHASE BRAVO: The horizontal visibility is between the 350m and 550m. AT PHASE CHARLIE: The horizontal visibility is between the 200m / 350m. AT PHASE DELTA: The horizontal visibility is less than 200m and the cloud base is up less then 200ft. The lower the visibility the bigger the consequence for the runway uses.

Here you see a random weather message called METAR: Meteorological Aerodrome Report. This report contains information about actual weather circumstances which is routinely prepared by the meteorological service in an airport. For example:

METAR EHAM 230755Z 16003KT 0100 R18C / 0250N R27 / 0150N R18R / 0175N R06 / 0225N FZFG NSC M03 / M03 Q1027 NOSIG =

METAR shown of Amsterdam Schiphol Airport at the 23rd of the month, observed at 0755Z. The wind is blowing from 160 ° speed 3kts. The horizontal visibility is 100m. The RVR value of RWY 18C is 250m( N). The RVR value of RWY 27 is 150m( N). The RVR value of RWY 18R is 175m( N). The RVR value of RWY 06 is 225m( N). FZFG NSC. TEMP / DEWP are both M03 °/ 26.6 ° F. QNH1027 NOSIG =