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Reported crosswind - does it mean much?

Often the anemometer is at the top of a ~10m pole.

This may actually be a regulatory requirement. Clearly it has to be at "some" height because the wind speed will be zero on the ground

But if you are passed a wind (pardon the expression) of say 25kt, and the pole is 10m, and you are flying a low wing plane, it isn't going to be anywhere near 25kt when you are touching down, is it?

I reckon this is why some people find they can exceed the "max demo crosswind" figure so easily.

Administrator
Shoreham EGKA, United Kingdom

10 m, are you sure? Those that I've seen typically have been around two to three meters. Anyway here is how it noramally works: I think the standards are pretty uniform within EASA.

An airport normally has at least two wind anemometers, one at each threshold. One is deemd the official one. Enroute traffic is given a 10 minute mean wind. Approaching aircraft are give 2 minutes mean wind, traffic on short final which request windcheck is given actual wind (varies by the second).

If the maximum wind is 10 kts or more than the mean wind for any such period of which the wind is averaged, gusts are reported. If the maximum wind is not 10 kts or more than the mean wind, but still considered to be significant it is reported as maximum. E.g. wind two five zero degrees 12 knots maximum 20.

As to the direction. If the wind is 2 kts or less, variations of 60 degree or more are reported as varable. If the wind is 3 kts or more, variations from 60 -179 degrees are reported as "variying between", variations of 180 degrees or more is reported as variable.

Most of this is probably part of the PPL sylabus but a recap never hurts

I forgot to say that I think they can give you a good picture of what to expect. When approaching the flare, I think the wind speaks for itself.

I reckon this is why some people find they can exceed the "max demo crosswind" figure so easily.

The "max demo crosswind" is also based on the 30 ft wind.

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