Wind on final, how long ?

[Alivebas]

When giving information to the pilot about the wind on final, what time scale should be taken into account ?

We have the option to select instantaneous wind, wind over the last 2 minutes, or the wind over the last 10 minutes. Of course, the minima and maxima of those timings are very different.

Are there any procedures published about this ?

Reason why I ask is because we have a discussion at my facility about what wind we should give the pilot, thereby reducing his playtime if we give to strong crosswind (which is what happens when we select "last ten minutes - wind" and give him the gusts)

Thanks for your help everyone.

[JohnnyEagle]

ICAO annex 3 describes this, appendix 3 I think. Short version, 2 minute winds, significant variations ((in direction and velocity)with max and min values. "Wind check", wind to departing aircraft and aircarft on short final is instant (3 seconds)

[Alivebas]

Thanks a lot Mr Eagle for such a fast and nicely detailed answer you gave me.

I will look at that annex. Thanks for your support here.

[Red Four]

Just to add, 10 minute wind/variation/gusts are normally for the METAR.

[kijangnim]

Greetings,
JAA makes it requirement to give the wind when there is a change, head, cross, and tail wind with precise values in terms of changes, I am sorry I dont have these values on hand, I will be looking for them.

[Spitoon]

But JAA don't/didn't make the rules for ATC.......

[Quintilian]

4444 refers to Annex 3, Ch. 4 and states that the following constitutes "significant change":

VRB 60 degrees or more

Wind-components:
Headwind: 10 kt
Crosswind: 5 kt
Tailwind: 2 kt

If I'm not tooooooooooooo mistaken

[Wojtus]

ICAO annex 3 describes this, appendix 3 I think. Short version, 2 minute winds, significant variations ((in direction and velocity)with max and min values. "Wind check", wind to departing aircraft and aircarft on short final is instant (3 seconds)

Annex 3 is not so clear about it. It just says that 2 minutes averages should be presented for ATS units. While 2-min average is commonly used by ATC, more details are still not definied:
- for a gusts to be declared, the max instant wind value should be taken from the last 10, or 2 minutes? Should it be compared to the mean wind from the 2 or 10 minute?
- similar, for variation of direction, are extreme directions from last 2 or 10 minutes valid?

And more questions - for a departing a/c, should I use the wind at departure threshold, mid-field or remote threshold? Does "wind check" implies instant wind, or 2-min average?

It's good if you have local rules covering that. ICAO is playing possum here.