YSSY Atis

[Jason H]

I noticed this morning that the ATIS said "wind 240/12 knots......wind at 500ft, 230/18 knots".

Why is it required to put this in when the wind is only changing 5 or so knots?

[Nigel C]

Only speculating, but perhaps if winds higher up were much stronger or from a different direction, then aircraft on approach would want to know that from 500' down the winds didn't vary much as that's when they'd most likely want the aircraft to be at its most stable in the approach?

Perhaps the forecast said something different?

Happy to be corrected by those in the know.

[Philip Argy]

Assuming a runway 25 landing, 230/18 has a higher cross wind component than 240/12 and the difference is probably material, but I'll defer to the drivers to tell us if there's more to it than that.

[Owen H]

I flew in this morning and they were using the 16's.

It also was stronger than that previously, at about 20kts, so there may have been earlier reports and they were continuing the trend.

Perhaps more importantly, the change involves tailwind components. It is quite a surprise to be making an approach and discover a tailwind at 500ft if you're not expecting it, particularly if reasonably strong. If they were using runway 25 the information would likely not have been present.

[Jason H]

It was for runway 16R/L ops.
It still seems as though that wind is normal though, I mean, wind increases in strength with altitude anyway, is that wind on the ATIS really THAT different from the norm that it required a mention?

[Owen H]

What did the ATIS before that say?

When I was there from memory it was in the vicinity of 22kts.

It is quite possible it was there for trend, allowing pilots in the vicinity to know what the wind was doing at the time.

Being told the 500ft wind is a great idea if there is tailwind around. With the winds I heard, the 500ft tailwind was calculated to be about 7kts, which is not inconsiderable. If on approach there was a 7kt tail at 500ft most crew would report it to ATC... and hence it appears on the ATIS. Although at most airports that would have been enough for the duty runway to be changed... but alas not Sydney.

I think this is a great demonstration of operationally relevant information being provided, particularly at an aerodrome that doesn't conform to the regular standards for runway selection.

[Jason H]

Not sure what the ATIS was before that, but thanks for the clarification

[Nigel C]

Originally Posted by Owen H

... particularly at an aerodrome that doesn't conform to the regular standards for runway selection.

Ah yes, but it does conform "to the regular standards for noise sharing"...

[Owen H]

Well, to Sydney's definition of them anyway .

Nowhere else accepts the downwinds and crosswinds that Sydney does for noise as they're outside the ICAO limits .

[Philip Argy]

http://www.airservices.gov.au/brief/...avreq?met=YSSY is generating this error at present:

Error 403: Forbidden
The query has failed, if problem continues please phone the Airservices Australia help desk on 1800 801960

Anyone know why?