We were doing quite well this morning with a steady flow rate matching
the actual landing rate. However this afternoon we had to change runways
twice as the front just nudged enough E to bring us 'Westerlies' for an
hour. This can be seen from the METARs:
EGLL 081750Z 12009KT 9999 FEW033 BKN044 07/06 Q0967
EGLL 081720Z 11006KT 080V150 9999 BKN042 08/06 Q0966
EGLL 081650Z 12006KT 090V230 9999 FEW034 BKN042 09/06 Q0966
EGLL 081620Z 22006KT 190V280 9999 FEW021 SCT034 09/05 Q0966
EGLL 081550Z 21007KT 9999 FEW034 SCT041 09/05 Q0966
EGLL 081520Z 15008KT 9999 FEW026 SCT036 09/06 Q0965
EGLL 081450Z 15009KT 9999 FEW009 SCT018 BKN030 08/06 Q0965
EGLL 081420Z 13012KT 9999 FEW010 SCT017 BKN025 08/06 Q0965
EGLL 081350Z 13012KT 9999 FEW009 BKN015 07/05 Q0965 TEMPO BKN012
Holding delays went up as a result.

Not predicted on the TAF, Jon, but I guess it might have deserved a
Prob10 in the days we used to have them!

Phil

is it that essential to land into the wind?

on dead calm days i dont see modern airliners having problems


On 08/11/2010 8:09 PM, Phil Layton wrote:
We were doing quite well this morning with a steady flow rate matching
the actual landing rate. However this afternoon we had to change runways
twice as the front just nudged enough E to bring us 'Westerlies' for an
hour. This can be seen from the METARs:
EGLL 081750Z 12009KT 9999 FEW033 BKN044 07/06 Q0967
EGLL 081720Z 11006KT 080V150 9999 BKN042 08/06 Q0966
EGLL 081650Z 12006KT 090V230 9999 FEW034 BKN042 09/06 Q0966
EGLL 081620Z 22006KT 190V280 9999 FEW021 SCT034 09/05 Q0966
EGLL 081550Z 21007KT 9999 FEW034 SCT041 09/05 Q0966
EGLL 081520Z 15008KT 9999 FEW026 SCT036 09/06 Q0965
EGLL 081450Z 15009KT 9999 FEW009 SCT018 BKN030 08/06 Q0965
EGLL 081420Z 13012KT 9999 FEW010 SCT017 BKN025 08/06 Q0965
EGLL 081350Z 13012KT 9999 FEW009 BKN015 07/05 Q0965 TEMPO BKN012
Holding delays went up as a result.

Not predicted on the TAF, Jon, but I guess it might have deserved a
Prob10 in the days we used to have them!

Phil

"Phil Layton" wrote in message
...
We were doing quite well this morning with a steady flow rate matching the
actual landing rate. However this afternoon we had to change runways twice
as the front just nudged enough E to bring us 'Westerlies' for an hour.
This can be seen from the METARs:
EGLL 081750Z 12009KT 9999 FEW033 BKN044 07/06 Q0967
EGLL 081720Z 11006KT 080V150 9999 BKN042 08/06 Q0966
EGLL 081650Z 12006KT 090V230 9999 FEW034 BKN042 09/06 Q0966
EGLL 081620Z 22006KT 190V280 9999 FEW021 SCT034 09/05 Q0966
EGLL 081550Z 21007KT 9999 FEW034 SCT041 09/05 Q0966
EGLL 081520Z 15008KT 9999 FEW026 SCT036 09/06 Q0965
EGLL 081450Z 15009KT 9999 FEW009 SCT018 BKN030 08/06 Q0965
EGLL 081420Z 13012KT 9999 FEW010 SCT017 BKN025 08/06 Q0965
EGLL 081350Z 13012KT 9999 FEW009 BKN015 07/05 Q0965 TEMPO BKN012
Holding delays went up as a result.

Not predicted on the TAF, Jon, but I guess it might have deserved a Prob10
in the days we used to have them!

Phil

Not guilty m'lord on this occasion !

From a TAF perspective it all depends on the the extent of the change in
terms of degrees and also the speed before and after the change. However, in
this case it a change to 130° to 210° would be valid in the TAF as it was a
swing of 60° or more and the wind was over 10KT before it veered - but no
doubt difficult to predict accurately for such a short time. If you were
writing a TAF based on the what happened it would quite awkward, either a
short BECMG of a SW'ly immediately followed by another short BECMG back to a
SE'ly or alternatively a TEMPO SW'ly for 1 hour. Either way it's a difficult
one to convey well within the constraints of the TAF rules.

As an aside, have you tried the Openrunway service for Heathrow, Phil ? I'm
sure you'd find that interesting and it also provides hourly predictions for
wind speed and direction amongst other parameters
http://www.metoffice.gov.uk/aviation...rts/openrunway

Jon.

"Jon O'Rourke" wrote in message
...
"Phil Layton" wrote in message
...
We were doing quite well this morning with a steady flow rate matching
the actual landing rate. However this afternoon we had to change runways
twice as the front just nudged enough E to bring us 'Westerlies' for an
hour. This can be seen from the METARs:
EGLL 081750Z 12009KT 9999 FEW033 BKN044 07/06 Q0967
EGLL 081720Z 11006KT 080V150 9999 BKN042 08/06 Q0966
EGLL 081650Z 12006KT 090V230 9999 FEW034 BKN042 09/06 Q0966
EGLL 081620Z 22006KT 190V280 9999 FEW021 SCT034 09/05 Q0966
EGLL 081550Z 21007KT 9999 FEW034 SCT041 09/05 Q0966
EGLL 081520Z 15008KT 9999 FEW026 SCT036 09/06 Q0965
EGLL 081450Z 15009KT 9999 FEW009 SCT018 BKN030 08/06 Q0965
EGLL 081420Z 13012KT 9999 FEW010 SCT017 BKN025 08/06 Q0965
EGLL 081350Z 13012KT 9999 FEW009 BKN015 07/05 Q0965 TEMPO BKN012
Holding delays went up as a result.

Not predicted on the TAF, Jon, but I guess it might have deserved a
Prob10 in the days we used to have them!

Phil

Not guilty m'lord on this occasion !

From a TAF perspective it all depends on the the extent of the change in
terms of degrees and also the speed before and after the change. However,
in this case it a change to 130° to 210° would be valid in the TAF as it
was a swing of 60° or more

Correction :-

That should read from rather than to, i.e. "However, in this case it a
change *from* 130° to 210° would be valid in the TAF as it was a
swing of 60°"

Jon.

"Phil Layton" wrote in message
...
We were doing quite well this morning with a steady flow rate matching the
actual landing rate. However this afternoon we had to change runways twice
as the front just nudged enough E to bring us 'Westerlies' for an hour.
This can be seen from the METARs:
EGLL 081750Z 12009KT 9999 FEW033 BKN044 07/06 Q0967
EGLL 081720Z 11006KT 080V150 9999 BKN042 08/06 Q0966
EGLL 081650Z 12006KT 090V230 9999 FEW034 BKN042 09/06 Q0966
EGLL 081620Z 22006KT 190V280 9999 FEW021 SCT034 09/05 Q0966
EGLL 081550Z 21007KT 9999 FEW034 SCT041 09/05 Q0966
EGLL 081520Z 15008KT 9999 FEW026 SCT036 09/06 Q0965
EGLL 081450Z 15009KT 9999 FEW009 SCT018 BKN030 08/06 Q0965
EGLL 081420Z 13012KT 9999 FEW010 SCT017 BKN025 08/06 Q0965
EGLL 081350Z 13012KT 9999 FEW009 BKN015 07/05 Q0965 TEMPO BKN012
Holding delays went up as a result.

Not predicted on the TAF, Jon, but I guess it might have deserved a Prob10
in the days we used to have them!

Phil

Certainly an interesting day weatherwise.

Saw a Facebook update from one of our recently-gratuated trainee air traffic
controllers that simply said "966!!" We dont get that low in the sims!

Extra care needed in the LTMA to watch out for level busts I expect.

Jim, Bournemouth
--
Bournemouth Weather readings online: http://www.g0ofe.com/weather

On 08/11/2010 21:52, Jim Smith wrote:


Certainly an interesting day weatherwise.

Saw a Facebook update from one of our recently-gratuated trainee air
traffic controllers that simply said "966!!" We dont get that low in the
sims!

Extra care needed in the LTMA to watch out for level busts I expect.

Jim, Bournemouth

I did write to folks in ATC on Saturday morning saying that the QNH
would go below 976 on Monday morning ( I said 09Z but in fact it was
06Z!!) and said that it would go to 968 - and it went to 965mb..so not
too bad.

The issue is MSL (Minimum Stack Level) goes up to FL90 below 976mbs to
provide 1000ft separation from 6000ft QNH - which has capacity impacts
in the LTMA.

Phil

On 08/11/2010 21:28, Jon O'Rourke wrote:


Not guilty m'lord on this occasion !

From a TAF perspective it all depends on the the extent of the change
in terms of degrees and also the speed before and after the change.
However, in this case it a change to 130° to 210° would be valid in the
TAF as it was a swing of 60° or more and the wind was over 10KT before
it veered - but no doubt difficult to predict accurately for such a
short time. If you were writing a TAF based on the what happened it
would quite awkward, either a short BECMG of a SW'ly immediately
followed by another short BECMG back to a SE'ly or alternatively a TEMPO
SW'ly for 1 hour. Either way it's a difficult one to convey well within
the constraints of the TAF rules.

As an aside, have you tried the Openrunway service for Heathrow, Phil ?
I'm sure you'd find that interesting and it also provides hourly
predictions for wind speed and direction amongst other parameters
http://www.metoffice.gov.uk/aviation...rts/openrunway

Jon.

I would go for a TEMPO! It was clearly a fine line. Farnborough were
Westerly for a few hours, and Gatwick never made it even though Shoreham
did! It was certainly a wonky old front!

Phil

On 08/11/2010 21:08, terylene wrote:
is it that essential to land into the wind?

on dead calm days i dont see modern airliners having problems



The issue was that it was not dead calm. There was a tail wind of 25kts
at one point on the approach to 09L which made aircraft break off the
approaches..

cheers for the info..

is 23 still used in stormy conditions?

On 08/11/2010 10:19 PM, Phil Layton wrote:
On 08/11/2010 21:08, terylene wrote:
is it that essential to land into the wind?

on dead calm days i dont see modern airliners having problems



The issue was that it was not dead calm. There was a tail wind of 25kts
at one point on the approach to 09L which made aircraft break off the
approaches..

On 08/11/2010 22:26, terylene wrote:
cheers for the info..

is 23 still used in stormy conditions?


Runway 23 closed in about 2003. There are only the two main runways
27R/L 09R/L now.