Windshear reporting - please help
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Joined: Apr 2003
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From: Sutton
Windshear reporting - please help
I'm interested to know how your airfield reports windshear. Have flown into the same major UK airport late on twice in the last week and both times the ATIS has reported windshear but with no further information.
Both times specifics were requested and no further information was given/available.
Now I know pilot reports on windshear can be as variable as their avoiding action for CBs/a bit of rain but for certain if people report plus or minus ten knots then this is significant.
My home base ATIS always provides (1) Pos / neg (2) Strength of reported shear (3) the altitude at which it was experienced.They continue to verify the presence of shear by asking subsequent landing aircraft for reports and update the ATIS accordingly.
This is useful as we change our final approach target speed (and sometimes even the flap setting for landing) depending on strength of the shear.
Met wise there are three major things which aircraft are not certified to deal with.
1. Extreme (as opposed to severe) turbulence (associated with severe rotors/super cells/ funnel cloud etc).
2. Severe icing (associated with freezing rain / super cooled water droplets etc).
3. Severe windshear. Whilst this kind of severe windshear normally is restricted to major continental land masses (US etc) it does happen in Europe once in a while. Last night I had plus or minus ten knots...seriously not good.
I'm not trying to sound alarmist but it appears that this particular field (or at least that late shift) has too casual an approach to one of the most significant threats we face.
Tin hat on.
Both times specifics were requested and no further information was given/available.
Now I know pilot reports on windshear can be as variable as their avoiding action for CBs/a bit of rain but for certain if people report plus or minus ten knots then this is significant.
My home base ATIS always provides (1) Pos / neg (2) Strength of reported shear (3) the altitude at which it was experienced.They continue to verify the presence of shear by asking subsequent landing aircraft for reports and update the ATIS accordingly.
This is useful as we change our final approach target speed (and sometimes even the flap setting for landing) depending on strength of the shear.
Met wise there are three major things which aircraft are not certified to deal with.
1. Extreme (as opposed to severe) turbulence (associated with severe rotors/super cells/ funnel cloud etc).
2. Severe icing (associated with freezing rain / super cooled water droplets etc).
3. Severe windshear. Whilst this kind of severe windshear normally is restricted to major continental land masses (US etc) it does happen in Europe once in a while. Last night I had plus or minus ten knots...seriously not good.
I'm not trying to sound alarmist but it appears that this particular field (or at least that late shift) has too casual an approach to one of the most significant threats we face.
Tin hat on.
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
I think you will find there was a tacit 'agreement' between airlines and ATC a while back NOT to report the extent of w/shear. There were instances where the 'reports' indicated the w/s to be in the 'severe' category and pilots quite correctly declined an approach. The solution was to stop that!
I believe you can still ask for 'pilot reports' from preceding a/c, however, and make your own decisions.
I believe you can still ask for 'pilot reports' from preceding a/c, however, and make your own decisions.
Thread Starter
Joined: Apr 2003
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From: Sutton
So if we have plus or minus 30 knots of windshear in the UK then this would not be reported as it might stop me making an approach. That is exactly why I would like to know!
Such a commercially orientated agreement (which deliberately withholds vital safety information) would result in a H&S Executive prosecution and criminal negligence charges if it led to an accident. No wonder it has not been formalised...do the CAA know about this?Talk about links in the accident chain. Shame we can't bolt some of these management types on a rocky flight into AMS (windshear capital of Europe).
Manchester certainly don't deliberately withold this information ...if it causes a delay (and prevents a stick shaker operating or flap limit speed being exceeded) then the team has worked together to avoid a dangerous situation.
Such a commercially orientated agreement (which deliberately withholds vital safety information) would result in a H&S Executive prosecution and criminal negligence charges if it led to an accident. No wonder it has not been formalised...do the CAA know about this?Talk about links in the accident chain. Shame we can't bolt some of these management types on a rocky flight into AMS (windshear capital of Europe).
Manchester certainly don't deliberately withold this information ...if it causes a delay (and prevents a stick shaker operating or flap limit speed being exceeded) then the team has worked together to avoid a dangerous situation.
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From: UK
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
OK, Porco - I'll listen on the ATIS for the plus/minus in them
. If it has changed it is welcome. My info came from a LGW ATC sup after I requested copies of ATIS broadcasts following 'an event' a few years ago (late 90's).
Edit: While we are on the topic' - the UK AIC, I believe, defines 'severe' as a speed change of >15kts. My company (in 1997) were unable to confirm that a reported +/- 15kts was, as I believe, 2 x 'severe'. It was at about this point that the reports disappeared from the ATIS. What is the opinion on this aspect of 'severe', remembering that the OPS manual says 'Do not commence an approach'?
. If it has changed it is welcome. My info came from a LGW ATC sup after I requested copies of ATIS broadcasts following 'an event' a few years ago (late 90's).Edit: While we are on the topic' - the UK AIC, I believe, defines 'severe' as a speed change of >15kts. My company (in 1997) were unable to confirm that a reported +/- 15kts was, as I believe, 2 x 'severe'. It was at about this point that the reports disappeared from the ATIS. What is the opinion on this aspect of 'severe', remembering that the OPS manual says 'Do not commence an approach'?
Joined: Mar 2002
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From: Sunny Warwickshire
We only report windshear on the ATIS and the tower advise the approaching aircraft the extent of the windshear determined from reports by landing crews.
Windshear is dynamic and as such one crew might get +15kts, the next might just say its a bit bumpy, the next might get -10kts, so if we changed the atis after every report to reflect the severity of the shear then the atis letter is going to change every 2 mins which means tha the poor sods who briefed themseles inboud with Alpha, suddenly get told that the information is Zulu and then have to get that and re-brief based on information which will no doubt have changed by the time they have completed the re-brief
Windshear is dynamic and as such one crew might get +15kts, the next might just say its a bit bumpy, the next might get -10kts, so if we changed the atis after every report to reflect the severity of the shear then the atis letter is going to change every 2 mins which means tha the poor sods who briefed themseles inboud with Alpha, suddenly get told that the information is Zulu and then have to get that and re-brief based on information which will no doubt have changed by the time they have completed the re-brief
Joined: May 2001
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From: London,England
One of the problems is that people report windshear when what they really mean is a rapid loss or gain of airspeed due to turbulence, a true windshear event is very rare and should result in a go-around. It would be interesting to know how many events reported by aircraft equipped with reactive windshear alerting (most modern aircraft with IRS systems) have actually set the system off, my guess is almost none of them. If you get a true shear then of course you should report it, you should also go-around if you are anywhere near the ground, landing and then saying we had severe windshear at 300ft is a bit daft really.
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Joined: Apr 2003
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From: Sutton
Max angle & Radar - I did sympathise (in the initial post) in terms of inaccurate pilot reporting.
The day in question was an airport north of the border but no details of the shear were available from the tower (except to say that one aircraft's windshear alert system had actually triggered).
Yes it is reported as windshear when it may actually be severe wind gradient, low level mechanical turbulence or rotors. Whatever someone chooses to call it ...it can still cause a flap overspeed (worst case severe structural damage) or stick shaker (worst case low altitude stall).
As mentioned in the initial post life threatening weather in Europe is rarer than in the US ( worst recorded windshear 80 knot loss with 90 degree change in direction)/ Africa etc but it does happen.
- 1987 RAF Hawk from Valley NW of Towyn experienced rotors with accelerations of 1.5 to 7 G. A civillian aircraft would have broken up.
- 1981 an F28 out of Amsterdam had it's wing ripped off in funnel cloud.
- In the UK there are, typically, between 18 to 30 CONFIRMED tornadoes each year...many more go unreported in remote regions.
Windshear is most likely when
- Thunderstorms are within 5 NM of the airfield
- During passage of fronts
- When there is a vector difference of 40 degrees between surface and 2,000 foot wind.
I know it is an increase to your already busy workload... but I say again please give us as much notice as early as possible.
BOAC - Boeing defines severe windshear as 15 knots or more. We are told not to go around for positive (amber warning) windshear. Can still bust the flap limit speed though.
The day in question was an airport north of the border but no details of the shear were available from the tower (except to say that one aircraft's windshear alert system had actually triggered).
Yes it is reported as windshear when it may actually be severe wind gradient, low level mechanical turbulence or rotors. Whatever someone chooses to call it ...it can still cause a flap overspeed (worst case severe structural damage) or stick shaker (worst case low altitude stall).
As mentioned in the initial post life threatening weather in Europe is rarer than in the US ( worst recorded windshear 80 knot loss with 90 degree change in direction)/ Africa etc but it does happen.
- 1987 RAF Hawk from Valley NW of Towyn experienced rotors with accelerations of 1.5 to 7 G. A civillian aircraft would have broken up.
- 1981 an F28 out of Amsterdam had it's wing ripped off in funnel cloud.
- In the UK there are, typically, between 18 to 30 CONFIRMED tornadoes each year...many more go unreported in remote regions.
Windshear is most likely when
- Thunderstorms are within 5 NM of the airfield
- During passage of fronts
- When there is a vector difference of 40 degrees between surface and 2,000 foot wind.
I know it is an increase to your already busy workload... but I say again please give us as much notice as early as possible.
BOAC - Boeing defines severe windshear as 15 knots or more. We are told not to go around for positive (amber warning) windshear. Can still bust the flap limit speed though.
Joined: Mar 2000
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From: On a radial
In my limited experience, whenever windshear is reported i scribble down all the details incl a/c type and the time it was reported. each subsequent aircraft that makes an approach i inform using
"At (time) a departing/arriving (ac type) reported windshear at (altitude). Airspeed loss/gain (number) knots, strong left/right drift."
plus any info on rotors etc.
i carry on giving this info until it appears the risk no longer exists, i.e i have no reports from pilots for some time, or i have an official met confirmation.
At the end of the day, people saying theyy would or wouldn't seems a bit weird. i'd rather an aircraft have too much info, than not enough and then having an incident.
Bring on the winter season
"At (time) a departing/arriving (ac type) reported windshear at (altitude). Airspeed loss/gain (number) knots, strong left/right drift."
plus any info on rotors etc.
i carry on giving this info until it appears the risk no longer exists, i.e i have no reports from pilots for some time, or i have an official met confirmation.
At the end of the day, people saying theyy would or wouldn't seems a bit weird. i'd rather an aircraft have too much info, than not enough and then having an incident.
Bring on the winter season
Joined: Apr 2003
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From: Near London, alledgedly..
I think we should all do that actually - at least thats how I was trained to deal with it. I pretty much give that line as far as I can fill it in with the reported details. And like inverted, I do it until no more reports or similar.
Thread Starter
Joined: Apr 2003
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From: Sutton
Well maybe I was just unlucky. This post was prompted by the fact that no details on the windshear was available on request. A subsequent conversation with the controller suggested that this was normal at GLA. The second of my two experiences was during the passage of a fast moving cold front...so it may well have been true shear. Again today going into home base and detailed were actively being sought by the tower controller to verify continued existence / extent of problem.
