caernarfon and wind turbines

[BigEndBob]

Anyone experienced strange windshear here.
Coming into runway 25 yesterday, over the caravan site, quite variable wind, noticed the turbines facing out to sea and turning. Hit quite surging sort of turbulence, struggling to descend and slow down, had to do a goaround.
Quite suprised such large structures allowed on a licensed airfield.
Thought wake vortex might be like a jumbo climbing out.
Could this be a factor in a recent accident?

[xrayalpha]

Dear BEB,

Please file an MoR about your experience.

Here at Strathaven, we have been fighting quite a few wind turbines (out of the 72 applications within three miles of the town!).

One proposer mentions: there has never been an MOR (Mandatory Occurance Report) filed about wake vortex and wind turbines. So there is no problem!

Of course, until now people have kept a more than sensible distance away from wind turbines, so that is why there hasn't been a problem. But now it appears there can be no choice - other than to avoid certain airfields.

I would like to file the first MOR myself, but then I might be open to accusations that I have "made it up" by the local developer. All I can say is: if the cloud is lowering and you are trying to get back to Strathaven from the west coast by following the A71, don't do it if there is a northerly component to the wind.

[mr_rodge]

Wasn't that the same runway where the accident occurred not long ago?

When were the turbines built? I flew in last September and didn't even notice them, however I landed on the reciprocal that day. Can't remember if there was anything on the Pooley's plate I used...

EDIT: Nope, just watched the video of my approach, they weren't there then.

[JDA2012]

Caernarfon apparently does have a runway 25 now (used to be 26) and this was the runway onto which the aircraft which crashed in May was attempting to land - discussion here (http://www.pprune.org/private-flying/515176-plane-crash-caernarfon.html).

I am a low-hour C150 PPL (passed in April) flying out of Blackpool, but have used 20&02 (unlicensed due to the turbines) and 08 (now 07) at Caernarfon; I have not yet used 25/26 but am planning a visit next weekend (27th-28th), so depends what the wind is doing!

I did not experience any problems on either occasion but do not recall if the turbines were turning at the time. Data available online (http://www.variablepitch.co.uk/stations/2348/) indicates that they were commissioned on 30th Nov 2012; they are in the 2013 Pooley's and mentioned on the website (http://www.caernarfonairport.com/), indeed there is an indemnity form that must be filled in before visiting.

I am aware that this post may be read as defensive of the turbines; this is not my intention, which is only to give information, as I am not sure how many ppruners have visited Caernarfon since the turbines went up.

[Mark 1]

Caernarfon can have some quite marked coastal effects.
A hot day and high pressure could mean that you enter the updraught and shear zone of the sea breeze on final approach to 25.

Long before the wind turbines appeared you could get much entertainment from watching successive arrivals trying to salvage their approaches.

I'm not saying that the turbines weren't a factor, but it may be interesting comparing the surface wind with the 1000', 3000' etc.

[Shoestring Flyer]

Hmmm.?..OP says flew in on 25?....I assume you mean 26. If the Wind turbines were facing out to sea I would have thought you were landing with a tailwind (?)and that 08 would have been the runway of choice?

[hotcloud]

It's now runway 25, was down there a few weeks ago when they were blacking out the old numbers and painting the new numbers, it is all to do with the changing magnetic variation. They have also increased the displacement on runway 25.

[Shoestring Flyer]

25...ok, but if the wind turbines were facing out to sea he was still probably landing witha tailwind!

[phiggsbroadband]

Hi when I first saw a picture of the turbines I thought 'Someone has done a nice job with Paintshop Pro'. But they are real !

Not only will turbulence be an issue, but what about someone doing a Go-around. Do you not have to side-step the runway in use to avoid conflict with any other aircraft, and then climb out parallel to the runway? Dodging a set of turbines might not be so simple in poor or patchy visibility.

[BigEndBob]

Thanks for all the links.
The wind was variable, but the turbines were facing about 270 degrees when landing on 25 and later veered towards the north so takeoff was on 02.
My thoughts were any wake vortex would blow across runway 25.

[flybymike]

25...ok, but if the wind turbines were facing out to sea he was still probably landing witha tailwind!
:confused:
If the turbines were facing out to sea then they were facing in to the prevailing wind. Runway 25 "faces" the sea. I can't see how you reckon on a tailwind?

[Shoestring Flyer]

I think you will find that it depends on the design of the turbine!!:=
Downwind turbines which are the type mostly used in the UK face downwind, whereas upwind turbines face into wind!!........

[Steve6443]

Downwind turbines which are the type mostly used in the UK face downwind, whereas upwind turbines face into wind!!........

Is this true? In Germany, I've been used to looking at where the turbine faces and that's where the wind is coming from. Would be strangely ironic but typically british if the turbines there face the opposite direction ;-)

[flybymike]

Indeed. The turbines not far from my back window are currently facing into what little wind there is, and always have done so when operating.

[Shoestring Flyer]

If people are relying on which way a wind turbine is facing to determine which runway to land on, or even which way the wind is blowing then they may come badly unstuck.
As I said it is down to the design of the turbine....some do indeed face the wind but equally and probably more wind turbines face away from the wind.

[BigEndBob]

I am hoping that ATC suggest a r/w based on anemometer and or windsock direction and not a wind turbine. Although it it doesn't take much imagination to assume the wind turbine is facing the wind, as all the other wind turbines i have ever seen.

It would be interesting to see research on the downwind effects of turbines, for instance release smoke behind the blades or from the tips and see where it goes.

I think if i designed turbines from a structural view point thought it would be better to push against its mounting rather than pull. And the blades are upwind of the mast.

[JDA2012]

In case it's of any use, I've found several planning documents relating to the turbines and associated substations.

These ones appear to be for the substations and LED beacons on the turbines, though they do show relevant boundaries etc.:
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250418.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250420.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250422.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250423.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250424.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250425.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250426.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-250428.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-255922.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/42325-255923.pdf

Minutes giving the reference for the application (C10A/0507/17/LL) as well as discussion of pros/cons considered:
http://www.gwynedd.gov.uk/ADNPwyllgorau/2011/Pwyllgor%20Cynllunio/2011-02-28/english/00_02_Minutes%20of%20this%20meeting.pdf

The application itself:
Application Details | Search for a Planning Application | Track & Trace | Gwynedd Council (http://www.gwynedd.gov.uk/swiftlg/apas/run/WPHAPPDETAIL.DisplayUrl?theApnID=C10A/0507/17/LL) (links to many other documents)
http://www.gwynedd.gov.uk/ADNPwyllgorau/2011/Pwyllgor%20Cynllunio/2011-02-28/english/05_01_Applications%20for%20planning%20permission.pdf
http://www.gwynedd.gov.uk/swiftlg/imagetemp/39645-230757.pdf

Interesting to note that the original plan was for 14 turbines all the way down the runway!

The turbines were originally to be 2-bladed WES30s, built by Wind Energy Solutions | Wind Energy Solutions (http://www.windenergysolutions.nl) :
http://www.gwynedd.gov.uk/swiftlg/imagetemp/39645-220109.pdf

However, those actually installed are 3-bladed Vestas V27 225kW turbines; the change is noted within this document:
http://www.gwynedd.gov.uk/swiftlg/imagetemp/39645-249334.07.12.pdf

This type of turbine does face upwind:
http://www.windpioneer.co.uk/pdf/wp_handout_V27_final.pdf

[BigEndBob]

I see the ownership boundary explains why they are so close to the runway02. Perhaps the place as a future as non flying airfield?

[baldwinm]

I am hoping that ATC suggest a r/w based on anemometer and or windsock direction and not a wind turbine. Although it it doesn't take much imagination to assume the wind turbine is facing the wind, as all the other wind turbines i have ever seen.


I have never seen a turbine that faces downwind, there may be some. Either way any turbulence is going to be downwind of the turbine.

It would be interesting to see research on the downwind effects of turbines, for instance release smoke behind the blades or from the tips and see where it goes.


Have a look at this photo of wind turbines in fog

http://ramblingsdc.net/Australia/WindFarms/WindmillTrails.jpg

Also have a look at

CAA Policy and Guidance on Wind Turbines (http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=detail&id=2358)

In particular see Chapter 2, section 8.

As others (including the CAA) suggest I urge you to file a MOR, see -

Accident and Occurrence Reporting | Aircraft | Operations and Safety (http://www.caa.co.uk/default.aspx?catid=1425&pagetype=90&pageid=8178)

[Shoestring Flyer]

'I have never seen a turbine that faces downwind'

Suggest you read below......scroll down to technical details

Aeolus Power (Wind-Energy) : Questions and answers (http://www.aeoluspower-windenergy.co.uk/faq.html)

[baldwinm]

Suggest you read below......scroll down to technical details

Aeolus Power (Wind-Energy) : Questions and answers

Fair enough...

but as I say I've never seen one. I've seen a lot of turbines.

[xrayalpha]

There are also the Proven turbine which have the rotor downwind and the gearbox into wind.

We have one a few fields away from us.

I might add, I do find the big turbines at Whitelee (each is higher than the Blackpool Tower!) a good indicator of upper wind direction and of general wind direction on a flickery day, since they turn into wind slower than the windsock does

[BigEndBob]

from the CAA doc;
Turbulence

8.1 Turbulence is caused by the wake of the turbine which extends stream wise behind
the blades and the tower, from a near to a far field. The dissipation of the wake
intensity depends on the convection, the turbulence diffusion and the topology
(obstacles, terrain etc.).
8.2 There is evidence of considerable research activity on modelling and studying the
wake characteristics within wind developments, using computational fluid dynamics
techniques, wind tunnel tests and on site lidar measurements. A thorough literature
survey would be necessary to establish the scale and the advances of the research
findings.
8.3 It is recognised that aircraft wake vortices can be hazardous to other aircraft, and that
wind turbines produce wakes of similar, but not identical, characteristics to aircraft.
Although there are independent bodies of knowledge for both of the above, currently,
there is no known method of linking the two. Published research shows
measurements at 16 rotor diameters downstream of the wind turbine indicating that
turbulence effects are still noticeable1. Measurement work has been focused on the
near wake due to technical challenges of the experimental set up, while modelling
studies are capable of examining the wake turbulence further downstream2 3.
Although models can be used to study the effects of the far wake, verification and
validation processes of these models are still ongoing4.
8.4 There are currently no Mandatory Occurrence Reports (MOR)5 or aircraft accident
reports related to wind turbines in the UK. However, the CAA has received anecdotal
reports of aircraft encounters with wind turbine wakes representing a wide variety of
views as to the significance of the turbulence. Although research on wind turbine
wakes has been carried out, the effects of these wakes on aircraft are not yet known.
Furthermore, the CAA is not aware of any formal flight trials to investigate wake
effects behind operating wind turbines. In the UK wind turbines are being proposed
and built close to aerodromes (both licensed and unlicensed), including some
developments on aerodrome sites, indicating an urgent need to assess the potential
impact of turbulence on aircraft and in particular, to light aircraft and helicopters.

Interesting and the photo of turbine in fog.

What galls me is that we shortly have to impliment a safety management scheme (sms) into an ATO from an RF soon.
For what purpose. So that unsafe situations or practises can be highlighted or cured. Does the CAA not run a sms.
Then something like this is approved and appears on a airfield.
So i can sign a disclaimer.
Rather not risk my neck.

[Lost in Cloud]

I flew into Caernarfon over the weekend and with them using rw25 I had no problem with the wind turbines whatsoever. I did take note of them just in case I had to go around (still no problem on 25).

I did think they would cause more of a concern or at the very least a distraction if I had an engine failure or had to complete bad weather / low level circuit when taking off but that was about it.

I landed without fuss, parked up and went down to the beach. On walking down you pass the start of rw02. If I was using 02 then I would be more than concerned about the proximity of the turbines to the runway, in normal conditions am sure it is fine but in any sort of emergency then they are definitely an extra burden in an already stressful situation.

On 02 there is little margin for error as well, take a cross wind left to right, pilot handling errors where you allow the aircraft to drift and things have the potential to go wrong. In the case 02 you would probably be more aware of the fact the turbines are there and initiate a slight turn to the left after take off, just to be sure.

I did leave thinking WHY put them there? But I suppose they have their reasons ££££

[BigEndBob]

Of course it will depend on the wind direction. But if the wind is westerly when approaching 25, you will be downwind of the turbines.

[JDA2012]

Flew into Caernarfon yesterday as planned, approaching from the south (Haverfordwest) and with 07 active, the turbines were facing inland (approximately NE) and turning. I did get a bit of turbulence on final but as this was over the sea/beach and I was in a C150 it may not be attributable to the turbines.