Wind turbines and radar obscuration

[hemac]

Although I am a PPL(H) I am posting on this forum in my capacity as an electrical engineer.
I am currently working on a new project, located in Hounslow, and there is a requirement for 2 large wind turbines to be mounted adjacent to the building.
NATS have vetoed the idea on the grounds that the turbine blades could intermittantly appear on Heathrow radar.
Is there a precedent for this type of thing or are NATS being unhelpful and discounting the idea out of hand?
Any information you might have on other turbine applications or installations that have been approved would be very useful.
Thanks
H.

[CUNIM]

Wind Turbines have demonstrated their ability to interfere with primary radar and will also hide aircraft in the shadow behind the turbine. The MOD have also vetoed these contraptions as they hide aircraft from their defence radars. When I see wind turbines replace power stations I will concede their usefulness, but to me they are a gift to the power industry and a curse on the poor tax payer.

[anotherthing]

Hemac,

There is a very strong possibility that the turbines would appear on radar. There are of course many wind turbines out there that are within theoretical radar coverage, but because of the nature of the radar characteristics or the actual function they are being used for, they might not have such a big impact and are therefore deemd not a high risk to operation.

Chances are very high that NATS own very higly trained engineers have looked at the proposal for these two turbines alongside the characteristics of the EGLL radar and the functons that it is used for, and have worked out that they may well interfere.

As flight safety is the potential issue, then they will have had no option but to object to the proposal. If you or your masters dig deep enough, they will be able to obatin the full details as to why NATS have come up with that decision.

[SINGAPURCANAC]

@CUNIM,
You are working either for Bush ruling family or for Exonn mobile,aren't you?
I do not understand people who are against alternative source of energies. :}

[Scooby Don't]

Having worked at a location which had a windfarm on a hill about 15nm from the radar head, and in the days when we used raw primary with a SSR overlay, the MTI never failed to filter out the windfarm. If you deselected the MTI, yes, there was a larger primary return. I never had an aircraft disappear behind the windfarm! Even at 30nm from the radar head, an aircraft would have to be below 2,500 ft or so to be blanked, and then the hills would have the same effect anyway. Frankly, I think the CAA is overreacting.

[790119167]

hemac,

The overriding problem is, as correctly identified earlier in this thread, that the primary radar returns generated by wind turbines cause huge problems for Air Traffic Controllers. Both military and civilian ATCOs have strict rules as to what lateral separation must be applied between an aircraft and a non-squawking contact (which a wind turbine might generate). The worst case scenario is that on a poor weather day, I might not actually be able to recover an aircraft safely and legally if wind turbines are 'painting' on radar close to the airfield. You can never guarantee that the 'object' you assume is a wind farm is not a non-squawking aircraft.
MoD and CAA will always seek to object to wind turbine installations that are close to arrival and departure routes or aerodrome radar patterns. Unfortunately, in the UK, airfields are closely spaced and airspace is congested; not ideal hunting ground for wind farms!

[Dont Hang Up]

NATS must ensure that radar detection probability is maintained within specification (in the high nineties percent). A casual observation that there does not seem to be a problem does not really cut it (can you really tell the difference between 96% and 97% just by watching the screen?). There are a host of subtle and insidious effects caused by reflection and multipath that can nudge radar integrity downwards. You cannot blame either the CAA, NATS or the MoD for being cautious. I do not believe they object to wind farm deployments out of hand.

[PPRuNe Radar]

The British Wind Energy Association have a page which might be of use.

BWEA & Aviation (http://www.bwea.com/aviation/)

[Fesch]

Whats more, wind turbines can also interfere with navigational aids.

[danieloakworth]

They have to be pretty close to interfere with navaids (and SSR). two turbines generelly isn't a big issue but that close to heathrow can completely understand the Nats view.

[NorthSouth]

Lots of ill-informed comment on here so far. Suggest you try this (http://www.caa.co.uk/docs/33/Cap764.pdf) as a first step to understanding the issues. Many airfields already have wind turbines within their radar cover without difficulties - it depends on traffic patterns, airspace classification, radar set-up and controller experience and attitudes to clutter in general.

To respond to some of the assertions:

The CAA is not responsible for objecting or not objecting to wind farms. That's an airport/air traffic service provider responsibility.

The 'shadow' effect is no different to the effects of any other tall thin object e.g. chimney, block of flats.

Neither NATS nor the MoD have a 'veto' on wind turbines, just as they don't have a veto on any other planning application. It's the planning system that decides. Once again CAP 764 is a good source for anyone looking for further explanation of the issues and the processes.

NS

[NutLoose]

Hasn't East Midlands Airport recieved approval to site 4 of them on the Aiport itself to offset their energy costs...... Odd thing is or am I being cynical, they could just as easily stick them anywhere as Energy provided goes into the national grid and the get revenue from it, so they would still be off setting the costs........ but I suppose it does not look like your doing your bit if they cannot be seen, just hope no one flies into one, If they could predict 100% the path of every aircraft in trouble we wouldn't have crashes would we..


What next Underground Airfields and runways? Ohh wait, the Koreans have apparently just done that.:mad:

[danieloakworth]

Actually CAA do reserve the right to object and have done so in the past.

[Standard Noise]

Well we've got it cracked down here in Ciderset. Put the turbine on top of the Mendips and it's obscured by the PE. Sorted.

Off topic slightly, this new turbine near us is owned by Ecotricity. They are usually more expensive than the other providers but I wonder how high a barrel of oil has to go before they become the cheapest?
Oh dear, I do come up with nonsense at the end of a nightshift.:bored: