LHR Temporary Midhurst SIDs?
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LHR Temporary Midhurst SIDs?
Presumeably because I like aircraft and fly (as Pax)a lot I have been asked by my local residents group to attend a couple of meetings about noise from new departure route trials at LHR.
One meeting is run by HAL at Ascot racecourse and one is the res Assoc for Bagshot and Windlesham .
The problem appears to be on Westerlies from LHR with all MID departures seemingly following a precise track over the said villages rather than what appeared to be past practise of turning some flights earlier than others towards MID and thus spreading the noise around.
Could any ATCO/ATC er with knowledge of this project let me know what the background to this is please, some mutterings about increasing capacity but from my simplistic viewpoint turning aircraft earlier or later depending on their destination would seem to allow for more departures than just sending them out in trail over a single path.
I doubt anyone has a lot of problem with the endless stream of minibus types heading for Paris or the near continent as they are already pretty high but some of the late night heavies to Mauritius South Africa Nairobi etc are still pretty low over this part of the world and no doubt make their presence noticed if it is the same route every night.
Any answers appreciated.
And btw I am not opposed to aircraft noise etc , anyone who bought property in the Surrey Heath area since 1980 or so had to be aware of occasional aircraft noise and I think the issue here is that the old scheme worked well from a noise point of view so why change it.
Thanks
PB
One meeting is run by HAL at Ascot racecourse and one is the res Assoc for Bagshot and Windlesham .
The problem appears to be on Westerlies from LHR with all MID departures seemingly following a precise track over the said villages rather than what appeared to be past practise of turning some flights earlier than others towards MID and thus spreading the noise around.
Could any ATCO/ATC er with knowledge of this project let me know what the background to this is please, some mutterings about increasing capacity but from my simplistic viewpoint turning aircraft earlier or later depending on their destination would seem to allow for more departures than just sending them out in trail over a single path.
I doubt anyone has a lot of problem with the endless stream of minibus types heading for Paris or the near continent as they are already pretty high but some of the late night heavies to Mauritius South Africa Nairobi etc are still pretty low over this part of the world and no doubt make their presence noticed if it is the same route every night.
Any answers appreciated.
And btw I am not opposed to aircraft noise etc , anyone who bought property in the Surrey Heath area since 1980 or so had to be aware of occasional aircraft noise and I think the issue here is that the old scheme worked well from a noise point of view so why change it.
Thanks
PB
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The new departure routes I think are DOKEN SIDs which end next to MID, they are P-RNAV routes which means that more aircraft can be packed closer together, it doesn't mean an increase of traffic on any route, just that the integration of departures and arrivals between all the London TMA airfields can be conducted rather more efficiently.
I would be wary of complaining about them, Gatwick residents may suffer the wrath of this in a few years time......
I would be wary of complaining about them, Gatwick residents may suffer the wrath of this in a few years time......
The new departure routes I think are DOKEN SIDs which end next to MID
The current trial involves an RNAV1 version of the MID SID, and a realignment of the SAM SID so that the early parts of both coincide.
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Pax britanica,
http://www.heathrowairport.com/stati...re_trial_2.pdf
The SAM and MID routes do not follow the same route on westerly ops.
http://www.heathrowairport.com/stati...re_trial_2.pdf
The SAM and MID routes do not follow the same route on westerly ops.
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Pax Britannia's post is exactly whyUK ATC will never manage to change any flight paths.
The routes have been moved to be more efficient for ATC reasons, the residents on the ground complain of noise. Don't forget these are the residents who bought/moved to a house near a major international airport, therefore they should expect noise, or the airport wanting to move routes.
I for one have no sympathy, however the airport authorities listen to NIMBYS, and thus trials are cancelled, efficiently lost.
IMHO, this is the same as buying a house by a river and then complaining if you get flooded!!!!
The routes have been moved to be more efficient for ATC reasons, the residents on the ground complain of noise. Don't forget these are the residents who bought/moved to a house near a major international airport, therefore they should expect noise, or the airport wanting to move routes.
I for one have no sympathy, however the airport authorities listen to NIMBYS, and thus trials are cancelled, efficiently lost.
IMHO, this is the same as buying a house by a river and then complaining if you get flooded!!!!
Yes, apologies for the confusion, I was getting my easterlies and westerlies mixed up, it's on easterlies that the two partly coincide. 
According to Heathrow and NATS, the early termination of the trials won't lead to any loss of data:
"It is the view of NATS and Heathrow that sufficient data will have been collected by 12 November to confirm the findings of these trial. Given that is the case, the trials will stop on that date."
"It is the view of NATS and Heathrow that sufficient data will have been collected by 12 November to confirm the findings of these trial. Given that is the case, the trials will stop on that date."
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NIMBY here living in the Surrey Bagshot/Windlesham/Lightwater triangle since 1977.
I had zero aircraft noise issues with the pre-trial system. Aircraft were, as pax britanica says, spread out and we all, including Virginia Water residents, got a SHARE of the noise.We are used to noise here, be it from Heathrow or the nearby M3 motorway and ,yes, we do benefit from living close to those area of transport.
BUT, we now find ourselves living under a new narrow flight path for all LHR Westerly traffic to France, Spain and the late night heavies to South Africa. Even the new trial routing to Southampton (SAM) gives us noise we didn't previously get. I have become a great fan of FR24!
The locals have been bending the ear of our man in Westminster, Michael Gove. Maybe he will help sort this out - if his lot are still in power after May 2015
I had zero aircraft noise issues with the pre-trial system. Aircraft were, as pax britanica says, spread out and we all, including Virginia Water residents, got a SHARE of the noise.We are used to noise here, be it from Heathrow or the nearby M3 motorway and ,yes, we do benefit from living close to those area of transport.
BUT, we now find ourselves living under a new narrow flight path for all LHR Westerly traffic to France, Spain and the late night heavies to South Africa. Even the new trial routing to Southampton (SAM) gives us noise we didn't previously get. I have become a great fan of FR24!
The locals have been bending the ear of our man in Westminster, Michael Gove. Maybe he will help sort this out - if his lot are still in power after May 2015
I live between Chobham and Windlesham. I used to get all MID departures from the 27s over my house, but now they pass about 3 or 4 miles west which I find annoying as I'm so used to them I miss them, especially the BA '380s and the slow climbing Springbok '340s.
Why can't they use the 'old' SIDs sometimes?
Why can't they use the 'old' SIDs sometimes?
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The departure routes used for the last 30 years or more were based on noise monitoring done in the 1970s. Quite often they put aircraft in places that ATC did not want them to be in as climbs were often delayed by the close proximity of the departures to aircraft in 'stacks' waiting to land. The problem until recently was two fold:
i) Routes had to be defined using ground based radio navigation aids which sometimes were not sited in a suitable place. The use of navigation equipment that has been available on most aircraft for over 20 years is now part of the ATC route planning process in areas near airports. The consequence for those on the ground in that, where ATC would previously instruct aircraft to fly routes that would vary slightly each time, with the new way of defining routes relying more on very accurate aircraft navigation systems aircraft will fly identical routes dozens of times a day.
ii) The Dept for Transport would not even consider approving changes to routes below 4000 ft. It now seems they will if a case can be made that fewer people would be affected by noise than before. This of course can mean those who were not previously affected (Gatwick/ADNID, Heathrow/SAM) could be in future.
My understanding is that the present series of Heathrow trials is intended to reduce the delay experienced by aircraft waiting to take off by reducing by one minute the separation for aircraft following different routes but which are quite close together for maybe the first 10-15 miles. It is intended to make Heathrow more resilient but NOT increase the number of flights.
i) Routes had to be defined using ground based radio navigation aids which sometimes were not sited in a suitable place. The use of navigation equipment that has been available on most aircraft for over 20 years is now part of the ATC route planning process in areas near airports. The consequence for those on the ground in that, where ATC would previously instruct aircraft to fly routes that would vary slightly each time, with the new way of defining routes relying more on very accurate aircraft navigation systems aircraft will fly identical routes dozens of times a day.
ii) The Dept for Transport would not even consider approving changes to routes below 4000 ft. It now seems they will if a case can be made that fewer people would be affected by noise than before. This of course can mean those who were not previously affected (Gatwick/ADNID, Heathrow/SAM) could be in future.
My understanding is that the present series of Heathrow trials is intended to reduce the delay experienced by aircraft waiting to take off by reducing by one minute the separation for aircraft following different routes but which are quite close together for maybe the first 10-15 miles. It is intended to make Heathrow more resilient but NOT increase the number of flights.
Last edited by EastofKoksy; 6th Oct 2014 at 11:09. Reason: Typo
Thread Starter
many thanks to all the contributors to my questions, and many thanks Gonzo for the link to the official HAL release and explanation of the trial.
A couple of questions or comments
1 It seems that for many years the original routes were not that strictly followed with aircraft being given different headings on both MID and SAM SIDS as they climbed out of LHR. No one seemed very bothered by that noise wise.
2. The new trial does bring the MID and SAM routes much closer together than the original routes which saw MID departures turning south for Midhurst quite soon after initial climb and SAM departures making it to just south of Reading before heading for SAMPTON. However as per 1, these were not set in stone and the actual picture was more scattered.
3. I would really appreciate a professional view on this but surely the old method was more resilient since separation could be achieved and maintained by turning aircraft south at differing intervals rather than have them stay in trail on a very narrow track where differences in speed and climb rate would seem to cause delay on take off clearances rather than ameliorate them or 'to make performance more resilient'
4. There is also the comment about more reliable separation from other aircraft in the London TMA such as LHR inbounds and Gatwick outbounds.
I don't quite see that either since the minimum level for Ockham arrivals the old routings w closer to Ockham but even the smaller aircraft were not going to make it very close to that height -taking LHR outbounds further west means some departures could climb above the initial FL60 restriction but the further inbound aircraft are from Ockham the higher they are so that looks like no real advantage either.
So as it stands HAL have asked NATS to implement a trial which has upset a lot of people for no real gain and nor does it seem to me at least that it would improve resilience , so assuming they are not completely illogical I am left wonder WHY?
PB
A couple of questions or comments
1 It seems that for many years the original routes were not that strictly followed with aircraft being given different headings on both MID and SAM SIDS as they climbed out of LHR. No one seemed very bothered by that noise wise.
2. The new trial does bring the MID and SAM routes much closer together than the original routes which saw MID departures turning south for Midhurst quite soon after initial climb and SAM departures making it to just south of Reading before heading for SAMPTON. However as per 1, these were not set in stone and the actual picture was more scattered.
3. I would really appreciate a professional view on this but surely the old method was more resilient since separation could be achieved and maintained by turning aircraft south at differing intervals rather than have them stay in trail on a very narrow track where differences in speed and climb rate would seem to cause delay on take off clearances rather than ameliorate them or 'to make performance more resilient'
4. There is also the comment about more reliable separation from other aircraft in the London TMA such as LHR inbounds and Gatwick outbounds.
I don't quite see that either since the minimum level for Ockham arrivals the old routings w closer to Ockham but even the smaller aircraft were not going to make it very close to that height -taking LHR outbounds further west means some departures could climb above the initial FL60 restriction but the further inbound aircraft are from Ockham the higher they are so that looks like no real advantage either.
So as it stands HAL have asked NATS to implement a trial which has upset a lot of people for no real gain and nor does it seem to me at least that it would improve resilience , so assuming they are not completely illogical I am left wonder WHY?
PB
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Using the current routes and method of navigation there is inherently a degree of uncertainty about the accuracy in the way they MIGHT be flown. It is not possible to reduce the time interval between departures because ATC would sometimes have to intervene in a random number of cases to maintain separation.
The whole point of the new routes and how they are flown using PBN capability would mean the time interval between aircraft taking off from Heathrow could be reduced in some circumstances without ATC intervention being needed to provide separation. The greater accuracy and certainty of an aircraft being able to fly any particular route is where the increased resilience in Heathrow airport operations would come from.
The whole point of the new routes and how they are flown using PBN capability would mean the time interval between aircraft taking off from Heathrow could be reduced in some circumstances without ATC intervention being needed to provide separation. The greater accuracy and certainty of an aircraft being able to fly any particular route is where the increased resilience in Heathrow airport operations would come from.
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Almost legal you have my sympathies. When you bought your house in 1977, who would of imagined that an airport would be built at Heathrow or Gatwick??
Or were the airports already in operation? Routes can and should be able to be changed at anytime.
Do you use the airport at all?
Or were the airports already in operation? Routes can and should be able to be changed at anytime.
Do you use the airport at all?
Thread Starter
Nimmer
I think you have the wrong idea here- few in the affected areas complain about LHR per se-many work there and all know people who do.
The issue is after 20 years of sensible cooperation and consideration about noise (something any business should do is minimise its impact on neighbours) HAL have introduced some new routes without much consultation which has lead to some spontaneous concern.
I doubt that 55 of the local population affected would vote for Boris Island they just want a sensible approach to something that might have minor benefits to HAL but significant impact on them-is that so bad?
I think you have the wrong idea here- few in the affected areas complain about LHR per se-many work there and all know people who do.
The issue is after 20 years of sensible cooperation and consideration about noise (something any business should do is minimise its impact on neighbours) HAL have introduced some new routes without much consultation which has lead to some spontaneous concern.
I doubt that 55 of the local population affected would vote for Boris Island they just want a sensible approach to something that might have minor benefits to HAL but significant impact on them-is that so bad?
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Nimmer - I use Heathrow and Gatwick several times each year. I also have a son who works at Heathrow so I have NO PROBLEM living with reasonable aircraft noise. My gripe is that the boffins at HAL have now chosen to re-route the previous spread of many Westerly departures into a single narrow path which happens to be over my house without so much as a by your leave - perhaps I didn't get the memo.
I see the trial is finishing early - has common sense broken out ?
I see the trial is finishing early - has common sense broken out ?
I suppose if the departures all stay (accurately) on the new route instead of being vectored over multiple tracks then fewer people will be bothered by aircraft noise (although more often). I guess for every village complaining about the new SIDs there could be 10 that are enjoying a break from aircraft noise.
If any new SID avoids the OCK hold then departures can be climbed sooner cutting fuel burn and noise complaints.
If any new SID avoids the OCK hold then departures can be climbed sooner cutting fuel burn and noise complaints.
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Pax,
Your questions should really be aimed at Heathrow Airport Ltd, links are on www.heathrowairport.com/noise.
Aircraft were turned off the 'old' MID route on passing 4000ft, which understandably occurs at different locations depanding upon aircraft performance. They were turned so that they could be kept climbing, rather than stopping at 6000ft underneath the OCK stack as they would do if kept on the route.
This required manual intervention from the controller each time. Theoretically, if the route is changed so that MID flights use the most desired track, they can be given continuous climb, clear of OCK, while remaining on their own navigation and thus significantly reducing ATC workload.
More generically, conventional navigation SIDs effectively require a 45 degree divergence soon after take off to enable a 1 minute departure separation. With RNAV SIDs, which are far more accurate, the aim, once data is gathered and analysed, is to reduce the required divergence to 21, or even 15 degrees (or even less). This would enhance resilience due to the increased departure rate from fewer 2 minute gaps on departure.
Your questions should really be aimed at Heathrow Airport Ltd, links are on www.heathrowairport.com/noise.
Aircraft were turned off the 'old' MID route on passing 4000ft, which understandably occurs at different locations depanding upon aircraft performance. They were turned so that they could be kept climbing, rather than stopping at 6000ft underneath the OCK stack as they would do if kept on the route.
This required manual intervention from the controller each time. Theoretically, if the route is changed so that MID flights use the most desired track, they can be given continuous climb, clear of OCK, while remaining on their own navigation and thus significantly reducing ATC workload.
More generically, conventional navigation SIDs effectively require a 45 degree divergence soon after take off to enable a 1 minute departure separation. With RNAV SIDs, which are far more accurate, the aim, once data is gathered and analysed, is to reduce the required divergence to 21, or even 15 degrees (or even less). This would enhance resilience due to the increased departure rate from fewer 2 minute gaps on departure.
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Combining SIDs close to the airport to concentrate flights along narrow corridors seems to be Government policy and also part of Heathrow strategy to reduce population noise exposure with a third runway.
See
http://your.heathrow.com/wp-content/...Assessment.pdf
Some of the mapped options in Appendix H seem to mirror the current trial changes to me.
See
http://your.heathrow.com/wp-content/...Assessment.pdf
Some of the mapped options in Appendix H seem to mirror the current trial changes to me.
Combining SIDs close to the airport to concentrate flights along narrow corridors seems to be Government policy and also part of Heathrow strategy to reduce population noise exposure with a third runway.
See
http://your.heathrow.com/wp-content/...Assessment.pdf
Some of the mapped options in Appendix H seem to mirror the current trial changes to me.
See
http://your.heathrow.com/wp-content/...Assessment.pdf
Some of the mapped options in Appendix H seem to mirror the current trial changes to me.
I guess good proofreaders are hard to find these days ...
Thread Starter
BOAC -I hope that was not because BOAC were early adopters of a sterile cockpit below 10000 ft.
Again , thanks to all and as the trial has been ended early perhaps HAL have got a hint of opposition and decided its not really worth the effort to pursue it.
Just a final question there was comment I heard somewhere that there was a plan to move Ockham hold somewhat to the west, again based on non ground based navaid use, any truth in that?
PB
Again , thanks to all and as the trial has been ended early perhaps HAL have got a hint of opposition and decided its not really worth the effort to pursue it.
Just a final question there was comment I heard somewhere that there was a plan to move Ockham hold somewhat to the west, again based on non ground based navaid use, any truth in that?
PB