LHR Temporary Midhurst SIDs?

[pax britanica]

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

[zonoma]

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......

[DaveReidUK]

The new departure routes I think are DOKEN SIDs which end next to MID

No, the trial of the offset DOKEN SIDs ended in mid-June.

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.

[Gonzo]

Pax britanica,

http://www.heathrowairport.com/static/Heathrow_Noise/Downloads/PDF/Westerly_departure_trial_2.pdf

The SAM and MID routes do not follow the same route on westerly ops.

[Nimmer]

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!!!!

[DaveReidUK]

The SAM and MID routes do not follow the same route on westerly ops.

Yes, apologies for the confusion, I was getting my easterlies and westerlies mixed up, it's on easterlies that the two partly coincide. :\

however the airport authorities listen to NIMBYS, and thus trials are cancelled, efficiently lost

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."

[almost legal]

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

[chevvron]

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?

[EastofKoksy]

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.

[pax britanica]

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

[EastofKoksy]

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.

[Nimmer]

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?

[pax britanica]

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?

[almost legal]

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 ?

[Del Prado]

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.

[Gonzo]

Pax,

Your questions should really be aimed at Heathrow Airport Ltd, links are on www.heathrowairport.com/noise (http://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.

[118.70]

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/uploads/2014/07/01-Heathrow-3RNW-Air-and-Ground-Noise-Assessment.pdf

Some of the mapped options in Appendix H seem to mirror the current trial changes to me.

[DaveReidUK]

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 (http://your.heathrow.com/wp-content/uploads/2014/07/01-Heathrow-3RNW-Air-and-Ground-Noise-Assessment.pdf)

Some of the mapped options in Appendix H seem to mirror the current trial changes to me.I love the part in that document where it talks about "Continuous Decent Approaches". [4.3.1]

I guess good proofreaders are hard to find these days ... :O

[BOAC]

Well, I never flew an indecent approach (Continuous or intermittent) in all my time.

[pax britanica]

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

[Nimmer]

Indeed HAL are running scared of the noise whiners. I wonder how they are going to cope with the deluge of abuse if they get an approval for a third runway??

[118.70]

Aren't all the holding stacks due to vanish with the introduction of "Point Merge"?

It seems odd to inflict the pain of nudging routes to avoid stacks when it will only be a short-term temporary gain until the other changes are made.

Is there a Masterplan vision of what the area will look like when LAMP is fully completed ? Or does it just develop piecemeal by growing like Topsy ?

[EastofKoksy]

It is not just about avoiding stacks it is also about reducing time intervals between departures on different SIDs.

Besides, if the stacks were abolished completely the point merge arcs for Heathrow would extend from Oxford to Petersfield and Hatfield to Tunbridge Wells!! LOL

[chevvron]

Public meeting chaired by Michael Gove MP this fri (10th) in Bagshot.(probably the one mentioned by pax britanica)

[HEATHROW DIRECTOR]

<<Aren't all the holding stacks due to vanish with the introduction of "Point Merge"?>>

Looking forward to watching that!

[pax britanica]

EoK , if part of this is to reduce time intervals on different SIDs why move MID and SAM tracks much closer together . I know I am an amateur but while the logic of the LHR argument holds up the practical implementation seems to negate what they claim they want to do.

Yes there is a local area (Surrey Heath) meeting on Friday and indeed another one on Monday (Ascot).

As for doing away with the stacks the NATS publication I read didn't mention LHR just LGW and LCY and the explanation of Point merge made it look exactly the same as todays system just putting the holds further out and adding a bit of a countryside tour between the hold and final approach vectoring .So I can see it making a difference when there are only a couple of aircraft that would otherwise be held but lets face it at LHR the holds are pretty busy all day .So at first glance it looks like a lot of window dressing to me

PB

[kcockayne]

HD

I'll come & watch with you !

pax britannica

Very insightful of you ! Are you really "an amateur"?

[DaveReidUK]

EoK , if part of this is to reduce time intervals on different SIDs why move MID and SAM tracks much closer together . I know I am an amateur but while the logic of the LHR argument holds up the practical implementation seems to negate what they claim they want to do.If it helps, the declared objective of the trials is as follows:

"This SID Trial package introduces six westerly SIDs, with the intention of investigating reducing the angle of divergence between RNAV1 SID tracks for one minute departure intervals. Currently a one minute departure interval would require an angle between SID tracks of 45° or more, however it is hoped that data gathered by this trial may lead to a reduction of the angle to between 10° and 30°"

[Norman.D.Landing]

A blog entry from John Stewart, chair of HACAN, the main aircraft anti noise lobby group.

Flight Paths Matter: there is a chance we can get them right
Posted on October 5, 2014
5/10/14

by John Stewart

Recent events have illustrated how much flight paths matter. As Mark Hookham put it in today’s Sunday Times “low-flying aeroplanes are causing uproar in affluent commuter towns and idyllic villages across Britain as airports test new flight paths” – Suburbia in revolt at new f light paths

Unless you are a Harmondsworth resident whose home is threatened by a third runway or an Indian farmer whose land is taken for a new airport, flight paths are what is likely to matter most to you. If planes could land and take off perpendicularly most local objections would fade away.

Flight paths are the motorways of the sky. Building new ones or doubling the traffic on existing ones will always bring a flood of complaints. It happened in Ascot and Teddington in recent months. Eighteen years ago it happened in Brixton, Stockwell and Clapham when landing procedures were tightened up. Aviation Minister Glenda Jackson told the House of Commons (28/10/97): “when the airport is busy, which is for much of the day, aircraft will join the ILS [the final descent path] further east over Battersea, Brixton or Lewisham.” Ms Jackson, the least sympathetic of recent aviation ministers, refused to meet with residents.

One resident wrote at the time: “I’ve lived in Clapham North at the same address for almost 20 years. Until 3 years ago one hardly noticed the planes, apart from Concorde, of course. Then in summer ’95, as if someone somewhere had flicked a switch, the occasional drone became a remorseless whine. It was like an aerial motorway, open from early morning till at least mid-evening.”

And flight paths are going to change again. This time driven by the new computer technology which enables planes to be guided more precisely when landing and taking off. The industry believes this will allow it to make more efficient use of airspace, thus saving on fuel, cutting emissions and reducing delays.

The American airports have gone for the easy option and concentrated flights on a very few number of routes. This has resulted in big protests in places like Chicago: Noise Complaints About O'Hare Skyrocket | AviationPros.com (http://www.aviationpros.com/news/11681350/noise-complaints-about-ohare-skyrocket) London City Airport, to its shame, is proposing to do the same thing: CAMPAIGNERS CALL ON CAA TO SUSPEND CONSULTATION ON CITY AIRPORT FLIGHT PATHS | HACAN East (http://www.hacaneast.org.uk/2014/09/campaigners-call-on-caa-to-suspend-consultation-on-city-airport-flight-paths/)

I believe concentration is indefensible in built-up areas. It is asking the chosen communities to bear all the pain. And, whenever surveys are done, they show that people prefer the flight paths to be shared, so that everybody gets a break – some respite – from the noise. That doesn’t mean piling the pressure on Ascot so that other areas can get some relief. What it does mean is finding a balance so that the fewest number people possible are truly disturbed by the noise.

I would argue the current situation across huge swathes of London and the Home Counties is untenable and change can only be a good thing. 40 planes an hour an overfly the Oval Cricket Ground or Clapham Common. This video of Vauxhall, 17 miles from Heathrow, gives a flavour of the disturbance: https://www.youtube.com/watch?v=rXf8o_khz8s. A report commissioned by HACAN from the consultants Bureau Veritas found that in Ruskin Park in Camberwell, almost 20 miles from the airport, “aircraft noise dominates the local environment”. And many under the take-off flight paths are experiencing a volume and concentraion of planes they never imagined possible twenty years ago.

Heathrow estimates that, if they get it right, most communities could get relief from the noise 50% or even 75% of the time. In an attempt to get an answer which works both for the industry and for as many residents as possible, Heathrow is doing more pre-planning and conducting more experiments than any other airport in the world before it puts its final proposal out to public consultation.

The devil will be in the detail and there will be areas where ‘if it ain’t broke, don’t fix it’ – maybe parts of West London which enjoy runway alternation. And real care should be taken to avoid the very few plane-free ‘oases’ which still exist. But there is a fighting chance of getting it right and banishing the dark era Glenda Jackson helped usher in nearly 20 years ago.

Ms Jackson is standing down at the next General Election.

[Nimmer]

I stand by my original statement whiners who bought a house near a major international airport.

It's not difficult to work out where Heathrow is read the signposts look at a map before you buy a house, flight paths can and should be changed to ensure the airport runs efficiently.

Think, why is the house such a good price, before you buy.

[zonoma]

The current system is no longer the best system and needs changing, there will always be gainers and losers. And it is not just about LHR departures, there are future projects being worked on for these routes (or similar) being passed to allow other changes further down the line. There is a lot of great information in the posts above, sad to see those requesting this information brushing some of it off thinking "that won't happen" in their opinion, get ready for a shock or two.

[pax britanica]

Mr N , as I said before the people in the effected areas know all about LHR, many live in these areas because of the proximity to the airport , many work there and many more fly from there. it is not noise per se but a seemingly random change that causes some inconvenience.

Mr Z , If you think there were ever low house prices in these affected areas think again-one of the most expensive areas on England outside a few London post codes. That of course also means the people who live there have the money and knowledge to fight their corner pretty hard and effectively. Google 'Camberley Mosque' if you don't believe me

And where on earth among western democracies does your idea that a major airport , railway factory etc etc should be allowed to run purely to suit its own objectives without any regard at all for environmental impact. That doesn't and should never happen. There are plenty of options about how flights can be routed using new technology and all it needs is a bit of thought and discussion to ensure majority of the traffic is kept over less or uninhabited areas in the region.

[Nimmer]

Mr PB, The last time I looked Heathrow was surrounded by built up areas, to try and avoid them would be impossible.

I don't know if you have noticed but there is a another fairly large airport to the south of a heathrow, also pumping out planes at 1 minute intervals.

How do you propose to avoid all major towns and all the other aircraft with your proposed flight paths?

However as you hinted, if the planes flew over the poor areas nobody would bother complaining.

My statement still stands, your a whiner who bought a house near a major international airport.

[EastofKoksy]

PB,

At first sight it looks illogical to try and reduce the time interval between take-offs by putting routes closer together. However, as someone has already mentioned, the increased accuracy of PBN means that route divergence for a 1 minute time interval could be cut from 45 degrees to around 20 degrees. The trials are collecting data to try and establish if this can be safely achieved.

If these trial routes are implemented, it would be possible when taking off from 27L/27R to go from 3 departures in 4 minutes with a combination MID followed by CPT followed by SAM to potentially 3 departures in 2 minutes. That is where the payback is for Heathrow.

From the point of view of pilots and controllers these routes are probably deliverable with appropriate safeguards. The only question that has to be answered - is the political pain worth the gain?

[pax britanica]

Dear Mr Nimmer

I was born and grew up 400m south of LHR and lived their for 25 years . Iwas a plane spotter in my early teens. My father , father in law and mother in law worked at LHR. My wife worked at LHR .I have lived close to LHR all my life and like aircraft. Noise does not bother me in the least as nothing in the air today comes close to a VC10, &)& or anything else I grew up with so I think you jumped to ever so slightly the wrong conclusion. I also do not recall making any personal attacks on you although I did suggest you checked your facts alittle more and had a little bit of understanding for peoples concerns

Have you ever looked at a map of the LHR area -it is not built up at all except to the east -west of LHR is Stanwell Moor Staines common Runnymede , Chobham Common Burnham Beeches Windsor Great park , Bagshot ranges, Broadmoor etc etc , for southern England it is one of the least populated areas that there is.

My remark about the residents of the area was that people have the knowledge to argue their case, many being airport workers anyway.

Also with tracks being the same for 20 odd years people have a reasonable expectation that noise should not be suddenly thrust upon them. HAL have claimed that this trial is for resiliency not movement increase and if they genuinely have a point then it need only apply to the busy times of the day- no need to use it at all after 7 30 pm when fights on the MID route drop off radically .

I am aware that there is an element of interaction with Gatwick partially because on a clear day I can see the Gatwick inbounds, LHR outbounds and inbounds to Ockham plus a whole lot of other stuff in the sky above me soI know airspace is congested.

I have no personal axe to grind merely having been asked to help out some who are concerned and affected by the change (it has no effect on me at all where I live).

I do not understand how bringing the SAMPTON and MID tracks much closer together to the point where they are almost on the same track on leaving LHR can increase departure rates or resiliency and that there are many better ways of achieving the stated objectives by using a combination of improved navigation performance with good judgement and flexibility and neither do many other people I have spoken to in the real world and on here
Anyways I think we have all beaten the issue to death on here for now. So thanks to all for comments on the matter and that includes those who feel that LHR should expand as it wishes with no regard for anyone at all.
PB

[DaveReidUK]

Also with tracks being the same for 20 odd yearsMore than twice as long as that, in fact.

To quote from one of Heathrow's factsheets:

"NPRs [Noise Preferential Routes] were set by the Department for Transport (DfT) in the 1960s and were designed to avoid overflight of builtup areas where possible. They lead from the takeoff runway to the main UK air traffic routes, and form the first part of the Standard Instrument Departure Routes (SIDs). The routes have not been altered since they were established in order to give people the predictablity of knowing where noise from departing planes will be heard. Their location remains the responsibility of the Government. As an airport operator, BAA [sic] has no authority to change them. Any significant changes to the NPRs would be subject to public consultation by the Government."

http://www.heathrowairport.com/static/Heathrow_Noise/Downloads/PDF/Departures11.pdf

[zonoma]

I do not understand how bringing the SAMPTON and MID tracks much closer together to the point where they are almost on the same track on leaving LHR can increase departure rates or resiliency and that there are many better ways of achieving the stated objectives by using a combination of improved navigation performance with good judgement and flexibility and neither do many other people I have spoken to in the real world and on here
Exactly, as I said yesterday, all the information explaining WHY the current trials DO make an impact and improvement is contained here in this thread, you are just not digesting or understanding it. The combination of improved navigation with good judgement has exhausted its limits, perfect navigation alongside further perfect navigation (I hesitate using 'perfect' but its the only word for now that improves what you think is acceptable) is the future. There will be plenty of opportunity in the new system for earlier directs to be given so the aircraft will not always follow the SIDs completely, however, in a trial, they must ALWAYS to gain the results needed. If ATC say "no delay" to an inbound, they can expect up to 20 minutes holding. Likewise a set time is built into departure taxi times allowing for time at the holding point. During "rush hour" this is all pushed to the limit, with the new routes "rush hour" can be eased and improved, saving huge amounts of fuel, CO2s & ultimately excess noise for the immediate surrounding areas. So the environmental issue is a huge driver behind these trials.This also includes those areas where the new proposed routes are now planned as aircraft are more likely to get continuous climb so will get higher earlier & avoid noisy "level-offs" both in and outbound. There are so many variables to operating an aircraft, change may look bad but the overall effect can be hugely beneficial.

[Nimmer]

So Mr PB,

You are basically a plane spotter, who has a little bit of knowledge, but is failing to listen to those who have the full picture.

Yet the various noise groups in the area are using you as an expert??

That is dangerous.

Nimmer

[pax britanica]

Nimmer

You really are one for name calling-yes I was a plane spotter from 1965 -1967 actually.

I don't for a moment doubt that there are benefits to what is being proposed or something like it , but as another poster has pointed out if you change something that's been pretty much the same for 40 years there will be issues with some people and they are entitled to react a bit.

I do not doubt that people who are expert on the matter have looked at this in detail but by just launching into it without any thought they have caused people concerns, one example being why not only use the new method when LHR is busy as opposed to slavishly sticky by it all day. Also I think all western airports make a serious effort most of the time to take into account the concerns of those who live in areas affected by them-you seem to think that just to get a few percent increase in LHR movements it is ok to completely ignore valid concerns and questions and so as you have been happy to stereotype me, spotter, whiner etc could I ask why your stake in this game is please. And I am not acting as an expert for anyone , I was just asked to help gather some information on it, and a lot of current and ex lhr and airline people have been very helpful on that point, and I was asked to do that because I have a little bit of knowledge and can probably ask the questions more easily.

I am a regular PPrune viewer and it amazes me that people often are very aggressive and moderately insulting to all sorts of people on here which is a sad commentary on todays world . yet ironically people who really do know what they are talking about are often very generous with helpful comments or references to detailed documents. I am not saying this negative attribute applies to you , and indeed I share your view that people who live near an airport that's been around for 60 years should generally not complain but that doesn't mean they have no right to express the occasional concern.
PB

[DaveReidUK]

one example being why not only use the new method when LHR is busy as opposed to slavishly sticky by it all dayIt's presumably the fact that the trials have been operating pretty well continuously since August that has led to the recent announcement by the airport that they now have enough data to allow their early ending.

Restricting the RNAV departures to certain times of day would have required a longer duration to gather the same amount of evidence.

With hindsight, that might have been a good subject for a consultation before the trial was designed.

[zonoma]

to get a few percent increase in LHR movements
This is why some respondants get upset, it has been said several times this trial has nothing to do with increasing ANY movements what so ever. The runway slots are all used, there will be no more issued. This is to reduce delays on the ground at the holding point where aircraft sit with all engines running burning up fuel for more time than is necessary. Should these new routes pass the tests and get the go-ahead to be used, a full public consulataion will have to be completed at a massive cost before any implementation. So yes, the project are well aware of the concerns to those on the ground affected by any change but the bigger picture (or enormous one in this case) must be significant enough for the project to continue with its work.

[Norman.D.Landing]

A few quick points as I understand them.

Govt policy currently is to concentrate departures.

RNAV overlays of the existing SIDS would change the route as replication isn't possible. Therefore even 'doing nothing' things will change.

Those communities under the routes, if RNAV overlays of the existing SIDS is where this ends up, would experience concentrated overflight.

However by testing PBN track containment and 10' 15, and 21 degree splits, NATS and Heathrow are attempting to add respite to those communities by adding more routes, and sharing the traffic around them in a predictable way. I'd imagine this would be like the current arrival alternation on arrivals. These are the fair flight paths John Stewart refers to in my earlier post.

I find it amazing that HACAN and Heathrow are aligned on this. How times change. :}

[DaveReidUK]

RNAV overlays of the existing SIDS would change the route as replication isn't possible.It's perfectly possible to replicate an existing conventional SID with an RNAV equivalent.

In fact that's exactly what has been done in the case of the easterly Midhurst SIDs (MID3J/3K).

[Gonzo]

Some you can, some you can't. RNAV SIDs are designed to different criteria than conventional SIDs.

[Norman.D.Landing]

Gonzo,

Thanks for the clarification. :D

Norman.

[pax britanica]

Anyone know WHY it is Government policy to concentrate departures?

As Zonoma says there is an awfully long way to go on this , and that was underlined at the public meeting I went to last night chaired by local MP. It was stressed many times that this was a performance data gathering trial not a new route trial and that no new routes could come in without Government approval and a lot of consultation and debate

The presenters , two from HAL and one from NATs were not great-one was pretty much Ok and admitted they had badly misjudged the actual impact on the Bagshot -Windlesham area a point reinforced by a succession of heavies droning over the local hall. they were ill prepared to deal with the very informed questions about climb performance, initial clearance altitudes and the fact that many people had almost monitored the whole trial on FR24 as well as Bagshot being about 500 ft higher than LHR .

Overall though I think both sides learned something and LHR said that if and when more trials were planned there would be a lot of upfront consultation and awaress .

The presentation of the issue was generally poor and took no account of the fact that this area includes a lot of airport workers including pilots and ATC types and retired of the same ilk. Equally there were some silly questioners who went on about sleepless nights to the clear bemusement of the HAL people as basically there aren't any and never have been in the last 40 odd years except the very occasional delayed departure.

They never actually explained why they chose to concentrate flights over an area that had a reasonable amount of traffic but which was not the main or dominant path used by the MID departures. There was a lot of talk about reducing angles between initial departure routes and they have certainly brought the MID and SAM routes a lot closer together in this area.

So -on the one hand the residents groups need to keep the extremists in check(complaints about night flights, claims there has never been any noise in Bagshot, how dare the EU mandate these changes etc in order to present a credible set of concerns but also HAL, NATS and the oft referred to as the driving force for this , the CAA need to sell the concept and handle the environmental issues a lot better than they did on this showing.

[DaveReidUK]

Some you can, some you can't. RNAV SIDs are designed to different criteria than conventional SIDs.No argument with the second part of your statement.

But it's hard to imagine a set of manoeuvres involving radials, QDMs and height/climb/speed restrictions (which is a pretty good description of what a SID is) that couldn't equally be defined with fly-by fixes, tracks, level/speed constraints and path terminators (i.e. as an RNAV1 SID).

Which ones did you have in mind that can't ?

[Comms Monkey]

Gonzo is absolutly correct, some conv SIDs can be replicated some can't. As no one in the UK has actually tried to replicate all the conv SIDs I have no idea which are replicable and aren't. It would cost quite alot to do that. I have been told by a procedure designer that it isn't possible and it's down to the actual PANS OPS criteria used to design RNAV procedures. I would bet that any conv SIDs that have sharp large turns would be tricky to replicate without the use of RF for example.

Going back to PBs question: "Why have MID & SAM Easterly SIDs initial tracks been changed to be the same?"

The official departure interval between conv SAM and conv MID SIDs is 3 mins, because the conv easterly MID SID ballons further east of the conv SAM SID track. If you make the initial SID tracks the same, as has been done with the trial RNAV SIDs, the departure interval may be reduced to 2 mins. Basically giving the TWR more flexibilty and decrease delays at the runway holding points.

[Gonzo]

Comms Monkey, I think the OP is talking about westerlies, not easterlies.

[Cough]

Amazing how many conventional SIDS seem to have been replicated at LGW!

(Not talking ANDIK!)

[Norman.D.Landing]

With ref to Pax Brit comment above. When you talk about well informed questions, does that include the one where the questioner asserts that aircraft over Bagshot are closer to 300ft, yes 3 hundred feet, than the 5-7,000ft the panel suggests?

:=

[DaveReidUK]

Amazing how many conventional SIDS seem to have been replicated at LGW!Indeed so.

I would bet that any conv SIDs that have sharp large turns would be tricky to replicate without the use of RF for example.

Note the > 180° turn that forms part of the LAM1X SID (RNAV1 equivalent of the conventional LAM4M SID).

No RFs involved there, only TFs.

[Crazy Voyager]

I thought (feel free to tell me I'm wrong) that you could replicate conventional SIDs with RNAV, but due to the improvement in track keeping when PBN is used the actual result for residents won't be the same as with conventional SIDs.

For example, if you have a turn on a conventional SID aircraft will natrually disperse over a wider area, due to the "inaccuracy" of conventional navigation compared to RNAV.

With an RNAV SID every aircraft will follow a much narrower corridor (less dispersal) which means that even if you try to replicate the original SID track the new RNAV procedure will concentrate traffic into a smaller area. This in turn will concentrate overfligths (and therefore noise) to a smaller area. Cuasing more respite for some residents but leading to an increase in noise for the ones directly under the new corridor.


Obviously all the above could be a load of rubbish though.

[DaveReidUK]

Obviously all the above could be a load of rubbish though.Well it could be :O, but I'd say it sounds like a pretty reasonable summary of the effective difference between PBN/RNAV navigation and the conventional ground navaid-based equivalent.

Those differences aren't specific to SIDs, that's just where they are more apparent.

And of course it's the ability to perform more accurate track-keeping that has been the driver for the recent trials, as previous posts have explained and with the effects on communities that have been noted.

[HEATHROW DIRECTOR]

<<the questioner asserts that aircraft over Bagshot are closer to 300ft, yes 3 hundred feet, than the 5-7,000ft the panel suggests?>>

I've not been following this thread - too complex for an oldie. However, that sentence caught my eye. Back in the 80s(?) it was my misfortune to have to entertain members of a noise group together with their arrogant and stupid leader. He told me that aircraft were flying down Windsor High Street at 500 feet. I showed him the SSR labels on the radar which suggested that they were over 1000 feet higher than that. He announced to his cronies that I had "fixed" the radar!!! That's the sort of idiot one has to deal with.

[DaveReidUK]

the questioner asserts that aircraft over Bagshot are closer to 300ft, yes 3 hundred feet, than the 5-7,000ft the panel suggests?Fortunately, there is a podcast of the entire meeting now on the net. At no point does anyone assert that aircraft fly over Bagshot at 300' (which would be rather difficult, given that Bagshot is 450' AMSL).

I have no idea where the OP got that idea from - there is a reference to tracking aircraft on FR24, and some having been noted at three thousand feet.

Heathrow Airport Trials Public Meeting ? 10th October 2014 | Surrey Heath Residents Blog (http://surreyheath-residents.co.uk/2014/10/11/heathrow-airport-trials-public-meeting-10th-october-2014/)

[118.70]

<<Aren't all the holding stacks due to vanish with the introduction of "Point Merge"?>>

Looking forward to watching that!From Appendix A.3

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/372488/noise--local-assessment.pdf


3.34 It is understood that Point Merge will not be taken forward at
Heathrow due to the limitations on the use of vectoring.
HD will be disappointed after all !

[chevvron]

Not fair!
Even though the 'trial' has finished, the departures are still passing several miles to the west of us instead of overhead, thus making our evenings quiet and 'empty' except after about 10 pm when they do seem to pass overhead.

[kcockayne]

Not only HD ! There are several of us who would want to watch Point Merge in action!

[Doug E Style]

Me too. If nothing else it would make a pleasant change from all the hours I spend every year in the holds at OCK, BIG, LAM and BNN.

[pax britanica]

As the opener of this particular can of worms I should apologise for the 300ft issue-it should read 3000 ft just a typo.

The trial definitely ended earlier than the revised date as various A320s bound for Midhurst started to appear over Camberley after November 1, and some of the late night heavies once again appeared well north of the trial track.

The issue will go on though because of the inept way HAL handled it especially coming up with tracks that meant all MID and SAM tracks went over Ascot, This will mean that less people will be inclined to support a third runway at LHR which is a shame because LHR is vital to the economy in the M3/M4 region.

On the other side of the coin there are still idiots complaining about 'streams of aircraft going overhead at Midnight' which of course just doesn't happen

And finally, I am right in reading that 'point merge ' will not be used at LHR and so arrival patters will stay much the same?

PB

[DaveReidUK]

And finally, I am right in reading that 'point merge ' will not be used at LHR and so arrival patters will stay much the same?The statement re point merge quoted in post #57 was from the CAA ERCD, and was purely in the context of their modelling of the proposed LHR NW runway scheme - I don't know if applies to other scenarios.