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147break
14th Jul 2004, 10:55
Anyone throw any light on this?

Teletext - Heathrow Noise Reduction (http://www.teletext.co.uk/news/story.asp?intArticleID=67466&intarticlenumber=2&intRegionID=7&intSubsectionID=1&From=I&indent=30)

Good idea or bad (i.e. Safety, what difference is 140ft going to make)?

147...

ETOPS
14th Jul 2004, 12:01
This would involve insetting the landing threshold by about 900 metres - a little like they tried at FRA a few years ago on 25L. Only trouble is it might compromise landing performance of some of the larger types so could be restricted to "shorthaul" Boeings, Airbus etc........

fruitbat
14th Jul 2004, 12:09
from BBC

Noise levels from planes above London could be cut after new landing plans were proposed by British Airways (BA).
The airline has suggested that landings should be made half-a-mile further down the runway at Heathrow airport.

This would allow planes to fly about 140ft higher over London, cutting noise levels for people who live near to the west London airport.

But critics say BA's plan published in its annual social and environmental report will make no difference to most.

Currently planes normally land only 150 yards from the beginning of the runway at Heathrow.

This plan is deceitful with a capital D

John Stewart, from Hacan Clearskies
BA chief executive, Rod Eddington, said: "The success of our business is not just about financial performance.

"It's also about gaining customer and employee loyalty and community trust.

"While we have made improvements in our environmental, social and economic performance, there are many challenges ahead and we are committed to manage responsibly and report openly about our performance."

But John Stewart, from Heathrow Association for the Control of Aircraft Noise (Hacan) Clearskies said: "This plan is deceitful with a capital D.

"Unless you live within a few hundred yards of the airport, the fact that planes are 140ft higher makes no significant difference to the noise you hear.

"The plan is simply designed to make it easier for both runways to be used at the same time."

eal401
14th Jul 2004, 12:24
But John Stewart, from Heathrow Association for the Control of Aircraft Noise (Hacan) Clearskies said: "This plan is deceitful with a capital D.
As if he'd say anything else to any suggestion (apart from closing LHR of course!).

Point Seven
14th Jul 2004, 13:12
And exactly how does it amke it easier for both runways to be used at the same time - as they are now anyway?

P7

:confused:

M.Mouse
14th Jul 2004, 13:49
Only trouble is it might compromise landing performance of some of the larger types so could be restricted to "shorthaul" Boeings, Airbus etc

It would reduce the runway to the length of LGW's main runway, I don't believe landing at LGW is a problem.

Pax Vobiscum
14th Jul 2004, 14:34
Times article: here (http://www.timesonline.co.uk/article/0,,4484-1178846,00.html)

It makes it clearer that John Stewart of ClearSkies believes it is "paving the way for mixed mode operation", whereby both runways are used for takeoffs and landings, rather than segregated into one runway for takeoff and one for landing as is the norm at present. Presumably this would allow a significant increase in capacity?

ATCO Two
14th Jul 2004, 14:35
If the Westerly thresholds are displaced, the turnoffs will be in the wrong places for maximum runway utilisation. This will reduce capacity as increased spacing would be required, and also severely limit any benefits to be gained from mixed mode operations.

ETOPS
14th Jul 2004, 15:25
M.Mouse

Not a problem for you - you're a Skygod, but have you ever seen some of the efforts the other guys put in? Saw an A340 from an "eastern" carrier performing a low flyby recently - nice touchdown (eventually) but a displaced threshold was the last thing he wanted.........

Jerricho
14th Jul 2004, 15:35
One way to reduce noise around Heathrow?

Stuff a sock in John Stewart's mouth.

Roobarb
14th Jul 2004, 17:24
Any document bearing this manís signature is likely to be followed by a retraction, correction, and deletion.

http://www.sausagenet.freeserve.co.uk/roobarb/roobarb_laugh.jpg

Iíll take on the opposition anyday. Itís my management I canít beat!

Not Long Now
14th Jul 2004, 20:17
So I suppose it never crossed anyone at BA's mind that if they displaced touchdown a bit to the west they'd end up a bit closer to T5 a bit quicker....
or is that purely coincidental...
will they be offering to do this on easterlies as well, help out queenie when she's at Windsor castle...

hmmm...

toon
14th Jul 2004, 20:53
So please tell me they are not seriously suggesting that a/c land further down the runway ?? nnnnaaaaaahhhhh, don't belive that one ! for one thing,come the subsequent enquiry when said a/c runs off the end and presumably being flown to sopa's as laid down in the manuals (sanctioned by the management) d'management would be held personally responsible !! That's taken to the eennth degree presuming they find a pilot stupid enough to do it (doubtful) !

oh, better idea for BA, why not move the whole runway by 1/2 a mile !!!

There ain't nothing as useless as the runway behind ya !!

J-Class
14th Jul 2004, 22:25
This is a stupid idea and I would be one pax petioning to make sure it doesn't happen. I like flying on planes which are allowed to use all the tarmac available, thanks very much. And I agree that given the number of floaty landings one experiences, one doesn't want to reduce the space available.

fescalised portion
14th Jul 2004, 23:48
I guess that would mean putting in a new glideslope antenna halfway down the runway. I can just see the guy in the tower during CAT 3, switching between the two, depending what's on approach.

ponshus
15th Jul 2004, 08:27
Are the little darlings intending to displace the landing threshold so far down the RW that another aircraft can line up for takeoff at the full length point underneath the lander?


If so, selling it as a nice to the neighbours noise reducing programme when the real intent is to massively increase runway utilisation and thus noise, has got to be the most dishonest ploy of the year. Also one of the more cynically dangerous, no doubt hatched up by a bean counter with shares in the local undertakers company.

:{

Basil
15th Jul 2004, 23:05
ponshus,
As a first posting may I say that your trivial little piece lacks style, elegance and is a tour de force of paranoia!!
Anything we can do to reduce the noise pollution of the environment for those who have recently moved to the Heathrow approaches is to be applauded and not treated in the derogatory manner which you seem to present yourself.
Your crass suggestion that anyone could be so base as to engineer an accident to benefit the local undertaker defies belief.
I wonder if the BAA is aware of your gross slander!!!

Hello?? :D :D

Captain Airclues
16th Jul 2004, 21:18
Basil

Should it not be 'libel' rather than 'slander'?

Anyway, how many times did I warn you not to buy that house in Cranford?

Airclues

Basil
16th Jul 2004, 21:34
Just testing old boy ;)

(as Timbertop used to say - for the ex GF boys)

woodpecker
16th Jul 2004, 22:02
What was it again?

Fuel in the bowser, height above you and runway behind you!

Who is actually advising Skippy? Bring back Porky! No, no forget the last suggestion.

Human Factor
26th Jul 2004, 23:52
Good stuff. He must have been to Rhein Main as well then!

Admittedly, I think it was used there for different reasons although I don't ever recall using it myself, despite having been there a zillion times after it was introduced.

Jerricho
27th Jul 2004, 00:16
As much as I miss the old girl, does anybody else see the irony of a thread about LHR noise and Speedbird002 ;) ;)

Seriously though, it was discussed a bit here (http://www.pprune.org/forums/showthread.php?s=&threadid=137563)

But I do actually have a question for our pilot guys and gals reference the whole idea. How will it effect minimum runway occupancy time, especially during really busy sequences and ATC need jets off the runway ASAP?

Gonzo
27th Jul 2004, 04:00
Noise? It's just a BA ploy to enable them to roll out long to vacate near T5 on Westerlies......

toon
27th Jul 2004, 06:53
no !!! surely not, landing further down the runway ??? just a publicity stunt, no self respecting pilot would allow that, idiotic managers again i'll wager ? it's about time they found something that generates cash to do !!!

incidently, is it already policy at luton ?? what, over the fields on 26 ?? maybe abit quieter for the sheep !!!, have yet to see anything on the airport plates that tells me to land a 767 further down a 6808' runway !!!

Pub User
27th Jul 2004, 09:01
This can't be correct surely? The only way to organise it would be to displace the threshold, along with the PAPIs and ILS/DME.

At LHR it may not be too bad, but at smaller airlields the greatly increased risk would be unjustifiable, just to add a few feet to the flight path of a LANDING aircraft.

I don't know where he got the idea that this is policy at Luton, perhaps he's watched the odd Cessna land well down the runway to save taxy time.

Clearly a glittering career in airline management is awaiting this young man.

HEATHROW DIRECTOR
27th Jul 2004, 09:39
Can 140 feet make that much difference to the noise footprint? I seriously doubt it. And did that guy properly research the implications, some of which have been mentioned here and on another thread? Again, I doubt it. Either the ILS glidepath has to be moved or ATC procedures might have to be revised to take account of some aircraft flying 140 ft above expected altitudes.

How about changing the the glidepath angles on the main runways to 3.5. That way aircraft over London would be considerably more than 140 ft higher... What effect would that have on normal aircraft operations?

arfur-sixpence
27th Jul 2004, 10:07
At LHR it may not be too bad, but at smaller airlields the greatly increased risk would be unjustifiable, just to add a few feet to the flight path of a LANDING aircraft.
there was no suggestion of doing it on short runways - just long ones (like LHR) where there is plenty of runway to spare for anything other than a 747 at max landing weight.

I guess it would need each runway to have two ILSs - but that should be manageable. Just ensure that they have clearly distinguishable idents (unlike IRR, ILL and IAA!).

ukeng
27th Jul 2004, 10:32
The plan is to move the ILS (glideslope only) beam to accomadate. Anyone living in close to the threshold will no doubt benefit even if it is only 140ft.
Having said that I live about 10 miles from Heathrow and you lot still make a right racket flying overhead :D

Carnage Matey!
27th Jul 2004, 11:58
Having a 3.5 degree glideslope would make even more noise because the only way you could slow the aircraft from 180kts to 160 kts would be to put the gear down early!

ZQA297/30
27th Jul 2004, 12:44
UK Eng, you are right.
I just spent several days with friends who live on the north side of Clapham Common. This seems to be the point many arrivals for the south runway are vectored to intercept final. Although I have flown over it many times, I was not prepared for how annoying it is on the ground to have an aircraft pass overhead every 60 seconds or so. It is like having someone vacuuming in the room above for hours on end. Not deafening, but very annoying.

When I overflew the area I followed the recommended noise reduction profiles, but I did not fully appreciate how much noise an aircraft produces even at 3 thousand ft or more, especially on a still day.

My friends bought the house having viewed it on a day when wind etc made the noise much less noticeable, and they thought they could live with it. They are now having second thoughts.

I am sure that any noise reductions achieved for whatever reasons valid or specious, will be appreciated.

747FOCAL
27th Jul 2004, 14:24
HEATHROW DIRECTOR,

The only thing that will be able to tell there is less noise is the monitors. No human can tell the difference in loudness of 2 events that are within a dB or two of each other, only a computer can. A 747 that is 140 ft higher may have noise reduction of maybe a dB. Unless it is an RR powered one.............:E

ZQA297/30,

At 3000 ft most aircraft are pretty quiet and will not be heard in a closed up house. You may notice some of the louder ones when outside doing yardwork or womething. There is a slight difference between an aircraft on approach and one on takeoff.

:)

egld0624
27th Jul 2004, 16:02
A possibly more likely glide slope/STAR/SID phenomenon in Europe proposed....

A more likely phenomenon from recent discussions at EBACE, Geneva in May et al from the European Aviation Safety Agency affecting glide slope approaches into main European hubs in the future will be the complete removal of low altitude holding patterns, entry points etc. The proposed long term goal described is to effectively go the other way on the glide slope:

i.e. simplify class airspace; produce high altitude entry points with a/c going down a theoretical glide slope at say FL250 (and way beyond/above that FL) at a 3 degree approach before joining the real glide slope lower down. (Long haul would join the slope at a lot higher up than local or short haul traffic). This would, as was argued, produce a 1 line straight-in approach in and out of airports.

- At least thatís the theory proposed for a simpler approach to landing and I wouldnít be surprised to SIDís as well as STARís

Ö.But knowing how quick & dynamic most of our EU governmental institutions are, I canít see this happening for at least 10 years.

I appreciate that this is different to the above proposed BA issue at EGLL but reducing lower altitude a/c from circling, hopefully is a more realistic approach to keeping the "noise down" than a shift of 140ft as well as more fuel management friendly too.


Apologies, if this is all old hat.

Kind regards,


EGLD0624 (@ 4.5 degree approaches.)

HEATHROW DIRECTOR
27th Jul 2004, 17:42
747FOCAL - I agree entirely and my posting about 3.5 glidepaths wasn't wholly serious. Watching the Farnborough Air Show my wife and I both commented on the difference between modern jets and those of yesteryear - VC-10, BAC-11, 707, etc. The overall noise is very considerably less now than it was in those days so it's difficult to know what would be needed to appease the anti-noise lobby.

ukeng
27th Jul 2004, 18:53
747FOCAL - you're quite right about the noise. I rarely notice them anymore when buttoned up inside my hovel but being summer and all that we have the doors and windows open a lot.
Not complaining though seeing as i'd be out of a job without them but I am glad to see the back of the flying pencil - now that was loud windows open or shut :ooh:
I scoffed at first seeing BA's proposals but unless it's all spin and hot air I really can't see any disadvantages...

BahrainLad
27th Jul 2004, 19:00
Coincidentally I spent the weekend staying just north of Clapham Common as well. The noise is almost continuous throughout the day, but within about 10 hours you get used to it. It certainly didn't disturb me lying in bed in the mornings and I had all the windows open.

In fact, according to my hosts, the best thing about the "long, pointy thing" was that it broke up the monotony of 747s/777s/330s rumbling across all day by providing something worth looking at! :ok:

mocoman
28th Jul 2004, 00:08
Sound, in a similar manner to light, is subject to an inverse square law.

This means that the intensity of a sound at a given level 'L' at distance 'X' from the source will be level 'L/4' at distance '2*X'.

Sound intensity and power however are also measured using a logarithmic scale; therefore 90dB is ten times greater than 80dB.

Since we are talking about a phase of flight that involves heights of 0-3000ft and a nett difference of 140ft on any part of the glide over the course of an approach, it seems that the suggestion would only have any noticable effect towards the final part of the approach.

The following calculates the difference, in dB, between the 'reference' sound (at current heights) and indicates the reduction obtained at the proposed heights. (I have rounded the difference in heights involved up to 150ft)

At the start of the final approach phase the difference between 3000ft (factor '1') and 3150ft (factor '0.91') is quite small.
intensity reduction=10log(0.91/1); result=-0.4dB

However, Taking the end of the final approach and landing phase; 300ft (factor '1') and 450ft(factor '0.44') the difference is rather more substantial.
reduction=10log(0.44/1); result=-3.6dB

Nevertheless, even such a reduction, AT OR CLOSE TO DECISION HEIGHT, would be only just noticable to human hearing under standard conditions, while ignoring any other ambient noise.

As we all know the area around EGLL would of course be perfectly silent if it were not for the aircraft (Yeah; right<vvvbg>).

Intensity Reduction Summary:
3000/3150ft : -0.4dB
2500/2650ft : -0.5dB
2000/2150ft : -0.6dB
1500/1650ft : -0.8dB
1000/1150ft : -1.2dB
500/650ft : -2.3dB
300/450ft : -3.6dB

A Quick Quote:
"As a general rule of thumb, depending on the sensitivity of the listener, most people will perceive a 3dB improvement as just noticeable, a 5-6dB improvement as very noticeable and an 8-10dB difference easily a halving of the sound level."
©Custom Audio Designs 2000

I would suggest that ulterior motives are examined and dissected.
:8
Please correct me if I'm wrong

747FOCAL
28th Jul 2004, 14:41
Not sure about your math there at the end. I believe the 0.4 dB at 3000 ft, but I think it would remain constant all the way down.

Most human better be able to tell the difference between 2 events that have 3 dB difference or they need to get their ears checked.

I agree with you though, the reduction gained for the increased risk of buying the street if you run over is not worth it. Me suspects there is more to this than meets the eye. :hmm:

ZQA297/30
29th Jul 2004, 00:24
To change the focus slightly.
Are displaced thresholds a rarity? I seem to recall both JFK and MIA having significantly displaced thresholds on at least one runway each.
In fact, does not MIA conduct LAHSO operations on a runway with a displaced threshold? ( The old 9R that intersects 12) Its been a while so I could be wrong.

slingsby
29th Jul 2004, 17:49
Next sim session lesson plan includes the Kasan (kaisan?) C130 style approach.
Seriously, maybe, BAA should evaluate (at cost) purchasing the affected properties according to Db levels. 80Db would get 80% of the cost of their house paid for, 90db = 90% and so on. The further out the lower the level of purchase price. Some people would then get back a substantial reimbursement of their home, yes I must say there would be some draw backs, but the overall cost would be significantly lower than all of the public enquiries and consultation papers put together.
Having lived very close to LHR and even listened to the rantings of HACAN once (nearly ended in bloodshed between themselves) I can say a certain individual has dug himself a huge cesspit and can't get himself out of it without losing face. HE will keep on and on until he gets his way or is on his way.
Oh, by the way, I used to live 2 miles south of LHR and on easterly ops, all the Compton departures used to clatter over my house at around 1500ft, beautiful, low and very noisy, now I live 10miles west and 5 miles south, different levels and I still love it.

mocoman
29th Jul 2004, 22:35
@747FOCAL

I understand your scepticism; probably 'cos I didn't explain properly.

Let's assume that your aircraft, at 160kts landing configuration is measured at 120dB at 200ft away from the measuring device.

Therefore at 400ft (double the distance) away the sound level will be 1/4 of the level at 200ft.

As I indicated the dB scale is a log scale therefore a reduction factor of 4 in sound level would only equate to a reduction of 6dB; meaning a reading of 114dB at 400ft from the aircraft.

However, move the measuring tool to a distance of 600ft from the aircraft and now you have a sound level that is 1/9th of that measured at 200ft; giving a dB reduction of around 9.5dB and a reading of 110.5dB on the equipment.

What I was trying to convey was the fact that, as you continue down the glide, the difference between the 'old-rules' altitude and the 'proposed-new-rules' altitude remains constant; but that the difference (I used 150ft in my example) becomes a greater proportion of the distance to the measuring equipment (punters or residents included) as you descend.

Therefore the difference in sound levels between the existing and proposed approach paths WILL increase as you approach the notional threshold.

However, as I wrote earlier, the only folks to knowingly benefit (...maybe :p) from such a reduction (in sound-level terms) would have to be VERY close to the runway threshold.

:8

arfur-sixpence
30th Jul 2004, 08:43
Didn't a fairly recent Airbus study indicate that a significant amount of noise on the approach is generated aerodynamically - maybe even equalling the amount of noise generated by the engines?

In that case, and anyway recognising that late on in the approach when dirtied up the engines run at higher settings, that means that it is the people living near the bottom of the ILS who get the worst hit.

In that case, surely this idea would give a significant improvement just where it is needed most and has to be worth serious consideration. Very few of the aeroplanes landing at LHR are likely to be at max landing mass/weight and even if they were I would expect a 747-400 at max landing mass to use less runway to land than the same aircraft uses to get airborne at max take off mass.

Meanwhile, Airbus (and hopefully Boeing) are looking at reducing the noise generated by landing gear, flaps, undercarriage doors, brake hydraulic pipes etc. Less aerodynamic noise = less drag = lower power settings = even less noise.

747FOCAL
30th Jul 2004, 17:15
mocoman,

I understand distance doubling and I still think you are being very generous. Very close the the airport eh noise will be so great from the aircraft that 140 ft will mean nothing. Maybe far out, the noise reduction will be just enough to drop the aircraft noise below the 65dB noise floor and then you no longer can hear the aircraft, but up close it will still sound like you are having a train come through the roof. :p

mocoman
31st Jul 2004, 23:39
Very close the the airport eh<sic> noise will be so great from the aircraft that 140 ft will mean nothing

Yep; I agree. Which is why I previously suggested that there are other 'forces' at work here.

:8