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LHR - Steeper Approaches trial 14 September 2015

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LHR - Steeper Approaches trial 14 September 2015

Old 11th Aug 2015, 22:39
  #41 (permalink)  
 
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Guys: I admit to not having read the whole discussion. Mea culpa.
I was operating out of a very noise sensitive EU airport for many years. Many major airports had a published low drag CDA profile. Having arrived from a UK operator, and been well taught, my standard profile was CDA low drag. My new local colleagues were not of the same thinking. There was no such philosophy in their region and no published CDA criteria. I battled to introduce it in the airline. Difficult. However, ATC didn't help with their early descents instructions. The ILS platform was 2000'agl. and my F/O's were dragging it in. At night ATC used 3000' for G/S intercept for noise reasons. I asked then why that wasn't also for daytime use. "Because it wasn't in the regs". I now sit and watch a/c drag it in at 2000' all day long. Daft for fuel, daft for noise, daft for environment. The locals are always complaining about noise. Why not raise the ILS platform to 4000'agl? The a/c are arriving from every which direction. If ATC want to cut you in short for spacing reasons, then they can ask for a CDA to whatever finals they need. Why is CDA not a universal airport thing? I've flown for airlines where CDA was SOP. I've flown into German airfields where low noise low drag CDA is published. Why is it not universal practice? This 3.2 slope instead of 3.0 slope is a piss in the pot for noise reasons. Start the slope at a higher height and keep idle thrust till 3.0nm. No level drag in. 3.0 or 3.2 from 6 or 8nm out is a gnat's cock of difference. 3.2 from 2500' agl or 3.0 from 3000' agl. Without the science I can almost guarantee that the latter is less noisy; from 3500' even less so. Is this experiment just another political sop to the uninitiated?
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Old 12th Aug 2015, 07:39
  #42 (permalink)  
 
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Originally Posted by RAT 5 View Post
I've flown into German airfields where low noise low drag CDA is published. Why is it not universal practice?
Heathrow typically reports 85-90% CDA compliance.
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Old 12th Aug 2015, 07:52
  #43 (permalink)  
 
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RAT 5, exactly the same experience here. I came from a UK operator who pushed the CDA concept very firmly indeed. When I left, I then took the same practices out to a European operation. The looks on the faces of the captains there when I selected V/S and told them I was trying to achieve a CDA was quite the picture. It's a cultural thing, they just don't get it. The amount of them who used to fly the platform to glideslope interception in Luton in blatant disregard (or ignorance) of the requests for CDA's there was quite something.
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Old 12th Aug 2015, 10:58
  #44 (permalink)  
 
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Quote:Heathrow typically reports 85-90% CDA compliance.
Only for the portion below TL. And dragging it in at 300 feet/min is called CDA.
I think it's a bit weird, but your country and your rules.
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Old 12th Aug 2015, 13:24
  #45 (permalink)  
 
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I live near Heathrow and bought my house in 1986. I got copies of the official approach and departure tracks (I still have the dye-line print) to make sure I was away from the flight paths. An ATC told me they were very unlikely to change. In 1986 there were very few flights after 8.30 pm at night. Since that time the departure tracks have changed and the number of flights has increased by 50%. Most of the extra flights are in the early morning and late into the night.

When I bought my house aircraft noise (and pollution related to the airport) was not an issue for me.

Please can we drop the argument that says 'you bought there so it is your fault'? When I bought it was reasonable to assume I would not be bothered by airport noise. I am. The air was clean. Now it is not.
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Old 12th Aug 2015, 13:30
  #46 (permalink)  
 
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I bought my house next to a quiet railroad ;-)
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Old 12th Aug 2015, 13:32
  #47 (permalink)  
 
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Guys and Girls please also note that 160kts to 4nm etc is an ATC request, if you accept then you have to fly it.
If you cannot for any reason tell them, and tell them what speed profile, i.e. 160 to 5nm you can accept.
Remember you are in charge of the machine not them. I know that we follow what they say usually without question, and it works well. But at the end of the day the buck stops with you.
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Old 12th Aug 2015, 14:08
  #48 (permalink)  
 
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Originally Posted by SLF3 View Post
Please can we drop the argument that says 'you bought there so it is your fault'? When I bought it was reasonable to assume I would not be bothered by airport noise. I am. The air was clean. Now it is not.
I don't think anyone has used the word "fault". But you did buy your house, as you say, near to the largest and busiest airport in Europe, then and now. I'm sure many other things have changed in the last 30 years. The open space you recall kids playing on now has houses on it. What was an easy drive now had traffic signals all along and takes three times the duration. Your house, from its prominent location, is now worth 10 times what you paid for it. Such is life.
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Old 12th Aug 2015, 14:43
  #49 (permalink)  
 
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"Guys and Girls please also note that 160kts to 4nm etc is an ATC request, if you accept then you have to fly it."

Actually it's an instruction not a request.


"If you cannot for any reason tell them, and tell them what speed profile, i.e. 160 to 5nm you can accept."


Absolutely. And please remember all requests to deviate from the norm should be made in good time (eg. Downwind) and not when there's some one else 2.5 miles behind you.


"Remember you are in charge of the machine not them. I know that we follow what they say usually without question, and it works well. But at the end of the day the buck stops with you."

Whilst I agree wholeheartedly with the sentiments there would have to be a valid reason. Repeated requests for non standard speeds would be noticed by the airport operator and I imagine your employer would be asked to justify any consistent non compliance.

We can't have the tail (one aircraft) wagging the dog (the entire airport operation) can we?
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Old 12th Aug 2015, 17:58
  #50 (permalink)  
 
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LHR - Steeper Approaches trial 14 September 2015

If people didn't routinely do 160/4 then I would imagine the whole heathrow operation would fall to pieces. It's easily doable. However in less than ideal conditions you will sometimes be doing it with gear and flap and dragging it in. The increased angle and 160/4 is a less than ideal condition, so unless there's a strong headwind I'll be dragging it in and it'll completely negate the trial.
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Old 13th Aug 2015, 15:01
  #51 (permalink)  
 
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Originally Posted by ImageGear View Post
It's a cheap attempt to "sell" the third runway to already hacked off residents - nothing more, nothing less. Looks good as a news item but has no legs - it won't live past it's "sell by" date.

Imagegear
I agree.
The third runway will itself greatly increase the risk of hazard to London reducing safety. Adding a steeper approach to further increase risk is small bear in comparison. However, it is obvious that commercial/political goals have more attraction than safety.
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Old 13th Aug 2015, 16:34
  #52 (permalink)  
 
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Heathrow released some more advance information on the forthcoming trial a couple of days ago.

Among the salient points:

- Average usage of the current 3 RNAV approach is around 5 arrivals per day (Feb/Mar 2015), almost all BA and mostly A320 family aircraft

- "Broad engagement" re the trial, with positive results, has taken place with: AF, AA, DL, SR, UA

- Specific impacts of the trial to be measured are on: separation, CDAs, runway occupancy times, go-arounds, speed control, joining point, noise (the latter to be measured under the 27L approach)

- "No differences recorded" for pilots who have flown the 3.2 approach in the sim, though pilots who have not done so are "expecting significant changes to the approach speed and the ability [to] carry out a continuous descent and LP/LD approach"

- No expected change for ATC except for familiarisation with the process

- From the ground "visually the aircraft may appear slightly higher and quieter" [sic]

http://www.heathrow.com/file_source/...oach_trial.pdf
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Old 14th Aug 2015, 00:02
  #53 (permalink)  
 
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LHR - Steeper Approaches trial 14 September 2015

Ok not a pro here but does that 0.2’ really have a measurable impact ? Seem very minor to my untrained eyes...
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Old 14th Aug 2015, 00:04
  #54 (permalink)  
 
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Isn't this just a test case for developing even steeper approaches that could pave the way for us seeing a small number of movements during the night? In such cases, flow rates would be small and 160 to 4 would be less of a significance.

I can't speak for others but for us at Emirates, our illustrious leader has for many years commented on the need to develop steeper approach technology to enable night time operations at Heathrow. We have seen the A318 handle the 5.5 slope at London City so it begs the question if we will ever see a A380 fly a RNAV approach, with a profile of more than 3.5 degrees.
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Old 14th Aug 2015, 05:41
  #55 (permalink)  
dkz
 
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Still, no answer on the wake turbulence issue. A "super" on a 3.2 degree RNAV and a min separation "heavy" with light winds
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Old 14th Aug 2015, 07:47
  #56 (permalink)  
 
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Originally Posted by Emma Royds View Post
Isn't this just a test case for developing even steeper approaches that could pave the way for us seeing a small number of movements during the night?
The first part is certainly true - Heathrow have said that "we believe approaches of up to 3.5 degrees are feasible in the longer term".

I'm not aware of any connection between that and a relaxation of the Night Quota (which would need Government approval).
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Old 14th Aug 2015, 09:08
  #57 (permalink)  
 
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"No differences recorded" for pilots who have flown the 3.2 approach in the sim
Sums it up really... Sim is a great academic tool, but poorly reflects reality e.g. shifting winds, ATHR mind of it's own. It's also why the ATC view of "you must tell us if you cannot do 165 to 4" early on is impractical.

It's only once on the approach, EAI? winds? that how feasible 160 to 4 comes, if you want the minimum noise technique. 160 to 4 is easy - just drop the gear when slowed from 180, with F2 and up comes the power.

As those familiar with the A320 series know, the quietest / most fuel saving approach is actually about 1/2 dot low at 180K F1. When ATC ask for 160 to 4, reduce V/S take F2, decelerate and inc the F2 "balloon" you can remain at idle all the way to ~1100R. That is feasible on a VMC ILS/MLS.

On an RNAV it is not feasible really - you need to fly the correct vertical profile, so the 180K to 160K decal is a challenge at 3deg if you want to be quiet during the 160K portion.

But as others have pointed out, the trial has likely already been written up as a success, and winter RNAV 3.2deg is likely lower than ILS 3deg anyway
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Old 14th Aug 2015, 10:00
  #58 (permalink)  
 
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this paper is a relatively thorough theoretical discussion of various aspects of a 3.2 ILS slope in Frankfurt:

https://www.ff.tu-berlin.de/fileadmi...g_Schubert.pdf

The theoretically predicted noise benefits due to a 3.2 glide slope angle were confirmed in the full flight simulator study. However, the benefits were slightly smaller than expected. Only direct noise measurements from real flight operation will provide the final proof.

the subsequent 2 year trial in Frankfurt showed a clear reduction in the maximum sound level ranging between 0.5 and 1.5 dB (A) depending on the monitoring station and the aircraft type.

0.5 to 1.5 dB reduction isn't a whole lot, but it's more than what newer aircraft/engines have contributed for arrivals over the last decade, as a lot of the noise is from the airframe. Evidence also suggests the noise footprint area is reduced by about 5-10% for every 0.25 degree increase in glide slope (...and I can hear some people asking "so where will this end?", but due to aircraft certification limitations I think that's not a realistic debate now).

Last edited by deptrai; 14th Aug 2015 at 11:37.
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Old 14th Aug 2015, 11:14
  #59 (permalink)  
 
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Who wrote this ?

The document issued by Heathrow [http://www.heathrow.com/file_source/...ach_trial.pdf] is a very poorly-scribed piece of work indeed, peppered with errors in both grammar and syntax, and does not to my mind represent the (hopefully) more clear thinking behind the project. It's a shame that Heathrow could not apparently run to the expense of having a literate person proof-read the document prior to publishing it. End of rant - back to mowing the grass.
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Old 14th Aug 2015, 14:51
  #60 (permalink)  
 
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3.2 is not a big issue, but cda + 160 to 4 and F3 can give you problems in light or tailwinds. Easy option, ditch F3 and land like Airbus intended FFull!
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