mptpa
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UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 12:23 am

Just in.... CAA putting in new classification for A380 separation on take-off and approach. Article here.
http://www.flightglobal.com/Articles...ke+vortex+category+for+Airbus.html
 
OldAeroGuy
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 12:57 am

Interesting that the UK-CAA is keeping the arrival separation between two A380's at 4nm, the same as two existing heavies. The Steering Group findings would have allowed the trailing A380 to close to 3nm.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
NYC777
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:00 am

Well this is more bad news for the A380.
That which does not kill me makes me stronger.
 
Poitin
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:01 am

So Three Minutes after A380 take off. That should really speed things up at LHR.


    Minimum radar separation during approach and departure will be 6nm (11km) for a trailing ‘heavy’ aircraft, 8nm for a ‘medium’ or ‘small’, and 10nm for a ‘light’ aircraft.

    While the steering group concluded that the A380 itself did not need to be subjected to wake constraints while in trail, the CAA will impose a minimum 4nm separation between two A380s.

    Non-radar separation for aircraft arriving behind an A380 will be kept to 3min for ‘medium’ and ‘small’ types, and 4min for ‘light’. Departure separations will be 3min for ‘medium’, ‘small’ and ‘light’, reduced to 2min for non-A380 ‘heavy’ aircraft.
Now so, have ye time fer a pint?
 
zvezda
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:07 am

The interesting question is how many slots a WhaleJet will need at LHR. Will it be 1.5 or 2?
 
cloudyapple
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:10 am

Quoting NYC777 (Reply 2):
Well this is more bad news for the A380.

The is the same bad news as the last bad news and the previous one re:wake vortex separation.

This same piece of information is being disseminated from the ICAO steering group to CAAs around the world and every time a CAA publishes its own guidelines based exactly on ICAO's findings it is being rehashed here as more bad news.

There is actually no news here on this thread. Please move on.
A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
 
sabenapilot
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:15 am

Quoting Zvezda (Reply 4):
The interesting question is how many slots a WhaleJet will need at LHR. Will it be 1.5 or 2?

Disappointingly enough for you, just 1.

Runways capacity at any airport is counted in movements per hour, not in cumulative separation distance and just like BA hasn't gained a SINGLE slot from downgrading much of their European routes from Boeing 757 to Airbus A320 (which has lower separation minima for the UK CAA) no operator will require more than one slot because they'd upgrade from Boeing 747 Boeing 777 or Airbus A340 to Airbus A380.

The A380 will thus fit in flawlessly and unproblematicly as promissed. bigthumbsup 
 
cloudyapple
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:22 am

Quoting Zvezda (Reply 4):
The interesting question is how many slots a WhaleJet will need at LHR.

1 slot. Whether the required separation is 2.5Nm or 10Nm it will be counted as 1 slot. We adjust the hourly runway capacity we declare according to demand taking into account various factors one of which is aircraft type. Airlines schedule accordingly. You bet BAA/airlines will complain if capacity drops significantly.

There are operational tricks to get round the issue. There will be little loss of capacity because of the A388. Laymen should not worry.
A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
 
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scbriml
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:29 am

Quoting Cloudyapple (Reply 7):
Laymen should not worry.

 rotfl  rotfl  rotfl 
Time flies like an arrow. Fruit flies like a banana!
 
OldAeroGuy
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 1:44 am

Quoting Cloudyapple (Reply 5):
The is the same bad news as the last bad news and the previous one re:wake vortex separation.


There is actually no news here on this thread. Please move on.

Isn't the UK-CAA decision on approach separation distance between A380's new news?

Doesn't this make the A380 approach situation worse than the 3nm between A380's allowed by the Steering Committee? Admittantly, this will hardly be a problem until there are many A380's in service, but it can't be good news.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Poitin
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 2:17 am

Quoting Cloudyapple (Reply 7):
There are operational tricks to get round the issue. There will be little loss of capacity because of the A388. Laymen should not worry.

"Yes indeed, AA Flight 578, all you have to do is stay out of the wake vortex of that 747 and you should be just fine! Cleared for take off, have a good day!"
Now so, have ye time fer a pint?
 
Poitin
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 2:28 am

Quoting Zvezda (Reply 4):
The interesting question is how many slots a WhaleJet will need at LHR. Will it be 1.5 or 2?

The question is how many take offs and/or landings can occur per hour during rush hours if the A380 and/or B748I are flying around the circuit. And as OldAeroGuy points out, it gets worse as more and more A380s show up at LHR.

It seems to me that this should be relatively simple to model on a computer given the time separation.

The next question is what is the time seperation after a 787 takes off? Is it one minute or two or three? If one minute, then you move more people per unit time with the 787 than with the A380.
Now so, have ye time fer a pint?
 
RIX
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 8:06 am

Quoting Cloudyapple (Reply 5):
There is actually no news here on this thread. Please move on.

- as far as I remember (may be wrong), the ICAO findings were just "recommendations", while this one is a strict rule. I mean, ICAO might say anything, but UK-CAA decision is the way it will work in practice.

Quoting Cloudyapple (Reply 7):
We adjust the hourly runway capacity we declare according to demand taking into account various factors one of which is aircraft type. Airlines schedule accordingly.

- the way I understand it, whatever the separation is, it can be "leveled" combining different aircraft types appropriately... then, the airlines will have to adjust... meaning, it is going to be a problem, and despite there is a known way to resolve it, it may be far from smooth for everyone. Plus, this or that way, more time (between departures/arrivals) is more time, whichever way you combine it. Hence,

Quoting Sabenapilot (Reply 6):
Disappointingly enough for you, just 1.

- indeed, just one. But 1.5 to 2 times bigger than regular one Big grin...
 
thegooddoctor
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 8:49 am

Quoting Poitin (Reply 10):
"Yes indeed, AA Flight 578, all you have to do is stay out of the wake vortex of that 747 and you should be just fine! Cleared for take off, have a good day!"

Laymen should not worry - I love that! Doctors usually pull that one out before they stick you with something sharp or uncomfortable  Wink
The GoodDoctor
 
eisman
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 9:22 am

While this might not relate to the thread, what effect will the A380 taxi and manuever speeds have on airport operations?
 
ShowerOfSparks
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 9:33 am

This is the first positive news in a while for the Bloatjet, everywhere it goes it will be referred to as "Super"  Smile
 
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United787
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 10:25 am

Quoting ShowerOfSparks (Reply 15):
This is the first positive news in a while for the Bloatjet, everywhere it goes it will be referred to as "Super"

Not to be confused with AA's Super 80s, which are anything but...
 
NAV20
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 10:32 am

Quoting Cloudyapple (Reply 7):
Laymen should not worry.

"0913:27.6
TWR American five eight seven heavy, wind three zero zero at
niner, runway three one left, cleared for takeoff.
0913:31.7
RDO-1 cleared for takeoff, American ah, five eight seven heavy.
0913:35.3
HOT-2 you happy with that distance?
0913:38.5
HOT-1 aah, he's.... we'll be all right once we get rollin'. he's supposed
to be five miles by the time we're airborne, that's the idea.
0913:45.5
HOT-2 so you're happy. lights?
0913:47.1
HOT-1 yeah, lights are on.
0913:47.8
HOT-2 takeoff check's complete, I'm on the roll. thank you sir.
0913:53.5
HOT-1 thrust SRS, runway.
0913:54.7
CAM [sound similar to increase in engine RPM]
0914:03.8
HOT-2 you got throttles."


[Edited 2006-11-07 02:34:01]
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
 
jacobin777
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 10:59 am

Quoting United787 (Reply 16):
Not to be confused with AA's Super 80s, which are anything but...

Speak for yourself buddy..those MadDogs rock.. bigthumbsup 
"Up the Irons!"
 
ComeAndGo
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 2:51 pm

Quoting Eisman (Reply 14):
While this might not relate to the thread, what effect will the A380 taxi and manuever speeds have on airport operations?

New airports with more space and more runways than today.
 
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flylku
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 3:33 pm

Quoting Cloudyapple (Reply 5):
The A380 will thus fit in flawlessly and unproblematicly as promissed.

Flawlessly? Perhaps. But, it will not deliver on the big productivity gains it was intended to in terms of passengers per hour. This is problematic.
...are we there yet?
 
OldAeroGuy
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 4:43 pm

Quoting Cloudyapple (Reply 7):
There will be little loss of capacity because of the A388.

With the UK-CAA regulations, I did a simple model to determine the possible passenger through put change due to the A380. It is not clear from the FI article if the approach separation with a Heavy leading and an A380 trailing is 3nm or 4nm so I ran the model for both.

Basic assumptions:

- Single Runway used for Approach
- 744 Pax @ 416
- A380 Pax @ 555
- 150 kt approach ground speed used for both airplanes
- 37.5 744 operations per hour saturates the single runway using 4 nm separation.
- Replace 774's with A380's incrementally.
- A380's added are either grouped together in a block or are interspersed among the 774's.
- Observe pax through put change.

Note that the A380 pax count is 33.4% higher than the 744.

Results in terms of percent through put change for Interspersed A380's using 3nm 744-A380 Separation:
Incremental A380's ; Through Put Change
1 ; 0.1%
5 ; 1.0%
10 ; 2.2%
15 ; 3.2%
20 ; 9.8%
37.5 ; 33.4%

Results in terms of percent through put change for Interspersed A380's using 4nm 744-A380 Separation:
Incremental A380's ; Through Put Change
1 ; -0.4%
5 ; -2.2%
10 ; -4.4%
15 ; -6.3%
20 ; 1.5%
37.5 ; 33.4%

Results in terms of percent through put change for Grouped A380's using 4nm 744-A380 Separation:
Incremental A380's ; Through Put Change
1 ; -0.4%
5 ; 3.1%
10 ; 7.6%
15 ; 12.0%
20 ; 16.5%
37.5 ; 33.4%

Conclusions:

With UK-CAA Approach Separation rules, interspersed A380's will degrade the airplane's potential for increased passenger through put.

Loss of through put is increased if the 744-A380 separation is 4nm.

Grouping A380's for Landing will allow nearly the full through put potential to be realized, especially as the percentage of A380 operations increases.

[Edited 2006-11-07 09:02:10]
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
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glideslope
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 7:36 pm

No surprises here. Poor wing design, IMO. They should have gone with a more Super Critical Design and higher thrust engines.
To know your Enemy, you must become your Enemy.” Sun Tzu
 
slz396
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 8:21 pm

Quoting OldAeroGuy (Reply 21):
37.5 744 operations per hour saturates the single runway using 4 nm separation.

I for sure wouldn't want to be on that halved 747 on final....  pray 

Quoting OldAeroGuy (Reply 21):
Basic assumptions:
- Single Runway used for Approach.

Care to do the same excercise with dual runway configuration as is actually the case, assuming a flexible attribution of landing and departing runways?

What I see from your calculation is that even in the most UNFAVOURABLE situation of unflexible single landing runway operations and only when combined with a a certain range of randomly interspersed A380s, you manage to produce theoretical negative numbers of through put.

Logic then dictates that in real live operations and with some clever planning, through put will not suffer and will indeed be higher than currently is the case.

BTW, it better be, since it seems like the idea of the UK-CAA is to use this class of separation not only for A380, but also for other larger than 744 planes. Maybe we should do this calculation for 748 ops in LHR too to see what the numbers of through put are then, just to put it in perspective?
 
cloudyapple
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 10:04 pm

Quoting OldAeroGuy (Reply 9):
Isn't the UK-CAA decision on approach separation distance between A380's new news?

This is being blown way out of proportion - how often is it 2 A380s will follow each other on approach? Why do we have approach controllers? They optimise the sequence to shift the maximum number of aeroplanes with the minimum overall separation. This is an insignificant piece of regulation.

Quoting Poitin (Reply 10):
"Yes indeed, AA Flight 578, all you have to do is stay out of the wake vortex of that 747 and you should be just fine! Cleared for take off, have a good day!"

Come on - operational tricks will be within what the book says can be done. Are you implying NATS controllers are going to break wake turbulence separation to achieve increased performance?

Quoting RIX (Reply 12):
- the way I understand it, whatever the separation is, it can be "leveled" combining different aircraft types appropriately... then, the airlines will have to adjust... meaning, it is going to be a problem, and despite there is a known way to resolve it, it may be far from smooth for everyone. Plus, this or that way, more time (between departures/arrivals) is more time, whichever way you combine it. Hence,

Different airport uses different methods to determine runway capacity. Some simply declare based on experience, some like NATS operated ones utilise simulation tools which takes into account a whole bunch of parameters. I am not going to elaborate what those parameters are here but it is a tried and tested piece of software. What it does is it gives you hourly capacity figures that will result in acceptable levels of system delay.

There are busy hours and there are slack hours even at Heathrow. The effect of a particular event in the day (an A380 landing for example) may have a localised impact for some minutes but is unlikely to perturb the daily overall by much.

That is a theoretical approach to preempt excessive delays but operationally many things can be done to alleviate any potential problems - we have a whole team of people on it.

Quoting Flylku (Reply 20):
Flawlessly? Perhaps. But, it will not deliver on the big productivity gains it was intended to in terms of passengers per hour. This is problematic.

I did not write the things you quoted me on.

Quoting OldAeroGuy (Reply 21):
Single Runway used for Approach

That's the problem. It's only statistical correct with all those given assumptions. Heathrow has 2 runways, can TEAM and will TEAM to reduce delay. Your calculations did not take that into account

Quoting Glideslope (Reply 22):
No surprises here. Poor wing design, IMO.

The wing is well designed. Except that it's optimised for the A389 - too much lift for the A388 and thus too big a wake turbulence. Do you know what a super critical aerofoil is? Do you know what the differences are between a conventional aerofoil and a super critical one? Can you tell me if a super critical aerofoil is always better than a conventional one?

[Edited 2006-11-07 14:23:17]
A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
 
LHRSpotter
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 10:35 pm

Quoting Poitin (Reply 10):
"Yes indeed, AA Flight 578, all you have to do is stay out of the wake vortex of that 747 and you should be just fine! Cleared for take off, have a good day!"

Did you mean AA Flight 587?
The fifth anniversary is this week (NOV 12th). R.I.P.
 
khobar
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 11:08 pm

Quoting Cloudyapple (Reply 24):
Come on - operational tricks will be within what the book says can be done. Are you implying NATS controllers are going to break wake turbulence separation to achieve increased performance?

Interestingly enough, in a previous thread, that exact accusation was made of LHR controllers (they ignore separation standards). Sounded absurd to me.

Quoting Cloudyapple (Reply 24):
The effect of a particular event in the day (an A380 landing for example) may have a localised impact for some minutes but is unlikely to perturb the daily overall by much.

But LHR is expecting the A380 to make up 1/8 of the traffic, and LHR does not employ mixed-mode/flexible runway ops. On the other hand, the good news is that, like the 747 traffic, most of the A380 ops will be clustered together.
 
cloudyapple
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 11:42 pm

Quoting Khobar (Reply 26):
Interestingly enough, in a previous thread, that exact accusation was made of LHR controllers (they ignore separation standards). Sounded absurd to me.

Somebody timed 2 arrivals to land about a minute apart and cried foul. I explained in that thread that was totally within reason. 3Nm spacing, 5kt tail wind gives you a bit over a minute inter-arrival. 2.5Nm will take it to below 1min. The critical thing was separation is based on distance. To convert to an equivalent time based spacing you need to know the strength of the prevailing wind.

Heathrow Director is one of the highest paid ATCO positions. One does not accuse him of cheating.

Quoting Khobar (Reply 26):
But LHR is expecting the A380 to make up 1/8 of the traffic, and LHR does not employ mixed-mode/flexible runway ops. On the other hand, the good news is that, like the 747 traffic, most of the A380 ops will be clustered together.

The TEAM procedure is available where arrivals can land on the departure runway. It's only applied when there is excessive delay. This has the potential to be used to solve some other operational issues.

When the day comes with 1 in 8 being an A380, Heathrow would have gone to mixed mode for a long time. 7Nm inter-arrival spacings should pose little problems with A380s interspursed with departures.

[Edited 2006-11-07 15:45:25]
A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
 
vv701
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RE: UK - New "super" Wake Vortex Sep For A380

Tue Nov 07, 2006 11:45 pm

I am not a 'professional' and am not therefore well qualified to comment on the affect of mixing 380s into the current mix of arrivals and departures. However it seems to me that ATC has a better control of departures than arrivals. While it is easy to delay the departure of a 380 for a few minutes so that two can take off consecutively I would have thought that keeping one in a stack until another arrived would be more problematic. So my conclusion - correct or incorrect - is that arrivals at a slot bound airport like LHR would be more critical than departures.

So what can I add to this debate? On 16 October I spent around three hours (2hrs 55mins and 37secs) below the final approach to 09L at LHR at not what I would regard as a peak period - lunchtime. I photographed each and every arrival and have now gone back and analysed the images on my Nikon F50, particularly the precise timings of each image.

I appreciate that every image will not have been recorded with the aircraft in exactly the same position with regards to the 09L threshold. But in a few cases I recorded more than one image of an individual aircraft. I can therefore state with a high level of confidence that my individual timings are accurate to within plus or minus 1.5 secs.

Here are my observations:

In an elapsed time of 2 hrs 55 mins 37 secs 118 aircraft landed on 09L.

The average spacing between all aircraft was 90 secs. At 150mph this spacing is equivalent to a distance of 3.75 miles.

The shortest spacing of any two aircraft (757 followed by a 330) was 49 secs.

The second shortest spacing of any two aircraft was 58 secs ( on two occasions with a 145 followed by a 320 and a 320 following a 320).

The largest spacing of any two aircraft was 188 secs with the next largest at 150 secs (744 followed by a 145).

Grouping the spacings into 5 second intervals shows a peak of 40 arrivals (33.9%) between 71 and 80 secs. The breakdown was:

46-50 sec 1 (0.8%)
51-55 sec 0
56-60 sec 6 (5.1%)
61-65 sec 11 (9.3%)
66-70 sec 9 (7.6%)
71-75 sec 17 (14.4%)
76-80 sec 23 (19.5%)
81-85 sec 3 (2.5%)
86-90 sec 4 (3.4%)
91-95 sec 4 (3.4%)
96-100 sec 7 (5.9%)
101-105 sec 5 (4.2%)
106-110 sec 2 (1.7%)
111-115 sec 4 (3.4%)
116-120 sec 3 (2.5%)
121-125 sec 4 (3.4%)
126-130 sec 3 (2.5%)
131-135 sec 6 (5.1%)
136-140 sec 3 (2.5%)
141-145 sec 1 (0.8%)
146-150 sec 1 (0.8%)

186-190 sec 1 ((0.8%)

All of the above were scheduled airliner flights with one exception, a BA 744 on an MCO-LHR charter flight.

Classifying the 747, 777, 767, 340 and 330 as 'heavies' (H), the 737, 757, 320 and 321 as 'mediums' (M) and the Avro85 and EMB145 as 'lights' (L), the 118 aircraft comprised 32 Hs, 83 Ms and 3 Ls.

Hs landed as singletons - that is preceded and followed by a non-H - on 12 occasions. They landed as doubletons 6 times (38.7% of H arrivals) and on one occasion with six (19.4% of H arrivals) on final consecutively. (Statistically after an H arrival the chances of the next aircraft being an H was around 2 in 7. In other words if the arrivals had been purely random one would expect to see an H following an H on 4 or 5 occasions. In actuality one followed another on 13 occasions. This is stastically significant enough to confirm that ATC were grouping Hs whenever possible, presumably to maximise landing slots.

The distribution of spacings between consecutive Hs was narrow, all falling between 91 and 120 secs. The peak of 6 (50%) occurred between 96 and 105 secs. The average spacing between consecutive Hs was 103 secs.

An M followed an H on 16 occasions. 72.5% of all such spacings were between 121 and 133 secs.

Twice an L followed an H with spacings of 136 and 150 secs.

What does all of this prove? Well, in this very narrow and possibly atypical period around lunchtime on 16 October, LHR was pretty busy. There was only one obviously unused slot and there was only one non-scheduled arrival - the aircraft used for the 20th annual BA Dreamflight returning to LHR as a charter after taking 192 seriously ill British and Bahraini children and their 96 accompanying adults on a holiday of a lifetime to Orlando, FL.

What would the effect be of adding 380s to the current mix or substituting them for some of the Hs? I leave that to others to determine.
 
aviateur
Posts: 562
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RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 12:08 am

Wake turbulence did not bring down AA 587. The A300 crashed because the crew -- the first officer in particular -- overreacted when encountering the vortices spun from the JAL 747 ahead, needlessly commanding full deflection of the rudder (in both directions). The overreaction itself is traceable, in part, to design of the rudder system: it is rigged in such a way that pilots could inadvertently kick in full deflection with relatively light inputs. The way I understand it, full deflection of the surface itself does not entail full deflection of the foot pedal. There may also have been a preexisting stress crack in the tail's composite skeleton -- result of a powerful turbulence enounter years earlier -- though this was never proven.

Wake turbulence? Well that's one way to look at it. Contributing factor, yes. Cause, no.

PS
Patrick Smith is an airline pilot, air travel columnist and author
 
Poitin
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RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 12:10 am

Quoting Eisman (Reply 14):
While this might not relate to the thread, what effect will the A380 taxi and manuever speeds have on airport operations?

According to some, SFO, which has narrow spacing between runways and taxi ways will be 50% shut down for as long as 15 minutes while a A380 is moving on the ground. Other airports will have much less disruption. The A380 will be welcomed to SFO by the politicians and hated by everyone else if there are more than a couple A380 movements a day there.

Quoting Cloudyapple (Reply 24):
Quoting Poitin (Reply 10):
"Yes indeed, AA Flight 578, all you have to do is stay out of the wake vortex of that 747 and you should be just fine! Cleared for take off, have a good day!"

Come on - operational tricks will be within what the book says can be done. Are you implying NATS controllers are going to break wake turbulence separation to achieve increased performance?

The departure of AA 587 was according the the "book". The pilots were warned. What they did not know is they would cross the vortex of the JAL 747. Had the copilot not use the rudders, they would have probably survived although brused. Had they waited a minute on the ground, they would not have felt a bump.

Quoting LHRspotter (Reply 25):

Did you mean AA Flight 587?
The fifth anniversary is this week (NOV 12th). R.I.P.

Sadly, yes.
Now so, have ye time fer a pint?
 
cloudyapple
Posts: 1261
Joined: Sun Jul 24, 2005 7:01 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 12:24 am

Quoting Poitin (Reply 30):
The departure of AA 587 was according the the "book". The pilots were warned. What they did not know is they would cross the vortex of the JAL 747. Had the copilot not use the rudders, they would have probably survived although brused. Had they waited a minute on the ground, they would not have felt a bump.

See reply above yours.
A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
 
OldAeroGuy
Posts: 3188
Joined: Sun Dec 05, 2004 6:50 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 12:51 am

Quoting Slz396 (Reply 23):
I for sure wouldn't want to be on that halved 747 on final....

It becomes a halved A380 in the all A380 case.

Quoting Slz396 (Reply 23):
Care to do the same excercise with dual runway configuration as is actually the case, assuming a flexible attribution of landing and departing runways?

The model does indicate the situation at LHR where one of the dual runways is used for departures and one for arrivals. There is no flexible attribution of runways due to community noise issues. In certain circumstances, arrivals are allowed to land on the departure runway under the TEAM concept. More about this below.

Quoting Slz396 (Reply 23):
Logic then dictates that in real live operations and with some clever planning, through put will not suffer and will indeed be higher than currently is the case.

The model represents two ends of the spectrum. Interspersed A380's are the worst case and grouped A380's are the best. The real world will be somewhere in between the two with the additional variables of smaller airplanes that require more separation and actual separations being greater than the minimums used in the model. You cannot assume that through put will not suffer or will not be reduced from the full potential of the greater A380 seat count.

Quoting Cloudyapple (Reply 24):
This is being blown way out of proportion - how often is it 2 A380s will follow each other on approach?

Actually this what you want to have. From a through put stand point, the more grouped A380's, the better.

Quoting Cloudyapple (Reply 24):
That's the problem. It's only statistical correct with all those given assumptions. Heathrow has 2 runways, can TEAM and will TEAM to reduce delay. Your calculations did not take that into account



Quoting Cloudyapple (Reply 27):
The TEAM procedure is available where arrivals can land on the departure runway. It's only applied when there is excessive delay. This has the potential to be used to solve some other operational issues.

As I understand the situation today, TEAM is only used when weather delays have reduced landing operations far below the 37. 5 per hour I used for the model and is then limited to six operations per hour.

Isn't community noise the problem with additional use of TEAM? The current arrival/departure runway concept at LHR is done to give communities relief from approach traffic. During west wind conditions, the arrival/departure runways are switched periodically to distribute arrival noise between the communities at the arrival ends of the runways. Since expanded use of TEAM will increase the number of approaches over a community associated with the departure runway during a relief period, TEAM expansion appears to be problematical.

On the other hand, if TEAM is expanded, it could increase operations at LHR, lessening the need for the A380 to increase LHR through put.

In any case, I provided the model data so we could have some quantitative numbers to discuss rather than keeping everything in the qualitative world. Let's keep talking.

Quoting Glideslope (Reply 22):
Poor wing design, IMO. They should have gone with a more Super Critical Design and higher thrust engines.

You've listed factors that are not relevant from a vortex separation standpoint. Airplane weight, wing span, and flap design are far more important.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Poitin
Posts: 2651
Joined: Wed Jan 25, 2006 6:32 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 12:59 am

Quoting Cloudyapple (Reply 31):
See reply above yours.

So, the wake vortex was still a major contributing issue. As I noted.

Quoting Poitin (Reply 30):
Had they waited a minute on the ground, they would not have felt a bump.
Now so, have ye time fer a pint?
 
OldAeroGuy
Posts: 3188
Joined: Sun Dec 05, 2004 6:50 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 1:10 am

Quoting VV701 (Reply 28):
The distribution of spacings between consecutive Hs was narrow, all falling between 91 and 120 secs. The peak of 6 (50%) occurred between 96 and 105 secs. The average spacing between consecutive Hs was 103 secs.

Your observations indicate my modeling is essentially correct. The model used 96 sec as the 4nm Heavy to Heavy separation time vs your observed 103 sec.

Quoting VV701 (Reply 28):
Classifying the 747, 777, 767, 340 and 330 as 'heavies' (H), the 737, 757, 320 and 321 as 'mediums' (M) and the Avro85 and EMB145 as 'lights' (L), the 118 aircraft comprised 32 Hs, 83 Ms and 3 Ls.

These statistics indicate that there is more potential for increasing LHR through put by replacing Mediums with small Heavies rather than Heavies with Super Heavies. Further bolstering of Point to Point?
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
slz396
Posts: 1883
Joined: Tue Oct 02, 2001 7:01 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 1:31 am

Quoting OldAeroGuy (Reply 32):
I provided the model data so we could have some quantitative numbers to discuss rather than keeping everything in the qualitative world. Let's keep talking.

You provided a theoretical model for which you certainly deserve some credit, but sadly it does not fit reality and is suitable for a purely intellectual discussion only as it assumes total saturation for the entire day and thus no possible 'overspill' to less saturated moments of the day as one would normally see.

Best proof your model does not match reality is one can easily used it to show there should be a significant increase in through put at LHR as British Airways phased out and continues to phases out their 757s in favour of new A321/A320s which fall in a lower separation category according the the UK CAA. Sadly for BA and LHR, reality in the air has shown this NOT to be the case, and so they haven't gained a single slot from it.

Second example is what happens if LHR needs to close a RWY for let's say 5 min, for instance because a plane reported a tyre burst and they need to collect the pieces of rubber from the RWY? Does this mean 3 (or 4?) flights for later that day automatically get cancelled or that 3 (4?) planes circling need to divert because they've just lost their landing slot at LHR because of this? Of course not!

There is what is called elasticity on the slot allocation system, meaning that the theoretical change in through put as found in your basic calculations is simply translated into some more speed advice and radar vectors to build up the optimal approach sequence and that ONLY at the worst moments of the day (i.e. total saturation) the entire approach sequence of that saturation moment might get shifted back slightly. Since LHR is capacity limited at peak times ONLY, these shifts are then easily absorbed later on during the day, thus permitting exactly the same number of approaches within the opening hours from LHR as before... it might mean some more work for the slot allocation manager at LHR, but all requests can still be accommodated easily.
 
jacobin777
Posts: 12262
Joined: Sat Sep 11, 2004 6:29 pm

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 1:45 am

Quoting Slz396 (Reply 35):

You provided a theoretical model for which you certainly deserve some credit, but sadly it does not fit reality and is suitable for a purely intellectual discussion only as it assumes total saturation for the entire day and thus no possible 'overspill' to less saturated moments of the day as one would normally see.

Actually VV701's data might prove OldAeroGuy's theoretical modeling to be correct...of course, more numbers are needed....but it certainly doesn't disprove OldAeroGuy's model(s)...
"Up the Irons!"
 
OldAeroGuy
Posts: 3188
Joined: Sun Dec 05, 2004 6:50 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 2:15 am

Quoting Slz396 (Reply 35):
You provided a theoretical model for which you certainly deserve some credit, but sadly it does not fit reality and is suitable for a purely intellectual discussion only as it assumes total saturation for the entire day and thus no possible 'overspill' to less saturated moments of the day as one would normally see.

The model does not assume that the saturation extends over the entire day. The situation that exists at LHR is that there are times in the day when arrivals do tend to be saturated. The daily arrival of airplanes from SE Asia represents one such time period. Slot saturation is always given as one of the justifications for the A380 to increase through put. If slot saturation doesn't exist for at least part of the day, then part of the argument for the A380 at LHR is removed.

Quoting Slz396 (Reply 35):
Does this mean 3 (or 4?) flights for later that day automatically get cancelled or that 3 (4?) planes circling need to divert because they've just lost their landing slot at LHR because of this? Of course not!

Where did I ever say this was the case? Landings can always be deferred through out the day. However, if the scenario you describe does happen at a peak traffic time, it increases the chances that airplanes will not be able to hold and may have to divert. Fuel reserves are finite.

Quoting Slz396 (Reply 35):
Since LHR is capacity limited at peak times ONLY, these shifts are then easily absorbed later on during the day, thus permitting exactly the same number of approaches within the opening hours from LHR as before

I agree, but these are the times that the A380 was supposed to provide better through put. The new separation category will reduce it's capability to provide that capacity, that is the point.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
OldAeroGuy
Posts: 3188
Joined: Sun Dec 05, 2004 6:50 am

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 1:03 pm

Quoting Slz396 (Reply 35):
ONLY at the worst moments of the day (i.e. total saturation) the entire approach sequence of that saturation moment might get shifted back slightly. Since LHR is capacity limited at peak times ONLY, these shifts are then easily absorbed later on during the day, thus permitting exactly the same number of approaches within the opening hours from LHR as before... it might mean some more work for the slot allocation manager at LHR, but all requests can still be accommodated easily.

After thinking about your response a bit more today, I suggest that if you want to continue with your line of reasoning above, you might consider engaging Leelaw to provide you the consul of a good attorney that you appear to need. If you persist in saying that LHR can accept more distributed arrivals throughout the day to relieve peak traffic periods, it can only lead to the conclusion that LHR is not really slot limited. Then we can drop the pretence that LHR is the poster child for slot limited airports waiting for the A380 to increase its through put.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
ShowerOfSparks
Posts: 136
Joined: Sat May 06, 2006 9:22 pm

RE: UK - New "super" Wake Vortex Sep For A380

Wed Nov 08, 2006 3:28 pm

Quoting Aviateur (Reply 29):
There may also have been a preexisting stress crack in the tail's composite skeleton -- result of a powerful turbulence enounter years earlier -- though this was never proven.

There is in fact a repair visible to one of the attachment points which can be clearly seen in the photographs of the wreckage. You can see in the picture some 20 -30 fasteners through the attachment lug at the base of the fin.
This lug appears to have broken along a line of these fasteners. As far as I am aware this repair doesn't seem to have attracted any attention at all by the investigators so maybe it's not a problem at all.

Up until this crash every pilot in the world had been trained to believe that below Va it was not possible to break the airframe by control inputs. Guess someone found a loophole in the certification regs.

The pictures mentioned can be viewed on the NTSB website.
 
NAV20
Posts: 8453
Joined: Thu Nov 27, 2003 3:25 pm

RE: UK - New "super" Wake Vortex Sep For A380

Thu Nov 09, 2006 3:35 pm

Quoting ShowerOfSparks (Reply 39):
There is in fact a repair visible to one of the attachment points which can be clearly seen in the photographs of the wreckage. You can see in the picture some 20 -30 fasteners through the attachment lug at the base of the fin.
This lug appears to have broken along a line of these fasteners. As far as I am aware this repair doesn't seem to have attracted any attention at all by the investigators so maybe it's not a problem at all.

Thanks, ShowerOfSparks, new information to me.

In return, you may not have seen this urgent Safety Recommendation issued last March by the NTSB. It arises primarily from investigation of damage to the rudder on a Fedex A300-series aircraft, caused by hydraulic fluid contamination; but the NTSB Recommendation text links the symptoms ('loud bang followed by vibrations') encountered in both the recent Air Transat rudder loss and the AA587 tragedy into the reckoning:-

"In addition to the damage that occurred during maintenance, the examination found a substantial area of disbonding between the inner skin of the composite rudder surface and the honeycomb core.........While at an altitude of 35,000 feet, about 15 miles south of Marathon, Florida, the flight crew heard a loud bang followed by vibrations that lasted a few seconds......Further examination of the vertical stabilizer determined that its two rearmost attachment lugs were damaged due to the high stresses associated with the rudder failure and separation. These high stresses may have been dangerously close in magnitude to those that caused the in-flight separation of the vertical stabilizer during the November 12, 2001, accident involving American Airlines flight 587."

It also says, in a footnote referring to the Air Transat case:-

"4. When the rudder separation began, the rudder started to flutter, or swing back and forth violently. This, in turn, led to the vertical stabilizer moving left and right and the stress in the lugs increasing to the point where the lugs became delaminated."

http://www.ntsb.gov/recs/letters/2006/A06_27_28.pdf
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci

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