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Runway Switch At LHR For A380  
User currently offlineItsonlyme From United Kingdom, joined Dec 2006, 149 posts, RR: 0
Posted (5 years 11 months 1 week 6 days ago) and read 9667 times:

Ok, there maybe a simple answer to this but what the hell.

Why, more often than not, do they switch runways for the arrival of SQ318 when its flown by the A380? What i mean by this is the arrivals will be coming in on 27R (the flightpath of which is right over my house) then SQ318 will land on 27L, then the next plane will be back on 27R. Somedays this wont happen, but when it does, i cant understand why. Infact, the very first time the A380 came to Heathrow (with the Airbus livery) the same thing happen. Can anyone shed some light on this? Its been bugging the hell out of me recently!

25 replies: All unread, showing first 25:
 
User currently offlineBMIFlyer From UK - England, joined Feb 2004, 8810 posts, RR: 58
Reply 1, posted (5 years 11 months 1 week 6 days ago) and read 9657 times:

Well, one reason is that 27L is closer to the A380 gates than 27R is.

Also, you have to take into account the layout of the taxiways at LHR.




Lee



Sometimes You Can't Make It On Your Own
User currently offlineBlackProjects From United Kingdom, joined Jul 2007, 756 posts, RR: 3
Reply 2, posted (5 years 11 months 1 week 6 days ago) and read 9624 times:

With all the taxi way works under way at Present it is safer to use 27 left less chance of getting stuck till the work is Completed.

 old 


User currently offlineKhobar From United States of America, joined Mar 2006, 2379 posts, RR: 4
Reply 3, posted (5 years 11 months 1 week 5 days 23 hours ago) and read 9488 times:

At one time, only one runway at LHR was A380 capable.

User currently offlineSirtoby From Germany, joined Nov 2007, 369 posts, RR: 22
Reply 4, posted (5 years 11 months 1 week 5 days 8 hours ago) and read 8903 times:

Could have something to do with the size of the next A/C and the required distance of an A/C behind the A380. The required distance was lowered some time ago, but is still higher than that for the B747-400, AFAIK.

User currently offlineKU747 From Kuwait, joined Mar 2008, 375 posts, RR: 0
Reply 5, posted (5 years 11 months 1 week 5 days 8 hours ago) and read 8864 times:

Is the answer all of the above? they all make sense to me.


707,727,73all,741,742,743,744,752,753,762,763,77all,300,310,319,320,321,332,333,343,346, L10,L15,DC10,MD11,SSC,VC10
User currently offlineSandroZRH From Switzerland, joined Feb 2007, 3427 posts, RR: 50
Reply 6, posted (5 years 11 months 1 week 5 days 6 hours ago) and read 8590 times:



Quoting Sirtoby (Reply 4):
Could have something to do with the size of the next A/C and the required distance of an A/C behind the A380. The required distance was lowered some time ago, but is still higher than that for the B747-400, AFAIK.

 checkmark 

Wake Turbulence spacing. They can bring the A380 in on the departure runway without sacrificing time for spacing on the arrival runway. Since wake turbulence stops when lift is lost, or in other words: When the nose-wheel touches down, they can continue with departures right after it vacated the runway, and dont have to wait for the two minutes spacing required. Would it approach the arrival runway in use however, the spacing would be applicable, which they can save bringing it in on the departure runway.

Another way to save a couple of minutes at already heavily congested LHR.


User currently offlineLHR27C From United Kingdom, joined Aug 2004, 1279 posts, RR: 16
Reply 7, posted (5 years 11 months 1 week 5 days 3 hours ago) and read 7070 times:

Itsonlyme, the best way to find out an instant answer to your question would be to post on the ATC section of PPrune which has a lot of LHR ATC regulars. Most of the reasons given on this thread seem unlikely.

The most plausible reason seems, as BlackProjects says, to be that there are some taxiway works going on around the area where the A380 would be expected to vacate 27R after landing (it's still using 27R for takeoff regularly).

Quoting Khobar (Reply 3):
At one time, only one runway at LHR was A380 capable.

Not any more.

Quoting BMIFlyer (Reply 1):
Well, one reason is that 27L is closer to the A380 gates than 27R is.

Nope - a good reason in the early morning when they can use both runways for landing and so pick the runway closest to the terminal, but not a valid reason when SQ318 arrives - why should the A380 be able to land on the runway closest to its gates while all other aircraft have to fit in with the runway alternation pattern?

Quoting BMIFlyer (Reply 1):
Also, you have to take into account the layout of the taxiways at LHR.

The taxiways at LHR (when they're all open!) support A380 operations from any of the four runways.

Quoting Sirtoby (Reply 4):


Could have something to do with the size of the next A/C and the required distance of an A/C behind the A380. The required distance was lowered some time ago, but is still higher than that for the B747-400, AFAIK.



Quoting SandroZRH (Reply 6):

Wake Turbulence spacing. They can bring the A380 in on the departure runway without sacrificing time for spacing on the arrival runway. Since wake turbulence stops when lift is lost, or in other words: When the nose-wheel touches down, they can continue with departures right after it vacated the runway, and dont have to wait for the two minutes spacing required. Would it approach the arrival runway in use however, the spacing would be applicable, which they can save bringing it in on the departure runway.

Another way to save a couple of minutes at already heavily congested LHR.

Sandro, this isn't true, at least not any more. Except for the past few weeks, SQ318 has been using the standard arrival runway with all other arrivals. For example a couple of weeks ago the A380 landed on 27R, and an A321 landed 2 minutes later (on 27R). It looks like the wake turbulence spacing has already been reduced.



Once you have tasted flight, you will walk the earth with your eyes turned forever skyward
User currently offlineThenoflyzone From Canada, joined Jan 2001, 2376 posts, RR: 12
Reply 8, posted (5 years 11 months 1 week 5 days ago) and read 5735 times:

Quoting LHR27C (Reply 7):
It looks like the wake turbulence spacing has already been reduced.

I highly doubt that ! A321 following the A380, you need 8 nautical miles. So if your count was indeed at 2 minutes, then that means that your A321 was on a visual approach behind the A380, and that the pilot was assuring his own spacing, which would seem plausible, since the A380 is hard to miss in the sky, and if i was following it, i would try to spot it too !

Or the count was at 3 minutes, which at 160 knots, is roughly 8 nm, and you rounded it out to 2 minutes !!

Thenoflyzone

[Edited 2008-08-18 10:34:30]


us Air Traffic Controllers have a good record, we haven't left one up there yet !!
User currently offlineCPH-R From Denmark, joined May 2001, 5977 posts, RR: 3
Reply 9, posted (5 years 11 months 1 week 5 days ago) and read 5630 times:



Quoting LHR27C (Reply 7):
Itsonlyme, the best way to find out an instant answer to your question would be to post on the ATC section of PPrune which has a lot of LHR ATC regulars. Most of the reasons given on this thread seem unlikely.

Unless PPrune's stance towards enthutiasts have changed in recent years, I wouldn't bother trying to post there. Or if you must, stick to their designated Anorak corner.


User currently offlineLHR27C From United Kingdom, joined Aug 2004, 1279 posts, RR: 16
Reply 10, posted (5 years 11 months 1 week 5 days ago) and read 5451 times:



Quoting Thenoflyzone (Reply 8):

I highly doubt that ! A321 following the A380, you need 8 nautical miles. So if your count was indeed at 2 minutes, then that means that your A321 was on a visual approach behind the A380, and that the pilot was assuring his own spacing, which would seem plausible, since the A380 is hard to miss in the sky, and if i was following it, i would try to spot it too !

Or the count was at 3 minutes, which at 160 knots, is roughly 8 nm, and you rounded it out to 2 minutes !!

Are you sure under UK ATC procedures, 8 nm spacing is required? Could it not be that after some months of experience with A380 ops at LHR, ATC has decided that spacing can be reduced?

Visual approaches at any of the London airfields are very rare.

I'm quoting from the LHR SBS logs which records when the aircraft passes over the threshold of the runway. Here are a couple of recent extracts from the logs when SQ318 was arriving in July, and the aircraft following it. Arrival time (GMT) is third column from the right.

SIA318 SQ318 9VSKE A388 WSSS 1746 301 27R
AZA5P4 AZ208 IBIXL A321 LIRF 1748 208 27R

SIA318 SQ318 9VSKE A388 WSSS 1754 303 27L
BMA3KD BD130 GMIDS A320 EIDW 1757 178 27L

SIA318 SQ318 9VSKE A388 WSSS 1748 303 09L
JAI124 9W124 VTJWE A332 VIAR 1751 331 09L

SIA318 SQ318 9VSKD A388 WSSS 1804 301 27L
VIR26 VS026 GVGOA A346 KJFK 1806 342 27L

So you can see that aircraft are following with a 2-3 minute gap, including those of size A320/321 category.

Quoting CPH-R (Reply 9):

Unless PPrune's stance towards enthutiasts have changed in recent years, I wouldn't bother trying to post there. Or if you must, stick to their designated Anorak corner.

Maybe true of the R&N section but the ATC forum is very helpful.



Once you have tasted flight, you will walk the earth with your eyes turned forever skyward
User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 24
Reply 11, posted (5 years 11 months 1 week 5 days ago) and read 5415 times:



Quoting LHR27C (Reply 10):
SIA318 SQ318 9VSKE A388 WSSS 1746 301 27R

Out of curiosity: Whas is the second last figure - "301" in this case ? All other I can recognize ...
-HT



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
User currently offlineThenoflyzone From Canada, joined Jan 2001, 2376 posts, RR: 12
Reply 12, posted (5 years 11 months 1 week 5 days ago) and read 5370 times:

Quoting LHR27C (Reply 10):
Are you sure under UK ATC procedures, 8 nm spacing is required? Could it not be that after some months of experience with A380 ops at LHR, ATC has decided that spacing can be reduced?

the Air Traffic Controllers do not decide what type of spacing to use, they just implement what the UK aviation authorities tell them to do, and i would find it odd that the UK authorities would go against the 8 n.m rule.

Quoting LHR27C (Reply 10):
I'm quoting from the LHR SBS logs which records when the aircraft passes over the threshold of the runway.

I do not know the accuracy of this information, but seeing a 3 minute separation on several days leads me to believe that the 8 n.m separation is being applied.

[Edited 2008-08-18 11:18:08]


us Air Traffic Controllers have a good record, we haven't left one up there yet !!
User currently offlineThenoflyzone From Canada, joined Jan 2001, 2376 posts, RR: 12
Reply 13, posted (5 years 11 months 1 week 5 days ago) and read 5342 times:



Quoting LHR27C (Reply 10):
SIA318 SQ318 9VSKE A388 WSSS 1748 303 09L
JAI124 9W124 VTJWE A332 VIAR 1751 331 09L

SIA318 SQ318 9VSKD A388 WSSS 1804 301 27L
VIR26 VS026 GVGOA A346 KJFK 1806 342 27L

On these 2 occasions, the following aircraft is a heavy, (non A380), therefore a 6 n.m spacing would be required.

Considering Heathrow Approach usually assigns 160kts on final, that would bring the spacing in terms of minutes to a little over 2 minutes. In the first example, we have a 3 minutes difference, which tells us the 6nm rule was enforced, and in the second example, we see a 2 minute difference, which would bring us to roughly 5 1/2 n.m - 6 n.m.

It would be safe to say that the SBS logs have a certain incertitude built in, i.e they round out the minutes.



us Air Traffic Controllers have a good record, we haven't left one up there yet !!
User currently offlineGCT64 From United Kingdom, joined Nov 2007, 1366 posts, RR: 1
Reply 14, posted (5 years 11 months 1 week 4 days 23 hours ago) and read 5296 times:

Quoting HT (Reply 11):
Quoting LHR27C (Reply 10):
SIA318 SQ318 9VSKE A388 WSSS 1746 301 27R

Out of curiosity: Whas is the second last figure - "301" in this case ? All other I can recognize ...
-HT

Parking stand number, in this case, stand #301.

[Edited 2008-08-18 11:37:09]


Flown in: A30B,A306,A310,A319,A320,A321,A332,A333,A343,A346,BA11,BU31,B190, B461,B462,B463,(..50 types..),VC10,WESX
User currently offlineLHR27C From United Kingdom, joined Aug 2004, 1279 posts, RR: 16
Reply 15, posted (5 years 11 months 1 week 4 days 22 hours ago) and read 5182 times:

Thenoflyzone

I'll try to find out what the current spacing used for the 380 is. Whatever the spacing, I find it interesting that it appears the A380 is not causing as many problems in terms of approach separation as many expected. (consider that the average spacing between two arriving aircraft at LHR is 2 minutes anyway)

Quoting Thenoflyzone (Reply 12):
the Air Traffic Controllers do not decide what type of spacing to use, they just implement what the UK aviation authorities tell them to do, and i would find it odd that the UK authorities would go against the 8 n.m rule.

ATC at LHR is provided by NATS which effectively governs most of the airspace in South-East England. They operate hand in hand with the CAA and it is NATS who conduct things such as airspace reviews. If they want to implement special procedures, they can - LHR has several ATC dispensations given its high level of traffic.

I do know for a fact that LHR will go down as low as 2.5nm spacing on final (between the right a/c types, of course), ant that's on ILS approaches.



Once you have tasted flight, you will walk the earth with your eyes turned forever skyward
User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 24
Reply 16, posted (5 years 11 months 1 week 4 days 22 hours ago) and read 5098 times:



Quoting GCT64 (Reply 14):
Parking stand number, in this case, stand #301.

Thanks for the info !
That's one one piece of data that never would have com eto my mind.
-HT



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
User currently offlineThenoflyzone From Canada, joined Jan 2001, 2376 posts, RR: 12
Reply 17, posted (5 years 11 months 1 week 4 days 22 hours ago) and read 5095 times:



Quoting LHR27C (Reply 15):
between the right a/c types, of course

YYZ has the same thing, but when wake turbulence is concerned, all of that goes out the window. You need to provide adequate wake turbulence separation.



us Air Traffic Controllers have a good record, we haven't left one up there yet !!
User currently offlineCloudyapple From Hong Kong, joined Jul 2005, 2454 posts, RR: 10
Reply 18, posted (5 years 11 months 1 week 4 days 20 hours ago) and read 4974 times:



Quoting LHR27C (Reply 10):
Are you sure under UK ATC procedures, 8 nm spacing is required? Could it not be that after some months of experience with A380 ops at LHR, ATC has decided that spacing can be reduced?

8Nm are indeed required. There is no question of this being anything less.

Quoting LHR27C (Reply 10):
Visual approaches at any of the London airfields are very rare.

Never at Heathrow.

Quoting LHR27C (Reply 10):
SIA318 SQ318 9VSKE A388 WSSS 1746 301 27R
AZA5P4 AZ208 IBIXL A321 LIRF 1748 208 27R

The significance of this data is that it is rounded (int) to the minute. and there is no specification and hence guarantee of accuracy. At 8Nm separation on final you are looking at 184sec between landings calm wind on average. Give or take a few seconds - go time it. So the A388 may have landed 17:46:00 and the A321 landed 17:48:59, giving you the required 8Nm.

Quoting LHR27C (Reply 15):
I'll try to find out what the current spacing used for the 380 is.

There is no need. ICAO standard 8Nm.

Quoting LHR27C (Reply 7):
Most of the reasons given on this thread seem unlikely.

You are wrong. The following is indeed correct.

Quoting SandroZRH (Reply 6):
Wake Turbulence spacing. They can bring the A380 in on the departure runway without sacrificing time for spacing on the arrival runway. Since wake turbulence stops when lift is lost, or in other words: When the nose-wheel touches down, they can continue with departures right after it vacated the runway, and dont have to wait for the two minutes spacing required. Would it approach the arrival runway in use however, the spacing would be applicable, which they can save bringing it in on the departure runway.

Another way to save a couple of minutes at already heavily congested LHR.

If necessary, the arriving A388 can be swapped onto the departure runway applying a TEAM procedure. This is a form of limited mixed mode with independent parallel approaches. NATS is allowed to land up to 6 arrivals on the departure runway if the average delay exceeds/is likely to exceed a threshold. This is not done for all A388 arrivals, only during arrival peaks.

I don't want to explain the TEAM procedure in great detail here but if anyone is interested it's on DfT's website.

I hope this clears things up.



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
User currently offlineCloudyapple From Hong Kong, joined Jul 2005, 2454 posts, RR: 10
Reply 19, posted (5 years 11 months 1 week 4 days 20 hours ago) and read 4957 times:



Quoting LHR27C (Reply 15):
consider that the average spacing between two arriving aircraft at LHR is 2 minutes anyway

Arrival spacings are distance based. Time intervals between arrivals are subject to variations depending on the strength of the wind. On a day where head wind is strong arrivals on 3Nm separation can be 3-4 minutes apart.

Quoting LHR27C (Reply 15):
I find it interesting that it appears the A380 is not causing as many problems in terms of approach separation as many expected.

Because the proper spacing of 8Nm was applied.

Quoting LHR27C (Reply 15):
ATC at LHR is provided by NATS which effectively governs most of the airspace in South-East England.

Enroute service for all of the UK's and North Eastern Quarter of the Atlantic's airspace plus tower service at 15 of the UK's largest airports plus Gibraltar.

Quoting LHR27C (Reply 15):
They operate hand in hand with the CAA

CAA is the regulator.

Quoting LHR27C (Reply 15):
f they want to implement special procedures, they can - LHR has several ATC dispensations given its high level of traffic

Most procedures however are based on ICAO PANS-OPS/ATM. Any differences are subject to safety cases being produced and approval by CAA.



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
User currently offlineLHR27C From United Kingdom, joined Aug 2004, 1279 posts, RR: 16
Reply 20, posted (5 years 11 months 1 week 4 days 19 hours ago) and read 4899 times:

Cloudyapple

Thanks for the insight - you obviously know a lot more than me about this!

Quoting Cloudyapple (Reply 18):
8Nm are indeed required.

Thank you.

Quoting Cloudyapple (Reply 18):
You are wrong. The following is indeed correct.

So, you're saying it's sporadic and will depend on whether there is a high volume of arrivals at the time of the inbound A380?

Quoting Cloudyapple (Reply 19):

Arrival spacings are distance based. Time intervals between arrivals are subject to variations depending on the strength of the wind. On a day where head wind is strong arrivals on 3Nm separation can be 3-4 minutes apart.

On the days in question from the logs, 2 minutes looked to be the average. The point was that compared to the runway's arrival rate in general on a given day, the extra amount of time between the A380 and subsequent aircraft is not as massive as some people have expected. LHR would, in theory, be most vulnerable to increased spacing because of its high runway utilisation rate. So it is good to see A380 ops having little effect on the airport's movement capacity.

Quoting Cloudyapple (Reply 18):
So the A388 may have landed 17:46:00 and the A321 landed 17:48:59, giving you the required 8Nm.

Or the SBS data is inaccurate, which seems to happen sometimes.



Once you have tasted flight, you will walk the earth with your eyes turned forever skyward
User currently offlineCloudyapple From Hong Kong, joined Jul 2005, 2454 posts, RR: 10
Reply 21, posted (5 years 11 months 1 week 4 days 11 hours ago) and read 4765 times:



Quoting LHR27C (Reply 20):
So, you're saying it's sporadic and will depend on whether there is a high volume of arrivals at the time of the inbound A380?

Yes it is decided tactically depending on the length/expected length of the arrival queue.

Quoting LHR27C (Reply 20):
Or the SBS data is inaccurate, which seems to happen sometimes.

I was not saying it was inaccurate but we simply didn't know HOW accurate it was. Assuming it's accurate, it looks like it's only accurate to the minute, not to the second and is always rounded down. Standard 3Nm separation on average means 70s between arrivals in calm wind. 4Nm is about 92-95sec, etc. These time values will depend a lot on factors like wind, aircraft type mix and hence approach speeds. Not all types do the standard 160kt to 4DME. It varies a bit.

The log however, simply does not allow you to distinguish between 61 seconds 119 seocnds for example, since everything in between is rounded down to 2 minutes.

But if you look at the radar and measure the distance separations, 3Nm means 3.0nm, 4Nm means 4.0Nm, no more, no less. Heathrow's FD is dead accurate.



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
User currently offlinePW100 From Netherlands, joined Jan 2002, 2366 posts, RR: 11
Reply 22, posted (5 years 11 months 1 week 2 days 20 hours ago) and read 4432 times:

I guess they want to land the A380 at the southern runway for ease of ground manouvering. If I'm not mstaken, it parks at pier 6. See this chart for LHR A380 rated taxiways:
LHR Aerodrome Chart A380 Ground Movement - ICAO

Big version: Width: 600 Height: 389 File size: 126kb
LHR A380-rated taxiways (shown in yellow)


Regards,
PW100



Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 24
Reply 23, posted (5 years 11 months 1 week 2 days 13 hours ago) and read 4314 times:

Is the A380 able to use all of the turnoffs from both runways, or does it have to taxi to destinct turnoffs (= occupying the runway for a prolonged period) ?
-HT



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
User currently offlineCloudyapple From Hong Kong, joined Jul 2005, 2454 posts, RR: 10
Reply 24, posted (5 years 11 months 1 week 2 days 9 hours ago) and read 4210 times:

Quoting HT (Reply 23):
Is the A380 able to use all of the turnoffs from both runways, or does it have to taxi to destinct turnoffs (= occupying the runway for a prolonged period) ?
-HT

South runway yes. North runway no. Long stretches of Twy A/B along the north side are only Code E. Add to this frequent push backs from T1 domestics add to the congestion.

Longer runway occupancy is not a big issue because of the increased spacing following any A380.

[Edited 2008-08-21 02:35:04]


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
User currently offlineHT From Germany, joined May 2005, 6525 posts, RR: 24
Reply 25, posted (5 years 11 months 1 week 2 days 8 hours ago) and read 4109 times:



Quoting Cloudyapple (Reply 24):
South runway yes. North runway no. Long stretches of Twy A/B along the north side are only Code E. Add to this frequent push backs from T1 domestics add to the congestion.

Longer runway occupancy is not a big issue because of the increased spacing following any A380.

Thanks for clarification.
-HT



Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !
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