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A380 landing roll

Old 30th Mar 2014, 22:14
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A380 landing roll

We already lose an arrival slot behind the A380 because of wake turbulence. Often A380s require to roll to the end of the runway on landing (3.6km) past a rapid at 2km and a square turn at 2.7km. This then costs a departure slot as well.

The reason given for the requirement to roll through is, the company schedules a tight turnaround and often the brakes don't have enough time to cool down before departure if they hammer them on arrival.

Does anyone else find this frustrating? And should the rest of the airport users be punished because the company has scheduled a tight turnaround??

Do other airports have a similar issue with this aircraft. Are A380s routinely allowed to roll through in Dubai?
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Old 31st Mar 2014, 17:48
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I am not sure how you "lose" an arrival slot behind the A380. Wake separation is wake separation A380 or not. The same could be said for traffic following a heavy? The flow rate into an airport should take into account the number of heavies per hour?
Out of interest, with increased spacing on arrival is it not possible to get a departure out in between, even with the aircraft rolling to the end of the runway?

When the A380 started into YYZ they used full reverse on landing and made all the high speed exits. They were told that they didn't have to because they were causing a lot of "detritus" to get blown all over the runway and taxiways. They usually now roll to the end. Both tower and approach work around it.
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Old 31st Mar 2014, 19:38
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The reason given for the requirement to roll through is, the company schedules a tight turnaround and often the brakes don't have enough time to cool down before departure if they hammer them on arrival.
Seriously? Do the brakes on an A380 take over 4 hours to cool down, even in a sub-zero Toronto?
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Old 31st Mar 2014, 23:57
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The trouble is some crews will roll to the end (without prior notice), and some will not. But when they do, that's reason for it. It just happens to be convenient that their gate is at the end of the runway.

It seems backward to me that everyone is doing their best to maximise the use of the runway at a very congested airport, but the A380s want to roll through because their turnaround is so tight.

B744s B773s A330s don't really affect our arrival rate much because during mixed mode the arrival spacing is 5 miles (2mins) anyway, and they almost always use the high speed exits. The flow behind the A380 is 4mins.

It's really not a problem if there are no departures waiting because with a 7/8 mile wake turbulence gap behind there is enough room for it to roll to the end, but certainly not enough for a departure to go.
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Old 1st Apr 2014, 06:14
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Yeh genius. And how does that help the departures waiting at the holding point? With a 7 mile gap I could get at least 2 and maybe 3 departures out instead of none when they roll through. Oh well who cares aye. It's not my money
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Old 1st Apr 2014, 07:04
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The "C" at the end of ATC may provide a clue. In Dubai we don't tend to ask people where they want to vacate we control it.
A380's have the brake to vacate system and depending on where we instruct them to vacate the plane works out the best way to get there so we have no issues with losing a departure slot.
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Old 1st Apr 2014, 08:57
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I don't have to ask or tell aircraft where they will vacate. There is a NOTAM requiring aircraft to vacate at the rapid exits, and if unable, inform ATC.

The issue here is totally about the aircrafts REQUIREMENT to roll to the end, for what to me seems to be a very selfish reason. If you're brakes don't have time to cool down, don't schedule the turnaround so tight.

When landing on the opposite runway which requires a long taxi back to the gate, they always vacate.

I'm happy for you that you were the first controller to coordinate with approach for a departure gap, or change the departure sequence to maximise use of the runway. Has nothing to do with the A380 rolling through. Genius.
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Old 1st Apr 2014, 09:35
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Tower Ranger.... well said.
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Old 1st Apr 2014, 09:40
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Charlie, you'll have to excuse me for disagreeing with you but if you are relying on a Notam to control your traffic you have bigger problems than a roll through to worry about.

We have around 40 A380's based here and they can vacate 2500m down the Rwy every time they are required to with no brake issues for their turnarounds on a dry rwy.with a fairly high ambient temperature.

You have asked a question that you appear not to like any of the answers to so just keep looking out of the window, enjoy watching the planes go past and ask one of the responsible adults at your unit to sort it out for you.
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Old 1st Apr 2014, 10:44
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So what you're really doing here is agreeing with me. They don't require to roll through at all. They want to roll through because they vacate at the end right next to their gate and they explain their decision with a story about brake temps.
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Old 1st Apr 2014, 11:12
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They don't require to roll through at all. They want to roll through because they vacate at the end right next to their gate and they explain their decision with a story about brake temps.
.......which by the looks of things you have accepted and come on here to moan about it. My company has a reporting system which, if I felt something was unacceptable, I would use to clear up issues such as this. Or I'd use my experience of once bitten, twice I take much more positive (AT) Control.
And it's not about you, the service provider anymore, it is all about the customer, and your superiors that count the pennies will tell you that all day, any day, and sadly you will just have to accept it.
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Old 1st Apr 2014, 11:49
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And it's not about you, the service provider anymore, it is all about the customer, and your superiors that count the pennies will tell you that all day, any day, and sadly you will just have to accept it.
I don't think the OP was concerned about himself, he was (I believe) trying to represent the interests of the many customers (departures waiting at the holding point) over the few (A380 inbound).

Is it really so wrong to voice frustration here that the system where he works isn't doing a good enough job at balancing the needs of all runway movements?

I do have sympathy with the OP and can understand why so few professional pilots visit this forum when we can't even empathise with our fellow ATCOs.
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Old 1st Apr 2014, 12:21
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I take it Charlie is from BNE? If so it goes something like this:


Landing on 19, the high speed exit A6 is at 2000m. And A7 (90 degree) is at 2700m.
When landing in BNE an EK 380 is circa 380000kg to 390000kgs (the take-off weight of a B744) as it will be carrying over 20t fuel as SYD will be the Altn. If exiting via A6, brake temps will exceed 450 degrees by the time of parking. If exciting A7 they will also be in excess of 400 degrees as the aircraft needs to slow to 10kt prior to the 90 degree turn. Both these numbers will delay the turn around of the flight departing to AKL as brake cooling is not available at BNE.
On 01, at the same landing weight the extra taxy distance from the runway end means that the brake temps will be the same from either A3 (90 degree) or using full length. So to help the airport flow, most crews will take A3 an shutdown engines while taxying to mitigate brake temps. There is insufficient engine stabilisation time to engine out taxy when using 19.
When 19 is in use for departure, the almost 4km taxy to runway start increases brake temps a lot. So cool brakes are needed before taxy starts. The short taxy to 01 means that a higher start brake temp can be accepted. Meaning the higher temp from A3 is not as limiting.
At most runways we use (ie not these little country type airfields), the high speed exits are placed at least 2500m down the runway, meaning they can be used without too much adverse effect on the brake temp.


So in short, no, the Ek 380 crews are not trying to ruin your day, they are trying to make the best of the runway you present them.


You may loose a slot, but in the mean time they have delivered the same pax load of almost 4 of those low cost 320s/737s that take the 40sec delay. No wonder the airport owner can build such nice car parks.


The Don
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Old 1st Apr 2014, 14:10
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as brake cooling is not available at BNE
Hang on a minute, I think I might have an idea ...
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Old 1st Apr 2014, 15:38
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Is there cocci stent wake separation being used around the world where the Super lands? What are various places using? I used to control in this 'BNE' place and at one stage we had to use 15 miles behind a Super, all types.
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Old 1st Apr 2014, 16:22
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Dave you buy em and we will use them, the sometimes once or perhaps two times a day they are needed.
If the airport needs the 380 to vacate earlier perhaps they will pay for them. But I am thinking there must be some serious airport problems if two arrivals, one in the morning and one in the evening cause so much of a problem. Total of 80 seconds per day lost due to runway exit at the end. Non if the other runway is in use.
Too many FIFO perhaps?

The don.
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Old 1st Apr 2014, 21:35
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But I am thinking there must be some serious airport problems if two arrivals, one in the morning and one in the evening cause so much of a problem. Total of 80 seconds per day lost due to runway exit at the end. Non if the other runway is in use.
From Deloitte:

Deloitte has calculated that in Europe the most valuable landing slots are those at London Heathrow, followed by Charles de Gaulle, Gatwick and Frankfurt. Based on a recent transaction the implied value of a pair of peak time slots at London Heathrow is currently worth between 25 and 30 million. The value of slots varies primarily depending on the time of day they are for.
80 seconds is an extremely expensive amount of time, perhaps not quite a pair of slots but definitely one half of a pair. I've had similar reports about A380 brake cooling times but I think a 3600m is excessive. 2000m should be achievable but considering the issues perhaps you could compromise with them on 2700m. Take control, both on the RTF and by engaging the airline with your issues.
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Old 4th Apr 2014, 03:14
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Landing on 19, the high speed exit A6 is at 2000m. And A7 (90 degree) is at 2700m.
When landing in BNE an EK 380 is circa 380000kg to 390000kgs (the take-off weight of a B744) as it will be carrying over 20t fuel as SYD will be the Altn. If exiting via A6, brake temps will exceed 450 degrees by the time of parking. If exciting A7 they will also be in excess of 400 degrees as the aircraft needs to slow to 10kt prior to the 90 degree turn. Both these numbers will delay the turn around of the flight departing to AKL as brake cooling is not available at BNE.
On 01, at the same landing weight the extra taxy distance from the runway end means that the brake temps will be the same from either A3 (90 degree) or using full length. So to help the airport flow, most crews will take A3 an shutdown engines while taxying to mitigate brake temps. There is insufficient engine stabilisation time to engine out taxy when using 19.
When 19 is in use for departure, the almost 4km taxy to runway start increases brake temps a lot. So cool brakes are needed before taxy starts. The short taxy to 01 means that a higher start brake temp can be accepted. Meaning the higher temp from A3 is not as limiting.
At most runways we use (ie not these little country type airfields), the high speed exits are placed at least 2500m down the runway, meaning they can be used without too much adverse effect on the brake temp.
thank you for that.

the sort of info famil flights were great for when more readily available ....
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Old 4th Apr 2014, 06:16
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So what we're saying is the on time performance of the A380 is king. Never mind the aircraft waiting at the holding point burning fuel.

Vacating at A7 means the difference between getting a departure or maybe two away, or none. This means up to an extra 3 mins for each aircraft waiting. If there are 5 aircraft waiting, cumulatively speaking that's 15mins of delay with engines running.

When an aircraft says they require something, that means it is not negotiable, they will roll to the end. It is not the byproduct of my lazy ADC as some wizards have assessed.

I also understand the frustration regarding the placement of the high speed exits (particularly on 19). Aircraft missing the high speeds is something we battle with every day and is probably the largest cause of go-arounds.

I think it's reasonable these aircraft vacate at A7
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Old 4th Apr 2014, 09:12
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GT3
 
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For a bit more info the BTV function in the A380 has runway usage timings on the display when you select what runway exit the aircraft will slow for. For example at Heathrow using N6 or N7 on 27L only has an extra 10 seconds or so (if I recall correctly) on the landing roll as the aircraft does not use the brakes until needed to slow for the turn.

However the difference in brake temps between the two exits was quite interesting and the turnaround times much shorter when using the "longer" landing roll out.
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