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Time based final approach spacing

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Time based final approach spacing

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Old 11th Feb 2015, 18:18
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Fair play kcockayne.

I guess I just feel slightly piqued when those who admit they are not familar with the project say that the changes are being introduced without evidence/safety assurance etc.

I'm not getting at you personally here, BTW. TBS is coming to all major airports, by 2024 at the latest, I think; according to EC Implementing Regulation 716/2014:

Time-Based Separation for Final Approach shall be operated at the following airports:
—
London-Heathrow
—
London-Gatwick
—
Paris-Orly
—
Milan-Malpensa
—
Frankfurt International
—
Madrid-Barajas
—
Amsterdam-Schiphol
—
Munich Franz Josef Strauss
—
Rome-Fiumicino
—
Zurich Kloten (5)
—
Dόsseldorf International
—
Oslo Gardermoen (6)
—
Manchester Ringway
—
Copenhagen Kastrup
—
Vienna Schwechat
—
Dublin
I'd far rather provide wake turbulence separation that is based on science and fact than on a 'finger in the air', one size fits all approach that takes no account of atmospheric conditions and wake behaviour. The 'tried and trusted' wake separation rules applied in tailwind conditions result in a significant increase in wake encounters as decay rate is low. The data shows that we need need to increase separation in tailwind conditions. The data also shows, and I am more than willing to be corrected on this, that there hasn't been a wake encounter on approach at LL when the surface wind has been above 10kts (or is it 15kts? Not sure).

As for a total reliance on technology, I think ATC is well past that point! Did we have the same arguments when radar was first introduced for civil ATC?
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Old 11th Feb 2015, 18:19
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Safety Cases & Risk Assessments reared their ugly head during the latter years of me being an ATCO. I well remember being asked to carry them out (the whole unit never having done one before). We asked the SRG for guidance on what had to be done & how to do it. Their response ? None ! (other than that we'd have to find out for ourselves -which we did with the help of EGSS SATCO/Chief Officer).
Prior to that, ATC adopted a "Fail Safe" Approach.ie if the Radar failed, & separation was likely to be compromised, then it would have to "fail safe". This was built into separation standards etc. & applied to the whole range of ATC procedures in this, & other areas.
Safety Cases & Risk Assessment don't quite fill me with the same sense of confidence in the system, somehow. It's not so much that they don't Guarantee a safe system subsequent to the failure; but, that they seem to assume that there WILL BE NO failure !
It's not just ATC. Just look at ETOPS operations. I accept that there have been no disasters (for which I am exceedingly thankful ; although there was a very near miss in the Azores with the TSC EA33; but, how can Risk Assessment & Safety Cases guarantee that there never will be ?
And IF there ever are any, no amount of Safety Cases & Risk Assessment exercises are going to avoid them !
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Old 11th Feb 2015, 18:31
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Gonzo

Just seen your latest. Thank you for your comments. I take your point about science & technology & would, in NO WAY, seek to accuse you of not going about these subjects without due diligence or without satisfying yourself as to their efficacy.
Reading my post, above, I guess that it becomes pretty obvious that we come from two very different ATC cultures. Mine being one where the ATCO was in "total control" & yours being one where you are prepared to totally trust in technology.
As I have said before in these pages, I am glad that I am now out of it....and, you probably are , too !
Nevertheless, I genuinely wish you well with it all. Maybe, one day I'll come back & visit & be totally impressed with it all. Or, maybe I'll still pick holes !
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Old 11th Feb 2015, 20:07
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kcockayne,

& yours being one where you are prepared to totally trust in technology.
Well now, lets not be rash!

I think we have more in common than you believe. Given the opportunity to do GMC from the old tower at Heathrow, with paper strips, and no A-SMGCS I'd bite your hand off, especially if it was bandboxed and really busy. That was FUN!

A simpler time.

Technology, and the demands of the industry, have moved on. I think we have just about reached the limit of ATCOs being in 'total control' in terms of capacity, and to keep on that upward curve, tool support is the only way forwards. An ATCO remembering the 6 UK wake categories and the separations is feasbile, but Static-Pair Wise separation, with a 96x96 matrix of individual aircraft pair separations to the nearest 0.1nm is beyond anyone's comptence.

I have raised, and still raise, issues with new projects, equipment and procedures. That's why I started getting involved in them.
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Old 13th Feb 2015, 02:28
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Interesting, we did timed approaches in non-radar environments back in the '70s, then went to radar separation, then were told that ADSB accuracy was going to improve all that, then I read here that GB is going back to "Timed approaches" again. What's old is new again.


V4F, (3 wonderful years retired now)
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Old 17th Mar 2015, 08:48
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Think this has started already? How's it going?
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Old 17th Mar 2015, 14:07
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Starts on 24th March, according to a NATS presentation I'm looking at.
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Old 26th Mar 2015, 22:46
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Forecast looks a bit blowy for the weekend.

Time to give TBS a whirl ?
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Old 27th Mar 2015, 01:13
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Cool

It has started now
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Old 27th Mar 2015, 07:38
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Originally Posted by 118.70
Forecast looks a bit blowy for the weekend.

Time to give TBS a whirl ?
Very droll.
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Old 28th Mar 2015, 16:38
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Flew down final at the standard 5nm behind a heavy (Cough in a medium) today despite 40kt headwind on final. Cleared to land at the normal point, with a normal slot delay on departure from the outstation.

Has TBS seriously started, or are you slowly easing into it?
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Old 28th Mar 2015, 17:16
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Originally Posted by Cough
Has TBS seriously started, or are you slowly easing into it?
A cynic might suggest that it will only operate Monday-Friday, 9-5.
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Old 28th Mar 2015, 18:39
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One CAA boss actually thought that ATC only worked from 9-5!
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Old 28th Mar 2015, 19:07
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Obviously eminently qualified to be a boss !
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Old 28th Mar 2015, 19:40
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Cough, yes, to both questions!


Bear in mind that it was only switched to Time mode on the 24th, so many ATCOs have not yet used it in such a mode outside of the simulator. Also, we are still in the phased introduction, so it may be that for a period around your arrival it was in distance mode anyway.


I've seen many wake pairs today separated by significantly less than that required under the distance separation criteria.
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Old 28th Mar 2015, 19:59
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Gonzo - Cracking to hear, we were both expecting to be quite a bit closer at the time, but a slow phase to this mode of operation without surprises is essential

Now, can we start on the CAA on moving the min radar sep for a medium to 2nm (only used in the TBS regime!).... Packing in us mediums would really help!
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Old 28th Mar 2015, 20:39
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As long as you get off the runway quickly!
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Old 28th Mar 2015, 20:43
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Cough,


2nm minimum radar separation is being worked on within SESAR.
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Old 28th Mar 2015, 21:01
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"2nm minimum radar separation is being worked on within SESAR"

I think Cough might like to benefit from this before he is due to retire!!
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Old 29th Mar 2015, 19:01
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HD - Was getting off the runway in time ever a problem in 40kt headwinds? 15kt TW to 100' always makes things exceedingly tight, though minimal holding!

Gonzo - Thanks for that - Will be a long time off then!

EastOfK - All I'll say is by the time that it does come along, I probably won't be concerned with medium wake vortex!
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