Hi Ferris
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It's not very good. How do you intend to hold a/c closer to the field at up to 13 000' ? You won't get them down and they'll get vectors all over the place to lose height. The mechanics of holding mean that the longer the hold runs, the higher and higher the aircraft are (if the in-trail-spacing leaving the hold is less than the distance around a pattern). You would also have to deal with the low-level overflyers (C130s etc) and insertions (Kish Isl). Departures would also be held down for a long time. I still don't see the problem with holding as we are now, and APP owning the bottom 2 levels. Holding is a vertical thing, so I have no idea why you want a/c run INTO the hold with 10nm spacing. Bringing them OUT of the hold is where the spacing is achieved. Also, how is the problem of the vectors after holding addressed? Read the pilot comments. It is almost a safety issue that at the moment we bring them out 10nm or whatever spaced, then APP still has to synchronise east, west and AUH arrivals. Flowing for threshold arrival times solves all that. It isn't rocket science, and could easily be achieved either manually or via automation (MAESTRO etc)
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Okaaay, so the whole of Europe are doing it wrong eh? My experience prior to here is only the UK but I think we do ATC pretty well there.
Holding - A/c enter the hold at FL150 or whatever is appropriate depending on the volume of traffic. A/c are then laddered down in the hold to the bottom then they leave at 8,000 feet so you can hold much closer to the airfield. The holding stack is therefore placed 25 to 30 track miles from touchdown. DESDI and BUBIN are too far away from one of the landing direction (DESDI is good for 12 and BUBIN for 30 but not vice versa) so a 3rd stack is needed. Actually overhead the DUB would work nicely (when we get access to another non-airfield radar) and also allow a totally non-radar procedural system to be designed in case someone with a shovel cuts the essential cable. A/c would route DESDI - DUB for 30 and BUBIN - DUB for 12. Having the hold overhead then means it conflicts with the SIDs for the minimum time and a/c approach the field 'down the pipe'.
Sequencing is an approach task. Owning the bottom 2 levels of a hold is insufficient and inefficient. Just ask any approach ATCO what he thinks when he sees Area trying to manage a stack on 100nm range settings. It's painful to watch. Control of the stacks should be delegated to the airfield - it is virtually everywhere else.
The system requires that
a) Area control gets the a/c descending to around FL150 before the handoff (just above is ok but 10,000 extra feet of fresh air is unacceptable). If they are at least 6 miles apart in-trail and speeded then they can be transferred in the descent to separated levels otherwise they have to be actually level.
b) A/c come out the hold at the bottom having been laddered down to enable more a/c to go in at the top. In my experience it is very difficult to fill a stack so that area run out of levels unless there is a runway blockage.
If everyone is doing it properly (with the Dubai Coordinator becoming a tactical planner and / or stack controller) then Area will probably be dropping to FL150 all night without the need to hold higher.
From the hold a/c are radar vectored (in the UK) but with the proposed introduction of RNP 1 to the UAE in 2005, properly designed post-holding STARs may be usable. It doesn't really matter how they get from the hold to the ILS as long as they do it expeditiously. The pilots will be happy with that because they don't get taken on any more midnight cross countries. Proper application of speed control in the Approach environment is essential in high capacity operations. Also the matter of runway occupancy by a/c needs to be addressed.
Low level joiners are a pain but easily accommodated. I believe Gatwick in the UK still has these and they're fitted in without any gnashing of teeth.
It is a mature system that has been refined over many years and needs only ATCOs who a reasonable amount of ability and flexibility. What is also essential to integrating multiple stacks is training and practice which is where our simulators comes in.
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This simplifies the task for everyone and gives the customer the best service
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Forcing them down early to hold at low altitude? Not exactly 'the best service'. Issuing gate or threshold arrival times so that sequencing can commence whilst still prior to TOD is a much better option for the customer. Especially with modern avionics. The AN12s etc just have to be 'pushed'.
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The better service comes from them getting on the ground safely and expeditiously with the minimum of delay from holding or sequencing. I have no experience of threshold arrival times so cannot comment on it. I am however willing to learn so tell me where this system is in use at another busy TMA operation with multiple airfields and I'll go look it up.
EuroATC
We take people with the correct level of maturity and experience. The controller you mention was valid at a very busy UK airport and has therefore proved their ability. That controller can teach the rest of us here in Dubai many things about how to operate a busy tower properly using modern techniques. I for one have no problems with employing people like this.
Unfortunately, many ATC providers worldwide are listening to their accountants not their controllers and are developing single validation units. If we want to continue to recruit high calibre people we have to move with the times.
Clipped wings
Yes we are getting off the original subject but the discussions that have developed are very valuable. Why go back - we all agree that those contollers behaviour is unacceptable. I believe one of them can change but the other just doesn't give a toss which makes it a management issue.
Please don't let this AFTN thing degenerate into a 'yes it is / no it isn't' type slagging match as this thread has been one of the few I've seen that has generated almost universal agreement amongst ATCOs and pilots.
regards
Granny