Planes may leave late in new system - Perth
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How do the HK controllers stop the distance from closing up?
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Blockla, you are full of it, I flew in/out of HK for over 4 years, how bout you ?
We regularly landed 5 nm behind a heavy ( sometimes just over 3 behind a medium ), think about it, we were at 1500'/5nm/GS 2-2 1/2 miles a minute when the heavy touched down, not exactly ground breaking death defying stuff, but please carry on in your little dream world.
Nautilus, is was not a perfect system and of course not everyone can hold 250IAS to 15nm, I am not that stupid. There was vectoring, speed reductions etc but the cold hard facts are they handled nearly double the movements of PH with their own unique problems like terrain, weather, multiple different nationalities and multiple airspace restrictions very close to HK.
I am not saying Aus ATCs are useless , I am saying the current system was great 15 years ago but it is a joke now ( just like the whole airport ) and it will get markedly worse in coming years, something needs to be done other than saying " we've reached capacity ".
We regularly landed 5 nm behind a heavy ( sometimes just over 3 behind a medium ), think about it, we were at 1500'/5nm/GS 2-2 1/2 miles a minute when the heavy touched down, not exactly ground breaking death defying stuff, but please carry on in your little dream world.
Nautilus, is was not a perfect system and of course not everyone can hold 250IAS to 15nm, I am not that stupid. There was vectoring, speed reductions etc but the cold hard facts are they handled nearly double the movements of PH with their own unique problems like terrain, weather, multiple different nationalities and multiple airspace restrictions very close to HK.
I am not saying Aus ATCs are useless , I am saying the current system was great 15 years ago but it is a joke now ( just like the whole airport ) and it will get markedly worse in coming years, something needs to be done other than saying " we've reached capacity ".
Hi Hong Kong Phooey. I think it is you that is full of it. For some basic sequencing facts...... Two aircraft 10 miles apart out on the cruise in the mid 300s flight level wise, if descending from say 100-110nm with a slow down to 250 knots 10-13000 feet on the arrival will see you need a 20 knot indicated diffference from the time they transition to the indicated speeds as the guy in front willl be around 2000ft below and for every 2000ft, you need 10 knots indicated of difference just to match the ground speeds plus the extra 10 knots to account for the ground speed slow down as they approach the star constraint of 250 knots and even then you willl physically have to pull the back aircraft to 250 knots about 15nm from the height/speed constraint point. That is to just keep to 10 miles. Now, at about 60 to touch down, with matched ground speeds to have 5nm at touch down, you need 10.2-10.4nm between the aircraft if you are going to use 230 knots at about 30, 210 at about 15 then allow (instruct) them to slow to the same speed on final. We do this day in and day out and while Hong kong is not somewhere I have worked, I am assuming the laws of physics work the same there. Interestinglly I have flown in there up the front and there are some seriously track mile chewing arrivals and the ATC use lots of short cuts on them to secuence.
So from the above, If you have a beautiful line of aircraft out in the cruise all exactly 10 miles apart to just keep that during the descent, first one comes down at 320, 300, 280, 260 and everyone gets slowed to 250 at the arrival point, 15, 30 and 45 miles away from it all in a big consateena. Throw a fifth aircraft into that and we have holding/vectoring. Four aircraft five miles apart in the cruise is two too many and will require some air traffic control to be inflicted. For example, the same scenario I used above, for each additional 10 knots of indicated difference, you will gain about a mile. To dumb it down, front guy at 310 knots, second guy at 290 knots keeps your gap, if they are 7 miles apart, you need an additional 30 knots to get your 10 so the back guy comes down at 260 knots. Throw another 30 into that and now we have serious delays. If you can force the aircraft to transition onto indicated (ie descend early) at about 140 miles, 30 knots will give you 10 miles from a dead heat (ie 310v280). This is all pure speed control, hands off ATC. I personally prefer to make you all go flat out, get down fast and stick you into a holding pattern where I can drive the speeds and the distances to actuallly make you get to where you need to be when we mant you as opposed to some lax interpretation of it.
edited to add, the above is pure speed control to keep SPACING as opposed to speed control to achieve a cross point@time scenario.
So from the above, If you have a beautiful line of aircraft out in the cruise all exactly 10 miles apart to just keep that during the descent, first one comes down at 320, 300, 280, 260 and everyone gets slowed to 250 at the arrival point, 15, 30 and 45 miles away from it all in a big consateena. Throw a fifth aircraft into that and we have holding/vectoring. Four aircraft five miles apart in the cruise is two too many and will require some air traffic control to be inflicted. For example, the same scenario I used above, for each additional 10 knots of indicated difference, you will gain about a mile. To dumb it down, front guy at 310 knots, second guy at 290 knots keeps your gap, if they are 7 miles apart, you need an additional 30 knots to get your 10 so the back guy comes down at 260 knots. Throw another 30 into that and now we have serious delays. If you can force the aircraft to transition onto indicated (ie descend early) at about 140 miles, 30 knots will give you 10 miles from a dead heat (ie 310v280). This is all pure speed control, hands off ATC. I personally prefer to make you all go flat out, get down fast and stick you into a holding pattern where I can drive the speeds and the distances to actuallly make you get to where you need to be when we mant you as opposed to some lax interpretation of it.
edited to add, the above is pure speed control to keep SPACING as opposed to speed control to achieve a cross point@time scenario.
Last edited by Plazbot; 27th Mar 2012 at 09:32.
Thread Starter
It shouldn't be too long before the rogues are revealed. If there are no rogues, then the Metron arrival rate needs to be lowered!
It would also help greatly if the Metron Perth arrival slots were coordinated with the departure slots; no point in being assigned an outport COBT for the return to Perth that you're never going to achieve because you copped a 20 minute departure delay from Perth on the outbound leg...
Fooey, you're going a bit hard on the ATCOs. Failed physics, did you?
It would also help greatly if the Metron Perth arrival slots were coordinated with the departure slots; no point in being assigned an outport COBT for the return to Perth that you're never going to achieve because you copped a 20 minute departure delay from Perth on the outbound leg...
Fooey, you're going a bit hard on the ATCOs. Failed physics, did you?
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Official announcement last night at West Angeles. Aircraft arrived on schedule," We are loading you immediately, but we will be sitting on the ground for 45 minutes due to our late arrival slot". Immediate loading probably down to some intermittent heavy weather in the area, giving flexibility to depart earlier if deemed necessary?
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HFK - to summarise, if you were 5nm behind a heavy when it touched down (which I am happy to believe), you weren't 5nm behind it at top of descent.
From your example, 5nm behind at 2.5 nm/min is two minutes between arrivals. 2 min spacing at cruise, say 7 nm/min is 14nm at top of descent. Please bear in mind arrival sequence distance has nothing to do with ATC rules, procedures, or abilities. It is down to how long you take from landing clearance to clear of runway.
Capn Bloggs - unfortunately, as far was I know, we never go back over bad arrival gaggles to see what went wrong. This and the fact we reward the rouges I think is a major failing on our part.
If METRON gave you unachievable times it would be pretty useless, and its from 'merika where they have real traffic so it can't be
ETA
That should be treated as an 'incident' and investigated.
From your example, 5nm behind at 2.5 nm/min is two minutes between arrivals. 2 min spacing at cruise, say 7 nm/min is 14nm at top of descent. Please bear in mind arrival sequence distance has nothing to do with ATC rules, procedures, or abilities. It is down to how long you take from landing clearance to clear of runway.
Capn Bloggs - unfortunately, as far was I know, we never go back over bad arrival gaggles to see what went wrong. This and the fact we reward the rouges I think is a major failing on our part.
If METRON gave you unachievable times it would be pretty useless, and its from 'merika where they have real traffic so it can't be
ETA
Hazard Alerts out again for traffic holding today
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Blockla, you are full of it, I flew in/out of HK for over 4 years, how bout you ?
Did you even comprehend what I wrote I know I'm just a dumb controller, but ahem... you have clearly and comprehensively demonstrated your blinkered view of the world... Perhaps you may like to retract the "Full of it" remark when you actually understand it... But that is probably naive of me! Perhaps you can quote some more "science" at me...
say 7 nm/min is 14nm at top of descent.
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I hope that Metron is just having some teething problems, because the enroute and arrivals guys are hating it at the moment.
I think Bloggs is onto something as well regarding decel rates. Everyone's playing by different rules when we say "adjust speed to...". It doesn't help with a million different a/c types in the mix either.
As an example, we see the scenario every day where the 146 comes in, meeting his/her time and the groundspeed is almost a constant in the cruise as it is in descent. Qfa and Voz come hurtling in as number 2, at a higher altitude and overtake the 146, relying on dropping the anchors on descent. Problem is, they cant get down cos they're now overtaking and need vectors to get back behind/continue descent.
"But we're meeting our time". Not if I can't get you down, you're not. Maybe we need to get more proactive and make you go down earlier, but then that throws out all of your profiles, especially without notice. I'm not blaming the pilots at all, you're doing exactly as you were told. Most of the time, anyway
I think Bloggs is onto something as well regarding decel rates. Everyone's playing by different rules when we say "adjust speed to...". It doesn't help with a million different a/c types in the mix either.
As an example, we see the scenario every day where the 146 comes in, meeting his/her time and the groundspeed is almost a constant in the cruise as it is in descent. Qfa and Voz come hurtling in as number 2, at a higher altitude and overtake the 146, relying on dropping the anchors on descent. Problem is, they cant get down cos they're now overtaking and need vectors to get back behind/continue descent.
"But we're meeting our time". Not if I can't get you down, you're not. Maybe we need to get more proactive and make you go down earlier, but then that throws out all of your profiles, especially without notice. I'm not blaming the pilots at all, you're doing exactly as you were told. Most of the time, anyway
Thread Starter
I hope that Metron is just having some teething problems
ANTICIPATED AIRBORNE TRAFFIC DELAYS FOR ARRIVING ACFT
BTN 1100-1250 TO 40MIN
BTN 1100-1250 TO 40MIN
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I think Bloggs is onto something as well regarding decel rates. Everyone's playing by different rules when we say "adjust speed to...". It doesn't help with a million different a/c types in the mix either.
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Into PER the other night, bit of a sequencing nightmare, got given a direct to haige, then a vector, then a slowdown, then a speed up, then got asked if we could take a visual? Lotsa balls being juggled no doubt, but I'm starting to wonder......
"but it doesn't help all that much not receiving a star until inside 60nm of the top of descent. "
Seriously? Many places in the real world you are not locked onto an arrival until 60 to touch down let alone top of descent. You do realise there is more than one plane in the sky right?
Seriously? Many places in the real world you are not locked onto an arrival until 60 to touch down let alone top of descent. You do realise there is more than one plane in the sky right?
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Plazbot,
Leaving the star that late only gives you 6 minutes in the cruise to adjust your speed, which will comfortably only give you about +/- 30 seconds. This then leads to descent speeds and profiles which are wildly different from the standard un-impeded profile that would normally be flown, so ATC won't be able to predict what each aircraft is going to do to try to satisfy the fix crossing time. After finally satisfying that requirement at V-min+companyrequirement and the speed brake out, once past the fix speed restrictions are quite often lifted and track shortening is given to help the flow past the fix.
Leaving the star that late only gives you 6 minutes in the cruise to adjust your speed, which will comfortably only give you about +/- 30 seconds. This then leads to descent speeds and profiles which are wildly different from the standard un-impeded profile that would normally be flown, so ATC won't be able to predict what each aircraft is going to do to try to satisfy the fix crossing time. After finally satisfying that requirement at V-min+companyrequirement and the speed brake out, once past the fix speed restrictions are quite often lifted and track shortening is given to help the flow past the fix.
You do realise that even something as small as the visual star vs the ILS star can change the fix crossing time by over a minute, and a change in runway can affect the fix crossing time by 3 minutes, don't you?
For a Julim 5A Star, the feeder fix is for Julim whether it is for runway 21 or 03. If the aircraft in the stream are seperated by two minutes then that is constant. As Bloggs pointed out the decel rates are then the issue and what happens inside 15nm.
I have lost count of the times I have been slowed after the feeder fix and then arrive at Woora with nothing between me and the threshold, that is 15nm space infront.
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Icarus,
No, the point is the ATC required fix time does not change, but the aircraft's estimate of crossing the fix does - eg when it's all crosswind and the runway changes from 21 to 03, suddenly your profile through julim changes from about 10,500 to 19,000 feet - descent point moves about 25nm downtrack, you are at much higher TAS for much longer, so your estimate moves forward by up to 3 minutes. Now you and everyone else have to slow down to still meet the arbitrary julim requirement even though everyone is in the same boat and the spacing is still the same.
No, the point is the ATC required fix time does not change, but the aircraft's estimate of crossing the fix does - eg when it's all crosswind and the runway changes from 21 to 03, suddenly your profile through julim changes from about 10,500 to 19,000 feet - descent point moves about 25nm downtrack, you are at much higher TAS for much longer, so your estimate moves forward by up to 3 minutes. Now you and everyone else have to slow down to still meet the arbitrary julim requirement even though everyone is in the same boat and the spacing is still the same.
Thread Starter
Leaving the star that late only gives you 6 minutes in the cruise to adjust your speed, which will comfortably only give you about +/- 30 seconds.
As for late runway changes, I don't recall any major dramas or panic about feeder fix compliance; either you can or you can't, simple as that. Not your fault. ATC just manage with vectors until everything settles down.
Originally Posted by Plazbot
Many places in the real world you are not locked onto an arrival until 60 to touch down let alone top of descent.
Okay, thanks Bloggs, I see what you thought he meant now.
Surely we are also mixing two different systems here. If I have a published slot time to land in PH then that is my slot. I still get Julim fix times which do not in any way relate to that landing slot time. This means the system is already broken and flow and approach are trying to play catch up. It seems to me that even if most aircraft depart at COBT ATC still only really play the game of dealing with what they have got inbound and sequencing as they go. I can see why that would be the case and I am not criticising the controllers, just the system they are given to use. Then expecting us to carry 25-30 minutes traffic holding after delaying a departure by twenty minutes makes me wonder.
Exactly. I took a thirty minute delay from PH with a seven minute delay from the destination. Broken by default, there is no way that it could work.
Surely we are also mixing two different systems here. If I have a published slot time to land in PH then that is my slot. I still get Julim fix times which do not in any way relate to that landing slot time. This means the system is already broken and flow and approach are trying to play catch up. It seems to me that even if most aircraft depart at COBT ATC still only really play the game of dealing with what they have got inbound and sequencing as they go. I can see why that would be the case and I am not criticising the controllers, just the system they are given to use. Then expecting us to carry 25-30 minutes traffic holding after delaying a departure by twenty minutes makes me wonder.
It would also help greatly if the Metron Perth arrival slots were coordinated with the departure slots; no point in being assigned an outport COBT for the return to Perth that you're never going to achieve because you copped a 20 minute departure delay from Perth on the outbound leg...
Thread Starter
Icarus, Metron (or CTMS before it) is designed to spread out the arrivals so the rate remains manageable, nothing more. Feeder Fix times then contorl the actual sequence to the runway. I thought that was obvious.
Are you implying we just ditch one or the other? If you think you can hit your "published slot time" to the +/- 30 seconds you're better than me. What about if you get held up departing an outport due to traffic? You just arrive 5 minutes late and land in formation with someone at their "landing slot time"?
Of course ATC has to fiddle/massage/delay/speed up aircraft by issuing feeder-fix times after everybody's in the air.
If I have a published slot time to land in PH then that is my slot. I still get Julim fix times which do not in any way relate to that landing slot time. This means the system is already broken
Of course ATC has to fiddle/massage/delay/speed up aircraft by issuing feeder-fix times after everybody's in the air.