feeder fix time/ required time of arrival (RTA)
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feeder fix time/ required time of arrival (RTA)
Quite often ATC will specify to cross a waypoint at a particular time.
How accurate must the aircraft be crossing this fix ?
Is within +/- 30 seconds good enough ? (considering that our timepiece only needs to be accurate to within +/- 30 seconds)
Some pilots aim to cross exact on time using whatever thrust/speed brake to make it happen whilst others happily accept anywhere within +/- 30 seconds.
Any ATC care to comment ?
How accurate must the aircraft be crossing this fix ?
Is within +/- 30 seconds good enough ? (considering that our timepiece only needs to be accurate to within +/- 30 seconds)
Some pilots aim to cross exact on time using whatever thrust/speed brake to make it happen whilst others happily accept anywhere within +/- 30 seconds.
Any ATC care to comment ?
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just a pilot but..
Depends on what equipment you are on. Dare say they expect the 320/73 guys to be pretty accurate (GPS Clocks).
I try as hard as I can to meet their request and if it looks as though I can't let them know. It kills the fuel savings and is annoying when they give it to you 1 second after top of descent. I do try to keep in mind how understaffed they are and thus don't ever complain.
Find most are quite appreciative if you help however/wherever you can.
I try as hard as I can to meet their request and if it looks as though I can't let them know. It kills the fuel savings and is annoying when they give it to you 1 second after top of descent. I do try to keep in mind how understaffed they are and thus don't ever complain.
Find most are quite appreciative if you help however/wherever you can.
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Computer Derived Threshold Times will be accurate only if the captain throws the computer out the storm window as he overflies the threshold in the go-round after being too intimate with the aircraft in front.
Depends on what equipment you are on. Dare say they expect the 320/73 guys to be pretty accurate (GPS Clocks).
Too easy - just wind it back (vernier throttle in the Bo, in my case!) until the ETA at the waypoint on the GPS is the same as the ATC required crossing time!
Even I can do it, so it must be real easy.
Dr
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The times are designed to give a specific distance between a/c; ie 10nm, 15nm etc. Ideally everyone would get it perfect, and it would all work. However, pilot preceding may be +30 seconds, so pilot following, although spot on time, will need to slow down/ be vectored to meet the required spacing. Add to the mix differing a/c types, speeds and altitudes and there are just too many variables for it to work perfectly every time.
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As I typed this I realised how involved it can get depending on Duty runway,traffic mix, and acceptance rates at SY. This is just part of my perspective as a SY arrivals North controller.
ATC are allowed a tolerance from the SY flow of +/- 1 minute on the feeder fix time, i.e Cross Boree/ Yakka at time XX +/- 1 minute. How this tolerance is applied by the arrivals sector can cause headaches for Sy Approach or make it run smoother. Remember this is the ATCs tolerance, not the pilots.
We are planning on the pilot getting it as close to the time as possible. Appreciating that the winds are not always as forecast, and this may throw things out for the FMS.
From the North of SY the jets are usually STAR'ed to go through Boree, and the turbos through Yakka for the Calga STAR. Domestic jets from the North when on 16 or 34 usually are programmed for the shorter runway 16L/34R on the Eastern side as this fits better with the traffic from the South. They will fly to the East and southern arrivals to the West. It makes sense.
Heavies B747, B777, A340, A380, International A330,etc are programmed for the the long runway 16R/ 34L.
The flow system we use computes a landing time from the feeder fix to fly the usual approach path to the runway and and computes backwards. i.e. if the aircraft is going to land at time XX they need to cross the feeder fix at time YY. i.e XX minus the approach path.
What the computer doesn't allow for, to the Arrival controller, is spacing . It does not show the first 2 minutes of delay to the Arrivals controller as it assumes the SY approach controller can stretch them in the terminal area. The arrivals controller can work out whether you can shorten the aircraft up or lenghten them out to work the best sequence into SY, according to the flow.
When we have the mix of jet aircraft for 16L/16R or 34L/34R, MAESTRO (the acronym for the flow tool) doesn't differentiate, it displays that the aircraft for the differing runways need to go through the feeder fix (Boree) at the same time. This is when it gets interesting. Our display can give us feeder fix time which shows the MAESTRO order, and at the click of a mouse, also the runway view which shows us whose landing first. We can then assess who we will make No.1 and No.2,3,4,5, etc through the feeder fix and adjust the time/ spacing to suit.
Depending on the mix with the turbo props , we can also send the domestic jets down through Yakka for the amended Calga STAR to make the sequence work. We do appreciate that domestic jets don't like being pushed down low on this STAR because of the increased fuel burn but we are endeavouring to make the sequence work. We can't send them down the Calga track if we have the slower turbo props as the jets eat them up on descent. ( Personally I love the Dash 8 D's, they hold their own and more against the jets).
When you get the situation that MAESTRO is telling you to put 4 jets through BOREE within 2 minutes (roughly 10-12 miles) , you look at the RWY view and work out the order that they need to be for landing. You then might make the front one a bit earlier and the last one a bit later and hand them off 10 miles between each to SY approach, they then have something to work with.
Also, there is no use in using your +/- 1 minute tolerance to SY if you allow your turbo-prop through Yakka to be 1 minute early and your jet through Boree to be 1 minute late when SY are sequenced to have the jet landing before the turbo-prop on the same runway.
The upshot of all this.
Please get as close to your feeder fix time as you can, and when we muck you about even though you have done everything right in meeting your RTA, it is probably because someone in front ( reduce further/ turn right or left) or someone behind (increase now to 300kts/ track direct to ZZ and buggering up your profile), or maybe me, has stuffed up the feeder fix time.
When you get the "Track to direct to Boree/Yakka , maintain max speed cruise and descent, cancel speed restriction below 10'000ft" We want you to go for it!
P.S. I am always bemused on the very rare occasion that a pilot complains about being held or vectored, that they think I or my colleagues are enjoying holding or vectoring 10 or more aircraft when we could be giving them direct feeder fix/ unrestricted descent and getting them out of our airspace. Anyone who flew into or north of sydney the last 3 afternoon/ evenings will know what I am talking about. Have a nice day.
ATC are allowed a tolerance from the SY flow of +/- 1 minute on the feeder fix time, i.e Cross Boree/ Yakka at time XX +/- 1 minute. How this tolerance is applied by the arrivals sector can cause headaches for Sy Approach or make it run smoother. Remember this is the ATCs tolerance, not the pilots.
We are planning on the pilot getting it as close to the time as possible. Appreciating that the winds are not always as forecast, and this may throw things out for the FMS.
From the North of SY the jets are usually STAR'ed to go through Boree, and the turbos through Yakka for the Calga STAR. Domestic jets from the North when on 16 or 34 usually are programmed for the shorter runway 16L/34R on the Eastern side as this fits better with the traffic from the South. They will fly to the East and southern arrivals to the West. It makes sense.
Heavies B747, B777, A340, A380, International A330,etc are programmed for the the long runway 16R/ 34L.
The flow system we use computes a landing time from the feeder fix to fly the usual approach path to the runway and and computes backwards. i.e. if the aircraft is going to land at time XX they need to cross the feeder fix at time YY. i.e XX minus the approach path.
What the computer doesn't allow for, to the Arrival controller, is spacing . It does not show the first 2 minutes of delay to the Arrivals controller as it assumes the SY approach controller can stretch them in the terminal area. The arrivals controller can work out whether you can shorten the aircraft up or lenghten them out to work the best sequence into SY, according to the flow.
When we have the mix of jet aircraft for 16L/16R or 34L/34R, MAESTRO (the acronym for the flow tool) doesn't differentiate, it displays that the aircraft for the differing runways need to go through the feeder fix (Boree) at the same time. This is when it gets interesting. Our display can give us feeder fix time which shows the MAESTRO order, and at the click of a mouse, also the runway view which shows us whose landing first. We can then assess who we will make No.1 and No.2,3,4,5, etc through the feeder fix and adjust the time/ spacing to suit.
Depending on the mix with the turbo props , we can also send the domestic jets down through Yakka for the amended Calga STAR to make the sequence work. We do appreciate that domestic jets don't like being pushed down low on this STAR because of the increased fuel burn but we are endeavouring to make the sequence work. We can't send them down the Calga track if we have the slower turbo props as the jets eat them up on descent. ( Personally I love the Dash 8 D's, they hold their own and more against the jets).
When you get the situation that MAESTRO is telling you to put 4 jets through BOREE within 2 minutes (roughly 10-12 miles) , you look at the RWY view and work out the order that they need to be for landing. You then might make the front one a bit earlier and the last one a bit later and hand them off 10 miles between each to SY approach, they then have something to work with.
Also, there is no use in using your +/- 1 minute tolerance to SY if you allow your turbo-prop through Yakka to be 1 minute early and your jet through Boree to be 1 minute late when SY are sequenced to have the jet landing before the turbo-prop on the same runway.
The upshot of all this.
Please get as close to your feeder fix time as you can, and when we muck you about even though you have done everything right in meeting your RTA, it is probably because someone in front ( reduce further/ turn right or left) or someone behind (increase now to 300kts/ track direct to ZZ and buggering up your profile), or maybe me, has stuffed up the feeder fix time.
When you get the "Track to direct to Boree/Yakka , maintain max speed cruise and descent, cancel speed restriction below 10'000ft" We want you to go for it!
P.S. I am always bemused on the very rare occasion that a pilot complains about being held or vectored, that they think I or my colleagues are enjoying holding or vectoring 10 or more aircraft when we could be giving them direct feeder fix/ unrestricted descent and getting them out of our airspace. Anyone who flew into or north of sydney the last 3 afternoon/ evenings will know what I am talking about. Have a nice day.
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Not having a go at props just a question or two
max1,
From an ATCers perspective would it make much difference (or negligible) if props and jets went to respective airports. For example PH seems to be one of the worst. But you have a look at the variety of types in and out and think "well its no wonder!".
How come we get make max speed to the field shortly after Top of Descent? Or worse - min speed. Having said that max speed seems to be the one that gets handed out the most.
With regard to the feeder fixes I usually manage to get there within 0 to 0.2 of a minute. At what point would the controllers like to know 0.4 0.5?
When you ask for say 220 knots do you want it asap (as in manually intervene V/S speed brake etc) or just slow as the FMC would do it?
Just a couple of things I'm often wondering..
From an ATCers perspective would it make much difference (or negligible) if props and jets went to respective airports. For example PH seems to be one of the worst. But you have a look at the variety of types in and out and think "well its no wonder!".
How come we get make max speed to the field shortly after Top of Descent? Or worse - min speed. Having said that max speed seems to be the one that gets handed out the most.
With regard to the feeder fixes I usually manage to get there within 0 to 0.2 of a minute. At what point would the controllers like to know 0.4 0.5?
When you ask for say 220 knots do you want it asap (as in manually intervene V/S speed brake etc) or just slow as the FMC would do it?
Just a couple of things I'm often wondering..
When you ask for say 220 knots do you want it asap (as in manually intervene V/S speed brake etc) or just slow as the FMC would do it?
Just a couple of things I'm often wondering..
Just a couple of things I'm often wondering..
They'll slow down or go down but not both!
This stuff you wont find written anywhere...
And while we're asking questions,
When STAR speed restrictions are cancelled, but without any other instruction (ie max speed to the field, reduce to 250 kts etc) does that imply that you WANT us to go fast? Or does it mean that you dont really care either way if we speed up or stick to the speed limits?
Of course given the option and conditions permitting I'm willing to bet most would open the taps
When STAR speed restrictions are cancelled, but without any other instruction (ie max speed to the field, reduce to 250 kts etc) does that imply that you WANT us to go fast? Or does it mean that you dont really care either way if we speed up or stick to the speed limits?
Of course given the option and conditions permitting I'm willing to bet most would open the taps
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Yeah mince I've wondered that as well.
What about this. 250kts below 10,000. Is there a 10kt buffer either side as with other speeds? Some guys I fly with say yes others no. I go for 250 no buffers just in case.
What about this. 250kts below 10,000. Is there a 10kt buffer either side as with other speeds? Some guys I fly with say yes others no. I go for 250 no buffers just in case.
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If you cross a fix a minute early (as allowed) you'll more than likely get a vector or an earlier than usual speed reduction to 230/210kts etc (for sep or the sequence).
If you are doing 260 kts when you were asked for 250, you may get a vector or a further reduction to 230kts.
You can trust a Boeing to cross a fix at a stated time, you can NEVER EVER (EVER) trust an airbus to cross a fix at a stated time (or meet a level requirement). Airbuses get you stood down, Boeings are trustworthy.
If you are doing 260 kts when you were asked for 250, you may get a vector or a further reduction to 230kts.
You can trust a Boeing to cross a fix at a stated time, you can NEVER EVER (EVER) trust an airbus to cross a fix at a stated time (or meet a level requirement). Airbuses get you stood down, Boeings are trustworthy.
Too easy - just wind it back (vernier throttle in the Bo, in my case!) until the ETA at the waypoint on the GPS is the same as the ATC required crossing time!
Even I can do it, so it must be real easy.
Even I can do it, so it must be real easy.
Times when I wish I had had a camera, No.5791.
What is known in the trade as having a "Nigel" as an F/O, when the Captain is having a quick leak.
Tootle pep!!
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RTA function.
NOTE: Arrival time control performance will be ±30 seconds when accurate forecast winds have been entered and the airplane is not thrust or speed limited
Although intended to be used on weigh points at least 1 hr down track, they will do the job as described above, even at relatively short notice.
NOTE: Arrival time control performance will be ±30 seconds when accurate forecast winds have been entered and the airplane is not thrust or speed limited
Although intended to be used on weigh points at least 1 hr down track, they will do the job as described above, even at relatively short notice.
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P.S. I am always bemused on the very rare occasion that a pilot complains about being held or vectored, that they think I or my colleagues are enjoying holding or vectoring 10 or more aircraft when we could be giving them direct feeder fix/ unrestricted descent and getting them out of our airspace. Anyone who flew into or north of sydney the last 3 afternoon/ evenings will know what I am talking about. Have a nice day.
I am always bemused by the fact that we can take off from a capital city, fly several hundred miles, at a time and speed known to ATC, only to be told in the last few minutes of cruise that we need to lose several minutes or hold.
As though we all magically popped up from nowhere. Most of us are too busy muttering expletives to complain on air.
You may not have magically popped up from nowhere but the aircraft that departs from a considerably closer aerodrome did. Giving delays a long way out (as per ALOFT into SY) works well when the arrivals are well known and orderly but once things get busy and less orderly it becomes harder to manage.
You might be able to lose 18 minutes flying PH to ML but we then have to get you through the six aircraft holding ahead physically but landing after you. Far easier and safer to do it first in first out.
Also once you've lost that time there's no way to make it up if the sequence changes drastically such as LAHSO becoming unexpectedly available. Fabulous, you lost your 18 minutes. Pity that in the end you really only had to lose 6.
In the end, yes your magic box can work miracles, unfortunately the magic makes no allowance for the other 53 aircraft doing their own thing too. You're just as likely to run up the @rse of the guy ahead because you chose to lose the time on descent and he was doing it in the cruise. Until all that can be coordinated it's down to a decidedly basic box of tricks called me!
You might be able to lose 18 minutes flying PH to ML but we then have to get you through the six aircraft holding ahead physically but landing after you. Far easier and safer to do it first in first out.
Also once you've lost that time there's no way to make it up if the sequence changes drastically such as LAHSO becoming unexpectedly available. Fabulous, you lost your 18 minutes. Pity that in the end you really only had to lose 6.
In the end, yes your magic box can work miracles, unfortunately the magic makes no allowance for the other 53 aircraft doing their own thing too. You're just as likely to run up the @rse of the guy ahead because you chose to lose the time on descent and he was doing it in the cruise. Until all that can be coordinated it's down to a decidedly basic box of tricks called me!
mince, generally it means it's optional & that you can continue your current speed below 10. If we want high speed we'll ask for max or nominate a speed. If you feel the urge to floor it then ask.
Personally if I'm not fussed I'll just say "cancel speed restriction". If it's to retain spacing in the sequence I'll say "cancel speed restriction, continue current speed".
Personally if I'm not fussed I'll just say "cancel speed restriction". If it's to retain spacing in the sequence I'll say "cancel speed restriction, continue current speed".
Mr. Hat, it'd actually work better based on speed inside say 30 miles than type. A turbo-prop will run an Airbus down any day - not knocking the bus just that they're often slow down final.
We know that giving you speed changes once you've commenced descent is a pain but the sequence is a dynamic beast, particularly when many aircraft are nominally arriving at around the same time - a small change can shuffle the sequence significantly. There are a myriad of things that cause this.
A couple of aircraft who clearly have incorrect estimates (say a turbo-prop is grounding 20kts faster than expected or an International heavy is on an early descent & has already lost three minutes). We try to allow for this but sometimes we guess wrong. Sometimes these things get spotted later than is ideal because we're busy separating.
A heavy has a rethink & decides he needs a longer runway, or the wind picks up a bit & is too much for the guy we were sneaking onto a different runway ahead of everyone. Conditions improve and we can shorten a few up, opening the sequence up ahead of you. Or vice versa & we have to wind the acceptance rate out a bit, as well as allow for the loss of track shortening. Etc.
We know that giving you speed changes once you've commenced descent is a pain but the sequence is a dynamic beast, particularly when many aircraft are nominally arriving at around the same time - a small change can shuffle the sequence significantly. There are a myriad of things that cause this.
A couple of aircraft who clearly have incorrect estimates (say a turbo-prop is grounding 20kts faster than expected or an International heavy is on an early descent & has already lost three minutes). We try to allow for this but sometimes we guess wrong. Sometimes these things get spotted later than is ideal because we're busy separating.
A heavy has a rethink & decides he needs a longer runway, or the wind picks up a bit & is too much for the guy we were sneaking onto a different runway ahead of everyone. Conditions improve and we can shorten a few up, opening the sequence up ahead of you. Or vice versa & we have to wind the acceptance rate out a bit, as well as allow for the loss of track shortening. Etc.
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You may not have magically popped up from nowhere but the aircraft that departs from a considerably closer aerodrome did. Giving delays a long way out (as per ALOFT into SY) works well when the arrivals are well known and orderly but once things get busy and less orderly it becomes harder to manage.
In the end, yes your magic box can work miracles, unfortunately the magic makes no allowance for the other 53 aircraft doing their own thing too. You're just as likely to run up the @rse of the guy ahead because you chose to lose the time on descent and he was doing it in the cruise. Until all that can be coordinated it's down to a decidedly basic box of tricks called me!
Unfortunately, like me it doesn't like normal descent + now min speed descent + holding + vectors + re-intercept star + max speed to the field + track shortening + cancel height rqmt + cancel speed restriction + on second thoughts slow back down to min speed; all in the one descent.
The idea of 52 other aircraft crews having this sort of schizophrenic workload at the same time, at the same place is just scary.