feeder fix time/ required time of arrival (RTA) [Archive]

max1

10th Nov 2010, 12:14

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.

Mr. Hat

10th Nov 2010, 20:32

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..

Going Nowhere

10th Nov 2010, 20:43

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..

Wondering the same thing. In the Q400 on a 3 degree descent at around 260-270kias, if we get told to slow down to say 220-230, it's going to take a loooong time unless we back the descent off.

They'll slow down or go down but not both! :E

mince

10th Nov 2010, 23:12

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 :ok:

Mr. Hat

10th Nov 2010, 23:16

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.

Jack Ranga

11th Nov 2010, 03:15

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.

LeadSled

11th Nov 2010, 06:26

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.

Eeeeerrrrrr ---- Aaaaas long as you don't fall ( or "plummet", the media preferred technical tern) out of the sky doing it, as did a BA 747 over Turkey a little while back !!!!! True story, all graphically witnessed by the QF1, about 4nm behind, and 4000 lower.

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!!

Skynews

11th Nov 2010, 09:05

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.

psycho joe

11th Nov 2010, 09:47

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. :ugh: As though we all magically popped up from nowhere. :ugh:

Most of us are too busy muttering expletives to complain on air.

le Pingouin

11th Nov 2010, 11:00

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!

le Pingouin

11th Nov 2010, 11:22

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".

le Pingouin

11th Nov 2010, 11:47

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.

psycho joe

11th Nov 2010, 12:53

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.

Wouldn't these be RPT with a known schedule.

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!

It could work miracles if it were allowed to. RTA + - 5 seconds, efficient descents, the whole bit. Why would the 52 other RNAV equiped aircraft be 'doing their own thing'?

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.:hmm: The idea of 52 other aircraft crews having this sort of schizophrenic workload at the same time, at the same place is just scary.

Skynews

11th Nov 2010, 13:20

I recall about 25 yrs ago, going into Sydney, we were tracking Calga - Sydney for runway 16, in a light turbo prop. At around 15 nm on final we were instructed to turn left heading (about) 080 and maintain max speed.
I remember having a dummy spit ( quietly). I simply didn't get it.

I think I have a better understanding now, I understand the " merging" concept, and that we all just can't keep heading towards the runway unhindered.

I imagine how easy it would be if we all maintained 310 kits to about 20 nm and then decelerated at the same rate to the same Vapp on the same descent profile. Predictable controllable enjoyable, and then I go to Darwin, it reminds me of the iPhone ATC game.Go fast, go slow, not given descent, when it gets busy "cancel Star" and vector here vector there, you name it, they have no idea of our limitations.:yuk:

Having said that and probably upset our RAAF friends, I think most ATC do a fine job, if I wasn't a pilot I think I could really enjoy the challenge, probably more "back then" but hey, that's life.

Blockla

11th Nov 2010, 13:39

Wouldn't these be RPT with a known schedule.And there are still many variables; using SY example, BTH, CB, NWA, WLM, ORG etc (will have known RPTs at times), but as you know they don't get away on time every time, some operators in the past didn't follow their departure times at all accurately. Pretty easy to get a 30 sec to 3 minute delay (or the delay removed because the CB jet didn't go on time) from somewhere to back up against an otherwise perfect sequence... Which means the whole thing is going wrong somewhere... Pigeon/Statue?

Then there are those pesky issues, such as a go-around, a medical flight, an emergency, an extra space due to taxiway congestion in an effort to get a few more airborne, weather (changing winds not scheduled, low vis etc.), a blocked frequency, unknown operational speed issue, etc. etc. If it were as simple as one follow the other etc then ATC would've been automated a long time ago.

I have also experienced FF (feeder fix) times given with 200+ miles to go getting completely bolloxed up... where speeds and vectors were needed to make it work... etc... Modern boeings seem to be more accurate, but there are also "how to get there on time" issues, go normal in cruise slow in descent vs go slow in cruise and normal on descent etc... It's not as simple as giving times and forgetting if the aircraft are a dead heat 80-120 before the fix...

In enroute we used to say "nail the first, stream the rest"... Which is easy when it's your stream, but if APP/DIR are merging arrivals alternatively from North East and West then what happens coming through RIVET etc is totally irrelevant if if the ones coming from the other ends aren't where they should be etc... I'm sure you'd rather comply with speeding/up/down as needed too to keep SY at 80 movements an hour rather than 75 etc... because everyone knows an airport not working at capacity isn't working... (let's not discuss political movement caps...)

PS you could fix almost everything if you went the European way and accepted delays in the holding stacks and on gates or airfield parking bays and forgot all about slowing down enroute, except for separation... I think the Australian way is much more 'efficient' even if pilots don't think so. Pilots don't seem to complain over here maybe because it's busier??? The reality it isn't, the busy bits are no busier they just last longer.

Jack Ranga

11th Nov 2010, 21:22

Wouldn't these be RPT with a known schedule

You need to get out a little more Joe! Out of your cockpit, into a TMA and watch what goes on. And not at a bull**** time of the day (unfortunately you'll only get in there when it's nice and quiet, PR have control of these now :ugh:. You need to get in there when it's busy.

Mr. Hat

11th Nov 2010, 22:14

I find that I have to be pretty proactive to achieve the fix times.

RTA in my machine works but does things that would work ok in a sim but in real life is a case of the machine over estimating its ability to handle turbulence and big wind changes. The speed bug sitting suddenly on MMo and then 1 knot above up/green dot speed is an example of RTA in my machine.

Personally I opt to not criticise as I don't have the full picture. I can say however a controller palming me to another frequency for further descent as I'm about to capture an altitude at high speed is very very annoying and is very uncomfortable for everyone on board. It seems also enroute to Perth from the east coast that the clearance seems to arrive a bit later than it should and we end up all arms and legs when its not what we expect.

Other than that I've accepted that when you fly along the east coast expect the worst.

One other thing. Max speed into say Gold Coast or Launceston doesn't work for Jets as the profile will bust just about every CTA step there is so why give it? Send us on a vector rather than put the workload to that level..

Skynews

12th Nov 2010, 00:06

Mr Hat, I don't get why a high speed descent would give you a shallower descent profile, I.e. Busting CTA steps?
I am guessing a bus?
Does it build in a long slow down level segment, if not I would have thought high speed = steep descent.

Mr. Hat

12th Nov 2010, 00:43

No was saying high speed=steeper descent and it clips the steps at the end (say last 45 miles). Box says shallower profile for slower speeds (no step problems).

The steps in these two locations in particular don't work for higher speed descents is what I was saying.

le Pingouin

12th Nov 2010, 01:12

Mr. Hat, sorry but does not compute. If you're higher & on a steeper descent how can you end up clipping steps that are under a shallower & lower profile? It only makes sense if you're ending up being lower further out on a steep profile....

le Pingouin

12th Nov 2010, 01:27

Wouldn't these be RPT with a known schedule.
So you're saying you're happy to lose a stack of time en-route on the off chance everyone departing from closer aerodromes gets away exactly on time?

You also need to get your head around the idea that times at fixes doesn't separate you from other traffic. All this you beaut automated stuff works wonderfully well when you're on your own but is ****e when there's other traffic in proximity.

Mr. Hat

12th Nov 2010, 02:06

Ah I forgot to say that this is a problem mainly when we get the cancel speed below 10,000 ft + make max speed to the field (i said it in my mind couldn't you hear me:ooh:? )

The 250/10000 ft shallows us out but when we take it out we run into trouble with the steps. Increases workload significantly where the steps are tight to begin with. I'm not spinning you a yarn i promise! Just my experience with it.

le Pingouin

12th Nov 2010, 02:14

Ah, makes more sense. Push nose down to gain speed & whoops, there's a step.

max1

12th Nov 2010, 07:09

Mr Hat
Personally I see airports as a vital piece of infrastructure, Farmer Bloggs coming in from Moree on a Dash, should have the same rights as Holiday maker Bloggs on a jet from Cairns, to use SY airport.
I won't go into the politics, there are far too many people making an industry out of that conundrum.

I read (somewhere) the other day that there are very few major airports that don't have parallel runways, we just happened to 'blessed' with a few.

Some of the cavalry have arrived to discuss points on this topic. I would urge any pilot who is interested to visit a centre. We get the rare frustrated comment about what is going on.

As regards to RTA, under radar we have a fairly good idea about who is trying to make good their RTA and who is taking the liberty of bullsh!tting. The vast majority of domestic pilots are endeavouring to get it right, and thank you. We also have some internationals, especially in the morning, who we watch like hawks. The SY flow are also adjusting the sequence based on the actions of the odd domestic and some internationals.

The joy of having some international carrier advise 3 minutes (15-20 miles) from the feeder fix that they are negative PRM, relaying this to the SY flow, and dealing with the fallout and revision to the RTAs is an interesting experience that I recommend to no-one.

As others have said, the sequence is a dynamic beast, the jet out of Canberra gets away with a 25 minute flight time. The jet out of Port Macquarie had a 37 minute flight time and held for 50+ minutes on Monday due to storms. As we sat there with 4 holding stacks going, I mused why the hell did they depart? Shouldn't someone have told them?

I see some press blurb about a project with lots of shiny suits patting themselves on the back because the SY-KLAX flight got unrestricted climb to cruising and direct tracking thereby saving the airline XX tonnes of fuel, I think we try to do that everyday.

I then look at MAESTRO as everyone is getting held into SY for 10+ minutes due to noise sharing, times that by the 15 aircraft that I can see, and think there's that fuel and then a fair bit more, plus all the poor buggers that are waiting for Farmer Bloggs from Moree, and Holiday maker Bloggs from Cairns to land, so they can pay their parking fees and get going. 40 on the Dash, 110 from Cairns. Thats a fair bit of excess parking, even given that not everyone is there to pick up just one punter.

Mr. Hat

12th Nov 2010, 07:55

Understood max1 thanks for the reply I read with much interest.

I suspected all along that those times were to be adhered to as best as possible. Am happy with my 0 to .2 at a maximum tolerance.

le Pingouin, if programmed from before top of descent it just stays steep until a deceleration segment (simplistically put). Normally that happens at 10,000 and its shallower thereafter. If the cancel speed + max speed happens after top descent generally the profile says your says something like 4560ft low and the power comes right up till it intercepts profile and then dives at idle. Either way certain ports have airspace that make the workload go ballistic should the crew opt to take the max speed below 10. Personally I've learned which ones do and don't and limit it accordingly.

Feel free to tell more. Its interesting to me. Gives me and others a bit more of a picture.

Dizzy Llama

12th Nov 2010, 08:26

keep it up max - great reading.

may even be a Chairman's award in it for you! :ok:

max1

12th Nov 2010, 08:36

Dizzy Llama,

Or more chats from mangement?

Nautilus Blue

12th Nov 2010, 23:12

Most of what max1 says goes for PH as well, without the noise sharing (thankfully), the parallel rwy and MAESTRO.

Wouldn't these be RPT with a known schedule.

PH, I think because we don't have MAESTRO, has slot times. All RPT operators submit schedules the night before, a sequence is worked out and landing times sent back to the companies. Some days it works better than others, some days it doesn't work at all. Unfortunately, we never go back and look at the days it doesn't to see if anything can be learned.

It could work miracles if it were allowed to. RTA + - 5 seconds, efficient descents, the whole bit. Why would the 52 other RNAV equiped aircraft be 'doing their own thing'?

A few issues. If you are on the same route as traffic immediately ahead/behind in the sequence, separation becomes an issue. For example, two jets, same route, same distance. #1 issued with a FF of x, calculates profile cruise, slow descent. #2 issued a FF of x+2, calculates profile cruise, slower descent. Now the top jet can't have descent until the distance opens up to 5 miles, the distance won't open until there is a speed difference, and there won't be a speed difference until they are on descent.

Another, for PH anyway, is sequencing prior to radar. If the flow waits until all the traffic is on radar to calculate the sequence, you will get significant delays at only ~120-140 miles out, so the sequence is now done further out and based on pilot estimates. (As an aside, PH ATC cannot see ADS-B.) Pilot estimates only have to be revised if they differ by 3 min or more. It's not unknown now for us to issue a fix time the aircraft can't meet because its now earlier than possible.

Additionally a lot of aircraft struggle to get +/- 1 minute, particularly if the winds are bad. In a sequence of 20, even an average of 5 seconds late adds up, and sod's law says the early ones never balance out the late ones.

I can say however a controller palming me to another frequency for further descent as I'm about to capture an altitude at high speed is very very annoying and is very uncomfortable for everyone on board. It seems also enroute to Perth from the east coast that the clearance seems to arrive a bit later than it should and we end up all arms and legs when its not what we expect.

Is that assigned A100 from ML Centre and then call PH APP for further? It is poor technique, but sometimes its quicker to tell you to call rather than coord a lower level with PH and then give it to you. What should happen of course is that you are transferred to APP before you need further descent. I was taught that arriving aircraft should never have to ask for descent. I have to confess I never knew leveling out on descent was a workload issue, I'll bear it in mind. We really do have very little understanding of how things that affect pilots unfortunately.

With regard to speed reductions and tolerances, we only see a radar calculated groundspeed rounded of to the nearest 10 knots. The speeds we issue tend to be 'suck it and see' because we issue indicated speed to control goundspeed. If you are doing 255 IAS instead of 250 we wouldn't know. If you are still catching, we'll slow you down more.

le Pingouin

13th Nov 2010, 10:24

Re. having to maintain when on a high speed descent. Sorry, but sometimes sh!t happens. We try not to let it but the hand-off process isn't automatic - I have to initiate it & the next controller has to accept you. All it takes is me being busy & starting the hand-off later than is ideal & him being busy so slow to take the hand-off. I can't just assign a lower level in someone else's airspace without their say-so, so you maintain. At least you that way you don't hit anyone.....

Unlike you I'm not staring at the one aircraft ;)

5miles

13th Nov 2010, 12:30

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.

No magic about it, simply other, possibly much smaller & slower aircraft departing from aerodromes within 20 - 30mins flight time. Could make an even bigger difference if your destination doesn't have capital city priorities.

And seriously, what would your complaints be based upon, or hope to achieve?

Wouldn't these be RPT with a known schedule.

TBH, known schedules mean nothing at the destination end. It's only actual times that have any bearing.

As for feeder fix times, +/- 30secs is workable so long as all other aircraft are that accurate, and fly expected speeds (and therein lies the crux). We regularly have an international MD80 series operator that can take anywhere from 9 to 15 minutes inside 40nm. Unfortunately we have no idea if today is Capt. Slow or Capt Quick's leg until well after the sequence is determined.

If you are early, just don't be surprised if you score a few extra track miles or further speed reductions. Likewise, if you're late, you might get asked to increase above normal profile speed.

Oakape

13th Nov 2010, 16:23

I always assumed that it was the same as leaving a holding fix. On time to 1 min early.

Me too, psycho joe.

Oakape

13th Nov 2010, 16:25

Can one of you guys tell me what descent speed above 10,000' you expect from RPT jets? A few years ago it was 300kts, but I have been told recently that it is now 280kts.

At EK we are expected to fly 'econ' descents & I have seen as low as 258kts & as high as 285kts on the 777, depending on weight & forecast winds. I imagine that this sort of speed variation would make the controller's job a little difficult to say the least so, when flying into the airports in Oz, I used to always program a 300kt descent above 10,000'. Now I am not sure what is required.

We also use the FMC default 240kts below 10,000' unless given a specific speed to fly.

rotorblades

13th Nov 2010, 23:19

Hi Max1
I mused why the hell did they depart

I did tell the pilot of the Port Flyer that there was significant delays verging on 1hour and would he prefer to take the delay on the ground, but the pilot said he'd get airborne and take his chance.

All the fun of the fayre but without the goldfish on monday.....

Rb

Nautilus Blue

14th Nov 2010, 03:53

Oakape -300 kts was what domestic jets used to fly, these days its mostly 280 kts. As a rule of thumb if you haven't been issued a time over a fix or a specific speed, it doesn't matter. We wouldn't base separation or sequencing on what we think is your descent speed, well not twice anyway! If you want to be sure there is no reason you can't tell us what your profile speed is when you are assigned descent.

le Pingouin

14th Nov 2010, 04:12

Oakape, in days gone past the domestics flew agreed speeds - 737 at 300kts & A320 at 320kts for instance. Now they just fly the econo descent as well, although generally it's at the upper end (at least it is when I ask). Tiger is the exception as they seem to use 320kts.

We expect International heavies to be slow so plan for it - I generally allow you guys at least an extra minute or two over a domestic when on descent as you tend to descend earlier & are slower inside 30 miles. Occasionally we get surprised and someone is doing 320kts.

Your actual speed only really matters when you're in trail with another aircraft & then we'll ask or give you a speed if needed. We'll increase you if it looks like you'll be later than expected at the fix, although that only works so much (too late & we drop you a spot in the sequence instead) - being late and a heavy is a bad combination on final for the following traffic.

In summary we expect profile, whatever that is on the day. So keep doing what you're doing & we'll adjust you as necessary.

Chief galah

14th Nov 2010, 05:57

Going back even further the B727's would do .85/350Kts to 20Nm or the DC9's .82/320Kts to 15Nm. Forget about passenger comfort.
Standard descent speed was .8/300Kts.
Anything below 280Kts would bring strong condemnation.

psycho joe

14th Nov 2010, 07:45

You need to get out a little more Joe! Out of your cockpit, into a TMA and watch what goes on. And not at a bull**** time of the day (unfortunately you'll only get in there when it's nice and quiet, PR have control of these now . You need to get in there when it's busy.

Jack, I think you may be right.

le Pingouin, Nautilus Blue, Max 1, thanks for the replies - some very good points there.

Nautilus Blue

14th Nov 2010, 08:30

Would there be any value in getting a video capture of an interesting sequence, adding a 'commentary' by the controllers involved and putting on the web?

Oakape

14th Nov 2010, 09:24

Thanks for the information Nautilus Blue & le Pingouin. Unless advised otherwise, I guess I'll just stick with econ then & keep the company happy.

Would there be any value in getting a video capture of an interesting sequence, adding a 'commentary' by the controllers involved and putting on the web?

Well I for one would be interested! I imagine that it would be very informative & a bit of a training tool to boot.

Blockla

14th Nov 2010, 09:25

Can one of you guys tell me what descent speed above 10,000' you expect from RPT jets? A few years ago it was 300kts, but I have been told recently that it is now 280kts. I'm not current with the procedures in Oz right now, but it seems little has changed.

I would expect you to be flying an "econ speed" descent unless I told you a specific speed. What "your econ" speed is is up to your FMS... It would be nice if pilots told us before tipping the nose over what speed they were planning, particularly if it's slower than 280K; sharing is caring... Mid 260's were seen a lot when econ speeds became fashionable and it did catch us out a bit. The cost index used by some is significantly different to others for many reasons, thus lots of different econ speeds even with same type same company...

As mentioned if you are on a FF time it matters not anyway in reality; if you are number 1 I'll be asking you what your speed is anyway due to the traffic following etc.

As for the original FF accuracy Q, I'd expect +/- 1 Minute. If you are early I might give you a speed and tell you to cancel the time, similarly if you are late.

The one that used to bug me was getting out of the holding pattern on time, often not much accuracy there... It annoyed me more if someone was 2 or 3 minutes late and didn't appreciate being told to speed up... 2 or 3 mins is a full slot, step on it pal... similarly coming out early and hot (above 250K) and being annoyed at being vectored to fit behind... Or coming out on time and being vectored or 'new speeded' because the one ahead stuffed it up; don't get cross with me...

Mr. Hat

17th Nov 2010, 08:10

Chief galah

Anything below 280Kts would bring strong condemnation.

Highly Amusing.

le Pingouin

having to maintain when on a high speed descent.

Is it possible though to get the hand over slightly earlier? Its the finger speed that is the trouble as the support pilot that can let flying pilot down in this situation in the haste to change frequency and then get a word in.

Great thread, my awareness at work has been a lot higher. I've been listening out for the internationals that give you grief and had a little bit of a chuckle at the tone of a Sydney controller dealing that exact situation.

On another note another one that disturbs me a little (read: a lot) is controllers blurting out instructions while were still doing anywhere between 100 - 50 knots whilst exiting on a rapid. The support pilot here is monitoring the roll out and in my type, the machine at this point is still a handful (read high workload) if something goes wrong the 186 POB would rather the support pilot isn't on the radio reading back something thats not absolutely vital. I guess were trained to expect anything - subtle incapacitation a tyre coming off anything.

Just my take. Regardless, myself and the majority of my colleagues respect you work and appreciate your efforts.

Look like the complete opposite to another thread running in the Airline forum!

le Pingouin

17th Nov 2010, 12:34

I work arrivals into ML & we can't hand you off too early as you'll be off the edge of the screen for TMA - they don't look out much beyond 40 miles. We try to hand-off in a timely manner but sometimes sods law intervenes & everyone is busy at just the wrong time. I aim to initiate the hand-off by 40 miles but if I'm late and TMA is slow to accept you're down to 30 miles fairly quickly. Obviously a problem onto 16 from the north.

Also because you have max and are approaching 30 miles I should have solved any separation & sequencing problems miles back so I've moved my focus on to other tasks. You're all done as far as I'm concerned except for the hand-off. I'll catch you in my scan of the screen but if I have several higher priority tasks to attend to you get to wait.

Any aircraft holding up the sequence is liable to being berated, encouraged to do better or hit with a wet fish. All sotto voce of course, well mostly :)

I'm not a tower controller but I'd guess some of it is just a lack of knowledge of the "other guys job" (I presume most aircraft would be a handful then too?) & taking the opportunity to fill a silence.

In the end we're all trying to do our jobs as best we can, some times less successfully than others. We're trying to move little green circles around & occasionally our best laid plans come unstuck - sometimes because we judge it wrong & sometimes due to pilot actions. Of course either way you get to wear the consequences as far as being dicked around goes.

Mr. Hat

17th Nov 2010, 19:35

Understood now I have the picture.

Do people bust control steps often? And if so what is usually the outcome? I've noticed different companies I've worked for have different levels of awareness of them from none to a must brief/monitor item.

Not sure about the other machines on the rapid. As you said "other guys job" so I can't say until I've flown em.

le Pingouin

18th Nov 2010, 02:06

We're supposed to keep you in CTA so assign levels accordingly - if you bust a step on descent then you've busted your level too, or I've screwed up. If I do assign a level below the current step it's because you're so far above it that to bust it you'd have bigger troubles than worrying about a CTA step on your mind.

Mr. Hat

18th Nov 2010, 03:18

Understood yes I noticed this in Melbourne. Not so everywhere though.

I've noticed the cleared levels in ML airspace coinciding with the steps.

Cheers again.

5miles

22nd Nov 2010, 12:17

Do people bust control steps often? And if so what is usually the outcome?

Within my terminal area, I occasionally see descent below the CTA step on a visual approach.
Although it is a pilot's responsibility to manage this aspect of their profile, if I see an aicraft hugging the steps, I would step them down till about 12nm.

IF I suspect or observe it's about to happen, I'd give the pilot a level maintain (and explain why) and/or give traffic if it's too late to catch before punching class G.

I'm curious as to how much of this is FMS related or pilot managed on the more modern types (A330/320, B777, B737 NG)

Capn Bloggs

22nd Nov 2010, 13:06

I occasionally see descent below the CTA step on a visual approach.
Precisely why I never call "visual" until I'm either in the zone or at the last assignable level before the zone.

I'm curious as to how much of this is FMS related or pilot managed on the more modern types (A330/320, B777, B737 NG)
Pilot-managed, sometimes via the FMS, with a great deal of difficulty, especially when not tracking direct to the field. In this day and age (big, very efficient "gliders"), it is a travesty that a 777 has to level off to avoid going OCTA on approach so that Dick and his no-radio mates can swan around at will.

le Pingouin

22nd Nov 2010, 14:39

I know we're living in a fantasy world but agree that maybe the steps need to be altered to contain modern aerodynamically efficient aircraft profiles, instead of those from the 1960s.....

Sorry, but an ultralight does not warrant the same consideration as a high cap RPT full of paying passengers. You can be excluded from a tiny extra portion of airspace to keep the fare paying public safe. The amount of trouble we have to go to to extend CTA steps is just ridiculous.

5miles

23rd Nov 2010, 00:09

Think I understand some of your concerns, but if the glide slope gradient on an ILS is perfectly achievable for a B777, why is there a need to adopt a more shallow approach on a VSA?
When left unchecked, I've seen A320/330s and the like at 2500' with 15miles to run.

Precisely why I never call "visual" until I'm either in the zone or at the last assignable level before the zone.

If you weren't to call visual until within my CTR then you'd likely already have been taken out for re-sequencing via an instrument app.
Also, what 'last assignable level' are you referring to? 500' above the CTA step adjacent to the zone, or other lowest safe?

Mr. Hat

23rd Nov 2010, 03:11

so that Dick and his no-radio mates can swan around at will.

Good point one that perhaps the Greens might be interested in? I know they are not pro aeroplane but the would have to support more efficient approaches surely.

but if the glide slope gradient on an ILS is perfectly achievable for a B777, why is there a need to adopt a more shallow approach on a VSA?

It all works out in theory but the reality is that modern jest and the FMS calculated descent profiles don't work in a number of palces around Australia. The descents aren't a straight line down they look more like a slippery dip and thats where it catches people out and increases workload, A few changes in airspace design would fix it.

Skynews

23rd Nov 2010, 04:43

Think I understand some of your concerns, but if the glide slope gradient on an ILS is perfectly achievable for a B777, why is there a need to adopt a more shallow approach on a VSA?
When left unchecked, I've seen A320/330s and the like at 2500' with 15miles to run.
The descent gradient for either will be identical until the point of speed reduction, and then configuring, and I think you get that, hence your question.
On a VSA we may, all things being equal, decide to configure later which may have an affect on gradient.
There are usually more track miles associated with an instrument approach, track miles = altitude. Also when you program an instrument approach into the FMS it places the altitude limitations in as well, often making you higher than for a VSA. E.g. If there is a limit of 3000 ft at the IAF for an ILS, the FMS will calculate the descent to arrive at the IAF at 3000 at the appropriate speed.

Capn Bloggs

23rd Nov 2010, 12:30

5 Miles,
if the glide slope gradient on an ILS is perfectly achievable for a B777
From what I hear, the problem is not on the ILS but further back where energy needs to be dissipated. Heavies often get held up on our "9000ft until 36nm" step.

If you weren't to call visual until within my CTR then you'd likely already have been taken out for re-sequencing via an instrument app.

Would I be right in saying that you are either at a non-radar tower or not in Australia?

amberale

25th Nov 2010, 03:30

Hi Cap'n.
I work @ the nations capital after years on BN approach and flow[outing myself here].
We usually have the Dash crews calling visual at 30 miles and half the jets not calling visual until on base.
This is a hassle as I am actually sitting in ML centre and only getting updates on the weather from my capable colleagues in CB tower.
I'm sweating on you getting visual as #1
I ask them about the cloud and they tell me that they can see you but you still haven't called visual.
There are terrain, noise abatement and GPWS issues so I can't drop you below 6000' unless you are visual.
Meanwhile number 2 is coming in on left base and I don't know whether I am going to have to pull you out for an instrument approach.
Theoretically it is a pilot responsibility to stay above the steps on a visual approach.
In reality, if there is likely to be traffic below you won't get assigned a level below the step.
Think R14 at BN with RED cct beneath or almost anywhere around ML.

Please tell me when you are visual.
Even if I assign you a visual approach I will be watching to make sure you stay in CTA.

One of our major customers told us in writing a couple of years ago that if they were early on their schedule they would fly econ, if they were on time they would fly profile and if they were late they would fly fast.
WTF???
We don't know where you are reference your company schedule so have no idea what speeds you are doing unless we ask.

Years of flowing has me distrusting 'busses.
The A320 FMS seems to ignore the higher descent speeds.
Untold times bus crews have advised that they can't make a FF time[think they will be later] only to have them sail through the ff early.
I'm not flaming here.
I just think there is a limitation with the FMS and we take it into account.
Likewise the bigger busses seem to be a pita if we stuff you around inside 20nm to run. your workload goes through the roof so we try to fix the sequence earlier.

A sequence is an attempt to make a stream of aircraft to the runway.
With 5-20 different aircraft types in the mix flying different profiles even in the same company it is usually 'organised mayhem'
Usually it needs tweaking by the approach controllers even when the arrivals controllers do a great job.

Not once in 30 years have I stuffed someone around for fun and I understand that you are busy too.
When there is a 5 way dead heat then someone is going to be delayed by at least 10 minutes.

I'm sure you folks would prefer to lose time in the cruise rather than be stuffed around in the terminal area.
Unfortunately, efficient runway usage at the major airports with sequences that go for an hour or more mean that we flow you with pressure[early] to 30 miles then have to tweak this inside 30.

Hope this helps, I'm back to the cricket.:}

AA

I'm back to the cricket

Capn Bloggs

25th Nov 2010, 04:21

Gday Amber,

We usually have the Dash crews calling visual at 30 miles and half the jets not calling visual until on base.
Local knowledge and also different performance probably plays are part in that.

This is a hassle as I am actually sitting in ML centre and only getting updates on the weather from my capable colleagues in CB tower.
I'm sweating on you getting visual as #1
Not a regular visitor to CBR, but I see that the only true visual approach is for non-jets, the Bungo via Endor. Unless you cut jets in short if they call Visual, would they not be following the STARs, which all go to/via an instrument approach?

Theoretically it is a pilot responsibility to stay above the steps on a visual approach.
Precisely why I defer calling Visual until later, especially if I am at an unfamiliar airfield. I can't set the CTA steps into the FMS and I don't believe that I should have a TAC chart out trying to make my jet conform with too-steep CTA steps in this day and age. If that annoys the system, then so be it. There should be a wholesale revamp/reform of the CTA steps around Australia as jets no longer drop out of the sky. It bewilders me that, at my home base, the amount of extra workload on pilots and controllers alike because of inappropriate steps is tolerated by AsA.

One of our major customers told us in writing a couple of years ago that if they were early on their schedule they would fly econ, if they were on time they would fly profile and if they were late they would fly fast.
WTF???
We don't know where you are reference your company schedule so have no idea what speeds you are doing unless we ask.
Communication problem for the AsA headshed methinks. Our company has a standard speed and given that aircraft have to fit into a system that has other users, it is reasonable that they also have a standard speed.

Untold times bus crews have advised that they can't make a FF time[think they will be later] only to have them sail through the ff early.
I'm not flaming here.
I just think there is a limitation with the FMS and we take it into account.

My aircraft is different but the FMS is the same type. From where I sit, it's a POP to hit a feeder fix time on the dot provided we're given enough warning.

With 5-20 different aircraft types in the mix flying different profiles even in the same company it is usually 'organised mayhem'
Selfish operators with no regard for the other people/operators in the system.
Metron will sort them out. ;)

Enjoy the cricket.

Nautilus Blue

25th Nov 2010, 05:14

inappropriate steps is tolerated by AsA.

Accepted wisdom at work seems to be that its political, RAPAC and all that.

From where I sit, it's a POP to hit a feeder fix time on the dot provided we're given enough warning.

Just curious, but does the amount of warning affect the accuracy as well as how much time you can gain/lose? For example, if instructed to lose say one minute while already on descent (I know we shouldn't) is that harder to get spot on than say 2 minutes but while still in the cruise?

Capn Bloggs

25th Nov 2010, 05:37

NB,
does the amount of warning affect the accuracy as well as how much time you can gain/lose? For example, if instructed to lose say one minute while already on descent (I know we shouldn't) is that harder to get spot on than say 2 minutes but while still in the cruise?
We either can or we can't. It's all a case of what the FMS says: if it says the FF time, then the aircraft should get there on the time provided the crew fly at the speed the FMS wants.

So the short answer is: no. If we get told to speed up/get our FF time brought forward, it's simply a case of seeing if we can achieve it. We can or we can't, no "accuracy", per se, involved.

Something else to consider (may have been brought up earlier in the thread): our FMS only indicates to whole minutes (at least until the last waypoint before the FF). So theoretically, an aircraft with a FF time of 12 could get there at the back end of 12, and a follower could get there at the front end of 14. That's quite a difference in separation compared to the other way round. Some of us adjust the descent speed to arrive just after the minute changeover.

Jack Ranga

25th Nov 2010, 08:01

It's all a case of what the FMS says: if it says the FF time, then the aircraft should get there on the time provided the crew fly at the speed the FMS wants.

If it's a Boeing it will, if it's a Bus it wont. Busses are like ASA managers, they promise they will then inform you at the last moment that it's not possible, not in writing so not enforceable :ok:

Capn Bloggs

25th Nov 2010, 21:54

If you are not ALL playing to the same songsheet (shared dynamic winds aloft) it is a zero net sum game. Same with descent speeds/profiles.

Flight planning systems, even NAIPS, give winds that are accurate enough and certainly do the job. Sure, speed management is required by the crew; you can't just set the speed to make the FFT at 200nm and then do nothing else.

John Citizen

22nd Mar 2011, 14:06

Two pilots have recently just told me that we can be arrive/leave at a feeder fix up to 30 seconds early :eek:

Now where does it say this anywhere please, anyone ?

ATC care to comment please.

Blockla

22nd Mar 2011, 18:48

The time separation at feeder fixes is initially strategic... the gap to achieve the landing rate becomes the tactical element (although most of the time they are the same)... If a pilot turns up 30 seconds early then so be it, hope the one ahead isn't 30 seconds late... This is when tactical control will be applied, vectors, speed or both, probably resulting in the crew blaming ATC for not knowing what they are doing...:8 In the ATC world 30 seconds is effectively the exact time. ie 20 and 30 seconds is the same minute as 21 and 29 seconds... both are on time for time 21...

haughtney1

22nd Mar 2011, 19:09

NZAA-YMML B777

Just after TOD "cross xxx at time xxx"....
"negative unable due a/c performance"...."big shiney plane 123, please state a/c performance issue"
"ahhh we would stop flying due to stalling":}

Just wondering if these RTA's consider real world performance?

makespeed250kt

22nd Mar 2011, 20:23

haughtney1, **** happens. It's a dynamic enviroment. Get over it and get on with it!

And yes, controllers would be aware that some FF times issued might be a stretch for the crew.

If ya can't do, expect vectors!

FFS

Mr. Hat

22nd Mar 2011, 20:35

I've flown with some guys that have a relaxed attitude towards it (30-45 seconds) and you could set your watch on getting vectors.

Jack Ranga

23rd Mar 2011, 03:27

If you bull**** about being able to meet the time and you're early, you WILL get vectored. (unless things are running better ahead of you)

If you are late you will either be re-calculated which could result in a self induced shafting or if they slow everything behind you everyone else gets a compound shafting.

If they give you a time that's un-realistic it may be to save extra R/T time (The controller knows you can't lose that much time and wants to know how many minutes to lose in a vector) or it may be just a tool that couldn't get into uni, has had nothing to do with aviation and doesn't understand what they are asking you to do (not many of these).

I think AIP says you can be a minute early, but that's hardly in the spirit of things is it? As a controller it's relatively easy to lose a bit of time, but gaining it when things have stuffed up is difficult at best and costly for airlines.

Would love you fellas to sit in with the flow or Approach or Arrivals (or whatever they call it these days) WHEN IT'S BUSY, not when PR (:ugh:) deems it acceptable for you to visit.