Go Back  PPRuNe Forums > Ground & Other Ops Forums > ATC Issues
Reload this Page >

270KT outer speed limit for london TMA

ATC Issues A place where pilots may enter the 'lions den' that is Air Traffic Control in complete safety and find out the answers to all those obscure topics which you always wanted to know the answer to but were afraid to ask.

270KT outer speed limit for london TMA

Old 17th May 2008, 21:04
  #1 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: southampton
Age: 43
Posts: 15
270KT outer speed limit for london TMA

Just wanted to get peoples (both atcos and pilots) reactions to the new 270kt outer speed limit restriction.

We`ve been told that unless traffic reasons dictate we should make all a/c inbound to the ltma fly at 270kts. Apparently this will reduce holding times at the stacks.

To people on my sector it seems a bit pointless and just adds rt when rt loading on some sectors (clacton especially) is at a premium.

Do pilots want to fly this speed- it seems we`re starting to interfere in how pilots fly their a/c by imposing more and more restrictions further and further from the airfields.

Just looking for peoples thoughts
wanderingdon is offline  
Old 17th May 2008, 22:25
  #2 (permalink)  
 
Join Date: Jan 2001
Location: UK
Posts: 2,044
My reading is that Ac will be issued a "fixed" IAS to fly... maybe our company's interpretation of the "rule"?

Problem today was, even before LTMA, we were asked to slow "Min Clean". Fine - we did, and planned descent on that basis (~200KIAS). Then in descent asked to go to 250K, then 280K level And then a different LHR STAR (BIG v LAM), and finally held for 10+ mins.

The acceleration to a low altitude 280K, level segment cost us a lot of fuel, especially when combined with an early descent, and a need to hold anyway.

So if you want some feedback, then being given a (fixed?) IAS to fly, prior ToD, great... it can save fuel / holding etc. But, to later increase that gets costly, and if you can, a "rule of thumb" of never requiring a subsequent increase in that IAS will be helpful in fuel terms. An "offer" of an increase might be fine, and may be accepted on occasion

NoD
NigelOnDraft is offline  
Old 17th May 2008, 23:25
  #3 (permalink)  
 
Join Date: Mar 2008
Location: Southampton
Posts: 35
nigel, were you on 701 or 905u ?

i was planning at the time and you were asked to go minimum clean as you were bringing up the rear of a huge bunch of heathrow inbounds at the time, nothing to with the 270kts restriction i may add!

min clean is used to create gaps when bunches arrive, so once achieved it should usually be lifted as invariably you'll be caught by the next bunch behind if we don't!!

we were planning on you being given the standard 3a arrival when our colleagues down the line selected you for a big 1e, there were two guys at 240 that would have been a better choice but there we go!
for what its worth i think the 270 restriction is a pile of cack, far too restrictive and only there cos ba don't want to be overtaken by every other bugger in the stacks!! i think the carbon emissions angle is there as a smokescreen.........anyone agree??

Last edited by Mr Red; 18th May 2008 at 12:57.
Mr Red is offline  
Old 18th May 2008, 07:41
  #4 (permalink)  
 
Join Date: Jan 2001
Location: UK
Posts: 2,044
Mr Red... Thanks for the reply - we were the 701

The "problem" is we want to plan for min fuel use, so when we are told to "slow Min Clean" we can only assume that is all the way to the hold... and probably holding as well. The ToD point is a long way different (earlier) for 200KIAS and 280KIAS etc. and then once committed to the descent the rate/angle of descent is very speed dependant, hence I presume the whinge from the 905U about Tanet - the restriction of which curiously is no longer on our charts

i think the carbon emissions angle is there as a smokescreen.........anyone agree??
Sod the carbon blah... the result of yesterday was that if ATC had asked us for a go around at a late stage we had already discussed/decided that the first reply to ATC thereafter would have had to include an 'M' prefix

Thanks again anyway - at some point this LHR planning will become possible, with everyone sharing the same picture, and perhaps an accurate "touchdown" time uplinked / updated etc. At the moment, as you illustrate, we can all end up with different mental models of who wants/expects what...

NoD
NigelOnDraft is offline  
Old 18th May 2008, 09:42
  #5 (permalink)  
 
Join Date: Feb 2006
Location: southampton
Posts: 225
we were planning on you being given the standard 3a arrival when our colleagues down the line selected you for a big 1e, there were two guys at 240 that would have been a better choice but there we go!
You don't have to agree to their choice, if it works better for you then tell them one of the two at 240 is going to do it. They only want one taken away from LAM is doesn't matter which one. In my experience the BIG stack swaps are always the crap choice of aircraft because the traffic manager making the choice doesn't make it on the basis of where the traffic actually is.

As for the 270kts speed limit.... worst idea ever, it really limits flexibility when you need it. CLN is hard enough without slowing the first ones up so that the rear ones catch up thus increasing the bunching. I also don't get the idea that it will reduce holding times, it will just delay it by a few minutes, everyone still wants to land at the same time, so wether they all get there at 300 or 270 makes no difference IMO. To reduce holding times in the TMA they need to reduce the amount of traffic in total, but that won't happen will it?
1985 is offline  
Old 18th May 2008, 13:27
  #6 (permalink)  
 
Join Date: Jan 2004
Location: London
Posts: 554
it really limits flexibility when you need it. CLN is hard enough without slowing the first ones up so that the rear ones catch up thus increasing the bunching
this.


fair enough if there are delays but what if there's no holding? better to get the first few of a bunch in quickly to reduce the holding for following traffic.
Del Prado is offline  
Old 18th May 2008, 14:21
  #7 (permalink)  
 
Join Date: Feb 2006
Location: southampton
Posts: 225
Del Prado

Good point and i totally agree but we have been told to reduce the speed to 270 kts on all LTMA traffic because it will save the environment.....

but won't getting them in quickly and on the ground asap save more fuel???? and thus carbon emissions....

its an idiotic rule thought up by some numpty in an office somewhere whos trying to justify their existence by jumping on the "green" bandwagon and hasn't thought or been told how it will affect day to day ops. There are other measures that would save fuel and carbon emissions, like direct routes, that would be better off being investigated rather than some arbitary speed restriction.
1985 is offline  
Old 18th May 2008, 17:22
  #8 (permalink)  
 
Join Date: Feb 2006
Location: Hants
Posts: 2,294
It is an advisory instruction only.

If as an ATCO you want to issue speeds greater than 270kts, you can do so. As pointed out, you need more flexibility to stream aircraft.

Having everything at 270Kts could actually cause holding in situations where normally the use of high speed on the first couple means everything comes straight off.
anotherthing is offline  
Old 18th May 2008, 17:52
  #9 (permalink)  
 
Join Date: Jul 2006
Location: USA
Age: 38
Posts: 111
here's a question from an uneducated american.

Why does EGLL have so many a/c holdings at the various HPs every morning and every afternoon?

Why can't the various center controllers sequence the traffic destined to EGLL with a good in-trail of 20NM then have the mid center sectors leading to the London LTMA reduce that to 10NM...? I know we do it here in the states alot and it seems like that's always never a problem. A lil delay vector here and there and everybody is sequenced with the correct in trail.

I'm just looking for an explanation, as I realize you guys have probably thought of that way before i was born and figured out it didn't work for one reason or another. I'm cruious why and what makes the TMA there such a complex airspace.
downwindabeam is offline  
Old 18th May 2008, 18:22
  #10 (permalink)  
 
Join Date: Oct 2000
Location: Berkshire, UK
Age: 76
Posts: 8,269
Some current people will surely respond but allow me to relate a little tale from long, long ago. I showed a few controllers from Chicago round Heathrow Approach and we were looking at the radar. One of the guys, pointing to the range rings said something like: "Now let's see - that must be 50, 100, 150.. miles?" I said "No, 10, 20, 30 miles". All of a sudden they realised what a very tiny little place the UK is compared to "back home".
HEATHROW DIRECTOR is offline  
Old 18th May 2008, 20:00
  #11 (permalink)  
 
Join Date: Jan 2004
Location: London
Posts: 554
It is an advisory instruction only.

If as an ATCO you want to issue speeds greater than 270kts, you can do so. As pointed out, you need more flexibility to stream aircraft.

Having everything at 270Kts could actually cause holding in situations where normally the use of high speed on the first couple means everything comes straight off.

how will the sectors know there will be no holding? CLN, for example are working traffic 20 minutes from LAM, how do they know what traffic is pending for OCK, BIG, BNN?

The 'habit' very quickly will become 270kts for everything. There's no way Heathrow will phone TC NE to tell TC EAST to tell CLN to keep the first few high speed (that's assuming LL identify a gap in the traffic 20 minutes away!)
At best you'll get 270kts from CLN, 270kts from EAST then 320kts from NE/LAM which is a waste of fuel along the lines of BOAC's post.
Del Prado is offline  
Old 18th May 2008, 22:08
  #12 (permalink)  
 
Join Date: Jun 2001
Location: southampton,hampshire,england
Posts: 833
In ATC a little knowledge can be worse than no knowledge sometimes. Unfortunately NATS, being the monopoly Area service provider, seems to write peculiar rules and instructions daily. The bulging offices are awash with wunderkind ideology. The increasing [en route] use of "minimum clean" takes no account of the savage fuel penalty. The latest "270knots" instruction is no more than a band-aid solution to chronic "full stack" scheduling. The only capacity/movement gains in the last 5 years have been a result of chipping away at the already reduced separation criteria.
[Tongue-in-cheek of course.....I would add that this is why UK uses different air to the rest of the world.....this enables a completely unique set of wake vortex separations to be used.]
055166k is offline  
Old 18th May 2008, 22:11
  #13 (permalink)  
 
Join Date: Feb 2006
Location: southampton
Posts: 225
The 'habit' very quickly will become 270kts for everything
.

Won't become my habit. Its a sh1t idea. If a pilot wants to fly at 270 kts i'll try to accomodate him but he'll probably be asked to fly quicker if hes at the front. I won't impose an arbitary speed on aircraft just because someone has decided that its a good idea, i don't know what the ideal economy speed for a A319 or B747 is but i bet they're different and not 270kts. Let pilots fly the aircraft and i'll concentrate on keeping them apart.

Why can't the various center controllers sequence the traffic destined to EGLL with a good in-trail of 20NM then have the mid center sectors leading to the London LTMA reduce that to 10NM...? I know we do it here in the states alot and it seems like that's always never a problem. A lil delay vector here and there and everybody is sequenced with the correct in trail.

I'm just looking for an explanation, as I realize you guys have probably thought of that way before i was born and figured out it didn't work for one reason or another. I'm cruious why and what makes the TMA there such a complex airspace.
The TMA is so complex because of the number of airports within 60 miles of each other. There are 10 LTMA airports plus another 10 ish whose aircraft fly through the TMA's airspace.

The problem with trying to get LL inbounds in trail is all to do with the size of the UK. For example coming from the east (northern europe, eastern europe, far east, middle east and scandinavia) you have about 60 miles in which to stream the traffic and you very regularly get 6-8 at a time and another 4 very close behind, you can't get 10 miles in trail let alone 20. To do that MAAS would have to start streaming for us over northern europe and to be frank they are far to busy with their own problems to do that.

Also as the LTMA get attacked from at least 4 directions you couldn't ever get all the LL inbounds in a sequence without them circling the UK twice

The problem with EGLL is simply the shear weight of traffic, there are too many aircraft trying to land at the same time. The only solution as i see it is to reduce the amount of traffic by half but that is never going to happen.
1985 is offline  
Old 19th May 2008, 07:47
  #14 (permalink)  
 
Join Date: Oct 2000
Posts: 156
Here are a few thoughts from a controller in the LTMA.
The 270 kts is a very poorly thought out idea, causes many problems and solves none. I agree with the comment that it is from an office worker 'trying to make a name for themselves' It should be scrapped immediately and let the pilots and controllers get on with their jobs.
If the landing rate is 38 and 42 are flowed in to LL, then there will always be holding. If you want to reduce holding, reduce the numbers of aircraft flowed into LL to match the achieved landing rate.
The choice of which aircraft to stack swop is complex. The person taking the decision will normally be one of the Group Supervisors (GS) in TC. The CLN sector should be prepared for the aircraft to be at FL150 level by SABER. Height is normally more important than speed.
The GS will be looking at the overall picture of inbounds to LL eg, is the cruising level OK to hold at BRASO? or how does this aircraft fit in with the inbounds to BIG from the SE? or which is the easiest for TC. Often the aircraft chosen will be the one(s) to the south of a bunch.
The problem on Saturday was more to do with flow. It was very quiet all afternoon and then a large bunch of planes arrived together. If flow was more precise, then perhaps these planes would be more spread out. Would it be better to issue an arrival time at BRASO/LAM rather than a slot departure time that can be 20 minutes wide?
Over+Out is offline  
Old 19th May 2008, 08:23
  #15 (permalink)  
 
Join Date: Feb 2006
Location: Hants
Posts: 2,294
Del Prado

Heathrow App quite often phone the TMA sectors and ask us to keep certain a/c high speed.

Until this 270kt 'advice' came out, there was no need for TC to then call AC and ask for certain aircraft at certain sppeds (or just simply ask for a/c a&b to be high speed) - they all usually came in like that anyways.

With the 270Kt 'advice' now here, maybe the TC N and TC S controllers will need to phone more often and ask the AC sectors to keep certain aircraft high speed... It's something that TC Capital quite often does to enable the streaming of 3 sets of traffic through VATON.

It's not been done before because it's not been an issue - if controllers now blindly follow the 270Kts advice then no doubt these telephone calls will increase.

As for CLN working in isolation etc - they have a radar, they can wind out and have a look at the holds, if there are only a couple of aircraft in each, then best practice would be to keep their front couple high speed - or certainly not bust a gut to get everything back to 270Kts.

The rule was thought up under the auspices of Vision 2011, allegedly by an office worker who has never been a valid ATCO nor worked in the Ops room... it's been jumped on as a good idea by people who want to be seen to be doing things 'green'.

It's not workable all the time and should not be blindly followed... remember the paragraph in MATS part 1 about (paraphrased) 'nothing in this manual shall prevent an ATCO from being allowed to do what they want if the situation merits it'?

If there is holding taking place then yes, 270Kts or less is good - at the moment when we have 15 mins delay we get a/c at 300Kts plus* - it's about educating all the controllers that a bit of thought about speed control might actually help - very much in the same way that they 250Kts outbound trial below FL100 in the LTMA, although mostly ignored, has made TC controllers think about which a/c they remove the speed restriction from on first contact instead of doing it with every aircraft which is what used to happen!

270Kts for everything is unworkable if it was a rule - it's not a rule, it's advice, any ATCO that would blindly follow it needs to think about the 'C' in ATCO i.e. they should take control.

* I know that sometimes this is the only way that A/C can be presented in a manner that gives TC a fighting chance - that's the whole point about this advice being flawed if followed blindly - controllers are paid to control, we are not sheep.


Over+Out

I don't think anyone that works in aviation will argue that Heathrow is bursting at the seams - it causes problems for the tower workers, the TMA and en-route workers. The only solution is to make Heathrow run at a lower %age of capacity in order to give it some breathing space and some flex.

The reason it is always flowed over the landing rate is again, for flexibility. The landing rate fluctuates - flowing for about a 10 min delay allows EGLL Dir to squeeze and extra aircraft or two in if the situation allows, thus helping maintain the overall %age of capacity use per day.

If Heathrow were to be capped at say 10% less capacity useage per day than at the moment, then no doubt it could be flowed for either the landing rate or even one or 2 below the landing rate... that's a slots and airline problem though, ATC just provide the best solution.

The overall result is a crap situation, for an overworked airfield, in an overworked piece of airspace - until the airlines start dropping slots, it will continue. Maybe the 'credit crunch' (used to be called a recession in my day) will help if the cost of fuel rises in the manner some people think it will.
anotherthing is offline  
Old 19th May 2008, 09:36
  #16 (permalink)  
wizad
Guest
 
Posts: n/a
its a load of s**t.

the first thing being done at the start of a shift is to call the LAS and agree to cancel the 270k procedure.
as noted in our comments book:
1) another crap procedure forced on us with no consultation and by those who have never held a licence... it looks good on paper so it 'must' be a good idea.
2)to fly 270k for 30 miles over 3000 mile flight, what a massive difference that will make.
3)nats and airlines seen to be doing something about carbon emissions so they look all concerned if any outsiders poke their noses in.... when in fact it causes more hassle and increases work load.

i suppose next we will be told we are not to take aircraft off sids on deaparture fro things like P-RNAV and then get moaned at for not moving anywhere near as much traffic and crap presentation to adjacent sectors because we cant make standing agreement levels.
 
Old 19th May 2008, 10:28
  #17 (permalink)  
 
Join Date: Feb 2003
Location: nr SAM
Posts: 70
I am a Clacton controller and have not and will not issue 270kts as a result of this "suggestion", but rather as part of my plan (yes I have them sometimes!) to stream as effectively I can for TC East.

I wrote quite a bit in the comments book yesterday all of which were negative. Having studied and worked in environmental management before ATC I am all for "saving the world" and think it is a good idea...in principal. Sadly in my opinion it is unworkable in the current configuration of airspace, amount of traffic etc.

I am always suspicious when an instruction (or trial procedure) appears and no valid ATCOs seem to have been consulted..especially just at the start of the peak summer season - great timing!!! We have just started to reduce the congestion on S13 frequency 128.160 (westbound towards LAM) with the excellent idea of getting pilots to report their expected STAR on first contact, and we now have to use up that saved time to issue 270kts? I don't think so!!

Maybe I am too cynical but I would be interested to know why we are being asked to slow down aircraft in the interest of reducing emissions, when we could just impose a more restrictive flow control and reduce the amount of arrivals in the first place? The other day I was controlling when EGLL lost one of their runways. Delays shot up to almost an hour and flow control was apparently immediately applied. Yet 20-30 minutes later two aircraft departed for EGLL, one from EBBR and one from EHAM, only to hold for 30 mins at BRASO and LAM - where is the sense of that?

Thinking about it though, would NATS get penalised for the extra minutes delay? oops, better not do that then

If ATCOs on the coal face can have access to ACCURATE and up to date EATs we can intelligently (don't laugh) issue speed control based on the situation. The guys I work with will use the radar to look at the situation at LAM, but for all we know it might just be that 3 appeared there at once, and there is no holding at the other stacks.

Sorry for waffling, but I have a bit of a bee in my bonnet about this.

Last edited by Phantom99; 19th May 2008 at 10:40. Reason: typical ATCO spelling
Phantom99 is offline  
Old 19th May 2008, 10:37
  #18 (permalink)  
 
Join Date: Sep 2002
Location: 24/7 Hardcore Heaven
Posts: 526
If only I'd thought o this idea...then I could have won myself an iPod. Bet some other idiot at CTC has got now instead....as usual.
mr.777 is offline  
Old 19th May 2008, 10:38
  #19 (permalink)  
 
Join Date: Feb 2003
Location: nr SAM
Posts: 70
Over+Out,

Thanks for the information about stack swaps, I have to admit though we are increasingly getting late requests for coordination (although I understand the stack swaps talked about on Saturday were done before the boundary).

If S13 and S14 are split then I will not as S13 planner agree to a lower level for BIG1E if either S14 is busy and/or has EGKK arrivals as we need to coordinate the descent with them.

I think more planners are starting to do this therefore we need to be told preferably by KEGIT or BULAM - any later and we are becoming more inclined to hand the aircraft over as per the standing agreement RFD and RFT for TC east to sort out. If it's quiet then we will do our best, but stack swaps and quiet don't really happen together very much! This probably doesn't help you very much to achieve FL130 by TANET but I have to protect my Tacticals as well.

This was discussed with the guys on Saturday I think by one of our LASs
Phantom99 is offline  
Old 19th May 2008, 10:40
  #20 (permalink)  
 
Join Date: Sep 2002
Location: 24/7 Hardcore Heaven
Posts: 526
If only I'd thought of this idea...then I could have won myself an iPod. Bet some other idiot at CTC has got it now instead....as usual.
mr.777 is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.