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 26th May 2008, 10:22
  #41 (permalink)  
Join Date: Mar 2007
Location: under the sea
Posts: 2,534
My old Airbus does not allow you to change the descent speed in the fms.The only way to fudge it is change the cost index until you get a speed approximating what is required.Once it is in the descent phase you can change the speed but this then screws up the path and you end up using speedbrakes to get the height off at Bexil.The whole profile descent in the fms becomes meaningless and you are back to vertical speed or level change.A direct to timba but be 150 abeam Bexil increase the workload as the fms does not generate abeams and the symbol generator of the efis cannot cope with the amount of waypoints in the South East of England and consequently hides Bexil on the ND!!A speed change again at Bexil further complicates the matter and the fms becomes just a navigation tool.Does the originator of this trial have a feel for the workload increase in the cockpit yet?
tubby linton is online now  
Old 26th May 2008, 16:41
  #42 (permalink)  
Join Date: May 2007
Location: swanwick carp lake
Posts: 232
eye in the sky,

Here is a free idea you can table at your next "tie wearing fool" meeting.

ban the use of headings in the london tma, too many headings means increased track miles which means we all dies of global warming.
ImnotanERIC is offline  
Old 26th May 2008, 17:05
  #43 (permalink)  
Posts: n/a
its not just this procedure, its the latest on a growing list of these noddy ideas that get dreamed up in an office and we are then told to get on with it.

tell you what, i reckon we should all drive with our handbrakes on..... god knows what the effect will be. but without asking the people having to do it lets give it a shot then get all defensive when im told its a s**t idea.

and eyeinthesky, i couldnt give a damn about how my punctuation and sentence structure is appearing. i dont work at a computer all day, well except from the times im filling in forms about how crap this procedure is.

how about you give being an ATCO a shot and i can sit here and criticise you.
Old 27th May 2008, 10:59
  #44 (permalink)  
Join Date: Jun 2001
Location: southampton,hampshire,england
Posts: 833
Hidden Agenda?

Interesting silence from the CAA. We know from evidence that NATS would like to airbrush the Regulator out of the picture. A monopoly area service provider is not healthy; and without competition there is no pressure to trim over 1000 non-productive jobs.
One way to cut costs would be to halve navigation charges and negate the need to flight-plan economical cost routes out of UK airspace at the expense of higher overall fuelburn.
If the concern over global warming and CO2 is genuine, may I suggest cancelling "Delayfest 2008" [RIAT Fairford] which should save a billion or so litres; disband the Red Sparrows to stop them pumping coloured diesel fumes all over the beautiful Shires. The hundreds of volunteer NATS staff that make RIAT possible could donate their time to reduce summer delays.
A note of caution to all airlline operators.......consider your fleet replacement programmes with care......"Nigel" alluded that the speed value may have been chosen with Airbus in mind......I wonder if that will affect potential Dreamliner sales? Not much point buying a sports car if you have to trail in behind a line of milk floats.
055166k is offline  
Old 27th May 2008, 11:08
  #45 (permalink)  
Join Date: Feb 2000
Location: solent-on-sea
Posts: 443
Now now, let's not pick on Fairford alone, there's also Farnborough....
Not Long Now is offline  
Old 27th May 2008, 16:09
  #46 (permalink)  
Join Date: Feb 2002
Location: Hongkers
Posts: 467
Not much point buying a sports car if you have to trail in behind a line of milk floats.
Bit like driving on the A96.
Ignored the warning once. Never again.
bekolblockage is offline  
Old 27th May 2008, 17:01
  #47 (permalink)  
Join Date: Jul 2002
Location: united kingdom
Age: 60
Posts: 248
just checked, I don't seem to be able to find the ipod winner that was for crossing out levels on strips
And I don't think Investigations have recieved any reports on the speed restriction - Stands well away and awaits incoming....
zkdli is offline  
Old 27th May 2008, 17:43
  #48 (permalink)  
Posts: n/a
Varying the speed in the descent is the most efficient way of managing the descent profile. The Airbus is pretty clever and knows this. If the aircraft is allowed to make a managed descent it uses a variable speed band in order to achieve the correct profile thus reducing the requirement to use highly inefficient speed brakes. This ruling has taken away a huge amount of flexibility, could actually increase fuel burn in some cases and will increase R/T loading as pilots will have to keep asking if they can fly at higher speeds in order to make the numerous altitude constraints.

I think the 250kt below FL100 ruling is a great idea but to remove the ability of the pilot and aircraft to efficiently manage the descent profile for the entire descent phase is, quite frankly, a step too far and may actually defeat the original objective of saving fuel.

Surely better for the airlines to tell ATC that most aircraft these days are descending at about 270 kt anyway due to the low Cost index, but allow us the flexibility to alter this, for instance, if we have a late descent clearance and can't make an altitude constraint. If ATC need a fixed speed for separation and streaming then we’ll do it. Common sense please!
Old 27th May 2008, 17:58
  #49 (permalink)  
Join Date: Feb 2006
Location: Hants
Posts: 2,294

I understand your point about being told to fly a high speed, only to be told a few minutes later to hold... unfortunately thats often the only way we can maintain an order and also get aircraft safely into the hold.

If we let aircraft wallow down at a poor descent rate then there's going to be alot of avoiding action handed out as a blob of aircraft arrive at holds at levels which are not seperated from adjacent holding areas, nor from other aircaft wanting to enter the same hold!

It's not a probelm unique to the LTMA, but it is exacerbated by the large number of busy airports crammed into a relatively small area.
anotherthing is offline  
Old 29th May 2008, 23:44
  #50 (permalink)  
Join Date: May 2008
Location: Hampshire
Posts: 1
The point here is...customer service.

The customers asked for it via the Operational Partnership Agreement. We are here to serve them so we comply. It's that simple!

If the consequences mean that complexity rises cos we can't make the levels then we restrict the traffic, the customer gets the feedback, then they, the customer, decide what they want us to do after the trial ends based on this info.

Whatever they decide, be it reduced capacity due to the 270kt restriction or going back to the way we've always done it, we have to do what they want. Like it or not, we are not here to only serve the pilot customers, we have to serve the airlines who buy the fuel that goes on their planes as well, and they are the ones with the say so, not us or the pilots, cos they are the ones who ultimately pay our wages.

Get on with it, feed back what you think and let nature take its course. We're only going to get more of these daft requests in future so I guess we ought to get used to it and remember that the customer is always right - even when he's wrong.
trialtrial is offline  
Old 30th May 2008, 09:50
  #51 (permalink)  
Join Date: Jun 2001
Location: southampton,hampshire,england
Posts: 833

Band-aid to fix a systemic problem. The NATS monopoly has designed an airspace utilisation model that favours certain airlines and routes whilst at the same time imposes draconian financial penalties on others.
A flight from Bristol to Glasgow or Inverness is capped at FL260/280 whereas a flight from Exeter to Glasgow regularly achieves FL380/400 because it is not included in the capping.
A flight from Bristol to Belfast is capped at FL240 [just one example]. Should NATS pay compensation for the fuel cost difference to the airlines affected by level capping?
Rationale....level capping is necessary to enable a more efficient volume traffic flow by best use of ATC sector resources..HOWEVER..as NATS is the beneficiary and has designed the airspace utilisation system, then it is only right to suggest that NATS compensates any operator who incurs fuel cost penalties in the current economic climate [ perhaps by a rebate of route charges].
055166k is offline  
Old 30th May 2008, 12:15
  #52 (permalink)  
Join Date: Feb 2000
Location: solent-on-sea
Posts: 443
I may have read it wrong but I'm sure the SI said "...shall not be used if it will prevent level restrictions being reached.." or words to that effect. So presumably anyone who uses it then wonders why the planes are high hasn't got the proverbial leg to stand on, and should only be using the 270kts if the levels will be made. So basically with most of the current routes and levels, should never be used....
Not Long Now is offline  
Old 30th May 2008, 12:56
  #53 (permalink)  
Join Date: Feb 2006
Location: Hants
Posts: 2,294

you are correct, and there are still numerous aircraft coming into theTMA stating on first call that they will be unable to make the level by restriction... I can only assume that they do not tell the previous sector that
anotherthing is offline  
Old 30th May 2008, 13:34
  #54 (permalink)  
Join Date: Apr 2002
Location: UK
Posts: 18
The customer is always right...

So they got together to decide this as a group?
Then demanded this from NATS?
Did they pitch it to NATS via the OPA explaining how it would definately have cost and environmental savings whilst being a viable proposition for the controllers to achieve with the airpace they have available?
Maybe they got together to work out complimentary departure times so their arrival times at the clearance limits are all staggered. I use clearance limit instead of holding fix as with this grand plan the holding will be reduced somehow?
If they asked for it without detailed knowledge of the consequences surely someone from NATS with that detailed knowledge explained the importance of aircraft meeting agreed levels and standing agreements and the use of good vectoring and good speed control to try to achieve some order with expedition.
Maybe the customer sat in the sectors required to do it and observed what was going on.
The customer should have what they want, I agree. But what they want should be decided with NATS and be sensible and achievable, not a daft request.
Controllers are professional and take a pride in their work generally and will probably bust a gut to make this work which is sometimes why trial procedures come in even when they offer little benefit.
Those who object being accused of disliking any change.
9th Dan Vectors is offline  
Old 30th May 2008, 16:28
  #55 (permalink)  
Join Date: Jan 2004
Location: London
Posts: 554
Like it or not, we are not here to only serve the pilot customers, we have to serve the airlines who buy the fuel that goes on their planes as well, and they are the ones with the say so, not us or the pilots, cos they are the ones who ultimately pay our wages.
TrialTrail, that concept is not being questioned but how much will it cost the airlines when their planes go round the hold because they slowed down at TOD and missed a 'delay free approach'? or how much will it cost the airline whose aircraft has to orbit because of missed Standing Agreement levels? or miss their EAT because traffic cannot be presented well due to bunching.

Wha's the point of getting the most efficient cost index in descent only to lose 3 or 4 places in the landing sequence.
Del Prado is offline  
Old 30th May 2008, 21:54
  #56 (permalink)  
Posts: n/a

what the customer wants they get?????

this aint asda mate, i suppose the 'customer' would like straight in approaches on every aircraft into the LTMA... yeah right.

quite simply, im not doing it... and especially as ive not seen any one in our ops rooms who think this is a good idea....

they may be the 'customer' but when youve got both pilots and atcos saying its a bad idea and doesnt work... alarm bells should be ringing my friend.
Old 31st May 2008, 14:00
  #57 (permalink)  
Join Date: Feb 2006
Location: Hants
Posts: 2,294
Are the office workers maybe correct?

It would help if controllers used their brains and did not control 'by numbers'

15-20 mins delays promulgated at EGLL today and stuff still coming in at 270Kts - how about slowing it down further and being even more 'green'?

Traffic for EGKK being presented poorly because it seemed that the controller was more interested in complying with 270Kts than common sense...

It's not hard - 2 A/C running to GWC 5 miles abreast, both on headings doing 270Kts is not efficient or good air traffic management, if you have to use 270Kts because you can't think for yourself, how about sticking the other one on a slower speed.. instead of letting a colleague down the line do the work

Also EGKK inbound NW of GWC, high and heading north, chucked without coordination in conflict with SAM departures - again, not exactly an advertisement for good ATC practices, in fact downright lazy

Maybe the office workers are correct - maybe as a whole we are becoming de-skilled as ATCOs and we should do things by numbers.

Before anyone jumps down my throat, there was also some very good use of different speeds by presenting sectors for TMA a/c today - nice to see some people like to exercise the rights their licence gives them instead of being lazy!!

I'm also sure that there was some poor presentation going outbound from the TMA today, but FFS people, don't blindly follow something just because it is in a TOI!!
anotherthing is offline  
Old 31st May 2008, 20:30
  #58 (permalink)  
Posts: n/a
anotherthing......put simply, i couldnt agree with you more.
Old 3rd Jun 2008, 09:11
  #59 (permalink)  
Join Date: Jun 2001
Location: southampton,hampshire,england
Posts: 833
Why 270 knots will not work:

London Terminal and Approach controllers are the world's finest. In the UK IFR operation they achieve a 98% landing rate efficiency at Heathrow over prolonged periods. HOW? Well they need a ready and available supply [or reservoir] of the correct mix of aircraft types to stream and sequence for best results. This is realised by the "full stack" principle which translates into absolutely no wasted space. If aircraft are streaming slowly towards the stack there will be an inevitable reduction in efficiency and I suspect there will need to be a 5% reduction in landing slots during peak demand.
THE CON: this is being "sold" to the airlines on the premise that the long 270 knot econ descent will result in minimum stack holding......in fact the gains can only be short term for the leading aircraft....eventually the stacks will still fill up but the aircraft will have burnt more gas at lower levels before they get there due to the flatter profile. Remember that hundreds of flights will still converge on London from all points of the planet, and they are catching up at a higher closure rate than pre-trial.
On the Area side these aircraft will be in my sector for longer and will be less "controllable". I expect the sector capacity to be modified accordingly...any bets on that?
Regards 055....[NATS third most experienced operational controller]
055166k is offline  
Old 3rd Jun 2008, 12:15
  #60 (permalink)  
Join Date: Jan 2008
Location: england
Posts: 3
No not a failed cadet, but a 13 1/2 year valid controller on the most busiest airspace that is being discussed at high level interfaces here....not been a problem to do 270kts and made not one ounce of workload difference!!.
3rd most experienced NATS controller....wishing you a happy retirement soon, long may you live in the dark ages of ATC , bring on 21st century ATC where people use radars, speeds and all levels available to move the eco friendly tin around the skies
big paddy 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.