250kts on departure
 

Just a quick straw poll, as the London TMA controllers are more than likely going to have to trial operations in March whereby we cannot take the 250kt speed restriction off you guys until you are above FL100.

This trial is supposedly going to stop aircraft 'bunching' at exit points (though how that will work when talking about 4 different major airports launching A/C independantly to the same exit points is a mystery to the coalface ATCOs)

The question I have is - our management, who are forcing this trial on us, inform us that the airlines have been informed....... to what extent do you guys know about this - or is it the case of both sets of management have agreed to the trial but not told the coalface workers??

What are your thoughts on this restriction?

Re: 250kts on departure
 

I think those new chunky new pit-props supplied by the management might just be made of balsa-wood.

Re: 250kts on departure
 

Does this still allow acceleration to clean speed (usually 280kts for a heavy -400) or is it going to be an across the board restriction.

Re: 250kts on departure
 

never heard this recently (in the past year at least) to be honest unless you have a huge transit accross the TMA (eg towards dvr from the north and its busy) it does not make a huge difference time wise (max 1 mniute i reckon) so all in all if its the flow and possible reduction in being kept low or holding on arrival then it can only be a good thing.

Just to iterate - NO

Re: 250kts on departure
 

May have some effect on the heavy jets wich prefer a high speed climb to clean up, but just means we, smaller twins, get to 100 sooner if we have to stick to a 250 limit.

Re: 250kts on departure
 

It shouldn't be.
Tactical VECTORING, not too dissimilar to approach radar methods, is the answer. At 250 kts you'll find aircraft a lot more "manoevrable" (they cover less ground in turns for instance).
AREA people have to do this in the UK and abroad (with varying degrees of success) daily. e.g. streaming into MAY, AVANT, DPE, MURUE.... corner posts etc , all from different points.
Haven't got "time" to do it? Split the sector. Give yourself more time. You may be surprised what is achievable.
Best Rgds
BEX
a coalface ATCO

Re: 250kts on departure
 

Haven't heard a thing from my lot...(BA)

Re: 250kts on departure
 

It's standard SOP in the US, at least at every major airport I've ever operated into or out of. Never been given "no speed restriction" below 10,000' when arriving or departing from an airport over there.

With reference to the 'heavy' jets requiring greater than 250kts min clean speed, I've never had any ATC restrict us to the 250kts on departure. On the B744 at typical T/O weights before an Atlantic crossing, our min clean speed will be around 260-275 knots. We always climb at 250 or min clean, whichever is greater. Occasionally, ATC may want to know what our min clean speed will be for their own decision making reasons but invariably, they are well aware that a heavy a/c will be slightly above 250kt min clean.

As has been pointed out already, the typical time difference of reaching a boundary or entry/exit point between 250kts and 300kts is around one minute or less depending how quickly you can reach 10,000'.

Thoughts on the restriction? Won't really make much difference. What is preferable is more direct routings.

Re: 250kts on departure
 

Cough

Thats the worry we have, that you guys flying the aircraft have not yet been told. So unless you do, we are going to be hit with the 'can we accelerate yet' question all the time.

Bexil

We do not have the time nor the space ... you should know that because of the way that we are presented with traffic running into Heathrow and Gatwick from the south (as your name implies you know this area). We often get traffic running abreast and certainly not streamed. Lets not turn this into a Swanwick/TC bunfight. The bunching will happen regardless of initial speeds. If the anticipated result is aircraft in one nice stream - it's not gonna happen. A/C will climb quicker, but we rely on knowing that certain aircraft will be very fast a 6000' so that we know they will clear the holding areas and be free to climb sooner.

As for Tactical vectoring - I think you will find we kinda know how to do this at TC due to the multitude of crossing tracks; but both you and I digress - the original post was to find out what the guys and gals at the other end of the Mic thought and also to find out if they had been told anything yet because our managment assures us they have.

BusyB1

The acceleration of A/C to clean up has not even been addressed - beyond the managments limited brainpower to realise the implications of letting some guys accelerate to clean up and the new separation problems that will pose... only so much vectoring we can do if you are stuck under the stacks and there are departures from Heathrow and Gatwick climbing to the same SID level, going to the same point!

Taking away these sorts of tactical tools form the coalface worker is another management interference and proves how little todays managers understand the coalface workers problems.

Eager Beaver

It won't help flow, it just means that A/C will get to the fix a minute or two later... airports will still be firing them off at the same interval - restrict that and you will benefit flow.

It is only for outbounds, it will have no impact on holding arrival. If you are going to hold, you will hopefully have been instructed to slow down before then anyways - usually as soon as you have level separation from any other A/C running in alongside you and you have met the level by restrictions.

You can't really restrict speed much more before then as the en route area guys (like Bexil) need the speed to make sure you get the height off, and to start implementing spacing as they usually get you in a bunch from the French.

We also need to make sure you get the height off to have you in levels which are separated from all the other holding areas.

Slim Shady

If we can get you in the clear to climb we will, then as you say, you can accelerate. So the 'natural separation' we have with different A/C types is also being taken from us to a certain extent!

Danny

That is exactly the point - it won't make much difference so why complicate matters? We are going to have some aircraft accelerating to get clean others doing 250kts, then the A340!!

Direct routeings are more the realm of the en-route guys - they have to sort the rubbish we throw at them before they can start doing that for you!! Tho if its quiet we will try to send you direct, but in a lot of cases it does not comply with En-routes separation requirements regarding parallel routes.

What galls us is the fact that our tactical tools are slowly being eroded by management

Re: 250kts on departure
 

personally when departing heathrow and being held at 6000ft I am happy to be allowed to speed up to get away from the heathrow holds but I do not have the big picture and I am happy to comply with any reasonable request to help everyone on their way. Lets also bear in mind that most bird strikes occur below 10,000 ft and the cockpit windows are not tested for bird strikes at 280 kts.
Safe flying everyone :ok:

Re: 250kts on departure
 

In the US, ATC are not allowed to cancel the 250kt limit below 10,000ft. However, the restriction does not prevent you from flying at minimum clean speed. FAR 91.117(d) states; "If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed".

Re: 250kts on departure
 

Whilst it is nice to be able to speed up it really does not actually make a lot of difference from my point of view, saves a fraction on time and fuel but not enough to matter. I would have thought that it makes more difference in flow control for ATC to be allowed to speed aircraft up so you can give the guy at the front of a queue of other aircraft a bit of a lead.

Re: 250kts on departure
 

Worth bearing in mind for the TC people that "expedite" may not yield as high a rate of climb as previously if we are kept at 250kts before we climb.

G W-H

Re: 250kts on departure
 

GWH

Yep - point taken however a lot of the time we keep EGKK Lam Deps at low speed - this helps them outclimb the Biggin stack and also means the radius of turn is smaller as it is less of a turn back to keep you clear of EGLL traffic inbound from the north east. (And turn radius is less)

That is us using speed as a tool - we are about to be denied using speed as a tool in different ways for different A/C.

Just to clear that up GWH as it may seem we are talking at cross purposes, I understand your true ROC may be less, but in ATC terms, although we may want a high fpm rate, what we are looking at in reality for us is your actual feet per mile rate. When you have accelerated, we are still judging your climb rate on how far away your traffic is.

We both want a good climb at times, but interpret it in different ways!

After a season on the north american continent i no longer see any need to accelerate past 250 below ten , going up or down, unless specifically requested. Climbing at high speed , cruising at high speed and descending at high speed use more fuel,(particularly in V/S)than they make up in time saved.According to my observations that is.

It does increase your chance of missing someone in a Fecked up situation, either an errant intruder or an unsure vistor to cas. If its good for that reason in uncas then its good for cas. Cant see any advantage to speeding up.

One thing that occurs to me is that pretty much every one can do the 280kts min clean speed of the heavy -400 but the -400s can't do the 250 standard speed without dragging flaps around and vastly increasing the fuel burn. My airline, a 737 operator wants us to get to econ climb speed as soon as possible after clean up for cumulative fuel (and emissions) savings. 280kts is a pretty good econ speed for the 737 and I should imagine most aircraft of that weight. Why not introduce a standard speed of 280 kts which every departing aircraft could adhere to and reduce fuel burn, flight times and emissions?

Kirk out…

As far as bunching goes, surely that is best avoided by everyone flying the same speed. What that speed should be will vary between aircraft types and operators requirements. Maybe the operators should be canvassed and then a compromise speed be arrived at. 280kts gets my vote, its a middle of the road speed with room to slow down or speed up comfortably by most types and closer to econ climb speeds than 250kts is. BTW this is the first i've heard of it as well.

OK, I realise that the point being made here is: and based on the original question:then as far as I'm concerned it makes very little difference except that anything that gets us pointed in the right direction and above all the low level traffic and on our way can't be bad. However, I am concerned if it is likely to be a retrograde step for you as an ATCO and is only being implemented as some sort of empire building exercise for managements pleasure.

Just done a check of my company's crew notices and not seen any info about this 'trial'. So, not filtered down to the coalface yet, but then again, we don't go above 250kts/min clean unless cleared to do so. Don't usually bother asking for it as I don't have the 'big BIG picture' anyway and the service provided is always top notch. Now, don't get me started about going into Boston! :yuk:

on the 737 the min clean is around 210-220 kts.Selecting VNAV will set the commanded speed at 250 kts.The speed restriction of 250kts/FL100 is set in the FMC ,and it's our SOP to follow that if not otherwise requested by the ATC.This will give the highest ROC to FL 100 ,most of the time.
The climb speed will be 280 kts( if turbulence expected) or something around 300 kts .
In London TMA,having to stop at FL60, we'll have to mantain 250 kts for a longer period of time.From what I've got from you,ATCO people,a higher speed will help by getting us faster out of your TMA. Of course ,with this trials that you've talked about ,things must be diff.
And,no,no-one told us at our comp about those trials you're doing at London TMA.

It's undoubtedly true that those on the various flight decks have no knowledge of this "trial". It seems to take a LONG time for the info to get from NATS to the Airlines to the Ops dept to the Pilots.

Why so? Dunno, but would hazard a guess there is a bottleneck somewhere on the airlines side. The info certainly is sent out to them.

The idea here is soley about better traffic presentation for aircraft exiting the LTMA, which will allow a greater throughput to the en-route sectors. The aircraft may not be at their best speed or even altitude, but they will be moving in an orderly fashion in the right direction.

The alternative is more departure restrictions, be they MDIs or simply holding selected traffic on the ground. Not good for anyone.

Whether a 250kt for all restriction is a good idea remains an untested one.

Bunching remains one of the biggest causal factors of Overloads. In the not too distant future the en-route sectors WILL refuse to accept traffic from the LTMA if poor presentation is leading to bunching and an unsafe situation. Just the same as TC quite rightly stop inbound traffic if neccessary.
Start to look at holding deps at SAM, DVR, CPT etc and stopping any futher departures until AREA can accept the traffic

With regard to LTMA inbounds, yes sometimes presentation is less than ideal and I regret that, and apologise. The reason is the short distance and high flight levels of traffic from Northern France. It's not always possible to restrict A/c speeds drastically in descent because they will not achieve the target levels. If presenation isn't brilliant, you can still "go vertical" and descend in the hold. Not pretty or pefect, but completely acceptable to approach.

There is no suggestion of "bashing" the opposition, be they AC or TC. The idea is to get the greatest (and safest) traffic through put. Examining long held cultures and ideas isn't always popular, but can lead to positive changes. There may be a better way.

Best rgds BEX

I had not heard about the trial, but March is a long way away and I would probably have forgotten about it by then if I was told now.
250 below 10,000' is a good idea in my view. I am amazed how often an airprox is preceded by the words " no ATC speed restriction".
Maintaining 250 Kts will not only give better spacing, it will reduce noise, get us above the 4,000' noise restriction sooner there bye allowing us to leave the SID on a heading for a shorter routing particularly on LHR northbounds.
Will this mean we can reduce the departure interval on the Detling/Dover LHR departures?
So , yes this one gets my vote.

Bad Bear,

in short no!!

If it was a case of only having A/C coming from one airfield, or even from both heathrow and gatwick, then it would have a good chance of working, as for the routes it will affect, they are roughly the same geographical starting point.

Unfortunately it is not just those airports, it is a case of integrating traffic from London City, Luton, Stansted, and Northolt as well, plus the other low lying airfields in that area that kick out the odd flight now and again.

Tied in with needing to use vectors to get A/C away from lots of different inbound routes and the holds to enable a climb, the bunching issue will still be there.

If we do not vector off the SIDs (which would go a long way to preventing bunching)

a) Heathrow and Gatwick SIDS are not separated via DET/DVR
b) A/C would get much later climbs due to A/C now coming into conflict with others that would never have been a problem before....
C) The ATCOS job becomes much more difficult because there will be lots of A/C 8 miles East of Biggin needing a climb
d) all of the above would make things less safe

Just to clarify Bad Bear, it is the taking you off the SIDS to give you a climb that is one of the main reasons for bunching, as you are vectored out of any natural stream that may have occurred. Whether you are flying at 250kts or not does not change that fact!!

The only real way to prevent bunching is for all the London TMA airfield to coordinate departures with each other..... I am not going to hold my breath as that is totally impracticable

Nothing in the NOTAMS so far, when will this become effective????

Allegedley March, tho we have not been informed officially yet, the paperwork has been drafted, but not released.

We need 21 days notice, so expecting it soon; we have been told by management that the airlines have all been informed

Ha, Ha! - rubbish:}

Well its not rubbish from our end. Our top guys have heard something, but nothing as yet to the troops.

It may well be that all UK airlines HAVE been informed, but as someone said above, they may not have distributed it a month or so early?

Well it'll stop our 14sicks holding up everyone else

Possibly a few urban myths here.....Actually, vectoring off the SIDs has been the CAUSE of much bunching.
There is a "culture" issue here.
As ATCOs (everywhere) we spend our time trying to shorten routes, climb a/c asap etc. Often we are our own worst enemy in that by shorting routes, and not stopping off climbs, we create many more conflicts than would actually exist if everything WAS left on the SIDs and climbed to vertically separated levels.
I might also take issue with: True. But if you stick to VERTICAL separation they can be. The two tracks do not merge until DVR. Ample time for some parallel headings or even a little dog leg to position one behind the other. Positioning is more important than an early climb.
So? if capacity is increased, being "held down" for 7 mins or so (28 miles) seems a small price (particularly when the overall journey is one of Several HOURS
There's that culture thing again, "Needing a Climb". Sure, they will need to be climbed, but it's NOT that urgent. Better positioning (and capacity) is what we're after here.
. Disagree here. Safest form of separation is VERTICAL, it's also the quickest and easiest to apply.

Next time you have the opportunity in the SIM, try it. Keep the sectors split so you have plenty of RT time Leave the a/c on the SIDs, restrict climb to vertically safe levels, and have a go at positioning the a/c in trail later in the SID. All the target levels to AREA are climbing to, rather than level at, so there's no rush.

It IS a BIG culture change, and many people don't react well to change as we are all too well aware. But try it. I have. It DOES actually work.

Best rgds
BEX

I very much appreciate the higher speed (at 6000´)to get out of London TMA. No reason though to blast through the first turns at high speed, but when on a straight course the higher speed is very much desired, weather permitting og course.
p.s. In the U.S (the land of the free) ATC is not at liberty to cancel the speed restriction. It´s the law!;)

Here in the States we do, indeed, adhere to a 250 kt below 10000' restriction. Houston TRACON (Dep/Arr controllers) did have a waiver to eliminate that restriction for a couple of years as a trial but they have since rescinded that and have restored the 250kt restriction.

Standard reason for having the speed held to 250kt is because of all the uncontrolled (i.e. general aviation) traffic below 10000'. I would think that even though there are not the numbers of light aircraft in the UK that there are here you still have a significant number clustered around your terminal areas and you would want to get the jets up and out of your lower airspace.

My company's SOPs require us to climb at BESEC (green dot for the 'bus) to 3000' agl before we accelerate to 250kts. Certain departure procedures like ATL and LAX want 250kts right away so we give them that.

Hopefully I will be flying into the UK in the next year or two after we sort out this merger so I will look forward to working with you gents in ATC. Until then I will keep myself up to speed as best I can via these discussions.

Another half-baked bonus-related management initiative - deep joy.
How can this increase capacity when the outbounds will be on the TC freq for a considerably longer time? Thereby reducing RT capacity - one of the great criticisms from aircrew these days is not being able to get in on the RT.
Miss the stack, climb like the clappers and give them to AC - then take on the next wave.
My very first "airmiss" 25+ years ago was a 727 departing given " no speed "
rapidly rammed up the rear by a " restricted" DC-9 on a different SID (& freq).
The sectors ARE split as often as possible and, in any event, only takes a few seconds to achieve.

I must disagree with the comments regarding bunching of aircraft out of the TMA. One of the main reasons for bunching must be the large tollerances to slot times airfields are given. DVR's from LL always meet DVR's from KK!
I see restricting aircraft to 250kts, increasing my work load and increasing noise to the environment because not all aircraft will be able to clean up.
I want high speed, if possible. so I can get aircraft up and away to another frequency.
I do not see this trial lasting long or being fully adhered too.

We were informed a couple of days ago about the trial in march.

Is this going to be similar to the trial currently being run at Manchester or is the said trial at Man now a fixture and fitting?

According to the airfield plates, it's now a fixture and fitting..
Although if it's quiet, the restriction is cancelled.

:ok:

RE:250kts
 

Danny -- on many occasions I have gotten "fly your best operational speed" directive from controllers out of some the U.S.'s major airports, including my last flight 2 days ago, on a aircraft that not to often has a clean speed over 250. So I'm not so sure on your comment that it's standard SOP not to be given over 250kts on departure. From what I understand the 250 rule under 10k is intended primarily to guard fast aircraft from effects of bird strikes. A valid though operationally frustrating concern since the most economic dep is always best rate climb from the ground up, correct?

BEXIL160 -- Vertical seperation safer than lateral seperation? how so?, I know that in LAX our company consulted with ATC as to if they reallly need the 250kt directed sid speed on our usual dep, and were told absolutely since there key concern was not vertical seperation (we could have flown the VNAP A procedure) but lateral seperation, because heavy's and lighter jets use the same or parallel runways for dep and the need for wake seperation. Another example is at YYZ in Canada where lateral seperation also seems more important to ATC as even on the ATIS you are to advise if you will intend a less speedy but more vertically efficient noise abatement procedure.

I don't doubt procedures my colleagues use in the US or Canada. Bigger places, more runways, different ATC "culture" etc, and the guys there do a great job.

Vertical separation in the UK? Because its quicker to apply (Think TCAS). The conflicting SIDs from EGLL and EGKK, aren't laterally separated (by enough). They ARE vertically separated by ATC, at least initially.

Using this inbuilt vertical sepn, and some tactical vectoring aided by the 250kt limit, it may be possible to increase the movement rates for departures. Deps would all become a lot more "systemised", and a lot less "point and shoot".

Downside? Less early climbs (not above 6000ft or so for about 7-10 mins), but more unrestricted climbs once with AREA.

To reiterate, the idea is an attempt to up the departure rates and still keep things orderly (and safe). It is a big culture change for some in UK ATC, and hence the percieved difficulties. Just because somethings have always been handled a certain way or ways, it doesn't mean that you shouldn't look for other methods that may improve traffic through put.

Keep an open mind. It's a trial at moment.

Rgds BEX

A question for our US airspace experts (if I may):
FAR91.117 Aircraft Speed states in para(a) 'Unless authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m. p. h.).'
Para (d) states 'If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.'
As others have already stated many of the 'heavies' at high weights will have a min clean above 250kt. Can therefore para (d) be applied - are min safe & min clean synonymous in this context - or should I be climbing with Flap 1 to 10,000ft?

Didn't have a clue but my company only tell us about fodcoms six months late and are implementing cap371v4 the day before they have to!!!:}