View Full Version : And on a lighter note - A340s....grrr

Cartman's Twin
8th Dec 2004, 12:29
Following my first ATCO posting in the Pilot's forum - here's me second!!

London terminal control ATCO person - working on the south side of Heathrow. Now I'm sure the A340 pilots among you may well love the plane - but from a purely professional point of view, I'm not particularly endeared to it.

Firstly it joins the exclusive club populated previously by the 747-100 alone of climbing solely due to the curvature of the earth. And secondly, some airlines SOP of flying at around 160knts until passing 4-5000' (and therefore half an hour into the flight) causes havoc with departure separations. Where 2 minutes would normally be perfectly acceptable we need a generous 3.

(This problem is exacerbated by the noise restriction whereby we can't issue a heading to get the a/c out of the ruddy way until it's passed 4000'.)

I'm not trying to change the world here just help my own understanding (and hopefully yours!) and maybe answer any odd questions you may be asked shortly after departure such as 'are you ACTUALLY climbing?' or 'what is your current speed and what are you accelerating to?' or 'are your wheels still on the ground?' etc.....

I'm a little curious about the differences between airlines too. Virgin bods - you seem to fly around the 210knts after departure whereas the Sri Lankan guy I spoke to last night managed about 155.

I would be pleased to here your points of view, it just seems so odd when after FL100ish it performs very similarly to a big 74 with 'normal' speed and climb rates.

Oh yes, just one more thing - I can't help but wonder how it'd cope with an engine failure at MTOW. No doubt the fuzzy logic would take over and all would be fine. I watched a prog on Disc Wings showing how an A340 responded to GPWS warning - if only you could climb like that every time!!

Take care one and all, speak to you sometime soon! (Tonight even...)

Where are we now?
8th Dec 2004, 13:04
Hi there,

I will try and answer your question as best I can.

Out of London on our usual Midhurst departure, there is a note on the Jepp plate concerning a gradient until 4000 ft. Instead of accelerating earlier, our company prefers to to continue the climb at V2+10, as per the performance until 4000ft before automatically going into CLIMB mode and accelerating. Begining the acceleration phase at an earlier altitude brings you closer to the noise monitoring equipment, thus an earlier triggering of the "bells" exists.

On all occasions, on departure, we realise that we are slow in the climb or to acclerate, but we feel we are not breaking any laid out/chartered rules. Should you require earlier acceleration, you may inform the crew out of, say 3000ft "continue acceleration" or "no speed restriction". Secondly, we never want to block the frequecy asking about acceleration at an earlier level. Usually the greendot speed (best lift/drag) at 270 tons is about 272 kts indicated and this is where the A340 would be best to climb at below 10000ft. After 10000, the climb speed/mach differs from company to company, due to the different Cost Index selection. CI-50 is different to CI-80 or CI-100 of another company. VA, Sri Lankan and other operators use different Cost Indexes which differ the performance of the A340, from each other. Technique is also different in various companies. Even the old VOR approach is done different in A340's between companies too. Some do fully mananged, other do fully selected whilst we are familar with managed lateral, but selected vertical. That's 3 different ways for 3 different airlines in just a VOR approach.

Further more, the A340 climbs very well with an engine out as it is only on 75% thrust when compared to say an A330 at 50% thrust with one out. I would prefer the 3 engine climb.

I hope this helps and I am open to learn more from the next guy, in the posts.

Cartman's Twin
8th Dec 2004, 13:30
Thank you for your reply WAWN (presumably a VIR chap (or indeed chapess...))

I was hoping for the odd serious reply and it's a 100% record so far!

On a slight tangent I know the old Fam flight's are starting to come back, although not, to my knowledge, on long haul A340, but this would be a typical case where so much could be learnt on both sides. Economics aside, we'd both benefit I'm sure.

You are absolutely correct that by flying at V2+10 you aren't contravening any rules, and I didn't mean to imply that you were - it's just a little different from 'the norm'.

In an effort to reinforce, I have taken to saying 'high speed is approved' rather than no speed restriction to Sri Lankan's in particular as they seem to actually slow down if you say 'no speed'.

To further my theme of improved understanding (surely a good thing), on the MID departure the 3000' restriction is to actually keep you inside controlled airspace, the 4000' restirctions provides procedural (1000') separation from Gatwick SAM and KENET departures (not forgetting the Non-Standard Wodley's for any Chanex bods!) and finally the 6000' separates from KK inbounds downwind.

Just out of interested what kind of N1 figure do you use in the climb?

Where are we now?
8th Dec 2004, 15:56
Climb thrust setting is determined by computers and differs for many reasons, based on many factors and the pilot has no say in the automation mode of the N1 setting. This climb setting continuously varies with altitude, temperature, etc... For the pilot, he just puts the thrust levers into the climb detent when the FMA (flight mode annunciator), on the the top lines of the PFD (primary flight display), calls for it.

No, I am not with Virgin, but rather another longhaul operator.

I cannot understand why a particular airline might be slowing down. If anything it should increase, although slowly and rate of climb will degrade while the aircraft lowers the nose to accelerate, from around 10 degrees in climb to around 7*-8* for acceleration.

8th Dec 2004, 19:58
The A340 will climb from lift off to 1500' AAL at V2 to V2+10 then automatically command an acceleration to 250 Kts or min drag speed (if higher) {about 270 kts at max AUW}at 1500' AAL then climb at this to 10,000' when it will accel to climb speed (~300 Kts/.8) You can frig the system to climb at any speed you like for noise abatement and/or performance. At VAA we do the auto speed schedule to at least 4000' to make the min gradient then accel if there is "no speed restriction" The ac doesn't accel and climb very well-especially the -300. Occasionally we do the early part of the climb at 190 with flap 1 -rather than completing the acceleration then climbing- if required to make a ht constraint. All this is do-able at MTOW on 3 engines without selecting full power-although I might! I know that many people moan about Airbus climb performance-especially the -300, but the ac is optimised for the cruise when an over powered ac is less efficient.

Quod Boy
8th Dec 2004, 22:14
:cool:Evening.All pretty much covered by previous posts.

I fly the 343 for M Rats,and the engines are running at full tilt,on take off,which always gets my attention,they are older machines,though.Im still amazed they run so close to the limit,but they do the job.

That said,the V2+15ktsto 1500,rarely proves a problem, we need to climb at 250 kts plus,in order to achieve the "green dot" spd,and that results in an auto flao retract,its the next bit,where climb is less responsive,once up there its a nice ship though,and usually the engines have cooled down.

The 345,is however rather more lively,fitted with Rollers X4.

Nice work as always,in London ATC.


Human Factor
8th Dec 2004, 22:48
Wow. On the 777, we can make 320kts within about three minutes of Aa and then climb at close to 2000fpm at max weight. I guess it shows the excess power requirement for a twin in order to make the single engine climb gradients. How does the A330 compare?

We can generally derate at max weight as well!

9th Dec 2004, 08:28
Well done CT...nice to have a chuckle on here.

But, I gather, from friends in Toulouse that there is far worse than the 340 to come..... the dreaded 380! It has not been designed to go up, down or sideways, but go very fast on the ground.
For obvious reasons, it has been nick-named the ''Ostrich'' by people in the know, at the factory!!

9th Dec 2004, 09:03
Hi all

I have read thru the comments on climb rates and speeds, which is very interresting, from a pilots point of view. Over the past 18 months, I have flown several times between Johannesburg, Dubai and Jeddah.

The experience has been varied. Flying in the B777 (cattle class) is an absolute pleasure - enough leg room, etc and a very stable flight, even when flying thru clouds or landing/taking off in rain.

The airbus flights have been extremely uncomfortable, both in terms of cabin arrangement and aircraft operation. In November, the landing at JIA was the worst I have ever experienced, with the A340-300 pitching, yawing and rolling, engines accelerating and deccelerating. It was one of those 1 approach & 4 landing efforts.

As a result of these experiences, I am NOT an airbus fan.

I am an aircraft mechanic, and have grown to respect the ruggedness and fly-ability of Boeing aircraft.

9th Dec 2004, 09:45
From my personal experience as a passenger only, the shortest take offs and steepest climbs that I have experienced are on the Boeing 757, perhaps due to the load factor and typical routes.

I oft recall departing the relatively short runway at GLA on a short hop to LHR or PMI or ALC, and the darned 757 would appear to hardly get enough revs up, but alas, off into the sky it went like a rocket and climbing ferociously. I was always left with the feeling that the take off run hadn't been completed properly!!

Lovely aircraft in all respects. Do those of you who pilot it like it too??

I often fly as pax on 340 and 330 too, so only too well know what the original poster is referring to.

9th Dec 2004, 10:31
There is a world of difference between the A340-200/300 and the A340-500/600. The smaller aircraft, even with the C4 engines, is far from overpowered! The 346 on two is probably not far short of the B777 on one, which gives an idea of the increased performance of the newer aircraft - and it's over 100 tonnes heavier than the 'little' one! Those non-pilots reading this should bear in mind that, because of our route structure, we are nearly always operating close to our maximum take-off weight, unlike short-haul 757s!

VAA, at LHR, always accelerates at 1500' AAL to 250kts/min safe, as per the published procedures. Even in a C2- powered A343, this technique will nearly always achieve the published minimum climb gradients up to 4000', so I've no idea why WAWN's company climbs at V2+10 to 4000'. This may be the very problem (and company) that Cartman's Twin is referring to. On the very rare occasions when the C2 A343 can't make the gradient at 250kts, we limit the acceleration to 190kts until the kit confirms that the constraints can be met, as Spocla says. This normally means accelerating to 250 at around 2800ft - and we would normally tell ATC if a late acceleration is required.

Once the 250kt speed restriction is lifted by ATC, and we are sure we'll make both the SID track and climb requirements, we accelerate to our normal climb speed - approx 300 in the A343, or 320 in the A346.

As for famils, I have carried at least 3 Swanwick ATCOs on flights in the last two or three months, so they are definitely back on - and on the 340 (and we don't do anything other than long haul)!

Cartman's Twin
9th Dec 2004, 11:30
Thank you for all your replies so far. There is obviously a huge variation between airlines and how they meet (or not!) the departure requirements.

A few points I'd like to make. Generally we anticipate all jet a/c to accelerate to 250kts after departure, not withstanding those lovely British 146....., and A340s! The speed limit on departure is just that - a maximum (not to be exceeded like the one on the M25...!) and there's no restriction on flying slower. The problem was that the Towers use 'Speed Tables' to determine departure separations, and the A340 is officially in the same League as B744 etc. Even taking the sprightly VAA boys doing 250 kts, a B744 accelerates faster and will catch you unless we're careful!

Trying to second guess an A340's speed on departure only tends to result in an embarrassing situation so most controllers I know just wait and see what you do! I'm glad that the boys (and girls) at Heathrow have got the idea now and use 'common sense' departure separations behind A340s.

The 340-6's do perform (in ATC terms only I hasten to add!) much better than the 'Shorter, Slower, Less Far' variants! And I will quite happily wait until after I retire (32 years away...) for the A380.

If My OpenFly is correct:

>> ..... the dreaded 380! It has not been designed to go up, down or sideways, but go very fast on the ground.

May I suggest that it's best suited to following the new, freshly widened M25 round to Dover then using the cliffs to effect a take-off! No conflict with Gatwick traffic apart from passengers using the M23...

Regarding the A330, I'm sad to say it doesn't perform anywhere near as well as the B777, but again I guess this comes back to the business of accountants. Boeing like to provide a bit more welly! The A330 is far more efficient, and shares climb performance as well as it's wings with it's elder brother.

Cartman's Twin
10th Dec 2004, 22:12
Oh yes, the exception to the Airbus/Boeing debate is of course the 319.

Whilst everything A321 and above appears in the 'dismal' category, the A319 is most people's favourite. 4-6000' minute - we'll have some of that. If only it could teach it's elder brothers...

Mind you my elder brother doesn't listen to a :mad: word anyone says....

SawThe Light
10th Dec 2004, 23:32
Cartman's Twin

You sure you're not related to 747Focal?

11th Dec 2004, 00:55
Yeah sounds like a smoke and mirrors attempt to start a Boeing/Airbus debate. Not again PLEASE!

11th Dec 2004, 02:51
Have read this thread with interest and also fly 340-300
I am pro the 340 - no problem with eng out and climb - I have found that a lot of crew/airlines fly the 340 too slowly

Out of LHR...

- try accel at 3000 agl and cancel speed - a/c will do great.

At moment we accell at 4000 ft baro to climb schedule of approx 300 ias if speeds cancelled.(depending on weight and cost index)

Just for interest have also tried accell at 1500 agl to green dot - about 270ias then accell again at 4000ft to climb speed of about 300 and also coped ok but bit risky as may "ring bells " if you do not fly accurately. (Tried this number years ago during trials)

I too, have noticed from a crew point of view, large differences in operating procedures but, as mentioned before, believe that we are being too conservative with speed and therefore fly the aircraft too slowly - hence messing around ATC.

I have flown 747 and find the 340 more friendly and nicer to fly - not knocking 747 as I did enjoy the aircraft but experienced Capt on the 340 can really make it "Sing"

Cartman's Twin
11th Dec 2004, 14:40
'Fraid I'm no relation to 747Focal - or at least not to my knowledge. Family tree gets a bit woolly after by 17 Uncles and 53 Nephews. Or at least that's how it feels buying Xmas presents for the lot of 'em!

I was very interested by Maybee's post. I found it hard to believe that the huge variation was down to SOPs alone - a bit of finesse helps it would appear! Next time I'm faced with a sluggish 340 I shall pass on your advice - just give it some welly old boy!!!!!

Just to add some straightness to the record I dont hold anything personally against Airbus, my only point is that from an ATCO's perspective they CAN present a challenge! I flew on a 330 to Cuba recently and slept well even though suffering the ill effects of food poisoning (apologies to anyone else on the flight...).

13th Dec 2004, 04:20
As a very nervous flyer that comes to this site to help overcome my anxiety through education and better understanding and would like to make a request.

I got pretty uncomfortable on a QF 747 evening flight out of Heathrow when all of a sudden the plane pulls back on the power, levels out and crawls along just after take off....to be fair I crapped myself!

Not a word from the flight deck, so I'm left to my own imagination and feeling very anxious to say the least. Then after a short time, full power again and me still worried until I had a chance to talk with the cabin crew.

I now know why this happened but I'd just like to ask you guys up front to maybe say a few words prior to depature about this proceedure to avoid excessive engine noise on takeoff. I am sure there are some PAX like me who don't know about this and would be put at ease....on the other hand maybe you guys get a chuckle at our expense.


Cartman's Twin
13th Dec 2004, 10:50
Hello WRX!

I'm sure you'll receive a few responses from the front desk boys n gals in due course, but before they point the finger I'd suggest that it can often be down to ATC.

There are several factors affecting the flight shortly after departure. Once they've wrestled the beast of the black-top they have to cpmply with minimum climb gradient requirements for noise/terrain clearance whilst also minimising noise produced by the aircraft! Once they get to between 3 and 6000' their levelling off/sporadic climb is down to ATC.

We give climb to an a/c as soon as possible but due to the conflicting traffic this can, unfortunately, be rather eratic step-climbs of 1000' at a time. This happens especially in the evening when the long haul departures come lumbering out of Heathrow and Gatwick. We do what we can to minimise these but sometimes it's inevitable, we'd much rather your departure climbed continuously and got 'out of our hair' as soon as possible.

I'm sure you'll get more responses but there's a starter for 10!

13th Dec 2004, 11:28
wrxflame, I'm sorry, but there just isn't time to explain the various noise and attitude changes that will occur in the minutes after take off - the guys up front are busy!

As you may have gathered in this thread, what happens is that the aircraft uses a high (not necessarily maximum) power setting to achieve the take off and a relatively steep but slow early climb to a procedurally-determined gate height (1500 feet at Heathrow for most aircraft). At that point, the power is reduced to a more neighbour-and-engine-friendly level, and the aircraft is accelerated to the ATC speed limit (250kts or minimum safe speed, whichever is greater) while the high-lift devices are retracted into the wing. As you can imagine, achieving that acceleration on reduced power means a significant attitude and noise change, which can feel like the aircraft is actually descending!

ATC may then require us to level while still maintaining that relatively-slow 250kts; another power reduction and a further lowering of the nose is then required. The next clearance will be to a higher altitude, so the power will be returned to its climb setting (which is quite high), and the aircraft will be rotated to a climb attitude. This transition from level flight to a climb and back to level flight may happen several times at busy periods, and explains the strange noises and attitude changes you experience.

The human body was not designed to operate in three dimensions, and the inner ear (your main motion sensor when sight is not available) is easily fooled into convincing your brain that certain things are happening to your body that actually are not. Being in the passenger compartment of an airliner is an ideal environment for these false sensations to be experienced! Please understand that we don't make any of these manouevres for our amusement, or to discomfit passengers.

13th Dec 2004, 13:58
To get back to the topic , I seem to remember reading somewhere , possibly on this hallowed site , that Airbi are built with optimum fuel economy in mind whilst Mr Boeings best are built with extra welly in reserve .

Hampshire Hog
13th Dec 2004, 14:45
Sorry this is not directly related to this thread, but wrxflame makes an interesting point re. pprune here.

I started looking on this site because I was a nervous flyer. That helped re-kindle an interest in aviation and now I'm doing my ppl.

Both my flying training and this site have helped me sit more comfortably in the back of several airliners, but if I'm going to fly in something I haven't flown in before, I still check out this site for views and info on the type. For example, I recently took a flight in a 146 for the first time and checked out what ppruners had to say about it. Helpfully, I read about the unusual wind noise on that aircraft as the flaps are set in flight. Now, if I'd heard the banshee noise unexpectedly it it would have scared the life out of me but, since I was expecting it, it was an interesting rather than a scary event.

Maybe we should have a specific forum for 'nervous passengers' to ask the professionals about those things that might otherwise lose the industry customer.

As I said, sorry to go off-thread. Very interesting to see ATCOs struggling at places like LHR (with 777s, 340s etc) in the same way they do with vastly differing performance between Cessna 152s, Tomohawks, Warriors and Duchesses at my training field! But then, life would be boring if we all flew the same planes wouldn't it!


13th Dec 2004, 15:41
LOL, No but you can bet I am going to take that "Osterich" comment all the way to the bank. :E I know exactly how they are going to do that and I can guarantee you pilots are not going to like it. :\ :uhoh:

14th Dec 2004, 04:04
My apologies for taking the thread off topic and throwing a passengers prespective in where it may not have been wanted or appreciated. I mainly surf the wealth of information here and haven't posted much at all.

I do have an a strong interest in all things aviation mainly due to my Father being in the RAF and then working for Scottish Aviation so it's in the blood.

So how did I find pprune....well you can blame a very good friend and Singapore Airlines 747 (now 777 I think) long haul Captain who shall remain nameless. He suggested I come and visit to see that it's rare to have any serious problems for the number of flights etc....

Thanks to those who replied and I do appreciate how busy it must be up front with no time for a friendly chat with the "SLF" as many of you call us. I thought that the crew would know before departure if there was going to be a need to "back off" based on the departure time but maybe I was wrong, not the first time 8-)

PS: I think the nervouse flyer section is a pretty good idea.

Cartman's Twin
14th Dec 2004, 09:36
No worries WRX, I too like the worried flyers section, my only fear is that mayb the odd unsprupulous individual might set loose the odd cat amongst the proverbial Guinnea Fowl......

I've always loved flying and my first experience of the up 'n' downing was enjoyable, although I fully understand how it could be unnerving for the nervous flyer.

Next time you, if nobody else, will understand the mildly eratic departure! And if in doubt blame ATC, that's what most airlines do !!!

:E :E :E

14th Dec 2004, 10:39
Retrofit all 200/300 with 600 engines. Simple!!!

Best part of that plan would be making all 340's look like proper aeroplanes instead of some drawing board scale nightmare!

Any plans Mr. Airbus???

Interesting to know from you Virgin Jocks how much better the 600 climbs than the 200/300.

The A340-600 is how it's mean't to look whereas the the first attempt looks as though some influence from the IL86 design bureau had crept in.

Incidently, climbing out of Manchester on the Sabre 727 a few years back brought similar frustrations from ATC. Max TOW, full tanks, 187 pax. Even with JT8-17 power gave Cessna 150 climb rates (if you were lucky). Pulling back to 1.65 EPR for noise abate left you with that sinking feeling! Block heights? Sorry Mr. ATC, won't quite make those in time!

So your frustration is nothing new. Just hope those A380 donks have enough suck and blow to lift that small town off the ground with some decent ROC!

Coop & Bear

14th Dec 2004, 10:51
The A340-600 is how it's mean't to look whereas the the first attempt looks as though some influence from the IL86 design bureau had crept in.

Interesting point; once heard an (urban legend?) that the nefarious Russkies nicked the plans for the A300 but lacking suitable high-bypass turbofans they had to fit the result with 4 rather than 2 donks, therefore: the IL-86.

14th Dec 2004, 12:32

RB211-535Cs or E4s would do a somewhat better job of uprating, being in the mid to late 30k lb class, rather than the Trent 500s.

Don't know what that would do for range though - as was pointed out, the CFMs are there for frugality rather than puff!

15th Dec 2004, 16:17
Putting Trent 500s on an A343 would be rather exciting! Over 100 tonnes of thrust on a 260 tonne airliner would solve any climb problems, certainly. Not sure the accountants would like it...

The A346 climbs a great deal better than the A343, even though it weighs 100 tonnes more. I'd say it climbs better than my previous aircraft - the late-model B742 with D4 RR's on.

16th Dec 2004, 00:17
MarkD as you said,
"as was pointed out, the CFMs are there for frugality rather than puff!"

And to an extent so are the climb profiles. You could probably get the 340-300 to altitude (lower levels anyway) a bit faster than a lot of operators currently do, but at the expense of some down track distance. The whole thing is cost in the end. If the profile at the higher altitudes is more of a cruise climb than a sprint to cruising level it may well be more economical.

16th Dec 2004, 21:04
"ATC: "Oh, just wondering, 'cos you have set a new European record......237Nm to top-of-climb""

"...it joins the exclusive club populated previously by the 747-100 alone of climbing solely due to the curvature of the earth... "

Even worse! Climbing with the curvature of the earth over a distance of 237NM should bring you to about FL500 !



18th Dec 2004, 00:39
I´m sure most of us in here have heard about the following conversation already, but for those who haven´t yet:

ATC: Lufthansa 1234, are you an A330 or an A340?
DLH1234: Huh? An A340 of course, why?
ATC: Well then, would you mind switching on your other two engines as well and expedite your climb? :E

18th Dec 2004, 19:04
CT said earlier in the thread: Next time you, if nobody else, will understand the mildly eratic departure! And if in doubt blame ATC, that's what most airlines do !!! :E :E :E

A couple of years ago, the flight deck advised that the delay was due to ATC, so I asked in PPRuNe if anyone could verify this. My intention was to learn if the carrier was telling the truth.

I was right Royally flamed for my trouble. I was accused of denigrating those fine people in ATC as well as their cousins and their Aunties. :sad:

"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.

18th Dec 2004, 19:16
I think that 'Where are we now' hit the nail on the head.

Any aircraft has to be certified for a single engine failure on take off.

That means, by definition, that with all engines running a twin engined aircraft has double the minimum amount of thrust needed, whereas a four engined one might only have thirty three percent more than the minimum, so comparing an A340 with a B777 is a little unfair.

There are exceptions of course such as Mr Boeings 744, which I once watched taking off from block 79 (half way down 09R) at LHR and he was going non-stop to Tokyo, quite impressive.

18th Dec 2004, 19:23

Being totally impartial working on Airbus/Douglas and Boeing jets i remember whilst attending an Airbus A300-600/310 ground engineers course, i still remember the instructor describing the A340-200/300 as the "only commercial airliner in production that could suffer a birdstrike from behind". This thread makes a little sense of what he was getting at!

18th Dec 2004, 20:10
There is an advantage for those who are measured on aircraft utilization, an A340 takes 30 mins longer to go from Europe to Chicago (for example) than a 747-400. That way you get better utilization on the A340 if you compare two aircraft that just go over and back each day.


Captain Windsock
19th Dec 2004, 09:06
Just a thought for Cartmans Twin. If you have problems with departure speeds, separation and speed tables why don't you put the A340 in a lower speed group. Problem solved!

Cartman's Twin
19th Dec 2004, 14:10
Hi All,

What an interesting read!!! I love FlightMec's quote - must remember that one!!

Regarding Capt Windsock's remark, your suggestion is quite sensible. I don't think it's likely to happen though. The basic requirment for the classification of Group 3 (the fastest group since Concorde left the skies) is that they can accelerate to, and maintain 250kts. Beyond that, it is the controller's discretion to lift the speed limit and separate the aircraft. The A340 itself is perfectly capable of maintaining 250kts, it just seems to depend upon the crew, their SOPs, the level restrictions and a mild dose of luck as to what actually happens.

As I said previously the Tower controllers are much more aware of the implications for us on radar and they don't try to squeeze to many fast jobbies behind the reverse bird-striker (I love that phrase!!), hence common sense prevails at last!

Good logic though Sir!

White Knight
19th Dec 2004, 14:22
Green dot speed on the 343 when heavy is around 260 knots so that's what you'll accelerate to after take-off and clean up! Our SOP's are to climb at either Green Dot or 250kts (whichever is greater) and then accelerate to en-route climb speed. On current cost index that's around 300kts or so. Does the climb rate really matter anyway once away from the airfield?

19th Dec 2004, 16:45
The simplest solution? Build a third parallel runway at LHR for the short hauls to clear space on the main runways.

What somebody suggested that over 25 years ago? That means it should be ready any day now. :rolleyes:

"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.

Cartman's Twin
19th Dec 2004, 21:57
Hello again!

Climb rate has a large impact upon the operation of ATC. To my knowledge (feel free to correct en-route bods) climb rate is mainly an issue in the TMA environment. For each SID there are generally 2 plans a controller may initiate to solve route/level conflictions and for jet a/c, and climb rate is usually the deciding factor between them. Of course our job is to deal with whichever combination we're faced with but it is always easier to solve a situation if the a/c have good rates of climb or descent.

For those of you departing to the south of Heathrow the most complex single departure is the Gatwick Lambourne SID. A right bugger. Most of the regulars have some idea of it's problem, having to climb around OCK and BIG and requiring you to be at or above FL130 by the Heathrow centreline. For the shuttle type flights their climb rates of 3-4000ft/min+ make the task much easier than a lumbering A330 at MTOW!

Unfortunately just building a third runway doesn't do a great deal to solve the problem. It may help Heathrow Tower to a certain extent shifting a/c off the ground, but I'm sure it would create an even more complex situation for the Ground controller (a VERY difficult position), and another problem is dealing with the buggers once they're in the sky! At the moment Heathrow launch one almost every minute and an extra runway wouldn't, by itself, do much to increase this. Most parties further down the food chain complain about being delayed on the ground (not entirely without reason) but you have to understand, and agree, that it's a far safer environment than risking overcrowding in the skies. That's always got to be the priority.

763 jock
21st Dec 2004, 10:04
Breaking news......Airbus announce product improvement package for Airbus A340-300.



Cartman's Twin
21st Dec 2004, 10:18
Would you take a look at that!!!!

They've uprated the motors to 146-300 spec!!!

21st Dec 2004, 11:34
White KnightDoes the climb rate really matter anyway once away from the airfield? For sure. Remember, we controllers are thinking about ground speed in longitudinal seperation. We mess with your airspeed to achieve distance ie. a ground speed. Eg if the Kenyan 767 takes off right behind you, and let's say you are both speed pegged at 300kts IAS, but after 10 minutes of flying time the 767 is 10,000' higher, there will be significant closing (over the ground). This means you can't have unrestricted climb (a step climb or other workload-increasing activity has to happen). Whereas if the 767 got away ahead of you, he is always going to run away from you- no further action required and unrestricted climb for both (unless you are going to cruise at the same level for long periods).
Also, a lot of protections are built into routes if you are cruising (hemisherical levels etc). By significantly extending the amount of time you are climbing, you are adding risk.

21st Dec 2004, 13:51
Forget departures! Try sitting behind an Airbus all the way to/from the Far East!!!!!!

31st Dec 2004, 16:23
Hello everyone,

with interest I had been reading a lot of the posts here.

I thought that most of the people posting here are well trained pilots themselves and therefore I had been waiting for a response regarding the performance of the A340 in regards to other aircrafts and the specialties concerning long haul flights and economy. But I didn’t see a comforting reply. I know the airplane you fly, always is the best in the world.:D

I would like to explain some of the facts regarding performance of the A340 with my humble knowledge from the flight school in Bremen.

If somebody knows better, please correct me.

Aircraft Performance can have a lot of different aspects. Like in the Olympics there
are sprinters, weight lifters, jumpers and long distance runners among aircrafts.
Top performers in a specific quality often lack behind in all the others.

The A340 is a slow aircraft and a airwayblocker..:D

That is not true. Design Cruise speed is M 0.82 and the plane is mostly flown at .83 ( flying at .84 is 6% more fuel consumption ).
design cruise for the 747 is also .83, but due to the conventional wing design the affects of flying faster do not matter so much in fuel consumption.
mostly the 747 is operated at .86.

Flying M.01 slower you are loosing 45 seconds per hour. That means on a flight to New York from Europe that will be around 8x3x45 seconds or 18 minutes.

It is different with the A340-600, which flies faster and doesn´t has the fuel penalties from the A340-300. the A346 is flying usually with .84 and the fuel saving is on a 13h flight tremendous.
747-400 - A346 .86 - .83 27t fuel -27minutes
747-400 - A346 .86 - .84 23t fuel - 23min.

same payload, same wind conditions etc..
would like to know, how the 777-300 ER is doing ?

The A340 is not climbing and slow during the climbout
The A340 is due to his wing design a slow climber, also there is the possibility of a derated climb.

The A 340 has a supercritical airfoil, which provides low drag at the design Mach
number of .82, without using too much wing sweep. The benefits are a high available
fuel volume, structural efficiency and good slow flying characteristics. However at
higher speeds the shock wave will move forward and the wave drag will increase
drastically. The wings of the A 340 also have a comparably long span, a large area and a very
shallow sweep angle.
A340-300 29,7; 747-400 37,5; B777 31,5 degrees sweep

The long span, and therefore the high aspect ratio reduce the induced drag, which is
especially beneficial at low speeds and high altitudes.
The aspect ratio of the A340-300 is at around 10,1; B747-400 is at 7,7; B777 is at 8,7

"An A 340 with the wing and technology of the B 747-400 would require
39 000 lbs thrust engines in order to take off with 257 to, whereas only 31 200 lbs
thrust engines are required with the A 340-200 efficient wing". ( Airbus statement )

The A340 and A330 have the option of a derated Climb which is normally used in my company I work for. This is not the same as a derated Take-Off! It takes a little more fuel because you need a longer time in lower levels, but you reduce the EGT’s significantly and that saves engine overhaul and reduces the risk of an engine failure.

But if you are heavy you have to fly faster anyhow then 250 knots and a normal climb out speed will be around 270kt-280kt.

With MTOW the A340 will reach initially FL330, I heard the 747 can only do 290 initially, is this correct?

Why aren’t there stronger engines on the A340 ?

Power considerations for an aircraft depend upon the operation at the highest power
demand. For a twin the one engine out case at MTOW sets the lowest possible limit. The thrust loss is 50% compared to 25% on a quad.
Therefore a twin has greater all engine thrust and better all engine climb rates. But the net climb gradient for 4 engine aircraft is also higher ( 3 ) compared with 2- engine aircraft ( 2,4 ).
The A 340 provides enough power for
takeoff as well as to reach the OPT/MAX FL with 300 ft/min residual rate of climb.

I have to admit the thrust to weight ratio is not the best and I love to have surplus power, but under the economic and environmental point of view, it is better to fly an A340 on the long routes and up to about 8 hours an A330.( or not to fly )

I suggest fly around the A340 if you are faster, just like you do on the ski slopes and if you climb better, just pass above.
But do not forget:
the airplane with the longer routing has the right of way. :D

always happy landings

2nd Jan 2005, 10:34
Ah, so that's it then. All you have to do is fly round the slower A340, or ask them to speed up to the best cruise speed of M.84.
I had no idea there was such a simple solution.

2nd Jan 2005, 10:47
design cruise for the 747 is also .83, but due to the conventional wing design the affects of flying faster do not matter so much in fuel consumption.
mostly the 747 is operated at .86.

No it's not.
The slowest any 747 goes is 0.84. Well, not unless there's a very good reason to go slower.
Most -100's do 0.84.
Most -200's do 0.85
Most -300's & -400's do 0.86

We operate at LRC, which may be from about 0.854 down to a minimum of 0.84.

With MTOW the A340 will reach initially FL330, I heard the 747 can only do 290 initially, is this correct?

Only the -100/200's. The -300's generally have much more powerful engines and can easily get up into the 30's no probs.
Most of the -400's - I think - can go straight to 330 or 350. The GE powered ones do best at this I think.