And on a lighter note - A340s....grrr
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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.
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.
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Breaking news......Airbus announce product improvement package for Airbus A340-300.
http://www.airliners.net/open.file?i...&TopOfYest=yes
http://www.airliners.net/open.file?i...&TopOfYest=yes
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White Knight
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.
Does the climb rate really matter anyway once away from the airfield?
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.
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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.
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..
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.
always happy landings
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.
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..
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.
always happy landings
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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.
I had no idea there was such a simple solution.
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.
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.
Last edited by 18-Wheeler; 2nd Jan 2005 at 10:59.
