Sonic
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Why A340 Cannot Be Twinjet?

Mon Nov 20, 2000 2:04 am

B777 is around same capacity with A340 and it is twinjet, twinjet cost to maintain is lower, so why A340 is still on production? A bigger A330 would change it.
 
na
Posts: 9211
Joined: Sun Dec 12, 1999 3:52 am

RE: Why A340 Cannot Be Twinjet?

Mon Nov 20, 2000 4:35 am

The difference to maintain a A340 compared to a 777 is marginal from what I heard. And is someone here who can actually give proof that the 777 is cheaper to maintain? Fleet Commonality and aircraft price or maintenance deals can sometimes be more important than a few dollars more or less on basic maintenance price. That can actually mean that for some airlines the A340 is cheaper, for others its the 777. Also having four engines instead of two is an issue with passengers on long distance.
 
Tarantine
Posts: 208
Joined: Tue Sep 19, 2000 12:53 pm

RE: Why A340 Cannot Be Twinjet?

Mon Nov 20, 2000 11:13 am

The A330 is similar to the A340, but it has 2 engines.
 
PerthGloryFan
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Joined: Fri Oct 27, 2000 9:48 pm

RE: Why A340 Cannot Be Twinjet?

Mon Nov 20, 2000 11:21 am

The A340 is available as a twin jet - it's called an A330.
Same fuselage sections, common cockpit (ok, one has 4 power levers & instrumentation, the other 2), different wings and engines.
The biggest advantage the A340 has is that it's not subject to any ETOPs restrictions.
It also means Airbus can offer airlines greater flexibility in selecting an airliner that more closely fits their specific air route, range, capacity, payload and costing structure requirements.
Of course whether Airbus end up making more money this way only the future will tell. Henry Ford did ok by offering only black Model Ts - btw I'm only comparing the product choices offered, in no way am I suggesting that Airbus products are "Model T" in terms of technology.  
 
sabenapilot
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Joined: Sat Feb 26, 2000 6:18 pm

RE: Why A340 Cannot Be Twinjet?

Tue Nov 21, 2000 3:04 am

Airbus offers its customers the choise between 2 or 4 engines on their single long haul widbody fuselage:
2 engines => A330,
4 engines =>A340.
The big advantage of this method is that the customer can choose for itself the best configuration in full respect of its own network. Boeing offers his customers no choice at all with its B777, so everybody must settle for 2 engines, which is not always the best and most flexible configuration (ETOPS, Trans Polar Flights, high and hot airports etc...). Of course there still is the B747, but that's a bigger plane and don't forget, it also is a completely different plane! A mix of B777 and B747s is far less economical then a mix between A330 and A340.

Several customers have opted for both the A330 and A340, like Cathay Pacific, Swissair, Austrian, Sabena, Air France, ...
 
sabenapilot
Posts: 2442
Joined: Sat Feb 26, 2000 6:18 pm

RE: Why A340 Cannot Be Twinjet?

Tue Nov 21, 2000 3:20 am

PerthGloryFan,

There is no difference between the wing of an A330 and that of an A340, apart from an extra pylon to fit the extra engine!
This simple but yet very complex realisation is considered to be one of the biggest aerodynamical achievements in civil aviation in the last 10 years!
In fact, believe it or not, but the mere additional weight of the 2 extra engines on a A340 make it possible for that A340 to have a higher max. take off weight!
 
prebennorholm
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RE: Why A340 Cannot Be Twinjet?

Tue Nov 21, 2000 6:16 am

PerthGloryFan wrote:
-------------------------------
The A340 is available as a twin jet - it's called an A330.
Same fuselage sections, common cockpit (ok, one has 4 power levers & instrumentation, the other 2), different wings and engines...
-------------------------------

The 330 and 340 wings are in fact identical except for such internal structures which are needed to support the different engine configurations.
Sabenapilot is correct pointing out that the more even engine weight distribution on the 340 wing makes it able to to support a higher MTOW with basically the same wing structure.
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs
 
PerthGloryFan
Posts: 725
Joined: Fri Oct 27, 2000 9:48 pm

RE: Why A340 Cannot Be Twinjet?

Tue Nov 21, 2000 5:23 pm

Thanks guys,
I knew the A330 & 340 had the same wing plan but thought there would be more complex differences wrt 2 & 4 engines.
Great piece of aeronautical design and engineering.
I've recently flown on both B777 & A340 with SQ.
- hmm, wouldn't want to pick a favourite though  
However, I think the A340 is certainly the nicest looking airliner since the B707.
PGF
 
Guest

RE: Why A340 Cannot Be Twinjet?

Wed Nov 22, 2000 7:46 am

Excuse me? Did someone just mention that the A340 is better than the B777 for hot-and-high? Uh- no. A340-200/-300 are actually underpowered.

Still, the A340-500/-600 will fix that problem easily, and an A340-300Adv is under development with bigger CFM56 engines.

And might I add that the A340 is the most beautiful airliner currently in production, aside from the B717?
 
Guest

RE: Why A340 Cannot Be Twinjet?

Thu Dec 07, 2000 4:59 pm

The A330 and A340 are indeed sharing the same wing. This was the whole idea of getting the new generation Airbuses in maximum commonality and, in turn, economics. From structural mechanics' perpective, the different mass distribution (higher total engine weight as well) arising out of four-engine configuration of the A340 relieves further the high bending moments at the wing/fuselage intersection created by the combination of lift (upward force along the wingspan) and payloads (downward force through the fuselage).

We do find airlines mixing A330 and A340 in their fleet. ETOPS is the most common consideration for operating the A340. The A340 also sells well psychologically because of the additional two engines. Cathay Pacific has a mix of B777, A330 and A340 due to its philosophy of tailoring aircraft to routes/inflight service levels.

I travel frequently on SQ, on both B777 and A340. I prefer the A340 to the B777 for the following reasons:
(a) The B777 business class seating are 7-abreast (2-3-2) whilst the A340 are 6-abreast (2-2-2). One will never be seating in between two fellow passengers on the A340. Similarly, the B777 economy class, same as that of the B747, are 10-abreast (3-4-3) whilst the A340, like its other sisters except A320 series, is 8-abreast (2-4-2). The 2-seater on the side of the A340 makes it a perfect day when you travel with your loved one.
(b) The lower engine rating coupling with half of its engine noise distributed further away from the fuselage make the A340 a truely quiet jet. The B777 was designed with more excess power to accommodate one-engine inoperative scenairo, therefore one would find it more noisy and higher vibration level during both takeoff and cruise.

Having said that, both are very well designed and good looking airliners of the generation.
 
prebennorholm
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Joined: Tue Mar 21, 2000 6:25 am

RE: Why A340 Cannot Be Twinjet?

Fri Dec 08, 2000 6:25 am

N-156F wrote:
-------------------------------
Excuse me? Did someone just mention that the A340 is better than the B777 for hot-and-high? Uh- no. A340-200/-300 are actually underpowered....
-------------------------------

Dear N-156F, The terms "underpowered" and "overpowered" are irrelevant. What is relevant is "runway performance". How long a runway is needed with a given payload and fueled for a given range.
Any twin drops to 50% power with an engine out while a quad drops to 75%. Therefore, if they were equally powered, then the twin would need a much longer runway. But the airports don't have specially long runways for twins only   so the plane manufacturers put in more power instead.
Read the runway requirement specs on the company web sites instead.
That said, the 340 also requires quite some runway. But then the design criteria didn't include to be operated from 6000 feet regional airport runways. It was designed to houl a considerable payload over a very long distance between large airports, and do it in an economic way. And that's exactly what it does.
Then there is the "visual fooling": When you see a 340 take off, then it is because the airline needs that 340 range performance, or you would see the cheaper medium range 330 instead. When you see a 777, then you can never know. Often they take off for a US domestic coast to coast flight with less than half full fuel tanks, and that of course transforms a powerful twin into a rocket. You never see a 340 on such a short sector, they always take off with full or almost full fuel load, and the fuel is almost half of the total weight.
Even on Atlantic routes neither the 340 nor 777 can't stretch their legs - the preferred Airbus is the 330 and they mix with 747s, 767s and plenty of 777s.
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs
 
scaredflyer21
Posts: 334
Joined: Fri Oct 06, 2000 6:52 am

RE: Why A340 Cannot Be Twinjet?

Sun Dec 10, 2000 8:03 am

Thats like asking why the 747 can't be a twin jet!
 
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VirginFlyer
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RE: Why A340 Cannot Be Twinjet?

Wed Dec 13, 2000 5:41 pm

Airbus tried offering a larger A330 as a direct competitor to the 777, but everyone went to Boeing. Therefore, the A330/340 family's main selling point in this market is the 340's lack of ETOPS requirements.
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