A345/6E to take on 777s??

[CX]

http://www.flightinternational.com/Arti ... +777+.html

I am quite suprised Airbus is doing it for the A340 with 4 engines rather than the A330 with 2.
From that article, it still doesn't look like the new A340s will better the 772LR/773ER in terms of fuel burn, so what really is the point? Yes it is improved, but probably not enough! And it won't be in service before 2011!!
I really want to know why the A330 can't be stretched to the A345/6 kinda length with the new technologies and put new engines on it...

[chornedsnorkack]

http://www.flightinternational.com/Arti ... +777+.html

I am quite suprised Airbus is doing it for the A340 with 4 engines rather than the A330 with 2.
From that article, it still doesn't look like the new A340s will better the 772LR/773ER in terms of fuel burn, so what really is the point? Yes it is improved, but probably not enough! And it won't be in service before 2011!!
I really want to know why the A330 can't be stretched to the A345/6 kinda length with the new technologies and put new engines on it...

Look at it this way: why make improvements to A330 that would only be in service in 2011 or after 2010? A350 is due to be in service then!

I have heard it hinted that perhaps A330 cannot be stretched to A345/6 size because big engines cannot be put under 330 wing. Not sure about the feasibility of a stretched 350, though there are no numbers available for stretches. But if you want a big twin in 2011, would you prefer a stretched 330 or 350?

340 is another matter. It might be possible to derive a quadjet from A350 the way A340 was derived from A330, or design an all-new quadjet. But is it worth the development cost? Improving A340 could provide a plane with limitations of fuel burn, but other advantages, with moderate development cost appropriate for a limited market.

After all, there is no big trijet in production after MD-11. And after 747SP and 747-400 are out of production, the smallest quadjet would be Boeing 747-800.

Now, apart from ETOPS, the other place where the redundancy of 4 engines might matter is takeoff. Twins have a lot of installed power to be able to take off with one engine out - but I suspect it is defined on a flat runway, right? Is it correct that a twin on one engine is generally much more limited in climb and safety margins than a quadjet on 3 engines? And that twinjets easily take off on 2 good engines from airports where they dare not operate with full fuel load because then 1 engine out would mean certain collision with hills or houses? Whereas the quadjets have much more comfortable safety margins?

In this case, there might be a continued need for (limited numbers of) small quadjets - to operate direct flights with small loads from marginal runways. And A340 might be improved (with moderate development cost) to cater for those routes with improved fuel economy and nonstop range...

[ryanCX]

Totally agree with chornedsnorkack... I'd like to believe that quadjets do havve a place in the future besides the 747s and the A380s.
But don't you think the A340-500 will be competing with the A350s too?

And this plan would have paid even better dividends to Airbus if it could be delivered before 2011.

[CX]

the A350 isn't THAT ultra long range like the 772LR, and I think the new A345E (as well as the current A345) will be THAT ultra long range...
I am not saying a new quad jet to be developed, but a twin that will do the job will less fuel burn...

My point is, if twin jet is as reliable and as safe as quad jets, you wouldn't want 2 extra engines unless you need it...
Let's see what happens...

And it looks like Airbus might shrink the A350 to really take on the A380 because at the moment, everything is directed at the 777 and maybe the 789, the 783 and 788 is safer than safe at the moment...

btw, Does the 773 seat more or the A346??

[5Y-KQV]

I think quads still do have a place in the future of aviation. If the A345/6 are enhanced to make them more efficient, I think their economics will be comparable to the big twins (with the extra safety margins of having more engines in the event of an engine failure) and this way AB will keep an important part of its customer base from going to Boeing.

I think I read somewhere that there is a "free flight" concept so to speak that would allow jetliners to fly the most direct route to their destinations may in the long run favor quads since they do not necessarily have to fly within a certain distance of an aleternative airport thus cutting flying times and associated costs. I will try to find this info and post back. I stand to be corrected on this statement.

Cheers,

Walter

[chornedsnorkack]

the A350 isn't THAT ultra long range like the 772LR, and I think the new A345E (as well as the current A345) will be THAT ultra long range...
I am not saying a new quad jet to be developed, but a twin that will do the job will less fuel burn...

My point is, if twin jet is as reliable and as safe as quad jets, you wouldn't want 2 extra engines unless you need it...
Let's see what happens...

Does a 1-engine twin have as good climb performance as a 3-engine quad?

[BelgianBoy]

When I first read Handling the Big Jets, I learned to my great surprise that in critical phase (Vr-V1), a loss of one outer engine on a quadrijet causing a greater couple, might be unsafer than the loss of one engine on a twinjet.

Further as one unquoted representative of SN Brussels Airways recently stated, more engines, higher maintenance costs ans more sources of failures.

I find it difficult to weight the pos and cons.

[CX]

Yes, I mean to beat, or just match the 777, Airbus not only need new engines and the mentioned improvements, they need to tak the A350 technologies and materials and make the thing significantly lighter...

[lastrow]

I wonder if a sort of wiki would be better to discuss such questions: it would be good to have all pros and cons of quads together with comments. Just want to add to the discussion:

- regarding the source from Sabena saying that quads are worse in occurring costs: I have read that especially the A342 and A343 had quite low maintainance costs because of their CFM56 engines which were also used on the single aisle Airbuses. Thus, an airline could save much maintainance and repair costs having a fleet full of these bread and butter engine series regarding engineer-training and spare parts. So I think that the cost thing or in other words the TOC of a quad is very specific to a particular airline.

- I have watched a couple of years ago a report on a German discovery channel kind-alike. They were comparing the 777 and A330 to the Quads. The interesting point is that they have reported that the bigger the plane gets the more efficient are quads in therms of aerodynamics. I am pretty sure that they have said so. However, I know that non-aviation reports are error prone and full of legends. Thus, it would be interesting to hear the opinion of some expert of this field. Does anyone know someone with such a background?

just my x cents

-lr.

[fokker_f27]

4 engines is only usefull if you need the, i think. That meand the plane burns twice as much fuel. And boeing sais: "Twinjets are just as safe as 4-engined jets. If fact: 4-engined jets have a higher chance of having engine trouble." Well duh.

[Knight255]

Does a 1-engine twin have as good climb performance as a 3-engine quad?

There are minimum specifications that MUST be met for an aircraft to be certified in the transport category. If an engine is failed for any particular reason, the pilot SHOULD not continue climbing, but rather search for an airport to land at to figure out why the engine failed. However, lately, some airlines have continued their flights with only 3 engines... :shakehead: As a pilot, I'm not comfortable with that idea.

[chornedsnorkack]

Does a 1-engine twin have as good climb performance as a 3-engine quad?

There are minimum specifications that MUST be met for an aircraft to be certified in the transport category. If an engine is failed for any particular reason, the pilot SHOULD not continue climbing, but rather search for an airport to land at to figure out why the engine failed. However, lately, some airlines have continued their flights with only 3 engines... :shakehead: As a pilot, I'm not comfortable with that idea.

The pilot should not perform a controlled flight into terrain or buildings while searching for the airport!

So, if a plane has an engine failure on takeoff run or climb, surely one major concern would be to get above the surrounding houses and hills and then, being able to turn safely, figure out a safe way to descend back to the starting or other airport.

[CX]

If the new A340 can be extended so that it seats similar to the new 747-8, or at least to seat quite significantly more than the 773s, then its cheaper maintainence(?) compared to the 748 may win it something...

I dont' know but if the new A340s can't even match the 777s in terms of performance/cost, then what is the point? especially when it won't be ready until 2011!

The plane itself doesn't seem to get too much improvements, only a few areas are being improved, the only hope comes from the engine perhaps...?

[chornedsnorkack]

4 engines is only usefull if you need the, i think. That meand the plane burns twice as much fuel.

Which is not clear. After all, don´t you think that the bigger the engine thrust the greater the fuel burn?

At present, it seems that 1 big engine burns slightly less fuel than 2 small engines. But is it going to stay this way? Especially if someone improves the small engines?

After all, someone needs to invent better engines for the B787, or it cannot compete with B777, with small and inefficient engines. But once efficient small engines exist, why not put 4 of them on a big plane like A340 or B748?

And boeing sais: "Twinjets are just as safe as 4-engined jets. If fact: 4-engined jets have a higher chance of having engine trouble." Well duh.

And the consequences of engine trouble are less critical on a quadjet.

[Knight255]

The pilot should not perform a controlled flight into terrain or buildings while searching for the airport!

Well, duh!! We're talking about planes that are certified to climb at max t/o weight with only one engine. I don't think a pilot would cruise around at 1-200ft. AGL looking for an airport.

[chornedsnorkack]

The pilot should not perform a controlled flight into terrain or buildings while searching for the airport!

Well, duh!! We're talking about planes that are certified to climb at max t/o weight with only one engine. I don't think a pilot would cruise around at 1-200ft. AGL looking for an airport.

The certified climb slope for twinjets on MTOW and OEI is said to be 2,4 %. Whereas the quadjets on MTOW and OEI are said to be capable of at least 3,0 %. This can make quite some airports suitable for quads but unsafe for twins, at least unless the twin has heavy payload/fuel limits to ensure climbing with one engine.

[BelgianBoy]

FIR amongst other which explains why BAE-146 are the only jets flying there.

[vc-10]

Don't Meridinia fly to Florence(FIR I think) with MD-80s? I know that the F70 and the Jumbolinos are the only jets into LCY, though Embraer are making the E-170 family certified for SWISS if they ever take delivery, though flybe might have trouble with their E-195s out of Gernsey.

New small engines will be here soon, as the next new planes will be the 737/A320 market, and they will need replcements for the CFM56 and V2500