Ignoring ETOPS etc, if Airbus were really to make an A340neo, with the A340-500 becoming A340-800, and A340-600 becoming A340-900, they would of course give it new engines.

The A345/A346's Trent 500 engines have 97.4 inch diameter fans. Do you think the A340neo's engines (I don't know, Trent 5000?) would have the 112 inch fans (the same as the Trent 7000) or would it be slightly smaller?

Also, how much more thrust would the "Trent 5000" have over the Trent 500?

The Trent 500 are around 50klbf, where there isn't much else. They could either go back to the 200/300 and bolt on a CFM LEAP, or keep it this size and use the GEnx or XWB-75 with around 65k.

Either way nobody would buy it over the A330neo. 8 abreast on a 4 engine aircraft just isn't profitable anymore, and it also isn't suited for cargo ops (pretty much the only reason the 748 sold anything).

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

unimproved wrote:

Either way nobody would buy it over the A330neo. 8 abreast on a 4 engine aircraft just isn't profitable anymore, and it also isn't suited for cargo ops (pretty much the only reason the 748 sold anything).

I'd buy an A340-800

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

That's a new one to me.
Name me one incident where the aircraft operated under ETOPS regulations and anyone got hurt because the aircraft didn't have more engines. I honestly can't remember any.

Horstroad wrote:

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

That's a new one to me.
Name me one incident where the aircraft operated under ETOPS regulations and anyone got hurt because the aircraft didn't have more engines. I honestly can't remember any.

Just because there's no accidents doesn't mean that profit should be before everything else. Also, isn't this the go-to argument that people bring up when trying to "prove someone wrong" just because they have this opinion?

acjbbj wrote:

I'd buy an A340-800

So make them an offer then. And ask a certain member on this board to draw you a nice new livery for it too.

As to ETOPS being unsafe, maybe change to something else from Flavor-aid.

acjbbj wrote:

Ignoring ETOPS etc, if Airbus were really to make an A340neo, with the A340-500 becoming A340-800, and A340-600 becoming A340-900, they would of course give it new engines.

The A345/A346's Trent 500 engines have 97.4 inch diameter fans. Do you think the A340neo's engines (I don't know, Trent 5000?) would have the 112 inch fans (the same as the Trent 7000) or would it be slightly smaller?

When Airbus was pushing the A340 Enhanced project, the engines would have been a variation of the Trent 1000/Trent 1700 on the 787/A350 called the "Trent 1500". This engine would have kept the same fan diameter of the Trent 500, but would have adopted an all new core using technology from the Trent 1xxx family.

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

You could argue it was actually Airbus lobbying the ICAO since the first frame to be approved for ETOPS (90 minute diversion limit) was the Airbus A300 in the mid-1970s.

That being said, Boeing did want longer diversion times than the 90 minutes allowed under the ICAO so that the in-development 767 could be used TATL on more direct routings. However, the FAA (due to it's Director at the time) was dead-set against it and in fact only allowed diversions of up to 60-minutes for US carriers - less than the ICAO. Boeing and PW had to complete an extensive validation program before the FAA allowed first 90 minute and then 120 minute diversions by 1985.

acjbbj wrote:

Horstroad wrote:

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

That's a new one to me.
Name me one incident where the aircraft operated under ETOPS regulations and anyone got hurt because the aircraft didn't have more engines. I honestly can't remember any.

Just because there's no accidents doesn't mean that profit should be before everything else. Also, isn't this the go-to argument that people bring up when trying to "prove someone wrong" just because they have this opinion?

How many spare tires do you carry in your car? Hypothetically, you could need two if there is a lot of debris so you should always carry at least two.

acjbbj wrote:

Just because there's no accidents doesn't mean that profit should be before everything else.

Obviously, as there are no incidents, the regulations and safety standards work and are not put behind profit.
ETOPS isn't even cheap either. Neither for the manufacturer to certify, nor for the operator. Do you even know what it takes to get and keep an aircraft ETOPS certified, or do you think they use twinjets just the same way the use trijets or quads?

I don't think we will ever see a new commercial aircraft with more than 2 engines again (unless we use an entirely different method of propulsion). And with the A380 dead, we will never see a quad NEO again.

Regarding your hypothetical case... I would use a similar fan diameter with a smaller and more efficient core. You wouldn't need any more thrust. Maybe even less with some weight savings. Look at the 777X.

And with ETOPS now applying to tri-jets and quads, as well, one can no longer truly say that it is only about economics.

acjbbj wrote:

Horstroad wrote:

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

That's a new one to me.
Name me one incident where the aircraft operated under ETOPS regulations and anyone got hurt because the aircraft didn't have more engines. I honestly can't remember any.

Just because there's no accidents doesn't mean that profit should be before everything else. Also, isn't this the go-to argument that people bring up when trying to "prove someone wrong" just because they have this opinion?

Just because you uninformed ideas does not mean have demonstrate your lack of knowledge to everyone. ETOPS is one of the great achievements of ICAO/Boeing/Airbus and the FAA working in harmony to make flying safer. More does little if anything to enhance extended range operations. No one is selling out for safety.

If you're going to NEO the A340, the 500/600 would be the wrong ones to do, because their payload/range is already pretty good, so you'd just have a heavy ULH machine. The 343 is structurally most efficient, and has engines in the size bucket you could use. In that case, you remove 4x CFM56-5C with a 72.3" fan, and replace them with 4x PW1135G that have 81" fans. IMHO that would be a pretty cool-looking plane.

LH707330 wrote:

If you're going to NEO the A340, the 500/600 would be the wrong ones to do, because their payload/range is already pretty good, so you'd just have a heavy ULH machine. The 343 is structurally most efficient, and has engines in the size bucket you could use. In that case, you remove 4x CFM56-5C with a 72.3" fan, and replace them with 4x PW1135G that have 81" fans. IMHO that would be a pretty cool-looking plane.

And you would have the benefit of the irony that the A340-300 was supposed to launch with PW GTFs.

Stitch wrote:

LH707330 wrote:

If you're going to NEO the A340, the 500/600 would be the wrong ones to do, because their payload/range is already pretty good, so you'd just have a heavy ULH machine. The 343 is structurally most efficient, and has engines in the size bucket you could use. In that case, you remove 4x CFM56-5C with a 72.3" fan, and replace them with 4x PW1135G that have 81" fans. IMHO that would be a pretty cool-looking plane.

And you would have the benefit of the irony that the A340-300 was supposed to launch with PW GTFs.

Ha ha yeah, though in retrospect I think the Superfan issues were a blessing, because it forced the wing extension and winglet, which ultimately helped the 330.

unimproved wrote:

The Trent 500 are around 50klbf, where there isn't much else. They could either go back to the 200/300 and bolt on a CFM LEAP, or keep it this size and use the GEnx or XWB-75 with around 65k.

Either way nobody would buy it over the A330neo. 8 abreast on a 4 engine aircraft just isn't profitable anymore, and it also isn't suited for cargo ops (pretty much the only reason the 748 sold anything).

The A330neo is not really an A340 replacement, especially A340-500/600. The A350 is, however. Does the same job with much lower OEW and fuel burn.

While we can have a fun discussion about an A340NEO, there is no point to such a product since the A350 can do the same job much more efficiently already.

acjbbj wrote:

Horstroad wrote:

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

That's a new one to me.
Name me one incident where the aircraft operated under ETOPS regulations and anyone got hurt because the aircraft didn't have more engines. I honestly can't remember any.

Just because there's no accidents doesn't mean that profit should be before everything else. Also, isn't this the go-to argument that people bring up when trying to "prove someone wrong" just because they have this opinion?

Dang. I thought "The thing you're afraid of has never happened in the history of humanity not once ever" was a pretty good argument. Who knew?

To rephrase my nana’s aphorism on husbands, if two engines aren’t enough, four ain’t too many.


Gf

LH707330 wrote:

If you're going to NEO the A340, the 500/600 would be the wrong ones to do, because their payload/range is already pretty good, so you'd just have a heavy ULH machine. The 343 is structurally most efficient, and has engines in the size bucket you could use. In that case, you remove 4x CFM56-5C with a 72.3" fan, and replace them with 4x PW1135G that have 81" fans. IMHO that would be a pretty cool-looking plane.

Aren’t there some niche routes that require 4 engines for performance reasons? In theory, since Airbus went out and certified an A330neo, what’s stopping them from hanging PW GTFs on the frame for a low-cost A340neo? It might sell 50 frames to airlines like AR for their Australia ops, or SAA, given that their home base of JNB restricts their payload.

LurveBus wrote:

Aren’t there some niche routes that require 4 engines for performance reasons?

You may take a (slight) payload hit, but most any place that can utilize a quad should be able to utilize a twin.

LurveBus wrote:

In theory, since Airbus went out and certified an A330neo, what’s stopping them from hanging PW GTFs on the frame for a low-cost A340neo?

They no longer have the ability to manufacture the A340 would be what is stopping them. (The FAL and parts production processes were modified to only make A330s once the A340 was retired from offer.)

LurveBus wrote:

It might sell 50 frames to airlines like AR for their Australia ops, or SAA, given that their home base of JNB restricts their payload.

Twins are good enough for them, now.

acjbbj wrote:

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

So doubling the risk of an uncontained failure is safer?

DocLightning wrote:

acjbbj wrote:

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

So doubling the risk of an uncontained failure is safer?

No, but if one fails you don't have as much asymmetry in the thrust for a four-engine plane than you do for a two-engine plane. Among a number of other advantages.

acjbbj wrote:

DocLightning wrote:

acjbbj wrote:

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

So doubling the risk of an uncontained failure is safer?

No, but if one fails you don't have as much asymmetry in the thrust for a four-engine plane than you do for a two-engine plane. Among a number of other advantages.

There are No other advantages.

The asymmetry is actually better on a twin anyway. For one, you have more rudder authority built in, and you also have a great deal more power to roll back on from the other side (just about any twin engine in service now will actually be at less than full rated to maintain a +300fpm in an engine out condition).

You also still don't have thrust coming from anywhere near as outboard as on a quad. Care to imagine what asymmetry issues you'd have losing two powerplants on one side of a quad? That carries similar odds against an engine out on a twin.

As well as a catastrophic failure increasing in likelihood (more engines + lower operating standards), you also have lower in general DR on a quad in pre ETOPS/EDTO days.

Even if you do have 'three other' engines serviceable, it's not as though you can dispatch with an open Chip Detect squawk. Or if a DPI is popped more than the alotted number of times.

You should really read up on exactly what's required for ETOPS powerplant reliability vs pre-EDTO quads. There's a lot you didn't know.

As for safety, how well can a quad or tri fly with one engine, worst case?

YIMBY wrote:

As for safety, how well can a quad or tri fly with one engine, worst case?

On a quad, that engine will take to the accident. On a tri, you’ll land somewhere, if the sums are done right and crew does their job.

GF

YIMBY wrote:

As for safety, how well can a quad or tri fly with one engine, worst case?

As for a four-engine jet flying on three engines, have a look at British Airways flight 268. The Boeing 747-400 had engine 2 surge shortly after take-off from LAX and ended up flying all the way to Manchester. The flight actually could have made it all the way to London if they were able to use the fuel in tank 2, but it appears the operator's procedures on fuel balance was different from the manufacturer's procedures.

GalaxyFlyer wrote:

YIMBY wrote:

As for safety, how well can a quad or tri fly with one engine, worst case?

On a quad, that engine will take to the accident. On a tri, you’ll land somewhere, if the sums are done right and crew does their job.

GF

Can I thus conclude that three engines is the optimal and the fourth just increases the risk?

Given more possibilities for failures - including breaking blades through wind and fuselage - four may be even more dangerous than two?

Nothing of the kind, there hasn’t been any crashes as a result of engine failure(s) in a very long time. Engine failure as a measurable safety risk is infinitesimal, regardless of number of engines greater than one installed.

GF

YIMBY wrote:

GalaxyFlyer wrote:

YIMBY wrote:

As for safety, how well can a quad or tri fly with one engine, worst case?

On a quad, that engine will take to the accident. On a tri, you’ll land somewhere, if the sums are done right and crew does their job.

GF

Can I thus conclude that three engines is the optimal and the fourth just increases the risk?

Given more possibilities for failures - including breaking blades through wind and fuselage - four may be even more dangerous than two?

More to break down. The reliability of an ETOPS certified and maintained twin has proven the reliability issue.

If I dare return to the OT, there's not a lot of room to enlarge the fans on a hypothetical A348 (maybe a few inches, but not much more). But the fans could be made of thicker, fewer swept blades and perhaps GTFed and then a smaller, more efficient core installed.

acjbbj wrote:

Ignoring ETOPS etc, if Airbus were really to make an A340neo, with the A340-500 becoming A340-800, and A340-600 becoming A340-900, they would of course give it new engines.

The A345/A346's Trent 500 engines have 97.4 inch diameter fans. Do you think the A340neo's engines (I don't know, Trent 5000?) would have the 112 inch fans (the same as the Trent 7000) or would it be slightly smaller?

Also, how much more thrust would the "Trent 5000" have over the Trent 500?

why would they need 112 inch fans on a 4 engine airplane? even the B747 didn't need or do that, The Most they might have needed for a 4 engine airplane was 70,000 Lbs, Thrust per engine. On a large twin? 65K-90K Thrust would not be out of the question,,

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

unimproved wrote:

Either way nobody would buy it over the A330neo. 8 abreast on a 4 engine aircraft just isn't profitable anymore, and it also isn't suited for cargo ops (pretty much the only reason the 748 sold anything).

..
I'd buy an A340-800[

The FAA didn't come out with the ETOPS concept, That was done be TWA who first modified the 767-231's to ETOPS by activating the center fuel tank where they Planned ETOPS operations before they sought approval from the FAA. Once they Got approval? American, Delta, and United all modified their B767-223's 232's and 222's to ETOPS Standards. Boeing built the B767-300ER which replaced all the -200's in service. Airbus Didn't have a dog in the Race for quite a while as the A300 was only flown by Eastern, Pan Am flew the A310 in ETOPS service before they wen under Later on I think American also flew the A310 in ETOPS service.

acjbbj wrote:

Wasn't ETOPS just Boeing lobbying the FAA?

If airlines and aviation really cared about safety, if they really put safety first, I don't think we would have ETOPS.

unimproved wrote:

Either way nobody would buy it over the A330neo. 8 abreast on a 4 engine aircraft just isn't profitable anymore, and it also isn't suited for cargo ops (pretty much the only reason the 748 sold anything).

I'd buy an A340-800

According to ICAO "safety is the state in which the possibility of harm to persons or property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and risk management."

The regulators and the airlines find the use of twin-engine aircraft along with ETOPS to be an acceptable level of safety. ETOPS is basically a set of risk controls put in place to reduce the hazards of flying twin engines with long diversion times. We've seen diversion times increase over the years as the risk management practice continues.

Stitch wrote:

And with ETOPS now applying to tri-jets and quads, as well, one can no longer truly say that it is only about economics.

EROPS applies across the board no matter HOW many engines an airliner has. ETOPS applies to more than just the engines. It applies to mechanical performance, chronic fault management, Engine performance monitoring, ETC. The standards are tough and they should be. And?
They get tougher as an airline seeks the higher ETOPS limits of 180 and 240 Minutes.

strfyr51 wrote:

Stitch wrote:

And with ETOPS now applying to tri-jets and quads, as well, one can no longer truly say that it is only about economics.

EROPS applies across the board no matter HOW many engines an airliner has. ETOPS applies to more than just the engines. It applies to mechanical performance, chronic fault management, Engine performance monitoring, ETC. The standards are tough and they should be. And?
They get tougher as an airline seeks the higher ETOPS limits of 180 and 240 Minutes.

The engines aren't even the most critical parts for EDTO/ETOPS any more. Modern turbofans are ridiculously reliable. As long as they have fuel and oil, the chances of failure are astronomically remote. Most pilots go through their entire careers without a single engine failure. Hold fire suppression capability becomes limiting on longer flights.