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Opus99
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RR finds cracks on IPC blades in Trent XWB engine

Tue Aug 11, 2020 9:41 am

https://www.ft.com/content/8d96dc32-dc7 ... 84671b5670

RR has found cracks in 20 Trent XWB engines that are about 4 to 5 years old. Newer engines do not appear to have those cracks. They are carrying out further inspections on engines of the same age.

Seems under control though...let’s see how things unfold.
 
AA737-823
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:31 am

Oh brother. Here we go again.
 
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Antaras
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:36 am

So, let me guess. QR, VN and AY are affected?
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Opus99
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:39 am

Antaras wrote:
So, let me guess. QR, VN and AY are affected?

Yes, apparently, airlines from the Middle East, Europe and Asia. SO think QR, LH etc
 
tomcat
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:46 am

According to the article below, it's not the fan blades that are affected but:
wear on a small number of Intermediate Pressure Compressor blades found on a minority of engines which have been in service for four to five years.


https://www.airlive.net/alert-rolls-royce-discovers-cracks-in-a350-engine-blades/

The similarity with the Trent-1000 problems is disturbing:
Cracking problems in the intermediate pressure (IPT) section of the turbine have plagued the engine since early 2016


https://www.theengineer.co.uk/rolls-royce-problems-trent-1000/
 
2175301
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:47 am

Here is an article that is not behind a paywall. It says the inspections are for a wear issue.

https://money.usnews.com/investing/news ... wb-engines

Here is another article behind a paywall that says cracks in the title.

https://www.telegraph.co.uk/business/20 ... -troubles/

So, which airlines have the A350?
 
2175301
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:00 am

A quick check with Wiki (not always the best source) indicates that only 64 A350 were delivered though the end of 2016. I presume these are the aircraft that are developing issues.

Here is Wiki list of airlines that put the A350 in commercial service prior to the end of 2016 (with date), it includes the total number of aircraft they relatively currently have. Sorry about the format

Qatar Airways: 15 January 2015, 48
Vietnam Airlines : 3 July 2015, 14
Finnair: 9 October 2015, 14
LATAM Brasil (formerly TAM): 25 January 2016, 8
Singapore Airlines: 9 May 2016, 41
Cathay Pacific: 1 June 2016, 39
Ethiopian Airlines: 2 July 2016, 12
Thai Airways: 4 September 2016, 12
China Airlines: 30 October 2016, 14
 
KFLLCFII
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:26 am

Is GE really the only competent turbine engine manufacturer?
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boerje
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:29 am

Opus99 wrote:
https://www.ft.com/content/8d96dc32-dc70-408b-8739-9b84671b5670

RR has found cracks in 20 Trent XWB engines that are about 4 to 5 years old. Newer engines do not appear to have those cracks.


So... Newer engines do not yet have those cracks or newer engines have different blades and therefore have no cracks?
 
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JetBuddy
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:34 am

The question is then if only 4-5 y/o aircraft are affected by this, did the construction of the IPC blades change after that, or are they similar on newer engines as well? If so they will have to be fixed down the line also.
 
Opus99
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:41 am

boerje wrote:
Opus99 wrote:
https://www.ft.com/content/8d96dc32-dc70-408b-8739-9b84671b5670

RR has found cracks in 20 Trent XWB engines that are about 4 to 5 years old. Newer engines do not appear to have those cracks.


So... Newer engines do not yet have those cracks or newer engines have different blades and therefore have no cracks?

I have that same question. I’m not entirely sure. Seems as though they do not yet have them. I think this was spotted as these engines have gotten to their 5 year inspection/overhaul etc (as I understand it)
 
StTim
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:45 am

KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?


GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

The engine manufacturers have been really pushing the envelope to get the fuel economies the frame makers are demanding. This push requires higher temperatures and higher pressures. To resist these they need then to use more exotic materials/coatings etc and also to use finer margins in the design.

This is the root cause of the problems.
 
Opus99
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 11:48 am

StTim wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?


GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

The engine manufacturers have been really pushing the envelope to get the fuel economies the frame makers are demanding. This push requires higher temperatures and higher pressures. To resist these they need then to use more exotic materials/coatings etc and also to use finer margins in the design.

This is the root cause of the problems.

Yup! there seems to be a negative correlation with fuel economy and durability. the challenge is meeting the fuel economy and also meeting the durability standard that customers expect.
 
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ikolkyo
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 1:24 pm

Just like how T1000 issues started, first few year were fine then issues started coming in.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 1:34 pm

How many billions have been spent on bleeding edge engines? Design, delay, corrosion, cracking, downtime. I suspect much of that money spent on offsets and a modest carbon tax would have done the world a lot better. Including the airlines. Petroleum may have some occasional peaks over the next ten years, but after that it will be a cheap commodity, always on the edge of oversupply.
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 1:59 pm

Opus99 wrote:
https://www.ft.com/content/8d96dc32-dc70-408b-8739-9b84671b5670

RR has found cracks in 20 Trent XWB engines that are about 4 to 5 years old. Newer engines do not appear to have those cracks. They are carrying out further inspections on engines of the same age.

Seems under control though...let’s see how things unfold.

Not a surprise that the newer engines do not show issues. The failure mode is corrosion, it takes time for it to happen.

We had a go at wondering why TXWB wasn't showing issues a few months ago ( viewtopic.php?t=1441333 ) but none of the suggestions offered ( mainly differences in bleed takeoff vs generators ) made much sense. It was even pointed out that T7000 was being run with relatively low limits between inspections presumably because it could have the same issue too.

Since these issues aren't causing IFSDs (yet?) they are in the category of annoyance rather than serious concern.
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 2:01 pm

TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article
 
DMPHL
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 2:02 pm

According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.

Let's hope that the scope of the problem is limited to that model. Although I've gotta think, despite Airbus' public projections of confidence that the scope is limited, that internally they are worried about another Trent-1000 debacle. I hope that isn't the case.
 
2175301
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 2:09 pm

JerseyFlyer wrote:
TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article



As they do not yet have a root cause behind the issue.... and sounds very similar to the early statements on the Trent 1000. May I offer to sell you a fantastic bridge.... Or perhaps you would like some lakefront property in the middle of the Sahara Desert.

Lets see how this all shakes out in the next 5 years...

Have a great day,
 
tomcat
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 2:16 pm

JerseyFlyer wrote:
TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article


Here is what I could find:
Another difference in the -97 is the wider use of blisks (bladed disks) across both the high-pressure and intermediate compressors.


Second sheet of the following pdf, top of right hand column:
https://www.rolls-royce.com/~/media/Files/R/Rolls-Royce/documents/news/featured-stories-archive/Trent-XWB-97.pdf

But I understood that the corrosion induced by the high sulfur concentration in Asia had something to do with a poor choice of coatings by RR, although a radical change of architecture may lead to less stress concentration at critical areas suffering from stress corrosion cracking.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 2:23 pm

DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.

Let's hope that the scope of the problem is limited to that model. Although I've gotta think, despite Airbus' public projections of confidence that the scope is limited, that internally they are worried about another Trent-1000 debacle. I hope that isn't the case.

When the Trent 1000 series first had issues, they were talking about Package A only, then other Packages were affected one after another. Even the Trent 1000TEN had its own issues.

As I had mentioned in one of the 787 RR issues threads, it was only time before the 350 had its own RR issues, as it was too early then for the 350 fleet to experience the wear and tear experienced by the 787 fleet. The similarities between the 787 and 350 are the timeframe between EIS and discovery of problems, around 4 to 5 years.
 
majano
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 3:00 pm

Not good news for either Rolls Royce or Airbus. The TXWB and the A350 are their flagship programmes and has been a source of reputation strength. These issues tend to take a long time and plenty of money to resolve. As someone else pointed out above, it started as a trickle on the 787, and ended up being a torrent. One has to hope that it remains a trickle here, or else it could be damaging. The language coming from RR is disappointing. One would have hoped for openness and admission that the problem could be wide-ranging, but corporates are corporates.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 3:03 pm

The FG link above says:

While Rolls-Royce says it is too early to identify the root cause of the lower durability, Frank Haselbach, chief engineer for large engine programmes, says it is “pretty convinced” the issues are unrelated.
...
“It is something that we didn’t expect to see but it is definitely of a much smaller character than we had a couple of years ago,” says Haselbach. “It happens later and is much less severe.

“We are quite happy that we found the issue before the issue found us.”

Small comfort, I would think.

It's not the same problem, but it's one with a different root cause yet to be understood.

It's far better than having IFSDs and having planes parked for many months waiting for new engines, but this is still a big problem.

The article says the engines will need a one hour on wing inspection every 200 cycles once they reach 2300 cycles so 4-5 years of service. They are finding a one in five or 20% failure rate so those engines will have to come off the wing and get torn down to replace the one or two cracked blades. I presume the inspections will be done at a maintenance hub but still it means that aircraft is grounded there till they can get the bad engine off and a spare one mounted. And of course the supply of spares is not infinite.

The article says the parts are providing about half the expected lifetime, it will be several months till the root cause is determined and years before there is a solution in place.

This is definitely not good news for the one RR product that was seen as relatively problem free. It's not as bad as the T1000 news was, but still a big negative, IMO.

DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.

Let's hope that the scope of the problem is limited to that model. Although I've gotta think, despite Airbus' public projections of confidence that the scope is limited, that internally they are worried about another Trent-1000 debacle. I hope that isn't the case.

Right. I guess time will tell if this is limited to the one variant. As above I do feel they've caught this one early, but now the operators are going to be burdened with increased down time for years to come. I presume the inspections can be done in maintenance windows but that 20% failure rate is worrisome.

I do feel it's very good that RR is getting out in front of the problem. I think they are downplaying the impact somewhat, but that's par for the course.

We do know the -94 has major differences but we also know its internal parts are being made to rotate faster to deliver more thrust from the same sized engine. The earlier thread I linked above has some interesting insider comments on it.
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Antaras
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 3:57 pm

That's why the customers love multiple engine choices. Imagine hard if RR1000 is the only choice for the 787, and the PW1300 is the only choice for the A320neo family, guess that those programs were dead.

Trust me, something "exclusive" aren't good these days.
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2eng2efficient
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:18 pm

Opus99 wrote:
StTim wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?


GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

The engine manufacturers have been really pushing the envelope to get the fuel economies the frame makers are demanding. This push requires higher temperatures and higher pressures. To resist these they need then to use more exotic materials/coatings etc and also to use finer margins in the design.

This is the root cause of the problems.

Yup! there seems to be a negative correlation with fuel economy and durability. the challenge is meeting the fuel economy and also meeting the durability standard that customers expect.


Very true, except that since these durability issues are covered by manufacturers’ warranties (they bear the ultimate cost of failure, not customers), there is no sign that manufactures are letting off the gas with respect to pushing the envelope. What guarantees do we have that the RR UltraFan won’t also have long term durability issues? It’s almost like a downward spiral of quality.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:35 pm

DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.


50 engines (in which case we're talking about 25 affected aircraft currently) or 50 aircraft with these engines (so 100 engines)?
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:39 pm

GuillaumePhilly wrote:
DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.


50 engines (in which case we're talking about 25 affected aircraft currently) or 50 aircraft with these engines (so 100 engines)?

It says 50 engines. That doesn’t necessary mean only 25 aircraft though, as a plane can have one affected engine and one okay engine.
 
tomcat
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:42 pm

GuillaumePhilly wrote:
DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.


50 engines (in which case we're talking about 25 affected aircraft currently) or 50 aircraft with these engines (so 100 engines)?


Go figure :-) ! There could be 100 XWB-84 in service:
The Trent XWB-84 engine is set to be subject to an Airworthiness Directive from regulator EASA, Rolls said, because of wear on a small number of Intermediate Pressure Compressor blades found on a minority of engines which have been in service for four to five years.

None of those engines have experienced abnormal in-flight operation, it said, adding that it would carry out inspections on all Trent XWB-84s of a similar service life as a precaution. There are just over 100 of them.


https://www.airlive.net/alert-rolls-royce-discovers-cracks-in-a350-engine-blades/
 
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Polot
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:49 pm

tomcat wrote:
GuillaumePhilly wrote:
DMPHL wrote:
According to the Thomson Reuters article, Airbus says that the cracks were discovered on a few Trent XWB-84 engines (not the -75, -79, -79B, or -97), and that there are about 50 of these engines currently in service.


50 engines (in which case we're talking about 25 affected aircraft currently) or 50 aircraft with these engines (so 100 engines)?


Go figure :-) ! There could be 100 XWB-84 in service:
The Trent XWB-84 engine is set to be subject to an Airworthiness Directive from regulator EASA, Rolls said, because of wear on a small number of Intermediate Pressure Compressor blades found on a minority of engines which have been in service for four to five years.

None of those engines have experienced abnormal in-flight operation, it said, adding that it would carry out inspections on all Trent XWB-84s of a similar service life as a precaution. There are just over 100 of them.


https://www.airlive.net/alert-rolls-royce-discovers-cracks-in-a350-engine-blades/

My interpretation is there are 100 XWB-84s of similar service life (not too surprising based on the rough number of planes built by end of 2016 given earlier in thread), not 100 XWB-84s total in service.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:53 pm

So all RR has to do is to swap out parts on the existing Airbus fleet that is mostly grounded and they can delay this issue for another 5 years while they continue to identify the root cause and determine a fix. Since they do not want to say it is the same as the issue which plagued the Boeing 787....
A question, since the A350's are for the most part not being used, I assume that unlike the Boeing 787 issue, they will not have to pay airlines compensation for a/c that are not in use.
So there is a silver lining in this pandemic for RR and Airbus A350 a/c.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 4:57 pm

Polot wrote:
tomcat wrote:
GuillaumePhilly wrote:

50 engines (in which case we're talking about 25 affected aircraft currently) or 50 aircraft with these engines (so 100 engines)?


Go figure :-) ! There could be 100 XWB-84 in service:
The Trent XWB-84 engine is set to be subject to an Airworthiness Directive from regulator EASA, Rolls said, because of wear on a small number of Intermediate Pressure Compressor blades found on a minority of engines which have been in service for four to five years.

None of those engines have experienced abnormal in-flight operation, it said, adding that it would carry out inspections on all Trent XWB-84s of a similar service life as a precaution. There are just over 100 of them.


https://www.airlive.net/alert-rolls-royce-discovers-cracks-in-a350-engine-blades/

My interpretation is there are 100 XWB-84s of similar service life (not too surprising based on the rough number of planes built by end of 2016 given earlier in thread), not 100 XWB-84s total in service.


That's how I read it as well but I don't understand this way of presenting the situation by the reporter or RR. It's not like the more recent engines will not age. So unless they are of a different design standard than the pre-2017 engines, they will end up with the same issues.
 
DMPHL
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:14 pm

tomcat wrote:
Polot wrote:
tomcat wrote:

My interpretation is there are 100 XWB-84s of similar service life (not too surprising based on the rough number of planes built by end of 2016 given earlier in thread), not 100 XWB-84s total in service.


That's how I read it as well but I don't understand this way of presenting the situation by the reporter or RR. It's not like the more recent engines will not age. So unless they are of a different design standard than the pre-2017 engines, they will end up with the same issues.


Yea that confused me, as well. I originally read it as 50 engines of the type in service, then like others assumed they meant 50 engines of the type that are at that particular service age.

And yes, unless they made specific structural/design changes to engines that entered service later, that 50 number doesn't really matter. Either they made those changes (which would indicate they were aware of the need for those changes, and would not have been surprised by these issues), or they didn't make any changes, which would indicate that as engines get to the 4-5 year mark, a significant percentage of them will start to have these issues.

While publicly they are, understandably, downplaying the seriousness of the issue, I hope internally they aren't just dismissing, out of disbelief or gobsmackedness, the possibility that it's a serious problem happening again. Even if the issue ends up being small, I feel like they have to assume the root problem is fundamental/structural and widespread, and confirm/rule out possibilities from there, rather than approach it from the perspective of a minor isolated issue with random root causes. I assume Airbus and and Airbus' customers are going to be taking it very seriously.

Also, didn't GE decline to put forward a bid for the A350 because it competes with the 77W/77X, for which it is the exclusive engine supplier? Although GE has so far proven quite reliable with the 777 family engines, exclusive engine suppliers are inherently risky, since any grounding event affects an entire fleet/family of aircraft worldwide, potentially requiring them all to be taken out of service.
Last edited by DMPHL on Tue Aug 11, 2020 5:19 pm, edited 1 time in total.
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:17 pm

par13del wrote:
So all RR has to do is to swap out parts on the existing Airbus fleet that is mostly grounded and they can delay this issue for another 5 years while they continue to identify the root cause and determine a fix.

I suppose that's one way to manage the problem, but they still need to inspect every 200 cycles, and those inspections could find more blades to swap, and each swap means taking the engine off the wing and tearing down the IPC to get at the blades to be replaced. It is true that getting 200 cycles can take quite a while in the current airline environment.
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Polot
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:21 pm

DMPHL wrote:
Also, didn't GE decline to put forward a bid for the A350 because it competes with the 77W/77X, for which it is the exclusive engine supplier?

GE originally had exclusivity on the A350 mk1 using derivatives of the GEnx on the 787. When the A350 was XWBifed GE wanted to power the A358 and A359 only, again with modified 787 engines. Airbus would only accept GE if they powered all three variants, and iirc with more tailor made engines so RR gained de facto exclusivity when GE refused Airbus’s demands.

Later (2011ish), when the A35K was revamped with greater capability RR gained official exclusivity for the A350-1000 in exchange for improving the Trent XWB more for that application.
 
744SPX
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:26 pm

Wow. I had assummed the XWB-75/79 were only for the A358 and that the XWB-84 was for the A359...
 
tomcat
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:27 pm

Let's hear what RR has to say about this finding:

There are currently just over 100 Trent XWB-84s that have been in service for four to five years. We have inspected the majority of them and found signs of wear on an average of only 1 or 2 IPC blades in a minority of those inspected. We have also taken the precaution of sampling a number of younger Trent XWB-84 engines and have found no unexpected wear.


Given the limited scale of additional work which we anticipate will be required at existing shop visits to address this wear, together with the availability of replacement parts and spare engines, we do not expect this issue to create significant customer disruption or material annual cost.


https://www.rolls-royce.com/media/press-releases/2020/11-08-2020-rolls-royce-trent-xwb-update.aspx
 
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 5:50 pm

par13del wrote:
So all RR has to do is to swap out parts on the existing Airbus fleet that is mostly grounded and they can delay this issue for another 5 years while they continue to identify the root cause and determine a fix. Since they do not want to say it is the same as the issue which plagued the Boeing 787....
A question, since the A350's are for the most part not being used, I assume that unlike the Boeing 787 issue, they will not have to pay airlines compensation for a/c that are not in use.
So there is a silver lining in this pandemic for RR and Airbus A350 a/c.

The difference for the A350, is WB aircraft currently have low utilisation, there is a good supply of new engines in the network, and MRO's are getting very good at engine switches.

Prudent operators will start de-pairing engines, so different aged engines on each aircraft. If airworthiness authorities mandate de-pairing, then worse than disclosed.

Dollar focussed operators will increase utilisation to trigger compensation, and get higher up the list for replacement parts.
 
strfyr51
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 6:43 pm

KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?

No, GE is NOT the only competent engine builder. Pratt and Rolls re every bit as competent although GE has been very safe in their engineering and Hasn't really gone out on a limb like the Trent engines for Rolls or the GTF by Pratt. If you look at the 767 and the 777 before GE paid Boeing to sole source their engines, the PW 4000 and before that the JT9D were every bit as reliable as the GE. GE paid GOOD money to be the sole source on the 777 and 787 and the later 747's Would they be so successful had they NOT paid Boeing to sole Source? Hard to tell. But? the KC-46's and C17's are all Pratt powered so we'll have to actually see whether they can weather the storm in years to come. The GTF is flying on the A321 and we can look at the reliability of those engines as well.
 
2175301
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 6:49 pm

Revelation wrote:
par13del wrote:
So all RR has to do is to swap out parts on the existing Airbus fleet that is mostly grounded and they can delay this issue for another 5 years while they continue to identify the root cause and determine a fix.

I suppose that's one way to manage the problem, but they still need to inspect every 200 cycles, and those inspections could find more blades to swap, and each swap means taking the engine off the wing and tearing down the IPC to get at the blades to be replaced. It is true that getting 200 cycles can take quite a while in the current airline environment.


The issue I see is that I don't believe that they can just replace an isolated blade or two. I believe they have to replace the entire row.

Could someone who does maintenance on the engine provide more input...

Have a great day,
 
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Revelation
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 6:53 pm

tomcat wrote:
Let's hear what RR has to say about this finding:

There are currently just over 100 Trent XWB-84s that have been in service for four to five years. We have inspected the majority of them and found signs of wear on an average of only 1 or 2 IPC blades in a minority of those inspected. We have also taken the precaution of sampling a number of younger Trent XWB-84 engines and have found no unexpected wear.


Given the limited scale of additional work which we anticipate will be required at existing shop visits to address this wear, together with the availability of replacement parts and spare engines, we do not expect this issue to create significant customer disruption or material annual cost.


https://www.rolls-royce.com/media/press-releases/2020/11-08-2020-rolls-royce-trent-xwb-update.aspx

Yes, that's from the RR media site, whereas the FG interview was with the chief engineer.

Iit's all true, but the words are carefully chosen to leave a certain impression.

A minority of engines are impacted. True, but is that the standard?

They could have been clear like the chief engineer was and said 20% but hey that would be too specific and might trigger questions so let's just go with ambiguity.

Young engines have no wear. Well yes, that should be the case, no?

Additional work at shop visits: what about the additional inspections? No mention of them in the presser.

Will the AD say it's OK to keep flying the engines with cracked blades till the next shop visit? Will airlines feel comfortable with that? How about insurers?

Again, this situation is not as dreadful as cracking blades causing IFSDs and having planes on the ground for months waiting for new engines, but that should not be the basis of comparison, should it?

The FG article suggests this incident should cost RR tens of millions of pounds rather than the billion plus the T1000 problems caused. Still, it's tens of millions that RR doesn't have these days and tens of millions it didn't think it would need to be spending till this problem arose.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
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enzo011
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 7:12 pm

StTim wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?


GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

The engine manufacturers have been really pushing the envelope to get the fuel economies the frame makers are demanding. This push requires higher temperatures and higher pressures. To resist these they need then to use more exotic materials/coatings etc and also to use finer margins in the design.

This is the root cause of the problems.



If the issues with the new engines from all manufacturers are because they are being pushed to the edge with technology to get fuel burn down, this should lead to the conclusion that all new engines will suffer from reliability problems a few years into their service time with airlines. So expect issues to pop up on the GE9X as well as lightsaber has been posting that they are using CMC's in the engine where it has not bee used before. So a lot of unknown unknowns that need time to see if there will be issues.

This will likely be the norm from now on, issues being discovered on engines and need to be sorted rather than no problems being found at all.
 
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LAX772LR
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 7:13 pm

StTim wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?

GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

Which icing issues? If you're referring to icing in fuel-flow at heat interchange (BA and DL incidents), that was RR, not GE.


Antaras wrote:
Trust me, something "exclusive" aren't good these days.

Though to be fair, there was (and still is) nothing stopping GE nor PW from being on the A359 nor the previously-offered A358....


strfyr51 wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?

No, GE is NOT the only competent engine builder. Pratt and Rolls re every bit as competent although GE has been very safe in their engineering and Hasn't really gone out on a limb like the Trent engines for Rolls or the GTF by Pratt. If you look at the 767 and the 777 before GE paid Boeing to sole source their engines, the PW 4000 and before that the JT9D were every bit as reliable as the GE. GE paid GOOD money to be the sole source on the 777 and 787 and the later 747's Would they be so successful had they NOT paid Boeing to sole Source? Hard to tell. But? the KC-46's and C17's are all Pratt powered so we'll have to actually see whether they can weather the storm in years to come. The GTF is flying on the A321 and we can look at the reliability of those engines as well.

Looking past the ridiculous amount of revisionism in this post, tell us:
When did GE become a sole source provider on the 787?
I myself, suspect a more prosaic motive... ~Thranduil
 
StTim
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 7:35 pm

LAX772LR wrote:
StTim wrote:
KFLLCFII wrote:
Is GE really the only competent turbine engine manufacturer?

GE has had it's share of issues over the years. The last one I am aware of affecting them is the icing issues.

Which icing issues? If you're referring to icing in fuel-flow at heat interchange (BA and DL incidents), that was RR, not GE.




No the icing issues affecting the GE engines on the 787 at altitude.

https://www.youtube.com/watch?v=GkCEEw0lKq0

I was well aware of the BA 777 incident at LHR having read the accident report.
 
RB211trent
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 7:52 pm

Can the moderators change the title in this thread as RR has not found cracks in fan blades. It’s IP compressor blades.
 
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lightsaber
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 8:04 pm

JerseyFlyer wrote:
TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article

I do not know the difference. Since this is corrosion stress cracking accelerated by exposure to Sulphur pollution, I wouldn't give a pass. In particular as it is taking forever to fix.

I read how a different root cause is expected. What is it? High Cycle fatigue? (HCF) Stress concentrations? I don't know. My sources at RR are limited to from vendors, so I cannot speak with authority.

I can be a cynical old engineer and note we'll hear more.

This sort of things happens to all engines. The LEAP has combustor liners cracking early on must be pulled every 6000 hours. These are GE parts, so no blaming vendors.

viewtopic.php?f=3&t=1447037

The JT9D had worse issues. I could discuss CF6 compressor rotor cracks that would make you turn green. The original GE90 should have been grounded due to fuel leaks into the cabin. The original 757 engines were replaced with a new design RB211 for a reason.

If you want to have hair on the back of the neck raised, the CF-34-10 on the ARJ-21 had component cooling arbitrarily cut in half for the parts on the outside of the engine. How COMAC solved that, I don't know (Western vendors no bid and they were the experienced vendors).

The current engines are reliable as they had their problems fixed.

I would fly on a Trent powered A350 or 787 (or GE powered). I certainly would fly on an A320NEO with Pratts (or GE). I will fly the MAX after return to service. I won't fly on the ARJ-21. The AD process makes faults public. That is why Western aviation is so safe. The FAA set up a really good, but not perfect, process.

It also happens to give us something to discuss. Public disclosure=safety.


Lightsaber
Winter is coming.
 
trex8
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Re: RR finds cracks on fan blades in Trent XWB engine

Tue Aug 11, 2020 10:14 pm

JerseyFlyer wrote:
TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article


The vibratory issue will not occur on the more powerful XWB-97 variant used in the A350-1000 because the first two-stages of the IP compressor in this engine are comprised of solid blisks (integrated blades and disks), rather than the XWB-84’s more conventional blade and disk configuration.


https://aviationweek.com/air-transport/ ... wear-issue
 
889091
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Re: RR finds cracks on IPT blades in Trent XWB engine

Tue Aug 11, 2020 11:23 pm

After 4-5 years, those engines will be out of warranty, so unless the affected airlines had signed up for RR's 'Power By The Hour' deal, who pays for these fixes?
 
trex8
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Re: RR finds cracks on IPT blades in Trent XWB engine

Wed Aug 12, 2020 12:33 am

889091 wrote:
After 4-5 years, those engines will be out of warranty, so unless the affected airlines had signed up for RR's 'Power By The Hour' deal, who pays for these fixes?

There can't be too many airlines in this day and age with these types of planes who haven't signed up for Total Care. Even DL has. Thats why the Trent 1000 has cost RR so much, they're on the hook for fixing any problem , plus in many cases also having to cover expenses the airlines have run up with grounded planes.
 
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Aesma
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Re: RR finds cracks on fan blades in Trent XWB engine

Wed Aug 12, 2020 4:07 am

frmrCapCadet wrote:
How many billions have been spent on bleeding edge engines? Design, delay, corrosion, cracking, downtime. I suspect much of that money spent on offsets and a modest carbon tax would have done the world a lot better. Including the airlines. Petroleum may have some occasional peaks over the next ten years, but after that it will be a cheap commodity, always on the edge of oversupply.


I think the fuel savings are much higher than the money spent on these issues. And the environmental benefits are impossible to calculate.

I agree with a carbon tax though, although this would push even more billions into developing even better engines, not the other way around.
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
 
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JerseyFlyer
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Re: RR finds cracks on fan blades in Trent XWB engine

Wed Aug 12, 2020 7:06 am

trex8 wrote:
JerseyFlyer wrote:
TWB-97 "cannot be affected" due to different architecture. Does anyone understand these differences between TXWB-84 and -97? Lightsaber?

"Haselbach stresses that the different architecture on the Trent XWB-97 for the A350-1000 means “it cannot happen” on the higher-thrust variant."

https://www.flightglobal.com/engines/a3 ... 08.article


The vibratory issue will not occur on the more powerful XWB-97 variant used in the A350-1000 because the first two-stages of the IP compressor in this engine are comprised of solid blisks (integrated blades and disks), rather than the XWB-84’s more conventional blade and disk configuration.


https://aviationweek.com/air-transport/ ... wear-issue


A case where more advanced technology bypasses the problem - maybe?

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