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Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:25 am
by superbizzy73
https://www.flightglobal.com/news/artic ... ge-454740/

Mods, please do move as you see fit. Just saw this come across the news. Does anyone know any more information about what happen?

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:32 am
by September11
Sounds like Southwest Airlines in 2018

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:34 am
by strfyr51
superbizzy73 wrote:
https://www.flightglobal.com/news/articles/korean-air-a220-suffers-significant-engine-damage-454740/

Mods, please do move as you see fit. Just saw this come across the news. Does anyone know any more information about what happen?

from the pictures? It looks like Foreign Object damage. but whatever it was? it ate that engine UP!! That's an overhaul for sure!!

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 7:57 am
by ITMercure
FOD? Why 'foreign'? It could also be that a fan blade broke and shattered, damaging other blades. Or that the fan case slightly ovalized, leading to fan tip friction that shattered metal pieces and damaged the fan.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 8:43 am
by c933103
Korean news published on the day after the accident occurred say Korean civil aviation authority and KE are investigating what sort of problem occured to the engine, and the authority would focus on the direction of manufacturing deficit in their investigation as the plane was delivered just a few months ago

The news also noted that the aircraft type delivery to KE was delayed due to production troubles related to the engine, and there were problems faced by the PW1500G engine during test flights before delivery that once caused KE to infinitely pushed back its introduction but decided to resume its introduction about two months after the incident when the problem was reported as fixed. As such, media reports question KE's decision to introduce the new aircraft model despite known engine troubles, and question KE's priority in passenger safety.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 9:04 am
by T prop
Fan blades? Those look like turbine blades.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 9:33 am
by zeke
Need a view from the front, damage can be seen in the core shroud and the bypass.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 10:08 am
by c933103
Video at https://m.news.naver.com/read.nhn?mode= ... 0000199417 contain higher resolution zoom in/highlight to the sane photo

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 12:05 pm
by SteelChair
Could have been many things. Rather disconcerting that we are just now hearing about it, almost a week has passed.

I'm sure a thorough investigation will be completed and remedial action will be taken, and though it is concerning, I have seen this tyoe of damage on many other engines over the years.if its FOD, that's somewhat of a relief

Of course, no statement from PW, the aviation press is asleep at the switch yet again.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 1:51 pm
by Revelation
strfyr51 wrote:
superbizzy73 wrote:
https://www.flightglobal.com/news/articles/korean-air-a220-suffers-significant-engine-damage-454740/

Mods, please do move as you see fit. Just saw this come across the news. Does anyone know any more information about what happen?

from the pictures? It looks like Foreign Object damage. but whatever it was? it ate that engine UP!! That's an overhaul for sure!!

http://newsinflight.com/2019/01/01/engi ... rbus-a220/ gives us:

Image

That will not just buff out.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:09 pm
by uta999
c933103 wrote:
Video at https://m.news.naver.com/read.nhn?mode= ... 0000199417 contain higher resolution zoom in/highlight to the sane photo


Love the way the news item includes clips of an A380, a 77W and cabin views of a WB, as well as them maintaining a 77W engine which is bigger than an A220 fuselage.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:10 pm
by Spacepope
Revelation wrote:
strfyr51 wrote:
superbizzy73 wrote:
https://www.flightglobal.com/news/articles/korean-air-a220-suffers-significant-engine-damage-454740/

Mods, please do move as you see fit. Just saw this come across the news. Does anyone know any more information about what happen?

from the pictures? It looks like Foreign Object damage. but whatever it was? it ate that engine UP!! That's an overhaul for sure!!

http://newsinflight.com/2019/01/01/engi ... rbus-a220/ gives us:

Image

That will not just buff out.

No, that will clearly take some bondo to fix. Maybe fiber strand.

Looks like it ate something hard. Question now becomes did said hard crunchy object come from inside or outside the motor....

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:27 pm
by william
uta999 wrote:
c933103 wrote:
Video at https://m.news.naver.com/read.nhn?mode= ... 0000199417 contain higher resolution zoom in/highlight to the sane photo


Love the way the news item includes clips of an A380, a 77W and cabin views of a WB, as well as them maintaining a 77W engine which is bigger than an A220 fuselage.


Worse than "Hollywood" movies. :lol: :lol:

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 2:56 pm
by FlightLevel360
The aircraft in question, HL8314, was delivered in late September 2018. It's very new and shouldn't have the problem the original CS300s have faced

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 3:03 pm
by richierich
Spacepope wrote:
Revelation wrote:
strfyr51 wrote:
from the pictures? It looks like Foreign Object damage. but whatever it was? it ate that engine UP!! That's an overhaul for sure!!

http://newsinflight.com/2019/01/01/engi ... rbus-a220/ gives us:

Image

That will not just buff out.

No, that will clearly take some bondo to fix. Maybe fiber strand.

Looks like it ate something hard. Question now becomes did said hard crunchy object come from inside or outside the motor....


Nothing to make one think this damage came from outside the engine...but with all the talk of drones these days, I can only imagine this is sort of what might happen should one ever get ingested. Not good on climbout or takeoff.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 4:43 pm
by GulfstreamFive
"On the day the incident happened, the aircraft departed Busan Gimhae International airport at 13.01 hours local time for Nagoya, where the engine failure was detected 25 minutes later. It subsequently made a return for Busan, and safely landed at Gimhae airport 59 minutes after departure."

So they were either at cruise altitude or close when the engine problem was detected. While it doesn’t rule out FOD, it does make FOD a less likely cause of the failure. (Unless ice occurred on only one side of the aircraft)

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 4:56 pm
by GlobalAirways
richierich wrote:
Spacepope wrote:
Revelation wrote:
http://newsinflight.com/2019/01/01/engi ... rbus-a220/ gives us:

Image

That will not just buff out.

No, that will clearly take some bondo to fix. Maybe fiber strand.

Looks like it ate something hard. Question now becomes did said hard crunchy object come from inside or outside the motor....


Nothing to make one think this damage came from outside the engine...but with all the talk of drones these days, I can only imagine this is sort of what might happen should one ever get ingested. Not good on climbout or takeoff.


Has anyone done a drone test on a commercial engine? You hear about them more and more entering air space. Maybe when they are cannoning the frozen birds during testing they can throw a couple drones in too?

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 5:07 pm
by Cdydatzigs
william wrote:
uta999 wrote:
c933103 wrote:
Video at https://m.news.naver.com/read.nhn?mode= ... 0000199417 contain higher resolution zoom in/highlight to the sane photo


Love the way the news item includes clips of an A380, a 77W and cabin views of a WB, as well as them maintaining a 77W engine which is bigger than an A220 fuselage.


Worse than "Hollywood" movies. :lol: :lol:


No real need to put Hollywood in quotes I'd imagine. It is a real place.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 5:09 pm
by RB211trent
Definitely not FOD. Internal failure resulting in damage downstream.

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 6:24 pm
by kalvado
A traditional question... Is it a write-off?
More elaborate version of the same question:
apparently rotor and stator blades from the last stage as seen in picture are scrap metal. Probably at least some of stages before that also damaged. What would that do to the engine in general? Shafts, bearings? Blade attachment points? SO is it worth to rebuild such an engine after all, or it is just spare parts donor at this point?

Re: Korean Air A220 Significant Engine Damage

Posted: Thu Jan 03, 2019 8:14 pm
by BreninTW
kalvado wrote:
A traditional question... Is it a write-off?
More elaborate version of the same question:
apparently rotor and stator blades from the last stage as seen in picture are scrap metal. Probably at least some of stages before that also damaged. What would that do to the engine in general? Shafts, bearings? Blade attachment points? SO is it worth to rebuild such an engine after all, or it is just spare parts donor at this point?


I doubt this particular engine would ever donate parts -- it's probably being subjected to a very detailed post-mortem as we discuss this. Regulators and the engineers at P&W will want to know what happened, and why, so that they can learn any lessons from it.

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 1:16 am
by Waterbomber
I don't think that it's an object going through the engine.
You are looking at the last stage of the low pressure turbine and its vanes that guide the airflow into the turbine blades. Some blades are sheared off. At this point pressure is pretty low so it's unlikely the airflow would have sufficient energy to carry an object to make the turbine blades break off like that.
Also it doesn't explain the damage on the tailcone.

If we look at the damage on the shroud, to me it looks like the turbine started rotating outside its normal axis and engraved itself into the shroud while turning. This can explain the shear point moving from the tip of the turbine blades towards the root as the turbine rotated clockwise which you can see from right to left. It also explains the shroud being broken and losing its circle shape.
Also it looks like the turbine blades' leading edge scraped the vanes.

So my speculation is a shaft or aft bearing failure.

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 1:11 pm
by Revelation
Waterbomber wrote:
If we look at the damage on the shroud, to me it looks like the turbine started rotating outside its normal axis and engraved itself into the shroud while turning. This can explain the shear point moving from the tip of the turbine blades towards the root as the turbine rotated clockwise which you can see from right to left. It also explains the shroud being broken and losing its circle shape.
Also it looks like the turbine blades' leading edge scraped the vanes.

So my speculation is a shaft or aft bearing failure.

Interesting analysis!

Given Pratt has had issues with the aft bearings, it's quite plausible.

I wonder if any of the low pressure spool parts can be reused after such a deceleration.

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 5:34 pm
by stephanwintner
@Waterbomber - makes some sense. But, if it was a bearing, then the oil sump chip detector and/or the vibe sensors are supposed to have sensed the failure and shut it down before that sort of damage...Still it's the best theory.

A flutter failure of the blades might look like that - but that'd be an enormous failure of the product design and certification process. And you're right it's not FOD, not there.

-Stephan

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 6:16 pm
by Tn55337
That picture looks a lot like pictures from the RR engines on the 787

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 6:18 pm
by JayinKitsap
A bowed shaft could cause the blade clearance to go negative. But to damage so many blades along their length would probably point to the blades hitting in the HP turbine. A tip hitting the wall would have debris mostly in the outer area due to centrifugal acceleration. The debris would need to ping pong thru several sets to get to the inner portion.

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Jan 04, 2019 7:07 pm
by RB211trent
Revelation wrote:
Waterbomber wrote:
If we look at the damage on the shroud, to me it looks like the turbine started rotating outside its normal axis and engraved itself into the shroud while turning. This can explain the shear point moving from the tip of the turbine blades towards the root as the turbine rotated clockwise which you can see from right to left. It also explains the shroud being broken and losing its circle shape.
Also it looks like the turbine blades' leading edge scraped the vanes.

So my speculation is a shaft or aft bearing failure.

Interesting analysis!

Given Pratt has had issues with the aft bearings, it's quite plausible.

I wonder if any of the low pressure spool parts can be reused after such a deceleration.

I would imaging damage like that could only occur if the location bearing failed, the aft bearing I believe is a roller bearing so not location. I’m not that familiar with PW engines only the V2500 so I may be wrong.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 7:22 pm
by stephanwintner
https://www.flightglobal.com/news/artic ... sa-455104/

Well, that's not adding any clarity to the matter....

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 7:48 pm
by WayexTDI
stephanwintner wrote:
https://www.flightglobal.com/news/articles/damaged-a220-pw1500g-undergoes-examination-in-usa-455104/

Well, that's not adding any clarity to the matter....

Can you summarize/provide another source? Article is for subscribers only.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 7:56 pm
by Momo1435
WayexTDI wrote:
stephanwintner wrote:
https://www.flightglobal.com/news/articles/damaged-a220-pw1500g-undergoes-examination-in-usa-455104/

Well, that's not adding any clarity to the matter....

Can you summarize/provide another source? Article is for subscribers only.

- The engine has been shipped to the USA for examination, P&W will tear the engine down completely.
- Airbus says they think it's an isolated incident, but they don't know for sure until the examination is completed.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 8:08 pm
by anxo75
Momo1435 wrote:
WayexTDI wrote:
stephanwintner wrote:
https://www.flightglobal.com/news/articles/damaged-a220-pw1500g-undergoes-examination-in-usa-455104/

Well, that's not adding any clarity to the matter....

Can you summarize/provide another source? Article is for subscribers only.

- The engine has been shipped to the USA for examination, P&W will tear the engine down completely.
- Airbus says they think it's an isolated incident, but they don't know for sure until the examination is completed.

What a wonderful aircraft! Everything that happens to it is an "isolated incident".

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 8:14 pm
by WayexTDI
Momo1435 wrote:
WayexTDI wrote:
stephanwintner wrote:
https://www.flightglobal.com/news/articles/damaged-a220-pw1500g-undergoes-examination-in-usa-455104/

Well, that's not adding any clarity to the matter....

Can you summarize/provide another source? Article is for subscribers only.

- The engine has been shipped to the USA for examination, P&W will tear the engine down completely.
- Airbus says they think it's an isolated incident, but they don't know for sure until the examination is completed.

Indeed, says nothing of value...

Thanks for the info though.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 8:58 pm
by JoeCanuck
Our view of the damage is from the front of the engine, right?

anxo75 wrote:
What a wonderful aircraft! Everything that happens to it is an "isolated incident".


Indeed. Almost every problem has been isolated to the engines.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:20 pm
by stephanwintner
@ Joe, no, that's a view from the aft at the back of the LPT. Between the turbine exhaust case struts at the stage 3 blades. Well, where the stage 3 blades should be.

@Wayextdi sorry didn't realize it was for subscribers. I'd agree with the summary Momo posted. (Subscribe mate, it's free! Good content too, I like it better than AvWeek)

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:25 pm
by strfyr51
ITMercure wrote:
FOD? Why 'foreign'? It could also be that a fan blade broke and shattered, damaging other blades. Or that the fan case slightly ovalized, leading to fan tip friction that shattered metal pieces and damaged the fan.

Foreign object Damage is a generic term for anything other than Air that goes down an engine which damages it, It could have been MANY things But anything other than Airflow? Would be considered a foreign Object.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:32 pm
by strfyr51
RB211trent wrote:
Definitely not FOD. Internal failure resulting in damage downstream.

and how could you say it's NOT? The leading and trailing edges pf the turbine are torn up so the damage had to come from Forward, Since we can't see the inlet? How would you know unless you did the Borescope inspection? Which you probably DIDN'T..

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:38 pm
by ro1960
GlobalAirways wrote:
Has anyone done a drone test on a commercial engine? You hear about them more and more entering air space. Maybe when they are cannoning the frozen birds during testing they can throw a couple drones in too?


Not on engines yet but on wing yes. Discussed here:
https://www.airliners.net/forum/viewtopic.php?f=3&t=1406301&p=20790949

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:39 pm
by kalvado
strfyr51 wrote:
ITMercure wrote:
FOD? Why 'foreign'? It could also be that a fan blade broke and shattered, damaging other blades. Or that the fan case slightly ovalized, leading to fan tip friction that shattered metal pieces and damaged the fan.

Foreign object Damage is a generic term for anything other than Air that goes down an engine which damages it, It could have been MANY things But anything other than Airflow? Would be considered a foreign Object.

Not to imply any links with this particular case.. But would rain (or snow and hail) be considered a foreign object as well? I assume rain operation has to be within the specs....

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 9:58 pm
by stephanwintner
strfyr51 wrote:
RB211trent wrote:
Definitely not FOD. Internal failure resulting in damage downstream.

and how could you say it's NOT? The leading and trailing edges pf the turbine are torn up so the damage had to come from Forward, Since we can't see the inlet? How would you know unless you did the Borescope inspection? Which you probably DIDN'T..


Since we can see the remains of only a few stage 3 LPT blades, but all of the stage 3 vanes, it's unlikely to be FOD. If major FOD had come through and taken out all of the 3rd stage blades, it would also have almost certainly trashed the 2nd stage blades. And if the majority of the 2nd stage blades had shed, those vanes wouldn't look the way they do. If it was minor FOD that left blade 2 intact, then it's unlikely to have failed so many blades.

If the thrust bearing failed, the LP turbine would move forward. Thus the 3rd stage blades would contact the 3rd stage vane trailing edges, resulting in damage similar to that visible. Alternately, a flutter issue on the blades could cause them to flail about and contact the vanes. Neither scenario requires FOD coming from the front, despite your "The leading and trailing edges pf the turbine are torn up so the damage had to come from Forward " certainty.

I could imagine that small FOD might have trashed one stage 3 blade. That loss of ring integrity might have unlocked the blade shroud Z notches, and maybe they fluttered in that state. So - maybe it is FOD - but that seems far-fetched. I'm speculating, but it doesn't look like FOD to me, or him.

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 10:00 pm
by JoeCanuck
stephanwintner wrote:
@ Joe, no, that's a view from the aft at the back of the LPT. Between the turbine exhaust case struts at the stage 3 blades. Well, where the stage 3 blades should be.

@Wayextdi sorry didn't realize it was for subscribers. I'd agree with the summary Momo posted. (Subscribe mate, it's free! Good content too, I like it better than AvWeek)


Are you sure? I may have it wrong but I didn't think the exhaust behind the LPT was painted. Plus...the blades of the first two rows we see, (I'm not talking about the large support struts), are canted in opposite directions. It seems to me that the first row of blades could be a stator, with the second row being the first stage of the low pressure compressor. Judging by the direction of the second row of blades, they look to be angled in the same direction as the low pressure compressor, not the low pressure turbine.

Also to me, it just doesn't look like these parts have seen any significant heat.

If I am correct, (and I may very well be out to lunch on this), then the damage could very well have been FOD ingestion.

Image

Image

Image

Re: Korean Air A220 Significant Engine Damage

Posted: Tue Jan 29, 2019 11:54 pm
by stephanwintner
JoeCanuck wrote:

Are you sure? I may have it wrong but I didn't think the exhaust behind the LPT was painted. Plus...the blades of the first two rows we see, (I'm not talking about the large support struts), are canted in opposite directions. It seems to me that the first row of blades could be a stator, with the second row being the first stage of the low pressure compressor. Judging by the direction of the second row of blades, they look to be angled in the same direction as the low pressure compressor, not the low pressure turbine.

Also to me, it just doesn't look like these parts have seen any significant heat.

If I am correct, (and I may very well be out to lunch on this), then the damage could very well have been FOD ingestion.


I used to work at MTU, on those exact parts. I'm 99% certain. If we were looking in the inlet, the fan blades would be in the way. Given the width of the field of view, I don't think we can be looking between the fan blades.

You're correct that the blade and vane face opposite ways, they always do - be it compressor or turbine, whichever way we are looking at them. The air coming off the blades will tend to swirl in one direction. The vanes face the other way, and turn that flow, in order to direct it into the next row of blades. If you refer to your last image and imagine the angle of those blades, you'll see it lines up with the airfoils closest to the viewer (not the struts) that are mostly broken off. (The image you found doesn't show the vane between the blades.)

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 12:20 am
by 787SIN
That is the exhaust section of the engine quite clearly. Last stage of LPT (3rd), with vane segments in front of it. Very unlikely to be the result of FOD damage if its just at the rear of the engine. Even with most ingestion events the debris is normally all but destroyed by the time it gets through the combustion chamber.

Although if you get a really bad ingestion event or a compressor blade/vane/blade lock etc. fail then you'll get a corn cobbed compressor from where the first failure occured, in that case, there may be metallic residue aft of the combustion chamber in the form of metal splatter. This sometimes blocks the cooling in the first stages (blades/vanes) of the turbine leading to burnback of the material due to localised hot spots potentially the resulting in failure of turbine parts. But as the front is usually toast by this stage it is unusual to get anything more than some blocked cooling holes/channels as the engine is unlikely to run for that long in this state.

For this one the look of the damage here appears to be very similar to what would be experienced if a blade had failed in the turbine, given it is a new engine in all likelihood a material defect that may have got past inspections following manufacture and a premature failure has occured.

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 1:37 am
by Waterbomber
787SIN wrote:
That is the exhaust section of the engine quite clearly. Last stage of LPT (3rd), with vane segments in front of it. Very unlikely to be the result of FOD damage if its just at the rear of the engine. Even with most ingestion events the debris is normally all but destroyed by the time it gets through the combustion chamber.

Although if you get a really bad ingestion event or a compressor blade/vane/blade lock etc. fail then you'll get a corn cobbed compressor from where the first failure occured, in that case, there may be metallic residue aft of the combustion chamber in the form of metal splatter. This sometimes blocks the cooling in the first stages (blades/vanes) of the turbine leading to burnback of the material due to localised hot spots potentially the resulting in failure of turbine parts. But as the front is usually toast by this stage it is unusual to get anything more than some blocked cooling holes/channels as the engine is unlikely to run for that long in this state.

For this one the look of the damage here appears to be very similar to what would be experienced if a blade had failed in the turbine, given it is a new engine in all likelihood a material defect that may have got past inspections following manufacture and a premature failure has occured.


I think that the really interesting part is the huge dent and cracks on the exhaust cone. If you ever had one in your hands you would know that that is a very solid part.
Also if you look at the angle of the damage and considering the high speed flow rushing out of the turbine section, it's almost impossible for anything to hit it at that angle.
So to me it looks like the thing "imploded" as if something put strain locally on its attachment points suggesting that something deformed inside, locally.
Reminds me a bit of a cherrymax rivet but in reverse.

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 4:27 am
by 787SIN
Waterbomber, with you on that, the damage does look odd, but with everything new generation you see weight taken out here and there so wouldn't be surprised if the cone was just impacted by high-velocity turbine debris and unable to withstand it. Also being that the cone is mounted directly to the aft bearing support frame inner flange I can't see what else it could be unless the aft bearing catastrophically failed, but then we would probably see way more damage than is currently seen.

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 5:03 am
by JoeCanuck
787SIN wrote:
That is the exhaust section of the engine quite clearly. Last stage of LPT (3rd), with vane segments in front of it. Very unlikely to be the result of FOD damage if its just at the rear of the engine. Even with most ingestion events the debris is normally all but destroyed by the time it gets through the combustion chamber.

Although if you get a really bad ingestion event or a compressor blade/vane/blade lock etc. fail then you'll get a corn cobbed compressor from where the first failure occured, in that case, there may be metallic residue aft of the combustion chamber in the form of metal splatter. This sometimes blocks the cooling in the first stages (blades/vanes) of the turbine leading to burnback of the material due to localised hot spots potentially the resulting in failure of turbine parts. But as the front is usually toast by this stage it is unusual to get anything more than some blocked cooling holes/channels as the engine is unlikely to run for that long in this state.

For this one the look of the damage here appears to be very similar to what would be experienced if a blade had failed in the turbine, given it is a new engine in all likelihood a material defect that may have got past inspections following manufacture and a premature failure has occured.


I checked out some pics from behind with the engine mounted on a 220 and I can confirm you are correct. The damage pictured is to the LPT.

Image

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 8:54 am
by RB211trent
strfyr51 wrote:
RB211trent wrote:
Definitely not FOD. Internal failure resulting in damage downstream.

and how could you say it's NOT? The leading and trailing edges pf the turbine are torn up so the damage had to come from Forward, Since we can't see the inlet? How would you know unless you did the Borescope inspection? Which you probably DIDN'T..

No I didn’t borescope that engine but I’ve borescoped hundreds of other engines (probably 100% more than you) and as mentioned in other posts FOD rarely causes damage past the hot section to the degree seen in the images. The damage is typical of a location bearing or internal failure. Seems to me that other posters who know what they are talking about seem to agree.

Re: Korean Air A220 Significant Engine Damage

Posted: Wed Jan 30, 2019 1:29 pm
by PW100
anxo75 wrote:
What a wonderful aircraft! Everything that happens to it is an "isolated incident".


What else on this aircraft had been classified as an "isolated incident" . . . ?

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Mar 01, 2019 5:06 pm
by stephanwintner
https://aviation-safety.net/wikibase/wiki.php?id=222410

This incident seems to have also had a failure of the 3rd stage LPT blade...

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Mar 01, 2019 5:30 pm
by ExMilitaryEng
stephanwintner wrote:
https://aviation-safety.net/wikibase/wiki.php?id=222410
This incident seems to have also had a failure of the 3rd stage LPT blade...


Above link (and 3rd stage LPT blade failure) refers to a Vietnam Airlines Airbus A321-272NEO, registered VN-A621(ex D-AVYP).
So indeed also a GTF (PW1130G-JM, with a maximum trust of 35,000 lbf?)

However I'm not sure how far we can link the two as the PW1500G (23,300 lbf of maximum trust?) did incur less many incidents, and those were generally of different nature.

Re: Korean Air A220 Significant Engine Damage

Posted: Fri Mar 01, 2019 6:17 pm
by stephanwintner
My Bad. Yes, ExMilitaryEng is correct, I should have pointed that out. They are different, but very similar engines, designed by the same guys at the same firms. I know that, but should have pointed that out for everyone.