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KLASM83
Posts: 500
Joined: Mon Aug 01, 2005 10:08 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:42 am

https://airwaysmag.com/airlines/united- ... 7s-pw4000/

Well, that's a good chunk of the fleet! Wonder how long it will be before they get the PW jets back up in the air?
 
SESGDL
Posts: 3049
Joined: Sat Jan 13, 2001 6:25 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:45 am

What is it with UA and issues with flights going to/coming from Hawaii? Coincidences of course, but a little eerie how many accidents and issues have occurred with UA Hawaiian flights.

Jeremy
 
ABpositive
Posts: 247
Joined: Mon Nov 07, 2005 2:36 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:47 am

Raptormodeller wrote:
The front fell off. Was it towed outside the environment.?


Yes, it's been towed beyond the environment. :)
 
nm2582
Posts: 209
Joined: Tue Jun 26, 2007 2:15 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:58 am

CALTECH wrote:
Hearing....

Message 2.5 Bleed Not In Commanded Position....

Engine Surge....

Then the Incident.......


Interesting. Any idea how much time transpired between the message and the failure?
 
gobears19
Posts: 11
Joined: Fri Jan 24, 2020 8:25 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:15 am

I know the older 737NG go through more rigorous inspections for similar reasons, stress fatigue on the fan blades. But do they know how long it takes for these things to be detectable before they break? Have they ever reported findings of the inspections and what repairs were done?

Wonder why they don't just replace the entire fan every x cycles...
 
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Aaron747
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:19 am

SESGDL wrote:
What is it with UA and issues with flights going to/coming from Hawaii? Coincidences of course, but a little eerie how many accidents and issues have occurred with UA Hawaiian flights.

Jeremy


It may seem that way but consider that in normal economic conditions, United has basically been one of the top major carriers to Hawaii for decades. Five or six incidents since the early 2000s? That's about the same as HA.
 
RogerMurdock
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:21 am

So it seems that, based on the actions of the regulators and airline, they've pretty much ruled out a bird strike.
 
nm2582
Posts: 209
Joined: Tue Jun 26, 2007 2:15 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:24 am

gobears19 wrote:
Wonder why they don't just replace the entire fan every x cycles...


Cost. Each blade is NOT cheap.
 
HAWKXP
Posts: 86
Joined: Tue Aug 19, 2014 6:03 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:43 am

I live 2 miles from where parts fell. Heard the engine go (didn't see) sounded like a sonic boom. Then a very strange whine.
 
ILikeTrains
Posts: 116
Joined: Tue Dec 24, 2019 3:18 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 3:01 am

ContinentalEWR wrote:
ILikeTrains wrote:
Depending on how long this goes on for, could this mean UA would pull 764’s out of storage to cover the load? I know a good portion of the 772 GE fleet is parked, so I imagine those would come back first if need be.


They could, though the 764s have been in long term storage for a while so it would take some time to get any or all 16 frames active and up and running. When you say a good portion of the 772 GE fleet is parked, does that mean all the ex-Continental 777 frames? All of them, AFAIK are GE powered, not PW. Guess I could look it up.


It didn’t look like many GE 772s are running, the United Fleet google doc shows only 4 of 22 running right now. Depending on how many of those 18 are parked versus in maintenance, I’m sure that mostly covers the gap.

I think United has a few 789s awaiting delivery that could help cover the gap. Or the 763s they have stored.
 
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Revelation
Posts: 27048
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 3:13 am

Jon O reports:

Boeing recommends an operational suspension of PW4000-powered 777s (aka grounding) “until the FAA identifies the appropriate inspection protocol.” Says 69 are currently in service and 59 are in storage.

Ref: https://twitter.com/jonostrower/status/ ... 0830775301

Seems the horse left the barn first though..

Boeing's presser:

Boeing is actively monitoring recent events related to United Airlines Flight 328. While the NTSB investigation is ongoing, we recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines until the FAA identifies the appropriate inspection protocol.

Boeing supports the decision yesterday by the Japan Civil Aviation Bureau, and the FAA’s action today to suspend operations of 777 aircraft powered by Pratt & Whitney 4000-112 engines. We are working with these regulators as they take actions while these planes are on the ground and further inspections are conducted by Pratt & Whitney.

Updates will be provided as more information becomes available.

Ref: https://boeing.mediaroom.com/news-relea ... tem=130829
Last edited by Revelation on Mon Feb 22, 2021 3:21 am, edited 1 time in total.
 
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litz
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 3:26 am

The thing to remember is, there are several different variants of the PW 4000, among other differences are fan casing size (and, obviously, also fan *blade* size).

The 772 uses the -112 variant.
 
DBKissORD
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Joined: Thu May 25, 2017 6:48 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 3:27 am

Anyone know what the useful life of a fan blade on these engines? Can they be used forever with regular inspections or is it limited at some point?
 
ltbewr
Posts: 15876
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 3:34 am

With the suspension of those 777's with this particular engine model voluntary by airlines or per orders by authorities, what planes will be used in substitution ? Pull some from storage, reassign different model aircraft from other routes ?
 
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Acey559
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 4:22 am

ContinentalEWR wrote:
ILikeTrains wrote:
Depending on how long this goes on for, could this mean UA would pull 764’s out of storage to cover the load? I know a good portion of the 772 GE fleet is parked, so I imagine those would come back first if need be.


They could, though the 764s have been in long term storage for a while so it would take some time to get any or all 16 frames active and up and running. When you say a good portion of the 772 GE fleet is parked, does that mean all the ex-Continental 777 frames? All of them, AFAIK are GE powered, not PW. Guess I could look it up.


There are some 777Cs (GE 777s) flying around but most (all?) are doing pure freighter work. Those are the planes that had 5000lb of sandbags added to the aft galley to allow full belly compartments.
 
bigb
Posts: 1513
Joined: Fri Nov 07, 2003 4:30 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 4:32 am

CaptainHaresh wrote:
mxaxai wrote:
N47 wrote:
I also wanted to comment on some of the previous posts that stood against the theory of a bird strike. My thoughts are that since the aircraft was above 10kft and thereby accelerated to ~300kts at which point striking a bird will have different impact that striking it after takeoff or initial climb where speeds are at least below 250. The extra momentum involved may be enough to cause the blades to detach.

The aircraft was at ~8,000 ft above ground, it's fairly unlikely (though not impossible) to find birds there.

Given that there was a nearly identical incident 2 years ago, the cause was probably undetected fatigue again.


UA is going to be in a tight spot if they have not made changes as recommended in the report of the 2018 incident and this incident proves to be a consequence of the same issue.
This can end up in criminal court due to negligence.
They can count themselves lucky that no one died on the ground.

The crew-ATC communications reflect a sloppy cockpit environment.
The captain sounds half asleep before the incident as he failed to remember his flight's callsign several times.
The engine explosion seems to have shaken him awake.
Why take a left turn when your right engine is out?

Did the fire extinguishing bottles malfunction?
Design flaw that prevents fire extinguishing spray in case of an uncontained failure?
Failure of the crew to pull the bottles?
They brought the plane back in a high stres situation, which is the most important. but they could have von


And what would you have done differently? :roll:
 
zippy
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 4:51 am

litz wrote:
The thing to remember is, there are several different variants of the PW 4000, among other differences are fan casing size (and, obviously, also fan *blade* size).

The 772 uses the -112 variant.


Yes, however the 747 that vomited engine bits all over the Netherlands was also PW 4000 powered.
 
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SumChristianus
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 4:54 am

zippy wrote:
litz wrote:
The thing to remember is, there are several different variants of the PW 4000, among other differences are fan casing size (and, obviously, also fan *blade* size).

The 772 uses the -112 variant.


Yes, however the 747 that vomited engine bits all over the Netherlands was also PW 4000 powered.


Is it too conspiratorial to suggest some connection between the two incidents... Like maybe some recent batch of parts for both sets of PW4000 engines was produced in one factory and damaged in some manner? It looks like thoughts are moving away from the bird-strike theory based on the actions that have been taken over the past few hours in the US and Japan.
 
jakubz
Posts: 155
Joined: Fri May 21, 2010 9:48 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 5:15 am

zippy wrote:
litz wrote:
The thing to remember is, there are several different variants of the PW 4000, among other differences are fan casing size (and, obviously, also fan *blade* size).

The 772 uses the -112 variant.


Yes, however the 747 that vomited engine bits all over the Netherlands was also PW 4000 powered.


Technically true, but that was a 94in PW4000. The B777 uses the 112in version. The 777's version is roughly 30% longer, and about 50% heavier. I suspect that while the engines are similar conceptually, there are plenty of differences to make them distinct models.

As a point of comparison, the lightest and heaviest RR Trent are the Trent 500 (11k lb) and Trent XWB (16k lb), which is a slightly smaller range. The fan blade sizes are also comparably spread.

(All states per Wikipedia)
 
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CALTECH
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 5:26 am

GalaxyFlyer wrote:
It’s not an explosion, it’s an uncontained fan blade failure, aka fan blade off, event. Cause is unknown and could be material failure as the result of bird strike, internal corrosion or defect. It’s similar other such events including several on RR BR700 engines and GE engines. The dramatics posted are extreme—not miracle, a well managed failure.


Well said sir, well said. Flight crew did their job professionally.
 
LGeneReese
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Joined: Sun Sep 22, 2019 3:36 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 5:38 am

Here’s an excellent analysis of the event by Captain Joe https://youtu.be/q5Wler87pwY
 
LGeneReese
Posts: 310
Joined: Sun Sep 22, 2019 3:36 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 5:49 am

ILikeTrains wrote:
ContinentalEWR wrote:
ILikeTrains wrote:
Depending on how long this goes on for, could this mean UA would pull 764’s out of storage to cover the load? I know a good portion of the 772 GE fleet is parked, so I imagine those would come back first if need be.


They could, though the 764s have been in long term storage for a while so it would take some time to get any or all 16 frames active and up and running. When you say a good portion of the 772 GE fleet is parked, does that mean all the ex-Continental 777 frames? All of them, AFAIK are GE powered, not PW. Guess I could look it up.


It didn’t look like many GE 772s are running, the United Fleet google doc shows only 4 of 22 running right now. Depending on how many of those 18 are parked versus in maintenance, I’m sure that mostly covers the gap.

I think United has a few 789s awaiting delivery that could help cover the gap. Or the 763s they have stored.

UA has three 789s stored undelivered at CHS.. these would be no help in the short term as post delivery induction would take 6-7 days at minimum.
 
United1
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Joined: Wed Oct 08, 2003 9:21 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 5:58 am

SumChristianus wrote:
zippy wrote:
litz wrote:
The thing to remember is, there are several different variants of the PW 4000, among other differences are fan casing size (and, obviously, also fan *blade* size).

The 772 uses the -112 variant.


Yes, however the 747 that vomited engine bits all over the Netherlands was also PW 4000 powered.


Is it too conspiratorial to suggest some connection between the two incidents... Like maybe some recent batch of parts for both sets of PW4000 engines was produced in one factory and damaged in some manner? It looks like thoughts are moving away from the bird-strike theory based on the actions that have been taken over the past few hours in the US and Japan.


Anything is possible but doubtful there will be a connection between the 747 incident in Europe and the UA 777 at DEN. It's much more likely they will find a connection between the Japanese 777 that suffered an engine failure last year and the UA 777 yesterday.

The PW4000 is really a family of engines that share a common heritage but the ones on the 777 are quite different than what powers the 744.
 
United1
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Joined: Wed Oct 08, 2003 9:21 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 6:12 am

LGeneReese wrote:
ILikeTrains wrote:
ContinentalEWR wrote:

They could, though the 764s have been in long term storage for a while so it would take some time to get any or all 16 frames active and up and running. When you say a good portion of the 772 GE fleet is parked, does that mean all the ex-Continental 777 frames? All of them, AFAIK are GE powered, not PW. Guess I could look it up.


It didn’t look like many GE 772s are running, the United Fleet google doc shows only 4 of 22 running right now. Depending on how many of those 18 are parked versus in maintenance, I’m sure that mostly covers the gap.

I think United has a few 789s awaiting delivery that could help cover the gap. Or the 763s they have stored.

UA has three 789s stored undelivered at CHS.. these would be no help in the short term as post delivery induction would take 6-7 days at minimum.


Pulling aircraft out of storage or rushing induction on the 789s probably isn't necessary. The wide body fleet that is operating really isn't being taxed so my bet is UA will just increase utilization in the short term. It sounds like UA is grounding the fleet while PW and the Feds determine what sort of inspections need to be done and how often. I may regret saying this but I don't see the 777s being parked for any significant length of time.
 
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CALTECH
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 6:42 am

Going to correct a post made by me earlier, the rumor or first scuttlebutt about UA328 was more opinion and speculation of a few folks more so than anything based on facts or actual knowledge. Even the blood all over the engine and or inlet might not have been based on a factual observation.
Still could be a birdstrike as a big bird can make a fan blade fail near the root of the blade. But this UA328 looks so much like the 2018 UA1175 incident which was a Fan Blade Failure near the root of the blade, so for me best to now wait till the facts come out about what happened. Everything has been locked and secured for the NTSB Investigation.
 
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drerx7
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 6:43 am

Checking the usual 772 suspect routes on the United app...773s, 789, 788, 753s, 752, and 738 are covering. I'd assume if this turns out to be a 2'3 month ordeal we'll see other aircraft activated that Are in storage.
 
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Faro
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 7:44 am

Revelation wrote:
Jon O reports:

Boeing recommends an operational suspension of PW4000-powered 777s (aka grounding) “until the FAA identifies the appropriate inspection protocol.” Says 69 are currently in service and 59 are in storage.

Ref: https://twitter.com/jonostrower/status/ ... 0830775301




Does this mean monetary compensation to the affected airlines?...if so, who would pay up, PW or Boeing or both?...I think by this point Boeing is sick and tired of compensations...


Faro
 
Amp1
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 8:26 am

This is a major problem for these engines. A fan blade failure can never be totally ruled out, so to get certification an engine has to demonstrate containment of high energy debris without the casing/intake/cowling separating from the engine. Clearly there is a fundamental problem with this containment system.
 
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kearnet
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 8:42 am

Not to be melodramatic, but as it has now been essentially confirmed to be a blade-off uncontainable engine failure, is anyone else thinking about UA 232?
 
889091
Posts: 366
Joined: Sat Apr 06, 2019 7:56 pm

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 8:51 am

Faro wrote:
Revelation wrote:
Jon O reports:

Boeing recommends an operational suspension of PW4000-powered 777s (aka grounding) “until the FAA identifies the appropriate inspection protocol.” Says 69 are currently in service and 59 are in storage.

Ref: https://twitter.com/jonostrower/status/ ... 0830775301




Does this mean monetary compensation to the affected airlines?...if so, who would pay up, PW or Boeing or both?...I think by this point Boeing is sick and tired of compensations...


Faro


If investigations show that PW is at fault, then PW would be liable. Unlike the 77W, customers had different engine choices for the 772. Not too dissimilar to QF32 and Airbus and RR.
 
majano
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 11:37 am

ltbewr wrote:
With the suspension of those 777's with this particular engine model voluntary by airlines or per orders by authorities, what planes will be used in substitution ? Pull some from storage, reassign different model aircraft from other routes ?

In response to your first question, it looks to me like the Japanese authorities "ordered" the temporary grounding and everybody else followed. First to follow were ANA and JAL which is to be expected.
 
kalvado
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 11:37 am

Amp1 wrote:
This is a major problem for these engines. A fan blade failure can never be totally ruled out, so to get certification an engine has to demonstrate containment of high energy debris without the casing/intake/cowling separating from the engine. Clearly there is a fundamental problem with this containment system.

Containment of high energy pieces doesn't look like a problem. NTSB mentioned blade piece embedded in a shroud, no wing or fuselage damage like WN1380 or QF32, or any other truly uncontained event.
While it is not a contained failure by the book, it is not uncontained by the book as well. More like engine falling apart after a contained failure.
 
Amp1
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 11:50 am

kalvado wrote:
Amp1 wrote:
This is a major problem for these engines. A fan blade failure can never be totally ruled out, so to get certification an engine has to demonstrate containment of high energy debris without the casing/intake/cowling separating from the engine. Clearly there is a fundamental problem with this containment system.

Containment of high energy pieces doesn't look like a problem. NTSB mentioned blade piece embedded in a shroud, no wing or fuselage damage like WN1380 or QF32, or any other truly uncontained event.
While it is not a contained failure by the book, it is not uncontained by the book as well. More like engine falling apart after a contained failure.

Agreed, which is what I was alluding to because an engine falling apart after a contained failure isn’t certifiable either.
 
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Aaron747
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 12:12 pm

Amp1 wrote:
kalvado wrote:
Amp1 wrote:
This is a major problem for these engines. A fan blade failure can never be totally ruled out, so to get certification an engine has to demonstrate containment of high energy debris without the casing/intake/cowling separating from the engine. Clearly there is a fundamental problem with this containment system.

Containment of high energy pieces doesn't look like a problem. NTSB mentioned blade piece embedded in a shroud, no wing or fuselage damage like WN1380 or QF32, or any other truly uncontained event.
While it is not a contained failure by the book, it is not uncontained by the book as well. More like engine falling apart after a contained failure.

Agreed, which is what I was alluding to because an engine falling apart after a contained failure isn’t certifiable either.


'Falling apart' doesn't really seem applicable here since the hot sections and fan shielding remained completely intact. Even in the 2018 incident NTSB only noted a minor warping/cracking of the Kevlar containment structure. The outer casing is not engine structure - it should certainly be looked into, but it's nowhere near the 'engine falling apart'.
 
Amp1
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 12:26 pm

Aaron747 wrote:
'Falling apart' doesn't really seem applicable here since the hot sections and fan shielding remained completely intact. Even in the 2018 incident NTSB only noted a minor warping/cracking of the Kevlar containment structure. The outer casing is not engine structure - it should certainly be looked into, but it's nowhere near the 'engine falling apart'.


The intake and cowling separating could hazard the aircraft and people on the ground hence why it would be classed as a hazardous event and needs to be prevented in the case of a fan blade off which needs to be non-hazardous.
 
ContinentalEWR
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Joined: Wed May 24, 2000 2:50 am

Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 12:40 pm

ILikeTrains wrote:
ContinentalEWR wrote:
ILikeTrains wrote:
Depending on how long this goes on for, could this mean UA would pull 764’s out of storage to cover the load? I know a good portion of the 772 GE fleet is parked, so I imagine those would come back first if need be.


They could, though the 764s have been in long term storage for a while so it would take some time to get any or all 16 frames active and up and running. When you say a good portion of the 772 GE fleet is parked, does that mean all the ex-Continental 777 frames? All of them, AFAIK are GE powered, not PW. Guess I could look it up.


It didn’t look like many GE 772s are running, the United Fleet google doc shows only 4 of 22 running right now. Depending on how many of those 18 are parked versus in maintenance, I’m sure that mostly covers the gap.

I think United has a few 789s awaiting delivery that could help cover the gap. Or the 763s they have stored.


I guess it makes sense that the GE powered 777-200ERs are mostly stored. They have longer range and were being used for ORD (Asia) and IAH long haul and some SFO to Asia service, having largely moved off being EWR and IAH exclusively based, but much of what flies in that category these days is being done on the 77W and the 787 fleet. Also, I think not all of the ex-CO 772s have been fully Polaris'd, though I could be wrong about that. The entire 764 fleet has definitely not. UA does have some pending 789 deliveries, and some frames ready at CHS, but not yet through the EIS program. Aircraft utilization is overall down so I think UA will be fine with what it has to cover the routes the impacted 777s are affected by.
 
ContinentalEWR
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 12:45 pm

Aaron747 wrote:
Amp1 wrote:
kalvado wrote:
Containment of high energy pieces doesn't look like a problem. NTSB mentioned blade piece embedded in a shroud, no wing or fuselage damage like WN1380 or QF32, or any other truly uncontained event.
While it is not a contained failure by the book, it is not uncontained by the book as well. More like engine falling apart after a contained failure.

Agreed, which is what I was alluding to because an engine falling apart after a contained failure isn’t certifiable either.


'Falling apart' doesn't really seem applicable here since the hot sections and fan shielding remained completely intact. Even in the 2018 incident NTSB only noted a minor warping/cracking of the Kevlar containment structure. The outer casing is not engine structure - it should certainly be looked into, but it's nowhere near the 'engine falling apart'.


Yes, but the potential for shrapnel piercing the cabin is very high and that could have been catastrophic. An entirely different incident altogether but in 1989, a UA 747-100 flying from HNL to AKL suffered a massive decompression when the cargo door ripped open shortly after it too off from HNL. Parts of metal were sucked into the engine(s) and there were fatalities as a section of the cabin wall ripped open. The 777 has, as we know, one massive engine on each wing, not two, but the potential for a much more catastrophic disaster was very much present in the 2018 and this week's incident. The whole point of the investigation is to determine the integrity of not just the engine but all its components. The 2018 incident was caused by fatigue in a metal fan blade that separated. The 777 is a well built airplane and it looks like many safeguards worked in the engine to prevent a disaster but none of that is assured.
 
ltbewr
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:04 pm

Perhaps too the 'shedding' of shrouds, engine covers as in this flight are intentional to absorb a major engine component failure ?
 
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Aaron747
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:11 pm

ContinentalEWR wrote:
Aaron747 wrote:
Amp1 wrote:
Agreed, which is what I was alluding to because an engine falling apart after a contained failure isn’t certifiable either.


'Falling apart' doesn't really seem applicable here since the hot sections and fan shielding remained completely intact. Even in the 2018 incident NTSB only noted a minor warping/cracking of the Kevlar containment structure. The outer casing is not engine structure - it should certainly be looked into, but it's nowhere near the 'engine falling apart'.


Yes, but the potential for shrapnel piercing the cabin is very high and that could have been catastrophic. An entirely different incident altogether but in 1989, a UA 747-100 flying from HNL to AKL suffered a massive decompression when the cargo door ripped open shortly after it too off from HNL. Parts of metal were sucked into the engine(s) and there were fatalities as a section of the cabin wall ripped open. The 777 has, as we know, one massive engine on each wing, not two, but the potential for a much more catastrophic disaster was very much present in the 2018 and this week's incident. The whole point of the investigation is to determine the integrity of not just the engine but all its components. The 2018 incident was caused by fatigue in a metal fan blade that separated. The 777 is a well built airplane and it looks like many safeguards worked in the engine to prevent a disaster but none of that is assured.


No disagreement on anything you mention - that’s all factual. My exception was to the poster phrasing it as the ‘engine falling apart’ - he was not differentiating between the motor and the nacelle casing. Big difference between the two. If stuff is ejected from the HPT that’s a whole different animal.
 
Antarius
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:26 pm

Aaron747 wrote:
ContinentalEWR wrote:
Aaron747 wrote:

'Falling apart' doesn't really seem applicable here since the hot sections and fan shielding remained completely intact. Even in the 2018 incident NTSB only noted a minor warping/cracking of the Kevlar containment structure. The outer casing is not engine structure - it should certainly be looked into, but it's nowhere near the 'engine falling apart'.


Yes, but the potential for shrapnel piercing the cabin is very high and that could have been catastrophic. An entirely different incident altogether but in 1989, a UA 747-100 flying from HNL to AKL suffered a massive decompression when the cargo door ripped open shortly after it too off from HNL. Parts of metal were sucked into the engine(s) and there were fatalities as a section of the cabin wall ripped open. The 777 has, as we know, one massive engine on each wing, not two, but the potential for a much more catastrophic disaster was very much present in the 2018 and this week's incident. The whole point of the investigation is to determine the integrity of not just the engine but all its components. The 2018 incident was caused by fatigue in a metal fan blade that separated. The 777 is a well built airplane and it looks like many safeguards worked in the engine to prevent a disaster but none of that is assured.


No disagreement on anything you mention - that’s all factual. My exception was to the poster phrasing it as the ‘engine falling apart’ - he was not differentiating between the motor and the nacelle casing. Big difference between the two. If stuff is ejected from the HPT that’s a whole different animal.


It is different however from a safety standpoint, they're equally serious. The nacelle could easily have killed people - we're lucky it missed.
 
airbazar
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:32 pm

ContinentalEWR wrote:
Yes, but the potential for shrapnel piercing the cabin is very high and that could have been catastrophic.

I'm not sure that the external panels that fell off would have enough force to piece the cabin. To my uneducated eye, it seems the engine failure worked as designed by keeping all the high speed, potentially dangerous "shrapnel", contained. I'm not even sure that this qualifies as a uncontained engine failure but I guess we'll have to wait for the official results.
 
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SuseJ772
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:35 pm

CALTECH wrote:
Going to correct a post made by me earlier, the rumor or first scuttlebutt about UA328 was more opinion and speculation of a few folks more so than anything based on facts or actual knowledge. Even the blood all over the engine and or inlet might not have been based on a factual observation.
Still could be a birdstrike as a big bird can make a fan blade fail near the root of the blade. But this UA328 looks so much like the 2018 UA1175 incident which was a Fan Blade Failure near the root of the blade, so for me best to now wait till the facts come out about what happened. Everything has been locked and secured for the NTSB Investigation.


Still. Opinion from people in the know is different than opinion of those of us just coming up with stuff. Even if this one proved wrong, I for one am glad you share what you share when you share. I have learned a lot from you and glad you contribute to this site the way you do.
 
PANAMsterdam
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:45 pm

Isn't it a bit overreacting of all parties involved by immediately (temporarily) grounding an entire fleet of planes (the 777's with this type of engine) after an engine failure? The plane landed safely and everybody walked off the plane alive.

Yes, it is a serious incident.
Yes, it needs to be investigated.
Yes, there is nothing wrong with advising additional inspections.

But for Boeing, United and Japan to announce grounding all these birds (again, the ones with this P&W engine type) after this seems to me a bit too much.

I don't think that if the whole 737 Max disaster hadn't happened, Boeing would have given the same advice.
 
Antarius
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:52 pm

PANAMsterdam wrote:
Isn't it a bit overreacting of all parties involved by immediately (temporarily) grounding an entire fleet of planes (the 777's with this type of engine) after an engine failure? The plane landed safely and everybody walked off the plane alive.

Yes, it is a serious incident.
Yes, it needs to be investigated.
Yes, there is nothing wrong with advising additional inspections.

But for Boeing, United and Japan to announce grounding all these birds (again, the ones with this P&W engine type) after this seems to me a bit too much.


This isn't the only incident. There were 3 similar seeming ones.

PANAMsterdam wrote:
I don't think that if the whole 737 Max disaster hadn't happened, Boeing would have given the same advice.


That's a positive thing. People were asleep at the wheel for the MAX fiasco. Hopefully, some lessons are learned.
 
RogerMurdock
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 1:55 pm

PANAMsterdam wrote:
Isn't it a bit overreacting of all parties involved by immediately (temporarily) grounding an entire fleet of planes (the 777's with this type of engine) after an engine failure? The plane landed safely and everybody walked off the plane alive.

Yes, it is a serious incident.
Yes, it needs to be investigated.
Yes, there is nothing wrong with advising additional inspections.

But for Boeing, United and Japan to announce grounding all these birds (again, the ones with this P&W engine type) after this seems to me a bit too much.

I don't think that if the whole 737 Max disaster hadn't happened, Boeing would have given the same advice.


I think if it was a one off they wouldn't have grounded the P&W subfleet, but UA1175 was only a few short years ago: https://aviation-safety.net/wikibase/206147 . The FAA had ordered inspections on P&W4000 fan blades as recently as March 2019. So there's more concern than usual- what is getting missed?
 
PANAMsterdam
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:02 pm

Thank you for your explanations Antarius and RogerMurdock!
 
smokeybandit
Topic Author
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:15 pm

If airlines didn't have a bunch of spares parked, would there have been a grounding? Is it possible the grounding is just being overly cautious at a time that won't really affect flight schedules?
 
Amp1
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:21 pm

If the fan blade off had not resulted in the engine/intake/nacelle tearing apart, it wouldn’t have resulted in a grounding. However that intake ring could have caused serious damage if it had hit the tailplane, possibly rendering the aircraft uncontrollable. It could also have caused fatalities on the ground. It hence became a hazardous event, which as it wasn’t an isolated incident has rightly resulted in the grounding.

It looks a major task to get them airworthy, as a fan blade off needs to be non-hazardous which would require significant redesign of that static structure.
 
gwrudolph
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:24 pm

I think all parties are being conservative as a result of the MAX situation. All had egg on their face big time
 
B717fan
Posts: 63
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Re: UA328 engine explosion at DEN

Mon Feb 22, 2021 2:32 pm

A new photo of the aircraft on the ground shows damage to the fuselage.
https://twitter.com/breakingavnews/stat ... 5947356161
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