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KarelXWB
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PW1100G Bearing Failure

Thu Jan 26, 2017 12:53 pm

According to a NK pilot on another forum, the airline replaced three PW1100G engines in the last three months due to "a wiped bearing".

901 suffered a wiped #3 and #4 bearing on the #2 engine with significant metal shavings contained in the engine oil and had damage to the prop fan. So the engine was replaced and repairs done to the right engine pylon. The aircraft was out of service for approximately 2 weeks while replacing the engine since the supply of available engines is extremely limited.


N902NK is now out for service for a left engine replacement, similar to what happened to N901NK last month, time of repair is unknown due to engine supply constraints.


N903nk is now out of service in Denver with the same issue that has affected 901 (November) and 902 (December)

Awaiting ferry permit to DFW which will most likely be an engine change.


According to another person on the same forum, similar events happened with Volaris and IndiGo.

So what is "a wiped bearing"? I went to Google and found the following article:

http://www.waukbearing.com/en/technical ... e:-wiping/

It says:

A wiped bearing surface is where surface rubbing, melting and smearing is evident. This may be due to a variety of causes, including:

Excessive load at start-up/run-down
Insufficient lubricant
Operational overload
Loss of clearance
Misalignment


So which one is causing bearing damage on the PW1100G engine, and how can it be resolved?
What we leave behind is not as important as how we've lived.
 
kurtverbose
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Re: PW1100G Bearing Damage

Thu Jan 26, 2017 1:42 pm

Could any of that be related to rotor bow?
 
kalvado
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Re: PW1100G Bearing Damage

Thu Jan 26, 2017 4:13 pm

kurtverbose wrote:
Could any of that be related to rotor bow?

As far as I understand, this is not a ball or roller bearing, this is metal sliding against metal with oil film in between. If that is the case, pushing inner ring in one direction can break oil film and cause a trouble..
 
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KarelXWB
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Re: PW1100G Bearing Damage

Thu Jan 26, 2017 4:17 pm

kalvado wrote:
this is metal sliding against metal with oil film in between. If that is the case, pushing inner ring in one direction can break oil film and cause a trouble..


According to the NK pilot, the ECAM messages in the cockpit showed oil warnings inside the engine.
What we leave behind is not as important as how we've lived.
 
kurtverbose
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Re: PW1100G Bearing Damage

Thu Jan 26, 2017 5:34 pm

Funny, I'd always assumed shaft bearings weren't plain bearings?
 
DfwRevolution
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Re: PW1100G Bearing Damage

Thu Jan 26, 2017 8:19 pm

KarelXWB wrote:
According to a NK pilot on another forum, the airline replaced three PW1100G engines in the last three months due to "a wiped bearing".

901 suffered a wiped #3 and #4 bearing on the #2 engine with significant metal shavings contained in the engine oil and had damage to the prop fan. So the engine was replaced and repairs done to the right engine pylon. The aircraft was out of service for approximately 2 weeks while replacing the engine since the supply of available engines is extremely limited.


According to another person on the same forum, similar events happened with Volaris and IndiGo.

So what is "a wiped bearing"? I went to Google and found the following article:

http://www.waukbearing.com/en/technical ... e:-wiping/

It says:

A wiped bearing surface is where surface rubbing, melting and smearing is evident. This may be due to a variety of causes, including:

Excessive load at start-up/run-down
Insufficient lubricant
Operational overload
Loss of clearance
Misalignment


So which one is causing bearing damage on the PW1100G engine, and how can it be resolved?


Setting aside the apparent string of bearing failures, I think this is a case of imprecise language. I've always heard the term "wiping" in the context of fluid film bearings like tilt-pad journal bearings. The information in the Waukesha link you provided is all related to fluid film bearings. Aviation engines universally use rolling element bearings. Failure modes with rolling element bearings are more often due to things like pitting or shaft galling. That would explain metal chips in the lubrication oil.
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Okie
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Re: PW1100G Bearing Damage

Fri Jan 27, 2017 2:38 am

DfwRevolution wrote:
Aviation engines universally use rolling element bearings. Failure modes with rolling element bearings are more often due to things like pitting or shaft galling. That would explain metal chips in the lubrication oil.

I am going to have to agree with you here.
Generally in that type of application you would see a ball bearing on one end to control thrust and positioning and a roller bearing on the opposite end to allow for expansion differences of the shaft to case/carrier because of the heat.
I have not heard of fluid bearings in that application. I have heard of "air bearings" in the ACM's on aircraft.
 
kalvado
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Re: PW1100G Bearing Damage

Fri Jan 27, 2017 12:24 pm

Okie wrote:
DfwRevolution wrote:
Aviation engines universally use rolling element bearings. Failure modes with rolling element bearings are more often due to things like pitting or shaft galling. That would explain metal chips in the lubrication oil.

I am going to have to agree with you here.
Generally in that type of application you would see a ball bearing on one end to control thrust and positioning and a roller bearing on the opposite end to allow for expansion differences of the shaft to case/carrier because of the heat.
I have not heard of fluid bearings in that application. I have heard of "air bearings" in the ACM's on aircraft.

And how those are normally lubricated? Sealed or forced oil flow?
 
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ikolkyo
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Re: PW1100G Bearing Damage

Fri Jan 27, 2017 12:32 pm

Pretty interesting how it's only this variant of the engine with the issue, so far anyways.
 
DfwRevolution
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Re: PW1100G Bearing Damage

Fri Jan 27, 2017 3:27 pm

kalvado wrote:
Okie wrote:
DfwRevolution wrote:
Aviation engines universally use rolling element bearings. Failure modes with rolling element bearings are more often due to things like pitting or shaft galling. That would explain metal chips in the lubrication oil.

I am going to have to agree with you here.
Generally in that type of application you would see a ball bearing on one end to control thrust and positioning and a roller bearing on the opposite end to allow for expansion differences of the shaft to case/carrier because of the heat.
I have not heard of fluid bearings in that application. I have heard of "air bearings" in the ACM's on aircraft.

And how those are normally lubricated? Sealed or forced oil flow?


Forced lubrication using a synthetic oil like MIL-L-23699.
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KarelXWB
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Re: PW1100G Bearing Damage

Wed Feb 22, 2017 8:01 pm

And now N904NK suffered the same issue. The failure seems to be consistent and happens around 300 hours.
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kurtverbose
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Re: PW1100G Bearing Damage

Wed Feb 22, 2017 10:13 pm

What's the sauce Karel?

(I do like a nice sauce).
 
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ikolkyo
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Re: PW1100G Bearing Damage

Wed Feb 22, 2017 11:18 pm

KarelXWB wrote:
And now N904NK suffered the same issue. The failure seems to be consistent and happens around 300 hours.


Unless it's a glitch, I see N904NK flying currently.

https://www.flightradar24.com/data/airc ... nk#c8a4d21
 
Woodreau
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 10:35 am

Engines were replaced on 904 on feb 8 and on 905 on feb 12

I guess they are getting very proficient at changing engines as the downtime has decrease from 2 weeks for 901 to 24 hours for 904/905
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KarelXWB
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 10:42 am

ikolkyo wrote:
KarelXWB wrote:
And now N904NK suffered the same issue. The failure seems to be consistent and happens around 300 hours.


Unless it's a glitch, I see N904NK flying currently.

https://www.flightradar24.com/data/airc ... nk#c8a4d21


Sorry, I meant to say earlier this month. N904NK suffered the same engine failure as N901NK, N902NK and N903NK.
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speedbored
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 10:59 am

KarelXWB wrote:
So which one is causing bearing damage on the PW1100G engine, and how can it be resolved?

Let's hope it is a manufacturing issue rather than a design issue.

But the fact that is seems to be happening so consistently on so many frames suggests that it might be more than just a bad batch.
 
mxaxai
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 11:39 am

speedbored wrote:
KarelXWB wrote:
So which one is causing bearing damage on the PW1100G engine, and how can it be resolved?

Let's hope it is a manufacturing issue rather than a design issue.

But the fact that is seems to be happening so consistently on so many frames suggests that it might be more than just a bad batch.


The good thing is that engine bearings are nothing new. A fix should be rather straightforward to implement should the bearing design be the issue. I do not expect a connection to the gearbox or other technology specific to the PW1100.
 
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Polot
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 2:19 pm

Woodreau wrote:
Engines were replaced on 904 on feb 8 and on 905 on feb 12

I guess they are getting very proficient at changing engines as the downtime has decrease from 2 weeks for 901 to 24 hours for 904/905

I suspect that is less NK getting proficient at changing engines and more PW getting proficient at supplying NK replacement engines.
 
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KarelXWB
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Re: PW1100G Bearing Damage

Fri Feb 24, 2017 8:20 pm

Polot wrote:
Woodreau wrote:
Engines were replaced on 904 on feb 8 and on 905 on feb 12

I guess they are getting very proficient at changing engines as the downtime has decrease from 2 weeks for 901 to 24 hours for 904/905

I suspect that is less NK getting proficient at changing engines and more PW getting proficient at supplying NK replacement engines.


I tend to agree. When the first engine failed last year, it was reported that Spirit had to wait some time for a spare engine.
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lightsaber
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Re: PW1100G Bearing Damage

Sun Feb 26, 2017 5:36 pm

mxaxai wrote:
speedbored wrote:
KarelXWB wrote:
So which one is causing bearing damage on the PW1100G engine, and how can it be resolved?

Let's hope it is a manufacturing issue rather than a design issue.

But the fact that is seems to be happening so consistently on so many frames suggests that it might be more than just a bad batch.


The good thing is that engine bearings are nothing new. A fix should be rather straightforward to implement should the bearing design be the issue. I do not expect a connection to the gearbox or other technology specific to the PW1100.

The PW1100G has slightly different bearings as the bearing speed is higher. This makes for a tougher bearing/shaft interaction.

Lightsaber
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Re: PW1100G Bearing Damage

Wed Mar 01, 2017 8:24 pm

GoAir had an engine issue lately:

However, GoAir denied any negligence on its part. "The aircraft (VT-WGB) reported oil chip detected warning on arrival at Delhi from Mumbai on February 8 morning. The manufacturer P&W has clearly prescribed checking intervals for engines at different stages of accumulated hours.


http://timesofindia.indiatimes.com/city ... 081445.cms

The interesting part is that GoAir crew received the same oil chip warning as the NK pilots, so we may have another customer with bearing damage.
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KarelXWB
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Re: PW1100G Bearing Damage

Wed Mar 01, 2017 9:24 pm

P&W has redesigned the bearing compartment and will be available by April 2017.

Image
https://twitter.com/shukla_tarun/status ... 2811397120
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KarelXWB
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Re: PW1100G Bearing Failure

Sat Mar 04, 2017 11:10 am

HK Express also suffered a bearing failure, which grounded one of their aircraft for 25 days.

Image
https://twitter.com/torbjorngk/status/8 ... 7456779264
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kabq737
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Re: PW1100G Bearing Failure

Sun Mar 05, 2017 11:43 pm

Wow this is getting a little rough. Have we seen any airlines change their engine choice or no?
320, 321, 333, 733, 73G, 738, 739, 744, 752, 763, 764, 772, 789, C208, CR7, CR9, BE20, MD88, MD90, E70, E75, E90, TRIM, SEEKER, C172N, DA40
 
StereoTechque
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Re: PW1100G Bearing Failure

Mon Mar 06, 2017 12:29 am

kabq737 wrote:
Wow this is getting a little rough. Have we seen any airlines change their engine choice or no?


We know QR cancelled their order and opted for the 737MAX but that was before these failures started occuring.
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KarelXWB
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Re: PW1100G Bearing Failure

Mon Jun 05, 2017 2:55 pm

In positive news, the bearing issue is now a thing of the past:

Meanwhile, Chris Calio, president of Pratt & Whitney Commercial Engines, confirmed that the company has completed developing improved combustor lining material and an improved carbon air seal for the PW1100G-JM’s Number 3 bearing. Together, distressed carbon air seals and degraded combustor linings have led to approximately 50 premature removals of PW1100G-JM engines from A320neos, most of them operated by Indian carriers GoAir and Indigo. “We completed the full retrofit of [already] fitted engines on about 50 aircraft about three weeks ago,” said Calio. “The full suite of hardware and software fixes is in today’s [new] production PW1100G-JMs.”


http://www.ainonline.com/aviation-news/ ... -fuel-burn
What we leave behind is not as important as how we've lived.
 
Solidus
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Re: PW1100G Bearing Failure

Tue Jan 02, 2018 12:14 pm

KarelXWB wrote:
In positive news, the bearing issue is now a thing of the past:

Meanwhile, Chris Calio, president of Pratt & Whitney Commercial Engines, confirmed that the company has completed developing improved combustor lining material and an improved carbon air seal for the PW1100G-JM’s Number 3 bearing. Together, distressed carbon air seals and degraded combustor linings have led to approximately 50 premature removals of PW1100G-JM engines from A320neos, most of them operated by Indian carriers GoAir and Indigo. “We completed the full retrofit of [already] fitted engines on about 50 aircraft about three weeks ago,” said Calio. “The full suite of hardware and software fixes is in today’s [new] production PW1100G-JMs.”


http://www.ainonline.com/aviation-news/ ... -fuel-burn


What about other carriers? Do they still flying with bearing issues and awaiting relacement same as for combustion chamber?
 
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Faro
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Re: PW1100G Bearing Failure

Tue Jan 02, 2018 12:56 pm

Just to summarise...is this the complete list of GTF snafu's or am I missing something?

- Rotor bow
- Combustor shriek
- Fan production delays
- Bearing/seal distress leading to gear box removal (one or two incidents?)


Faro
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