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sgbroimp
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Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 5:39 pm

Vigorous CFM-7B fan blade inspections at WN for about a week now. Anyone heard if they have found any more "clunkers"?
 
strfyr51
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 7:07 pm

sgbroimp wrote:
Vigorous CFM-7B fan blade inspections at WN for about a week now. Anyone heard if they have found any more "clunkers"?


No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.
 
estorilm
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 9:29 pm

strfyr51 wrote:
sgbroimp wrote:
Vigorous CFM-7B fan blade inspections at WN for about a week now. Anyone heard if they have found any more "clunkers"?


No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.

Really? It's clearly relevant for accountability purposes in this case.

NTSB suggestions were made, FAA "proposed" inspections, WN didn't "want" to do them.. blah blah.

So, yes - I'd kinda like to know how many other engines were possibly ready to let loose.

Rewind a couple weeks, all is good and we could all be happily staring out the window next to that engine without a care in the world.

Spare me the safety stats of flying, the 737, CFM56, etc - I know this. My point was that this could be a large-scale "missed opportunity" safety incident, which I think many of us thought was largely an "80s kinda thing" in the industry.
 
mmo
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 9:44 pm

For enquiring minds......

https://www.flightglobal.com/news/artic ... ec-448081/

Apparently, no deficiencies found on the inspections so far.
If we weren't all crazy we'd all go insane!
 
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 11:21 pm

No cracks found with the inspections. A anomaly on one was detected, not even really sure about that. It was changed to be safe and further testing will be done on it. At approximately 96,000 for a pair of Cfm fan blades, it can get expensive real quick. Hopefully the incident blade wasn't missed down in Central or South America, as according to the Southwest Tech Ops Union Rep.......
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 11:22 pm

Going to take about 30 - 40 days. WN is going to take a shot......
Last edited by CALTECH on Thu Apr 26, 2018 11:24 pm, edited 1 time in total.
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Thu Apr 26, 2018 11:23 pm

No cracks found with the inspections. A anomaly on one was detected, not even really sure about that. It was changed to be safe and further testing will be done on it. At approximately 96,000 for a pair of Cfm fan blades, it can get expensive real quick. Hopefully the incident blade wasn't missed down in Central or South America, as according to the Southwest Tech Ops Union Rep.......
You are here.
 
WIederling
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 7:16 am

CALTECH wrote:
No cracks found with the inspections. A anomaly on one was detected, not even really sure about that. It was changed to be safe and further testing will be done on it.


Are the blades exchanged in situ and then good to go
or does the fan have to be rebalanced ?
Murphy is an optimist
 
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fr8mech
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 7:33 am

WIederling wrote:
Are the blades exchanged in situ and then good to go
or does the fan have to be rebalanced ?


I can't comment specifically on the CFM...haven't worked on any in a real long time. But, generally if the moment-arm of the new blade is close enough (as defined in the AMM) to the removed blade, only a vibration survey need be done. Balance only if the survey comes up bad. Some AMM's allow you to replace matched symmetrical pairs. This reduces the probability of needing to balance the fan. But, a survey is required.

In the case of this AD, it looks like the blades have to come out for the inspection, so a survey would be done regardless of whether any blades are replaced.

Someone with access to the AMM should be able to get more specific about the CFM as installed on the affected 737's.
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Dalmd88
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 1:36 pm

Rumors at DL are no cracks found and the inspections on the 'critical' engines should be done by the end of the week. I suspect we didn't have as many as WN had in the 30k cycle range. DL jumped into the 737NG later than WN.

Blades on the NG get changed as a pair set. That means a suspect blade and the one 180 opposed get changed. Dynamic on wing balance is real easy. There is an onboard computer in the e/e compartment. You ground run the engine, check the box. It give a very good solution for moving the spinner weights to achieve a balance. Move the weights and rerun to check. Every time I've done it it always checked good on the recheck run.
 
estorilm
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 1:40 pm

The two blades that let loose must have been beyond a fluke thing then. I don't usually believe in coincidences, but if the reports are to be believed (I'm sure we'd know if they had found something) then the entire thing is just weird.

The only two blades in the entire fleet of impacted engines have already let loose, yet not a single other blade is even beginning to show signs of fatigue? So strange. I guess all of these engines are already being inspected anyways, so the obvious stuff will have been caught over the years, but still.

Guess it's good for the industry, as nothing blatantly obvious or negligent seems to have occurred by any of the parties involved, but on the other hand - how COULD such an event have been prevented? Generally there's always an answer to such a question, but it seems to be a little more elusive in this situation. :(
 
sgbroimp
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 2:07 pm

strfyr51 wrote:
sgbroimp wrote:
Vigorous CFM-7B fan blade inspections at WN for about a week now. Anyone heard if they have found any more "clunkers"?


No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.


Well excuse me but my wife does as she, along with about half a million others are flying WN next Friday.
 
yeelep
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 5:31 pm

fr8mech wrote:
WIederling wrote:
Are the blades exchanged in situ and then good to go
or does the fan have to be rebalanced ?


I can't comment specifically on the CFM...haven't worked on any in a real long time. But, generally if the moment-arm of the new blade is close enough (as defined in the AMM) to the removed blade, only a vibration survey need be done. Balance only if the survey comes up bad. Some AMM's allow you to replace matched symmetrical pairs. This reduces the probability of needing to balance the fan. But, a survey is required.

In the case of this AD, it looks like the blades have to come out for the inspection, so a survey would be done regardless of whether any blades are replaced.
The blades are numbered with a marker before removal. The blades are then removed,cleaned, inspected, lubed and reinstalled in the same location they were removed from. No vibe survey required.
 
7673mech
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 6:02 pm

Definitely a need for a survey.
Not for Southwest but I did two yesterday. (Surveys, GE did inspection.)
 
7673mech
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 6:05 pm

estorilm wrote:
strfyr51 wrote:
sgbroimp wrote:
Vigorous CFM-7B fan blade inspections at WN for about a week now. Anyone heard if they have found any more "clunkers"?


No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.

Really? It's clearly relevant for accountability purposes in this case.

NTSB suggestions were made, FAA "proposed" inspections, WN didn't "want" to do them.. blah blah.

So, yes - I'd kinda like to know how many other engines were possibly ready to let loose.

Rewind a couple weeks, all is good and we could all be happily staring out the window next to that engine without a care in the world.

Spare me the safety stats of flying, the 737, CFM56, etc - I know this. My point was that this could be a large-scale "missed opportunity" safety incident, which I think many of us thought was largely an "80s kinda thing" in the industry.


Lost in the theatrics that some of you seem to get into .... I know of several operators here in the US that were doing the inspections with in the time frame of scheduled maintenance. Ultra sonic inspections that is .... so to say WN and or other operators didn't want to do them is not true.
 
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 7:17 pm

WIederling wrote:
CALTECH wrote:
No cracks found with the inspections. A anomaly on one was detected, not even really sure about that. It was changed to be safe and further testing will be done on it.


Are the blades exchanged in situ and then good to go
or does the fan have to be rebalanced ?


Change the bad one and the one 180' on the other side. The blades, platforms, blade spacers and blade brackets are marked. They are put back together and a Vibration survey engine run at different power levels is performed. On the engines where nothing was replaced, the engine passes vibration limits easily even with the lubing of components since every piece goes back where it came from. Even with some components replaced, if instructions and requirements are adhered to, the engines should pass the Vibration survey engine run easily. Otherwise, weight mapping will be required.
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 7:19 pm

4 engines a night are being performed in MCO on the RONs.
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sgbroimp
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 8:23 pm

An equally big question in this matter is when (or if) they get all the broken blade parts, will they conclude that current test methods would have caught the defect? If yes, great. If not, a second round of inspections will be needed. In the Sioux City UAL Crash (CF-6 rotor failure) investigation determined eddy current testing was needed, not simply ultra sound to spot the metallurgy issues. We have a way to go on this one from an investigation standpoint.
 
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airportugal310
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 9:04 pm

7673mech wrote:
estorilm wrote:
strfyr51 wrote:

No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.

Really? It's clearly relevant for accountability purposes in this case.

NTSB suggestions were made, FAA "proposed" inspections, WN didn't "want" to do them.. blah blah.

So, yes - I'd kinda like to know how many other engines were possibly ready to let loose.

Rewind a couple weeks, all is good and we could all be happily staring out the window next to that engine without a care in the world.

Spare me the safety stats of flying, the 737, CFM56, etc - I know this. My point was that this could be a large-scale "missed opportunity" safety incident, which I think many of us thought was largely an "80s kinda thing" in the industry.


Lost in the theatrics that some of you seem to get into .... I know of several operators here in the US that were doing the inspections with in the time frame of scheduled maintenance. Ultra sonic inspections that is .... so to say WN and or other operators didn't want to do them is not true.


Smells like a journalist to me...too many of them around here lately posing as "aviation professionals"
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 9:25 pm

7673mech wrote:
estorilm wrote:
strfyr51 wrote:

No and they're Not going to tell you. The question is? For What and for Whom?? The FAA knows, and GE knows. other than that?
Nobody else needs to know.

Really? It's clearly relevant for accountability purposes in this case.

NTSB suggestions were made, FAA "proposed" inspections, WN didn't "want" to do them.. blah blah.

So, yes - I'd kinda like to know how many other engines were possibly ready to let loose.

Rewind a couple weeks, all is good and we could all be happily staring out the window next to that engine without a care in the world.

Spare me the safety stats of flying, the 737, CFM56, etc - I know this. My point was that this could be a large-scale "missed opportunity" safety incident, which I think many of us thought was largely an "80s kinda thing" in the industry.


Lost in the theatrics that some of you seem to get into .... I know of several operators here in the US that were doing the inspections with in the time frame of scheduled maintenance. Ultra sonic inspections that is .... so to say WN and or other operators didn't want to do them is not true.


Southwest did 'resist' the inspections, also in internal documents.....

http://www.startribune.com/faa-orders-f ... 480209133/

'The National Transportation Safety Board also blamed metal fatigue for the engine failure on a Southwest plane in Florida in 2016 that was able to land safely.
That incident led manufacturer CFM International, a joint venture of General Electric Co. and France's Safran SA, to recommend in June 2017 that airlines conduct ultrasonic inspections of fan blades on many Boeing 737s.
In August, the FAA proposed making the recommendation mandatory. The oldest blades would be inspected within six months, while many others would face an 18-month deadline. CFM commented that the longer deadline be shortened to 12 months.
During the public-comment period, which closed in October, Southwest and several other carriers raised objections. Southwest pushed back against CFM's request for a 12-month deadline, and American Airlines asked for even more time — 20 months.
The FAA never issued a final decision.'
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Fri Apr 27, 2018 9:34 pm

Above in a post, it is officially called a fan blade shim, not a bracket......

Removal
https://www.youtube.com/watch?v=qMwwIXEI53M

Installation
https://www.youtube.com/watch?v=XiDi3T4LLPE
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fr8mech
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Re: Blade Inspection Results - Curious Minds Want to Know

Sat Apr 28, 2018 12:21 am

yeelep wrote:
The blades are numbered with a marker before removal. The blades are then removed,cleaned, inspected, lubed and reinstalled in the same location they were removed from. No vibe survey required.


Interesting. If we pull a blade set, for any reason, we do a vibe survey. Usually a no-brainer if no blades are changed.
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Dalmd88
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Re: Blade Inspection Results - Curious Minds Want to Know

Sat Apr 28, 2018 12:54 am

fr8mech wrote:
yeelep wrote:
The blades are numbered with a marker before removal. The blades are then removed,cleaned, inspected, lubed and reinstalled in the same location they were removed from. No vibe survey required.


Interesting. If we pull a blade set, for any reason, we do a vibe survey. Usually a no-brainer if no blades are changed.

Same think for every blade set change I've ever done; PW4000, PW2000, CF6, CFM56. All required a survey after a fan lube.
 
yeelep
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Re: Blade Inspection Results - Curious Minds Want to Know

Sat Apr 28, 2018 6:45 am

737 MM 71-00-00-800-811-F00 Table 502. Re-installation of blades in same position (example: after fan blade lube). Test: none.
If your manual requires a vibe survey. It is more restrictive than the manufacture requires.
 
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CALTECH
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Re: Blade Inspection Results - Curious Minds Want to Know

Sat Apr 28, 2018 3:59 pm

yeelep wrote:
737 MM 71-00-00-800-811-F00 Table 502. Re-installation of blades in same position (example: after fan blade lube). Test: none.
If your manual requires a vibe survey. It is more restrictive than the manufacture requires.


No longer valid here. EC from Engineering changes AMM to reflect:


'Task 71-00-00-800-811-F00

Power Plant Test Reference Table

Test 7 Vibration Survey will be performed after;

Re-installation of several blades or a complete set of blades in the same position(Example:after blade re-lube or after fan abradable repair)'.




Best to make sure and be on the safe side.
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yeelep
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Re: Blade Inspection Results - Curious Minds Want to Know

Sat Apr 28, 2018 6:34 pm

My reference is up to date. So, yes, it is valid.
 
Tn55337
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Re: Blade Inspection Results - Curious Minds Want to Know

Sun Apr 29, 2018 11:08 am

The CEO of wn said on the q1 earnings conference call that they did find 1 cracked blade prior to 2017. They have not found any more during the latest round of inspections.
 
frmrCapCadet
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Re: Blade Inspection Results - Curious Minds Want to Know

Sun Apr 29, 2018 3:15 pm

Given the maturity and safety record of modern commercial aviation most accidents are likely to be one-off events. Hard to correct for them. Very properly the major NTSB investigations look into all of these. But politically very difficult to cope. 100% correction is not possible.
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sgbroimp
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Re: Blade Inspection Results - Curious Minds Want to Know

Sun Apr 29, 2018 6:41 pm

frmrCapCadet wrote:
Given the maturity and safety record of modern commercial aviation most accidents are likely to be one-off events. Hard to correct for them. Very properly the major NTSB investigations look into all of these. But politically very difficult to cope. 100% correction is not possible.


Of course you are right, no question. If Pensacola had been the one-off, everyone would have seen it as just that, but then you have two, similar (not identical break area, ok) in nature and then one has to start asking if this is a coincidence, what did the two busted blades have in common etc., as they should. Maybe they came out of the same plant, same day same batch etc., then no more coincidence. But the jury is still out and will be for a while until all inspections are done....
 
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Balerit
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Re: Blade Inspection Results - Curious Minds Want to Know

Wed May 02, 2018 5:01 pm

I would imagine it is too soon to release positive results yet, the whole lot has to be done first and there are a lot of procedures and paperwork involved. I personally think we should look at all fan blade issues, not just from one manufacturer. There could be an operational issue causing this problem and if I recall there have been quite a few incidents. I mentioned in another post about SAA's B747-300's throwing fan blades on the inboard engines. It was eventually found to be caused by vibration due to the new 'stretched upper deck' disrupting the airflow pattern. Maybe there are similar issues. These days new pips are rushed into service, who knows maybe they're causing problems and is certainly the issue with the B787 engines.
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