Exhaust V Band Clamp Failure

[Rmnpilot]

Well it finally happened.   I have the riveted exhaust clamp that is on the exhaust side of the turbo.   I was doing my 25 Hour Oil change today and began checking the exhaust clamps.   I got around to the turbo exhaust clamp and it was loose enough to move.   It wasn’t like that 25 hours ago.   Looked around and didn’t see any cracks, but did see discoloration so tried to torque the clamp to 50 in-lbs.  No joy.   Looked closer and noticed something.  See it?  

I took a closer look and sure enough.  Caught a fingernail.  Pulled it off the exhaust and confirmed.  
 

 

I cannot find the part anywhere.   Lycoming is 200 days out.  The AD has everyone looking, buying or hoarding.    Check these every time you do an oil change.   Check your exhaust pipe on preflight.  I last flew a week ago and all was fine.    
If anyone has a source or lead on the exhaust clamp, please reach out!  Lycoming p/n 40D23255-340M or Eaton NH1009399-10

Ryan 
 

[hammdo]

Can those be TIG welded? Maybe the AC 43 has a procedure. I guess it depends on the metal of the clamp…

-Don

[LANCECASPER]

2 hours ago, hammdo said:

Can those be TIG welded? Maybe the AC 43 has a procedure. I guess it depends on the metal of the clamp…

-Don

NO!!! Not chance.

Ryan is very fortunate that didn't give way. He did a great job of inspecting it regularly and doing that could very well have saved his life. When that clamp gives out that turbo exhaust becomes a blow torch and makes it through the firewall rapidly. There have been deaths caused by this very thing. The original ones were spot-welded and had to be replaced. The newer riveted ones are limited to two re-torques after installation and then they must be replaced. A service bulletin on early M20Ms revised the firewall, which gives you maybe another minute or two to get it on the ground.

https://www.mooney.com/wp-content/uploads/2020/12/SBM20-283A.pdf

Any TIO540 Lycomings were affected by this I believe. https://www.federalregister.gov/documents/2010/07/26/2010-18023/airworthiness-directives-piper-aircraft-inc-models-pa-32r-301t-and-pa-46-350p-airplanes

[LANCECASPER]

3 hours ago, Rmnpilot said:

I cannot find the part anywhere.   Lycoming is 200 days out.  The AD has everyone looking, buying or hoarding.    Check these every time you do an oil change.   Check your exhaust pipe on preflight.  I last flew a week ago and all was fine.    
If anyone has a source or lead on the exhaust clamp, please reach out!  Lycoming p/n 40D23255-340M or Eaton  NH1009399-10

Even Textron who has always had them in stock says they are 4-8 weeks out. (txtav.com)

LASAR says to call for availability o the Piper Part number/same clamp (NH1009399-10)

 

 

[LANCECASPER]

 

[N201MKTurbo]

So, the old airplane AC says we can use standard parts for replacement parts. I can get a Rajay exhaust clamp on EBay for $35. Wouldn’t that meet the regulations?
 

Just trying to make trouble…

https://www.summitracing.com/parts/sum-694250?seid=srese1&gclid=EAIaIQobChMImfeMpsLEgAMVxRWtBh3_wwOuEAQYASABEgJyRvD_BwE

[EricJ]

50 minutes ago, N201MKTurbo said:

So, the old airplane AC says we can use standard parts for replacement parts. I can get a Rajay exhaust clamp on EBay for $35. Wouldn’t that meet the regulations?
 

Just trying to make trouble…

https://www.summitracing.com/parts/sum-694250?seid=srese1&gclid=EAIaIQobChMImfeMpsLEgAMVxRWtBh3_wwOuEAQYASABEgJyRvD_BwE

If it meets the specs! 

[kortopates]

How old is that v-band clamp? Is it really as rusted as it looks? Doesn’t really look like exhaust soot, but maybe?


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[Rmnpilot]

7 hours ago, kortopates said:

How old is that v-band clamp? Is it really as rusted as it looks? Doesn’t really look like exhaust soot, but maybe?


Sent from my iPhone using Tapatalk

I’ll take a look at the band Monday for a date code and also review the logs when I’m able, to confirm the age.  Other than the soot it didn’t appear to be any more discolored than the other clamps. 

[kortopates]

2 hours ago, Rmnpilot said:

I’ll take a look at the band Monday for a date code and also review the logs when I’m able, to confirm the age.  Other than the soot it didn’t appear to be any more discolored than the other clamps. 

Thanks, Time in service would be very interesting.

For what its worth, I learned from Mike that George Braly (GAMI and TATI) has developed a very elegant replacement V-band clamps with no rivets or spot welds that could offer a terminating action for the A.D.. They are working with their ACO to get an AML STC for these clamps. 

 

[Rmnpilot]

12 minutes ago, kortopates said:

Thanks, Time in service would be very interesting.

For what its worth, I learned from Mike that George Braly (GAMI and TATI) has developed a very elegant replacement V-band clamps with no rivets or spot welds that could offer a terminating action for the A.D.. They are working with their ACO to get an AML STC for these clamps. 

 

I saw that George had posted about it over on beechtalk along with a prototype photo.  Given that the AD effects so many engines, it’s great that he has something in the works.   I’d gladly be the test subject.  I figure regardless of the solution, I will continue to give the exhaust a tug and do a visual if needed.   I’m a savvy client as well so once I get things figured out I’ll update things and copy you. 

[LANCECASPER]

12 hours ago, kortopates said:

How old is that v-band clamp? Is it really as rusted as it looks? Doesn’t really look like exhaust soot, but maybe?

I would think the oldest it could be would be around 2004 when the Service Bulletin came out to replace the welded with the riveted clamp. (https://www.mooney.com/wp-content/uploads/2020/12/SBM20-283A.pdf)

In addition to age, it would be interesting to see how many hours in service it has. The correct clamp and only the two retorques are not enough caution apparently. When they are subjected to that kind of heat the 500 hour replacement that the FAA talks about might make sense.

One other thing, the way it is installed I think plays a part. These tend to get over-torqued by a mechanic that may not be familiar with what that does to the metal gaskets on each side of the clamp. I think that may have caused the discoloration on this one, since it looks like exhaust was allowed to escape. I watched an very experienced Mooney mechanic install mine on a Bravo and tapping with a mallet during the tightening keeps everything "square" while it's being torqued. 

[Rmnpilot]

The clamp that failed was manufactured in 2004, and installed in 2006 to comply with M20-283A.  I need to figure out hours.    I have a new one on order from Textron at 200+days. 

[LANCECASPER]

12 minutes ago, Rmnpilot said:

The clamp that failed was manufactured in 2004, and installed in 2006 to comply with M20-283A.  I need to figure out hours.    I have a new one on order from Textron at 200+days. 

Since it's got rivets on it, unless it had been re-torqued twice already it should have complied with the Service Bulletin.

How's your exhaust?

[Rmnpilot]

As far as I can tell, the exhaust is fine.  Everything was clamped together and holding tight, I could just rotate the clamp so knew there was an issue.  I’ll get it pulled when I’m back later this week to inspect.  I’ll be using Delta for my travels for the time being as I work through my options. 

[LANCECASPER]

39 minutes ago, Rmnpilot said:

As far as I can tell, the exhaust is fine.  Everything was clamped together and holding tight, I could just rotate the clamp so knew there was an issue.  I’ll get it pulled when I’m back later this week to inspect.  I’ll be using Delta for my travels for the time being as I work through my options. 

The exhaust gets "thin" and it's hard to tell from the outside.

[Fly Boomer]

3 minutes ago, LANCECASPER said:

The exhaust gets "thin" and it's hard to tell from the outside.

Curious how to test for “thin”.

[Rmnpilot]

Good call.   One of the groups I consult with locally does Non-Destructive Testing.  They can ultrasound the exhaust for me when I pull it to confirm thickness uniformity.  

[LANCECASPER]

5 minutes ago, Fly Boomer said:

Curious how to test for “thin”.

The exhaust usually gets "rebuilt" at overhaul, but sometimes don't last that long depending on how aggressively the engine is leaned. Since these clamps are so expensive and the tailpipes crack at the "Y" it's a good time to make sure the tailpipe is good so you don't have to "waste" a re-torque on the clamp.