M20K-231 - cotter pins found in engine

[Pilot64]

Hi Folks,

The Continental TSIO-360-LB-1B engine in my Mooney M20K-231 was rebuilt 2 years ago. At my last (current) annual, the A&P found 3 broken cotter pins in the oil screen, and followed up with a Boroscope camera to identify that at least one of the pins did indeed come off of the castle nut that secures the connecting rod. The shop that performed the rebuild (Daytona Aircraft Services) has offered to make any repairs necessary at their cost, even though the warranty on the engine has expired, however I would have to cover all costs to remove, ship, and reinstall, including the labor billed by the current A&P. The shop manager (Jake Clemens) has told me that this is not uncommon, and the plane should be safe to fly. I am not comfortable flying this airplane. Continental has recommended that the engine not even be started. The shop manager said he could refer me to a ferry pilot. I contacted the ferry pilot, and explained to him the situation and Continental's recommendation. He discussed the situation, and determined that he would be willing to ferry the airplane the 2.5 hours to the shop. I told him I was not comfortable flying, and why, so I have been upfront about my concerns.

My questions - just how common is this? I have not heard of this happening before, and it doesn't seem like something that should be common in an engine with less than 120 hours SMOH. Are my expectations unreasonable that the original engine shop should cover the costs to get this resolved? Is it acceptable that there are likely other airplanes flying around with the same issue, and is there really no danger here? And finally, IF I allow the ferry pilot to return the plane to the original shop, am I legally liable if something does happen because I allowed him to fly the plane, after full disclosure of the facts? My gut says don't let *anyone fly it, and don't start the engine, but I wanted to hear thoughts from this community.

Attached are pictures of the pins and the boroscope photos.

Thanks!

Edited July 21, 2022 by Pilot64
Updated information

[mike_elliott]

46 minutes ago, Pilot64 said:

And finally, IF I allow the ferry pilot to return the plane to the original shop, am I legally liable if something does happen because I allowed him to fly the plane, after full disclosure of the facts? My gut says don't let *anyone fly it, and don't start the engine, but I wanted to hear thoughts from this community.

I am not a lawyer, but have the distinct impression you cannot dismiss your liability potential with disclosure of an issue. If something goes pear shaped, you most likely will be named in a suit. It is what PI  lawyers do and they are good at it.

Please barristers, tell me I am wrong and he is "safe" from negligence by letting someone else fly the plane after disclosing the issue. And if true, I hope you are paying this ferry pilot very very well to assume the liability if that is your expectation.

[KB4]

1 hour ago, Pilot64 said:

Continental has recommended that the engine not even be started.

Follow your gut and Continental. 

[carusoam]

Welcome aboard, 64.

Also ask what causes cotter pins to break off...

and now... you have three.

Sounds like three nuts have been loose and breaking the cotter pins.  Where the cotter pins are the last effort to keep the castle nuts locked in place... proper torque is the first line of defense...

This is not a situation I have even heard of before.  The OP has three independent ones...

But, i’m Only a PP...

I know a guy, that may have seen this before... he sees a lot of things... @M20Doc torque, castle nut, broken cotter pins.

Best regards,

-a-

[MB65E]

No thanks! Something is moving. 

-Matt

[Cody Stallings]

Well, I guess I come from a different time/type of Customer service.

120Hrs SMOH an I’m sure that O/H was in the $40/50K Range. Why are we pulling this engine off? It’s not because you want too! Why is it your financial responsibility?  In my option, It’s not.

FAA Form 8120-11 being brought up in the next conversation may help you out. I would bet if someone were to send the cotter pins out of your screen to a metallurgy along with the cotter pin that the O/H manual calls for, there would be a difference in the two. An that’s where SUPS come from!!!

Lets be honest, calendar time(out of warranty) is not what caused that. The 120hrs on the engine didn’t cause that. That issue was put in place long before you ever had your engine reinstalled. It’s from trying to save money during the O/H process. Clearly none of this should be out of your pocket with Con recommendation of don’t start it.

They need to seen a couple guys to your place, remove the engine, fix it an reinstall with a giant thank you to you for your understanding an sorry for the inconvenience.

I have had to do it in the Propeller world if one springs a leak or something of that nature. It’s called customer service. 

[ArtVandelay]

How come only one leg of the cotter pins bent?


Tom

[Guest]

I’ve never seen this one before and have to agree with Continental’s opinion.  Good for your maintainer for pulling the suction screen, many don’t even know that there is one in a TSIO360.  It appears to be a materials failure.  I would be sending the cotter pins to Continental to see if they are even the correct part.

I would be asking the engine shop what they plan to do to your engine?  Are they going to disassemble it completely inspect it then reassemble it? Or pull the cylinders and replace the rod nuts and bolts and install new cotter pins?  

If the later have them sent their technician to you, if the former you’ll have to send the engine to them.  If the engine shop didn’t make the defective cotter pins, you would have to prove that they installed them wrong or used the wrong part, in order to encourage them the pay the entire tab.

Clarence

[Bravoman]

 From a legal perspective, the ferry pilot might be deemed to have assumed the risk, but why go down that road? Moreover, you would not be able to assert that or any other defense against an injured third-party. I could also see the potential of criminal liability. The better course would be to get the overhaul shop’s insurance company in the loop and assert a claim for the entire repair, including removal and reinstallation of the engine where the plane sits.  I agree with the others above that the original poster should not be responsible for any portion of the cost associated with what clearly consequentially flows from the errors of the overhaul  shop.

[KB4]

 Because this is NOT a common issue, (based on other MSers) my concern would be not letting that shop anywhere near my Mooney.  

First get the metallurgy test as @Cody Stallings suggested if that comes back as we all expect it will. Hire an attorney to recover your damages. You cannot use pep boys cotters on certified aircraft. If they did so, that’s negligence.  I would be very reluctant to have them touch your engine unless it turns out the cotters were correct. But even then, I agree with @Cody Stallings were the castle nuts even torqued to specs? Unlikely if they are moving enough to shear off. 

If metallurgy tests confirm non certified metals in pins, you have a good claim. If the shop has insurance you are golden. 

[Pilot64]

Thank-you all for the warm welcome and for your responses and comments. Rather than reply to each comment, I'll summarize my comments on the responses:

Carusoam: Yes, my biggest concern is why, and more concerning, why *three?
Cody:  $40-50K is accurate, albeit low :~  I agree completely about the expectations for customer service. I'll take a look at 8120-11, thanks for the tip. The shop did respond with "the cotter pins are just standard stainless steel cotter pins (p/n MS24665-227).  Parts like that are purchased in bulk and used as required, There is no 8130 for them as they are “standard parts”.  I am not sure if the 8120-11 would apply here or not, but it is worth investigating further.
Art: That is yet another concern, only 1 leg was bent, what else may not have been installed according to the service manual?
M20: Yes, the current A&P said it seems common for shops to *not pull the suction screen - the maintenance shop that did the rebuild also did my first annual after the rebuild.. The current annual is my second after the rebuild. I try to get the plane in front of a different shop every 2-3 years, just for the extra set of eyes, then (usually) go back to the original shop.
Hyett: I would probably blame myself a bit if something happened on the ferry flight, and the engine shop, too, because that's who the ferry pilot likely spoke with to determine if he was willing to fly the plane. I did not hide any facts or any of my concerns. I told him that I was *not willing to fly the airplane, and I explained to him precisely why. I would not have even considered hiring someone to fly the airplane - that was the recommendation from the shop that performed the rebuild, which incidentally, is the *only party that has suggested flying the airplane. I have to try to balance risk with reward, and I do believe the risk is heavier than the reward, in spite of the fact that the ferry pilot had already accepted the risk.

Edited June 7, 2019 by Pilot64

[Pilot64]

Any suggestions on where I might send the cotter pins for the metallurgy tests? I contacted Continental, and on initial contact, they suggested that someone on their team might be willing to do the analysis. On a follow-up email, they indicated they were not interested in testing the pins, and recommended again not flying the airplane until the engine was torn down, torque checked, and cotter pins replaced. They did send a copy of the service manual, showing proper installation (attached).  Also, as an FYI, the shop that performed the overhaul is an Authorized Mooney Service Center at a class C airport, they should not be a fly-by-night (pun intended) shop!

[Rwsavory]

Something very bad is happening to makes these pins break off.  I would get someone independent of the overhaul shop to do an inspection before you send it off for repair.  You may have a legal claim against the overhaul shop, notwithstanding the expiration of the warranty period.  A consultation with an attorney would be helpful.  

[philiplane]

Don't over think this. The most likely cause of the breakage is simply improper installation, resulting in loosening of the cotter pin, and subsequent breakage due to vibration. If the nuts were torqued correctly there is little danger of anything coming apart. 

That said, the shop owes you a fix.

[skydvrboy]

8 hours ago, M20Doc said:

If the later have them sent their technician to you, if the former you’ll have to send the engine to them.  If the engine shop didn’t make the defective cotter pins, you would have to prove that they installed them wrong or used the wrong part, in order to encourage them the pay the entire tab.

As a quality professional, I'm going to have to disagree with this statement.  It doesn't matter whether they used the right part, wrong part, or installed them right or wrong, they are still liable because they procured the parts for the job.  If the supplier is at fault instead of the overhaul shop, it is the overhaul shop that needs to seek reimbursement from the supplier, not the customer.  The customer paid the overhaul shop and that is the only company they need to deal with to make them whole.

[carusoam]

So far...

You have a few responses from some high level Mooney mechanics, a lawyer, a quality professional... and a PP with no mechanical knowledge... 

With the engine in an unknown condition... something has caused the safety cotter pins to depart their stations...

There isn’t a lot of reason to fly it...

Removing an engine to ship it happens often around here.... including putting it in the back of a VW to drive it a few hundred miles away...

My Continental engine got boxed up and sent to Alabama... (from NJ)

It is interesting that the cotter pins have failed in a similar fashion at the eye loop...

its not like we are saving a lost WWII plane from the Alaskan tundra, thousands of miles from a road...

Getting to the bottom of what happened is somewhat important... how many other fasteners inside the engine are done the same way?

Knowledge is power... - Somebody 

Go MS!

PP thoughts only, not a mechanic, reporting stuff I have seen on MS...

Best regards,

-a-

 

[Bolter]

2 hours ago, Pilot64 said:

Any suggestions on where I might send the cotter pins for the metallurgy tests? I contacted Continental, and on initial contact, they suggested that someone on their team might be willing to do the analysis. On a follow-up email, they indicated they were not interested in testing the pins, and recommended again not flying the airplane until the engine was torn down, torque checked, and cotter pins replaced. They did send a copy of the service manual, showing proper installation (attached).  Also, as an FYI, the shop that performed the overhaul is an Authorized Mooney Service Center at a class C airport, they should not be a fly-by-night (pun intended) shop!

I have dealt with materials issues before.  A company I trust, and may be small enough to take interest in your small job is Metals Technology Inc (MTI) in Northridge, CA  Phone: (818) 882-6414.  Another is Pacific Testing: http://www.pacifictesting.com/  I would start with MTI as I think this is more in their specialty range.  Ask for Dan Fitzgerald.

Based on the failed parts you found, it does not look like the they were installed per the procedure of one bent up, one bent down.

[thinwing]

Looking at the way all three cotters have broken...it appears that can only happen in sheer...like cutting sheet metal with metal shears.That can only occur if the castellated nut is rotating around the drilled bolt.Rod end nuts and bolts are typically only torqued once than thrown away...torque amount is critical cause the bolts are being stretched against the rod caps.Rod end failure with catastrophic engine failure can occur at any time now.Im wondering if three Rod end caps are involved.Do not start engine

[ArtVandelay]

I would contact the overhaul company, and have them hire the ferry pilot to fly it, would take you out the the loop from a liability standpoint as well as expenses.

 

 

Tom

 

[DanM20C]

It’s hard to tell from the photos but are they Cad plated?  If so I believe they are the incorrect part.  

The ones that are supplied with the connecting rod bolt kit (from continental) are not cad plated, I’m assuming they are S/S.

Good luck,

Dan

 

[David_H]

Just another random opinion: The owner would likely shoulder any liabilities until another party takes possession of the engine in some form. If a ferry pilot acted as the owner's agent to deliver the plane, then it may still be considered as still being in the owner's possession. This seems like a terrible grey area to be in as an owner. The shop should be required to fully shoulder this liability burden. 

Whenever someone hands the controls over to another pilot... it's always good practice to say: "Your Airplane" and unmistakably hear back from the other pilot: "My Airplane" so that PIC responsibilities are completely clear. In this case it might be appropriate to say: "Your Engine... in writing please."

 

[Guest]

If the airplane and engine are un safe for the owner to fly, would it magically be safer for someone else to fly?   If there were an accident on the ferry flight, the owner would still loose an airplane that needed an engine repair.  Doesn’t make sense to me.

Clarence

[Yetti]

6 hours ago, thinwing said:

Looking at the way all three cotters have broken...it appears that can only happen in sheer...like cutting sheet metal with metal shears.That can only occur if the castellated nut is rotating around the drilled bolt.Rod end nuts and bolts are typically only torqued once than thrown away...torque amount is critical cause the bolts are being stretched against the rod caps.Rod end failure with catastrophic engine failure can occur at any time now.Im wondering if three Rod end caps are involved.Do not start engine

This is the key post.   Generally cotter pins are safety items in castle nuts.   The torque is what stretches the bolt and holds things together.   The torque was probably not done and the safety is no longer in place.  The engine is fixin to come apart in a catastrophic fashion.

[Bob_Belville]

If this is the engine I think it is there may be an issue with a Continental service bulletin changing the cotter pins and/or the way the pins are to be bent. I think there was an issue of clearances. So, this was a known condition. The sb was issued before the engine was overhauled.

I could be confused, I am neither a mechanic nor the son of a mechanic.



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[Shadrach]

On 6/7/2019 at 12:34 PM, philiplane said:

Don't over think this. The most likely cause of the breakage is simply improper installation, resulting in loosening of the cotter pin, and subsequent breakage due to vibration. If the nuts were torqued correctly there is little danger of anything coming apart. 

That said, the shop owes you a fix.

This^^^^

I have never found a nut backed out against a cotter. I find it hard to fathom how a nut would shear a pin. I cannot envision a failure mode that would cause such a thing. I think Phillip is correct. I understand your concern but if I had to bet, my money would be on that engine running for the rest of its life without a rod fastener coming loose.. The shop should certainly fix it. It should not cost you a dime.  I would ask the shop arrange the ferry flight. Given they are a Mooney Service Center they should be able to easily find a qualified ferry pilot.

Edited September 18, 2019 by Shadrach