M20K-231 - cotter pins found in engine

[philiplane]

Why take the engine off the plane in the first place? Pull cylinders as needed to access the rods, check bolt torques, cotter pin them, and reassemble. It's a two day job at most.

[whiskytango]

One reason to pull the engine rather than do a ferry flight to the shop is that there may be no internal damage to the engine at this point.  The next time the engine is started may result in catastrophic failure due to fastener separation.  Doing an IRAN on the engine in its current state may be significantly easier than after a catastrophic failure.  The overhaul shop, who I think is definitely responsible for making the owner whole again, could argue that they are not responsible if the engine sustains significant damage after it is operated in a known un-airworthy condition.

[DMM]

My two cents.  I have no particular expertise in this area but suspect the cotter pins broke from fatigue. If the head of the pin wasn't peened close to the nut face and/or the prong wasn't tightly wrapped against the bolt end, it would flex as the rod reversed directions during rotation.  (see the figure Pilot64 posted).  I guess after one prong broke off inertial forces could cause the other prong to straighten as the pin was pulled out.  Of course using the wrong size pin or the wrong material could cause this as well.   I would definitely want a full explanation from the shop on why this happened and how they plan to fix it.  Good luck going forward - I know this has to be disappointing. 

[mike_elliott]

2 hours ago, Shadrach said:

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.

Ross, I think you mean to say they should easily be able to find a qualified ferry pilot who doesnt mind the possibility of being involved in possibly a lengthy bit of litigation and have culpability himself for a potential catastrophe. My name is certainly not going into this hat.

[Shadrach]

44 minutes ago, whiskytango said:

One reason to pull the engine rather than do a ferry flight to the shop is that there may be no internal damage to the engine at this point.  The next time the engine is started may result in catastrophic failure due to fastener separation.  Doing an IRAN on the engine in its current state may be significantly easier than after a catastrophic failure.  The overhaul shop, who I think is definitely responsible for making the owner whole again, could argue that they are not responsible if the engine sustains significant damage after it is operated in a known un-airworthy condition.

Going broken pins to separation separation is a bit of a "stretch"... Speaking of stretch, if the bolts were not properly torqued (stretched) I suspect that rod problems would have shown a long time ago. To put it in perspective, using conservative estimates, That engine has done around 15,000,000 revolutions without a fastener coming loose.

It really should be the shop's problem to get the airplane or one of there mechanics to a place where things can be remedied.    

[Shadrach]

3 minutes ago, mike_elliott said:

Ross, I think you mean to say they should easily be able to find a qualified ferry pilot who doesnt mind the possibility of being involved in possibly a lengthy bit of litigation and have culpability himself for a potential catastrophe. My name is certainly not going into this hat.

I don't think it's as risky as it's being made out to be. I get why you would not want to fly it.  I've heard of numerous ferry pilots taking on more risky endeavors. One in particular occurred  about 15 or so years ago. The guy in the hangar across from mine ferried and hand flew a C414 from Frankfurt, GER to somewhere in the Southern, USA with the gear pinned down and a non-working AP.  Much of the over water portion of the trip was IMC.  That sounds exhausting to me and infinitely more dangerous. He was in his late 60s or early 70s then so perhaps he had more of a Que será, será attitude. He's in his 80s now and still doing domestic Ferry flights.  The real question is whether the shop would be able to talk the FAA into a Ferry permit.

Agree the best outcome would be for the the shop to send an MX to the plane.

A quick question though, would you consider flying a plane with an engine on which the cotter pins had never been installed?  I think the risk is about the same.

[mike_elliott]

23 minutes ago, Shadrach said:

I don't think it's as risky as it's being made out to be. I get why you would not want to fly it.  I've heard of numerous ferry pilots taking on more risky endeavors. One in particular occurred  about 15 or so years ago. The guy in the hangar across from mine ferried and hand flew a C414 from Frankfurt, GER to somewhere in the Southern, USA with the gear pinned down and a non-working AP.  Much of the over water portion of the trip was IMC.  That sounds exhausting to me and infinitely more dangerous. He was in his late 60s or early 70s then so perhaps he had more of a Que será, será attitude. He's in his 80s now and still doing domestic Ferry flights.  The real question is whether the shop would be able to talk the FAA into a Ferry permit.

Agree the best outcome would be for the the shop to send an MX to the plane.

A quick question though, would you consider flying a plane with an engine on which the cotter pins had never been installed?  I think the risk is about the same.

Absolutely not. I don't fly in any plane I know has a mechanical issue.  Continentals position is clear and would be hard to defend any action taken to the contrary in a court. Maybe you would get away with it, but why risk it? Save the shop a buck at the potential liability of loss of life and the ferry pilot's assets?

Heck if you have a commercial license, you are qualified. If you dont, you are qualified, you just have to do it for free, which is about what you would be doing it for if you charged anyway compared to the risk involved. In fact, if you did it for free, you might be less culpable without a contract involving consideration.

 

[MB65E]

20 hours ago, DanM20C said:

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

 

I don’t know why they still make cad plated cotter pins. I try to use stainless ones whenever possible. The cad pins are so brittle!!

-Matt

[Guest]

6 hours ago, mike_elliott said:

Absolutely not. I don't fly in any plane I know has a mechanical issue.  Continentals position is clear and would be hard to defend any action taken to the contrary in a court. Maybe you would get away with it, but why risk it? Save the shop a buck at the potential liability of loss of life and the ferry pilot's assets?

Heck if you have a commercial license, you are qualified. If you dont, you are qualified, you just have to do it for free, which is about what you would be doing it for if you charged anyway compared to the risk involved. In fact, if you did it for free, you might be less culpable without a contract involving consideration.

 

Mike,

There don’t seem to be many volunteers for this mission.

Clarence

[Guest]

On 6/7/2019 at 11:52 AM, Pilot64 said:

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.

It is possible that the cotter pins in question are a standard Mil Spec cotter pin, the IPC lists a Continental number under the rod bolt part number.

Clarence

 

[RLCarter]

All three broke close to the eye of the cotter, leads me to believe either the cotter pins had a manufacturing issue or were installed improperly...i.e. tapped in to seat them causing a crease or shear line at the hole in the nut...... Just a thought

[David_H]

Isn't liability generally cited as a driving reason for charging exorbitant fees in Aviation? If the shop isn't willing to shoulder the liability then what exactly did the OP get for the ridiculous OH cost?

Either incorrect parts were used or another failure mode is present. Either way, this looks as if the responsibility should be the burden of the overhaul shop.

The fact that we're discussing this says this is likely not a very good shop. It's too bad that people sometimes seem to get skewered for calling shops out for this kind of poor work and even poorer customer service. If they are indeed a MSC... this is a Mooney group and they should be rightly called out.

Lastly, the OP should make sure to purchase an extremely nice bottle of spirits to give to his mechanic for finding this mess. This mechanic could have saved his and other lives. I don't even know the mechanic... but am thankful that he did his job and found this.

Edited June 9, 2019 by David_H

[takair]

Beyond the question of remaining torque on the bolts, there is the question of where the pins may have been enroute to the finger screen. From the OPs picture, it looks like one piece may still be unaccounted for.  A small piece of cotter pin can cause some significant scoring if it migrated into an oil passage and then a bearing or prop governor.  Just another consideration if deciding to ferry.

[Shadrach]

2 hours ago, takair said:

Beyond the question of remaining torque on the bolts, there is the question of where the pins may have been enroute to the finger screen. From the OPs picture, it looks like one piece may still be unaccounted for.  A small piece of cotter pin can cause some significant scoring if it migrated into an oil passage and then a bearing or prop governor.  Just another consideration if deciding to ferry.

It’s possible they went elsewhere but my guess is that none of them left the crankcase. Seems unlikely they’d get through the pump screen.

[Guest]

The missing piece is a good question.  Still in the engine, stuck in the sludge in the bottom of the sump, or out the drain valve/plug. One could always try Jose’s method of pouring a gallon of varsol or Stoddart solvent into the sump to rinse it out and see what comes out.

Clarence

[Danb]

Rumor is bob you stayed at a holiday inn last night 

[KB4]

On 6/7/2019 at 12:12 PM, Pilot64 said:

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!

No facts to support, but I have heard that many pilots have been killed by the mistakes of mechanics, they are human and just as susceptible to error as the rest of us. Statistics do say that IF something likely to go wrong it’s more probable to happen within X hours of your annual.  

 

[Danb]

Years ago a buddy of mine had a couples jugs replaced, on his first flight he lost his engine and was luck enough to land back in Wilmington, after inspection and teardown the mechanic left a shop rags in the engine which was chopped up throughout the engine, kinda  mistake 

[Guest]

Does anyone know what the outcome of the OP’s engine problem was.  He hasn’t posted much since.

Clarence

[carusoam]

Hasn’t been back this way since late June...

@Pilot64 have you stopped by lately?

Best regards,

-a-

[Pilot64]

8 hours ago, carusoam said:

Hasn’t been back this way since late June...

@Pilot64 have you stopped by lately?

Best regards,

-a-

Hi Clarence, et all,

This is in the hands of the attorneys now, which is why I have been quiet. Prior contacting an attorney, the engine shop offered to repair the engine, but only if I would fly the airplane to them, have it flown to them at my expense, or have the engine removed and shipped to them at my expense. I did not think any of those options were fair, under the circumstances. I will post an update once the issue is resolved. Thanks to everyone for all the comments, they were really helpful. I knew what I thought was the right thing for the engine shop to do, but before I jumped to any conclusions, I wanted to know what "the majority" thought - I wanted to be fair to the engine shop.

Kindest Regards.

 

[Guest]

10 hours ago, Pilot64 said:

Hi Clarence, et all,

This is in the hands of the attorneys now, which is why I have been quiet. Prior contacting an attorney, the engine shop offered to repair the engine, but only if I would fly the airplane to them, have it flown to them at my expense, or have the engine removed and shipped to them at my expense. I did not think any of those options were fair, under the circumstances. I will post an update once the issue is resolved. Thanks to everyone for all the comments, they were really helpful. I knew what I thought was the right thing for the engine shop to do, but before I jumped to any conclusions, I wanted to know what "the majority" thought - I wanted to be fair to the engine shop.

Kindest Regards.

 

Sorry to hear that you’ve had to resort to a lawyer to resolve this mess.  Hopefully if all gets resolved and you get flying again.

Clarence

[kortopates]

I hope your able to get the repairs moving soonest.

You might be interested to note that Continental no longer uses those drilled bolts and castellated nuts with the cotter pins. Their obsolete and you may find the bolts and nuts are no longer available. The good news is that they now use a self locking  Spiralock nut which does a much better job and supposedly holds it grip impervious to vibration. These are spec'd for your LB engine as well by Continental. So if I were you, I would be looking at my available options to get rid of the cotter pin arrangement entirely going with the new Spiralock nuts and bolts when the repairs are done. If you got a factory engine, that's what you would get. The problem is that this may likely require new connecting rods in that I suspect the new hardware is not compatible with the old rod's you have and new current production connecting are some like $1600 each. But if your only option was to pay out of pocket for the update, you might also be able to buy used serviceable ones for much less which would allow the new hardware. You'd have to do a little research to find out what connecting rods are on there now and then check with Continental to find out your options (they are very specific about what fasteners can be used with which rods). 

Secondly, if I was in your shoes, in an effort to expand my options, I would carefully wash the sump out with solvent and strain the contents with cheesecloth in an effort to find that one missing cotter pin - if I understand correctly that all that isn't accounted for. If you know all the pieces are accounted for, then I would go for the quick and efficient repair of R&R'ing the rods in situ, its not much more than a top overhaul in labor and it seems everybody wins. You get your plane back in the air and I bet even with the expense of new rods to get rid of the cotter pins (if necessary), you'll have an easier time collecting from the original engine builders insurance for paying for all your expenses since the cost should be far less than the current alternative and you'll be flying a lot sooner. Even if you can't find that one missing piece, I'd still seriously consider this option, although not risk free compared to if you can find it, I'd talk to some engine builders that don't have a stake in this for their thoughts before throwing in the towel on a complete engine disassembly.  An engine rebuild may be the only safe thing to do without knowing where the missing piece - I am not an engine rebuilder and can't speak to that.

[Gagarin]

These pins were improperly installed. They broke at the head because the leg was stretched when it was bent.

 

How to Properly Install a Cotter Pin

By Debbie Lamb|May 2, 2018

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Installing a cotter pin prevents parts from backing out of or slipping off other parts. Standard, straight cotter pins, also called split cotter pins, have two straight prongs that are spread apart to keep other fasteners, such as bolts and nuts, in place.

 

 

 

credit: prabhjits/iStock/GettyImages

How to Properly Install a Cotter Pin

 

VIDEO OF THE DAY

 

It is essential to properly install a cotter pin -- it can mean the difference between life and death when working with machinery or structural assemblies.

Selecting the Right Cotter Pin

Always buy new cotter pins whenever you need to install or adjust them. Never reuse cotter pins, because the metal weakens when bent and can break off if bent repeatedly.

 

Cotter pins are sold with different diameters (sized for the hole in the bolt or other part that needs securing), head sizes (the head is the loop at one end of the pin) and prong lengths. The usable length of the cotter pin is measured from beneath the head to the end of the shorter prong. It is acceptable to use a pin that's too long because you can trim the prongs to an appropriate length, but a pin that is too short may not perform its job properly.

Cotter pins come in a variety of materials including steel, stainless steel and copper. Select the correct cotter pin material for your project. For instance, when installing a cotter pin where corrosion is a problem, you may need to use stainless steel. Also choose the size of the cotter pin according to the size of the hole. The pin should be the largest size possible for the hole, with the head of the pin slightly larger than the hole to ensure that the pin will not wiggle in the bolt.

 

Installing a Cotter Pin

Insert the cotter pin into the hole of the bolt until the head of the pin rests against the bolt. Secure the cotter pin by spreading the prongs in opposite directions, using pliers if desired.

Use diagonal cutters to cut excess length from either prong, according to your application standards. Cutting the prongs to the correct length helps when it is time to replace the pin. Leaving excess prong length can lead to snagging injuries. However, the prongs must be long enough to prevent the pin from slipping back out through the bolt.

If the cotter pin has a curve on one side rather than two straight prongs, ensure that the bolt rests firmly between the "v" on the cotter pin.

[jlunseth]

On the legal liability issue, remember that as the owner or operator you are responsible for the airworthiness of the aircraft. 91.403 .  This is not a clear cut case of airworthiness (as, for example, where the aircraft is out of annual), but I would not bank on that.  A ferry permit is probably required, not just a ferry pilot.  You or the ferry pilot get that from the FSDO.  Its a separate issue from legal liability in case of an accident, because if the aircraft is operated while it is not airworthy, the FAA can commence admin proceedings against you the owner. So be sure, if you have a ferry pilot fly the plane, that you also have a ferry permit.