Mooney Service bulletin M20-345

[Dmax]

M20_345.pdf

[Pinecone]

Thanks for posting this.

Might want to mention that it only applies to Smooth Skin Elevator aircraft.

[EricJ]

Let's hope that doesn't turn into an AD.

 

[KSMooniac]

4 minutes ago, EricJ said:

Let's hope that doesn't turn into an AD.

 

Actually, this is exactly what should turn into an AD to get rid of this issue from the fleet.  Flying around with inadequate counterweights due to failure is a safety-of-flight issue...and it could be worse if it breaks in flight and gets stuck somehow and limits elevator travel.  It should not be prohibitively expensive to rectify, either, unlike a spar crack or other major malady that has plagued other brands.

Thanks for sharing this, Don!

[EricJ]

3 minutes ago, KSMooniac said:

Actually, this is exactly what should turn into an AD to get rid of this issue from the fleet.  Flying around with inadequate counterweights due to failure is a safety-of-flight issue...and it could be worse if it breaks in flight and gets stuck somehow and limits elevator travel.  It should not be prohibitively expensive to rectify, either, unlike a spar crack or other major malady that has plagued other brands.

Thanks for sharing this, Don!

Except if it's an AD it'll ground the affected fleet until the factory gets around to making and distributing replacements.    Fingers crossed they're getting ahead of it.

[DCarlton]

Seems like I remember someone on MS looking for replacement weights just a few weeks ago due to cracks.  

[KSMooniac]

17 minutes ago, EricJ said:

Except if it's an AD it'll ground the affected fleet until the factory gets around to making and distributing replacements.    Fingers crossed they're getting ahead of it.

The AD would not ground the fleet... it would only ground the ones with cracks, which absolutely should not fly in any case.

[Fly Boomer]

18 minutes ago, EricJ said:

Except if it's an AD it'll ground the affected fleet until the factory gets around to making and distributing replacements.    Fingers crossed they're getting ahead of it.

PARTS LIST: Mooney International Corporation, Service Bulletin Parts Kit(s): N/A at this time

[EricJ]

33 minutes ago, KSMooniac said:

The AD would not ground the fleet... it would only ground the ones with cracks, which absolutely should not fly in any case.

The SB doesn't have an inspection criterion for cracks.   It says if you have that part number DO NOT FLY until the part is replaced.

"NOTE 2:
If elevator balance weights are the original 430018-1 style, DO NOT FLY, the balance weights will need to
be replaced with new weights developed by Mooney in a later revision of this Service Bulletin."

[KSMooniac]

Ah!  I read too fast... I thought the "abnormal" verbiage indicated safe to fly unless you damage was found vs. the do not fly if you have this version whether or not it is abnormal.  Dang. 

I still maintain it is a critical safety issue, but this isn't a sudden failure scenario, so I disagree with grounding if an inspection reveals no anomalies.  

[Ragsf15e]

I’m not sure of all the different kinds of elevators, but is this one “smooth”?  It’s got rivets all the way back, but not the bigger indentations.

Also, I read that sb a couple times and it’s unclear to me if all smooth elevators have that or only some of the smooth elevators?

“There are specific aircraft with smooth skin elevators, that utilized….”

[EricJ]

7 minutes ago, Ragsf15e said:

I’m not sure of all the different kinds of elevators, but is this one “smooth”?  It’s got rivets all the way back, but not the bigger indentations.

Also, I read that sb a couple times and it’s unclear to me if all smooth elevators have that or only some of the smooth elevators?

“There are specific aircraft with smooth skin elevators, that utilized….”

Yes, that is a "smooth" elevator, as opposed to those that have the deep stiffening dimples along their chord.

And, yes, the SB is not well written.   It's fairly confusing, actually, imho, compared to what one normally expects for these.

It appears to be primarily focused at M20F models (sorry), and requires inspection of the weight to determine whether it has the plug in the end for the "hybrid" style, apparently identifying it as a particular part number.    You might need to scrape some paint off the end to see if that's what you have or not.

All that said, right now this is a Service Bulletin and compliance is not required for Part 91 airplanes in private use.    Definitely a good idea to make an inspection, though.   If your weight looks like the one in the pic in the SB I'd probably want to do something, but otherwise discretion may be applied.  

Fingers crossed Mooney comes up with suitable replacements for those affected.

This is a "non-smooth" elevator:

[mooniac15u]

11 minutes ago, Ragsf15e said:

I’m not sure of all the different kinds of elevators, but is this one “smooth”?  It’s got rivets all the way back, but not the bigger indentations.

Also, I read that sb a couple times and it’s unclear to me if all smooth elevators have that or only some of the smooth elevators?

“There are specific aircraft with smooth skin elevators, that utilized….”

The photo in the sb shows what they mean by smooth elevator as opposed to the beaded elevator. That's a smooth elevator in your photo.  Not all smooth elevators have the hybrid counterweights but some smooth elevators do.  No beaded elevators have them so, beaded elevators don't need to be inspected.  If you have a smooth elevator the next step is to inspect your counterweight to see which type you have.  That photo doesn't look like you have the affected counterweights but maybe the paint is covering it.

[Ragsf15e]

17 minutes ago, EricJ said:

Yes, that is a "smooth" elevator, as opposed to those that have the deep stiffening dimples along their chord.

And, yes, the SB is not well written.   It's fairly confusing, actually, imho, compared to what one normally expects for these.

It appears to be primarily focused at M20F models (sorry), and requires inspection of the weight to determine whether it has the plug in the end for the "hybrid" style, apparently identifying it as a particular part number.    You might need to scrape some paint off the end to see if that's what you have or not.

All that said, right now this is a Service Bulletin and compliance is not required for Part 91 airplanes in private use.    Definitely a good idea to make an inspection, though.   If your weight looks like the one in the pic in the SB I'd probably want to do something, but otherwise discretion may be applied.  

Fingers crossed Mooney comes up with suitable replacements for those affected.

This is a "non-smooth" elevator:

Yeah their “smooth” elevator picture actually has the rivets like mine I think, but it’s so zoomed in and blurry that it looks even smoother!

The other thing that would be nice is if they mentioned if you could see the circular insert from the outboard or inboard side or both?  The pictures seem to show outboard side but I wasn’t 100% sure.  Hopefully I can look closer through the paint and see, but I’m not sure how many times it’s been painted over…

[DCarlton]

My '67F (Serial 670429) is just coming out of annual.  I checked the weights today with my mechanic.  I did NOT have the suspect hybrid elevator weights.  We logged SB compliance.  

Gotta wonder what time period they used the hybrid weights.  Will be interesting to see who reports having them.  

[Ragsf15e]

24 minutes ago, DCarlton said:

My '67F (Serial 670429) is just coming out of annual.  I checked the weights today with my mechanic.  I did NOT have the suspect hybrid elevator weights.  We logged SB compliance.  

Gotta wonder what time period they used the hybrid weights.  Will be interesting to see who reports having them.  

No doubt.  Fs were built for ~10 years or so.  Maybe they could have narrowed it down? But it seems to suggest that it’s more than just Fs.  And some salvaged parts could be there as well.

[Marauder]

Let’s hope you smooth skin guys don’t need to replace these elevators. When I was looking into reskinning or replacing costs, Mooney wanted $3k per elevator side. — And that was when Mooney was still making planes.

I can’t remember who told me about the changeover from smooth to beaded. But the reason it done was it is a lot cheaper to make the beaded because it eliminated the labor to install all those little ribs in the elevator.


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[EricJ]

27 minutes ago, Marauder said:

Let’s hope you smooth skin guys don’t need to replace these elevators. When I was looking into reskinning or replacing costs, Mooney wanted $3k per elevator side. — And that was when Mooney was still making planes.

I can’t remember who told me about the changeover from smooth to beaded. But the reason it done was it is a lot cheaper to make the beaded because it eliminated the labor to install all those little ribs in the elevator.


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It also seemed to be coincidental with the advent of the 201, and I wonder whether it didn't have something to do with stiffening the surfaces to be able to resist flutter at higher speeds...pure speculation on my part.

Also, I don't have an IPC that covers F models, but it might be useful to look in the IPC and see what serial numbers of aircraft used the part number for the elevator weight shown in the SB.    That might help people determine whether they're likely to have it or not.

[Utah20Gflyer]

It would seem an over reach to ground planes where no corrosion was evident. 

That would be like grounding all aircraft because the spar could be corroded.   If you have a corrosion issue then deal with it, if you don't then monitor the situation on occasion and proceed as normal.  

[Utah20Gflyer]

1 hour ago, Marauder said:

Let’s hope you smooth skin guys don’t need to replace these elevators. When I was looking into reskinning or replacing costs, Mooney wanted $3k per elevator side. — And that was when Mooney was still making planes.

I can’t remember who told me about the changeover from smooth to beaded. But the reason it done was it is a lot cheaper to make the beaded because it eliminated the labor to install all those little ribs in the elevator.


Sent from my iPhone using Tapatalk Pro

I don't think counterweight replacement requires any reskinning.  It is riveted to the corner of the elevator.   I believe it can be removed and replaced quite easily provided you can get a replacement part.  

[Pinecone]

I don't know about vintage models, but I know the counterweights can be changed on the 252 and Encore.

The upgrade from 252 to Encore requires replacing the 252 counterweights in installing Encore ones.

[hammdo]

If I read the SB right NO kits are Available? Do not fly and no kits? That seems odd to recommend that and not have repair kits available…

-Don

[David Lloyd]

6 hours ago, DCarlton said:

Seems like I remember someone on MS looking for replacement weights just a few weeks ago due to cracks.  

Picture in this thread recently looks much like the picture in the SB.

The counterweight part number in the SB is used only on the F, and only on1967 and earlier. C, D, E all used another part.   I think 1968 they used the beaded elevator skins all models.  The problem counterweight could show up on other models if the elevators were replaced with salvaged parts as mentioned in the SB.

[kortopates]

21 minutes ago, hammdo said:

If I read the SB right NO kits are Available? Do not fly and no kits? That seems odd to recommend that and not have repair kits available…

-Don

You don't want them to ignore the problem till they have weights available do you?

A loss of balance weight could result in a catastrophic flutter event - not that I've heard of any such events yet! But  just say'n.

But I am sure Mooney will work with anyone contacting them with these installed, to get replacements in your hands asap. 

[Ragsf15e]

I’m wondering how hard it’s going to be to verify… I’m sitting at an airport all day so I went for a walk… took 5 minutes to find a ‘67F with smooth elevators.  No way to tell without sandpaper i think?