Mooney Service bulletin M20-345

[Shadrach]

17 hours ago, Sheriff23 said:

67 M20F serial number 670093.

Went to go fly today….and check the SB.

I think my plane has the bad weights and they’re bad  I didn’t fly today and will have the shop check it…..anyone have any spare weights sitting in their hangar?!?  

 

 

There is no question those are hybrid weights and they appear to be deteriorating.   This further illustrates that no paint removal is need to determine if the weight is a hybrid. Paint removal may be needed to determine the condition of the counterweight.

[Igor_U]

17 minutes ago, Sheriff23 said:

67 M20F serial number 670093.

 

 

 

Wow, these are bad. My F is 2 planes ahead of yours and with weight(s) in a fine shape. I bet it will be difficult to find a spares even if factory supports this change. At this point maybe salvage yard would be the best place. Expect the price to be high they'll realize the demand is high.

 

12 minutes ago, Shadrach said:

What seems plausible to me is that Mooney had counterweights that were identical from an application standpoint if not from a manufacturing standpoint.  If the weights are functionally identical, the only reason not to mix and match a set during manufacturing is aesthetic.  Did you notice the visual difference prior to the SB.

Ross,

Having been working in Aerospace design for over 30 years, this rubs me wrong way and is not how we do things in industry. Change in fit, form and function would require different Dash number if not the p/n. At least not in Part 25 world, since I never worked for small airplane manufacturer.

But, it is plausible explanation. It was easy to spot a difference between RHS and LHS weight as one has noticeable "plug" characterizing hybrid design so after reading the SB, I knew I have a Hybrid weights. I just never paid attention to other one, being smooth and possibly newer design. 

cheers,

 

 

[Shadrach]

16 minutes ago, Igor_U said:

Wow, these are bad. My F is 2 planes ahead of yours and with weight(s) in a fine shape. I bet it will be difficult to find a spares even if factory supports this change. At this point maybe salvage yard would be the best place. Expect the price to be high they'll realize the demand is high.

Ross,

Having been working in Aerospace design for over 30 years, this rubs me wrong way and is not how we do things in industry. Change in fit, form and function would require different Dash number if not the p/n. At least not in Part 25 world, since I never worked for small airplane manufacturer.

But, it is plausible explanation. It was easy to spot a difference between RHS and LHS weight as one has noticeable "plug" characterizing hybrid design so after reading the SB, I knew I have a Hybrid weights. I just never paid attention to other one, being smooth and possibly newer design. 

cheers,

I understand your distaste. However, there really is no other explanation that I can envision.  We know that during model year 1967, F models were manufactured with both solid and hybrid weights.  We also know that only one part number existed in the 1967 model year IPC.  Given the level of "detail" in the POH, I'm not that surprised that the IPC might not distinguish between 2 versions of the same part.

As you have seen in my previous posts, I own a time capsule of an airplane that my Dad bought from our local Mooney dealer, Weber Aircraft  in early 1968.  It is a 67 model with a July AW date and was used as a factory demonstrator by the dealer. The plane is as close to all original as they get and I have very complete logs. There is no way the counterweights were replaced. So Mooney must have been using both weights under a single P/N. There may be a more complicated explanation, but I doubt there is anyone still living that could explain.

[Pinecone]

6 hours ago, Shadrach said:

Seems sketchy to fly with compromised counter weights. I gather from previous posts that you’re a boat guy that has experience pouring sailboat keels. There’s no way to prep the surface inside those cracks and I’m sure it’s oxidized.

I am not suggesting this is a fix.  But for a person who is going to fly anyway, it would help.

Not, you can clean it out well, but a low viscosity material will soak in some.

Used to own a sailboat, but never cast a keel.  My boat had a 1500 POUND keel.

 

[Shadrach]

8 minutes ago, Pinecone said:

I am not suggesting this is a fix.  But for a person who is going to fly anyway, it would help.

Not, you can clean it out well, but a low viscosity material will soak in some.

Used to own a sailboat, but never cast a keel.  My boat had a 1500 POUND keel.

 

That seems heavy when you first think about it, but it's pretty light in the world of sailboats.  When you said you were buying by the ton, I assumed large castings.  Are you casting projectiles?

[Guest]

Give Mooney a little time and I’m sure they’ll have new weights available.

[Sheriff23]

2 hours ago, M20Doc said:

Give Mooney a little time and I’m sure they’ll have new weights available.

Since my weights are in poor shape I spoke with Mooney today. They are sourcing a vendor to produce the replacements, but they do not have a timeline for production and distribution.

They did advise me that used/salvage parts are a viable option with part number part number 430016-7 (solid weight). Both require replacement at the same time and they use a different balance/moment.  
 

I am waiting for word from my shop, but I am looking for used solid weights to minimize downtime. 

[Pinecone]

18 hours ago, Shadrach said:

That seems heavy when you first think about it, but it's pretty light in the world of sailboats.  When you said you were buying by the ton, I assumed large castings.  Are you casting projectiles?

I am not buying by the ton.   There is a guy locally that buys it by the ton or more, then casts it into reasonable size ingots.  I buy it 100 pounds at a time from him.  In the old days, I would buy from the scrap dealer and process myself.

Yes, my boat was only 4000 pounds for a 28 footer.  I like fast things.

 

[goodyFAB]

On 10/6/2022 at 6:49 PM, Ragsf15e said:

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?

Why go any further ? You don’t have a galvanic corrosion issue even if you did have the hybrid weights. (Which I don’t think you do- I don’t think they were doing body work to hide the weight) 

[Gary0747]

Galvanic corrosion requires two dissimilar metals and an electrolyte between them   The electrolyte might be contaminated water or worst case water containing a salt.  I suspect the most aggressive corrosion will be airplanes that have been kept outside or hangared in a humid climate near the ocean.  If the weights have been sealed well with paint there is likely less of a problem.  Some may never need to be replaced if totally sealed  

[tony]

On 10/11/2022 at 2:15 PM, Igor_U said:

Wow, these are bad. My F is 2 planes ahead of yours and with weight(s) in a fine shape. I bet it will be difficult to find a spares even if factory supports this change. At this point maybe salvage yard would be the best place. Expect the price to be high they'll realize the demand is high.

 

Ross,

Having been working in Aerospace design for over 30 years, this rubs me wrong way and is not how we do things in industry. Change in fit, form and function would require different Dash number if not the p/n. At least not in Part 25 world, since I never worked for small airplane manufacturer.

But, it is plausible explanation. It was easy to spot a difference between RHS and LHS weight as one has noticeable "plug" characterizing hybrid design so after reading the SB, I knew I have a Hybrid weights. I just never paid attention to other one, being smooth and possibly newer design. 

cheers,

 

 

The Mooney CM manual, which would have been approved by the MIDO,  should have a clause that would require a change in part number if the methods of construction have changed.

 

[Grandmas Flying Couch]

Serial 670200 I don't think I have the hybrid weights.  

 

 

[EricJ]

Gah...I forgot there were two thread on this.   What are the affected people doing so far?   Flying?  Replaced already with new or used parts?

[Shadrach]

On 1/3/2023 at 10:03 PM, Grandmas Flying Couch said:

Serial 670200 I don't think I have the hybrid weights.  

 

 

Those look solid.

[Igor_U]

On 1/3/2023 at 7:03 PM, Grandmas Flying Couch said:

Serial 670200 I don't think I have the hybrid weights.  

 

Those look solid but you can check with the strong magnet. "Hybrid" weights have steel plug...

Mooney came with revised (Rev A) SBM20-345 with additional instruction.

You may inspect the weight now (and at each annual) but you have to remove them which is not really practical. 

[EricJ]

5 hours ago, Igor_U said:

Those look solid but you can check with the strong magnet. "Hybrid" weights have steel plug...

Mooney came with revised (Rev A) SBM20-345 with additional instruction.

You may inspect the weight now (and at each annual) but you have to remove them which is not really practical. 

The instruction actually says to remove the elevators, strip the paint off the counterweights, inspect them, repaint them, rebalance the elevator, and then replace it all.   It's not trivial.   

 

[1964-M20E]

If anyone is in real need for the counter weights.  I have a set of elevators and rudder from a 65 E model with solid weights.

 

PM with an offer

[Igor_U]

On 1/21/2023 at 8:57 AM, 1964-M20E said:

If anyone is in real need for the counter weights.  I have a set of elevators and rudder from a 65 E model with solid weights.

PM with an offer

Looking at the IPC, your C should have weight p/n 430016 and F 430018-1. SB calls for 430016-7 as a replacement. I have no idea if these are the same or interchangeable. 

 

BTW

I just received the email form FAA that this is an AD2023-02-04. Airplanes are fun.