Mooney Service bulletin M20-345

[EricJ]

46 minutes ago, Shadrach said:

I reserve the right to reassess if Mooney issues a subsequent AD with an overly expensive termination.

Mooney won't issue an AD, only the FAA will based on their own determination of whether the issue rises to the necessity of an AD or is adequately served with an SB.   Whether the affected community addresses the SB sufficiently may make a difference.

Often when an AD comes out related to a previous SB the AD will just cite the existing SB for mitigation and compliance, so the wording of SBs often matters from that standpoint.

I think Mooney did the right thing here since this is a genuine safety-of-flight issue.    Issuing an SB brings out the awareness without any legal obligation for Part 91 operators like ourselves.   So whether it ever turns into an AD or not may just depend on whether it appears that the fleet is getting properly updated with replacement weights where needed or not.   This way people have time to get it taken care of, but whether or not they do may have an influence of whether there's a subsequent AD or not.

If it ever does turn into an AD and the AD just cites the SB, then the fleet with the affected part number will be essentially grounded until they're replaced.

[Shadrach]

4 hours ago, EricJ said:

Mooney won't issue an AD, only the FAA will based on their own determination of whether the issue rises to the necessity of an AD or is adequately served with an SB.   Whether the affected community addresses the SB sufficiently may make a difference.

Often when an AD comes out related to a previous SB the AD will just cite the existing SB for mitigation and compliance, so the wording of SBs often matters from that standpoint.

I think Mooney did the right thing here since this is a genuine safety-of-flight issue.    Issuing an SB brings out the awareness without any legal obligation for Part 91 operators like ourselves.   So whether it ever turns into an AD or not may just depend on whether it appears that the fleet is getting properly updated with replacement weights where needed or not.   This way people have time to get it taken care of, but whether or not they do may have an influence of whether there's a subsequent AD or not.

If it ever does turn into an AD and the AD just cites the SB, then the fleet with the affected part number will be essentially grounded until they're replaced.

You’re correct of course. Poorly worded on my part. However, my understanding is that there is a lot of collaboration between feds and manufacturers. Mooney will have a large role in determining the termination. I think the FAA does a reasonable job of addressing comments generated from a NPRM but not always… The Hartzell recurring ECI AD is the first example that comes to mind. It took several years to get that AD revised from an annual requirement to the still onerous 100 hour requirement.

[67 m20F chump]

3 hours ago, MooneyMitch said:

Curious….. does the weight appear cracked, as described in the SB?

They could have used it for the picture in the SB.

[DCarlton]

12 minutes ago, 67 m20F chump said:

They could have used it for the picture in the SB.

Just FYI, I emailed my SB compliance form from the last page of the SB to Mooney yesterday and they acknowledged immediately.  They might be interested.  

[67 m20F chump]

I talked to them on Friday and sent pics.  Wasn’t sure if I needed to send the form back or not.  Spoke to Frank Crawford.  I think he wrote the SB after Don Maxwell brought it up.

[1980Mooney]

54 minutes ago, 67 m20F chump said:

They could have used it for the picture in the SB.

 

40 minutes ago, DCarlton said:

Just FYI, I emailed my SB compliance form from the last page of the SB to Mooney yesterday and they acknowledged immediately.  They might be interested.  

 

24 minutes ago, 67 m20F chump said:

I talked to them on Friday and sent pics.  Wasn’t sure if I needed to send the form back or not.  Spoke to Frank Crawford.  I think he wrote the SB after Don Maxwell brought it up.

So are your planes grounded?  Grounded until you find a salvage non-hybrid weight or Mooney supplies a replacement?  Or do you keep flying and just cross your fingers hoping they don't disintegrate while you are in high speed cruise or turbulent IFR?  In addition to the expansion caused by corrosion I would think they would be particularly susceptible to freezing weather especially if parked outside - water getting in the cracks and then expanding as it freezes incrementally flexing the outer metal off with each freeze-thaw cycle.

Does anyone have clauses in their insurance policy related to flying with defects identified in SB's?  My USAIG is silent on the subject. 

Edited October 8, 2022 by 1980Mooney

[67 m20F chump]

It hasn’t come apart in the last 55 years.  It’s not an AD so I think it’s good to go but I will replace it when they get weights.  I was waiting for my IA to sign off my new prop so I will get his thoughts Monday.

[Shadrach]

5 hours ago, 67 m20F chump said:

They could have used it for the picture in the SB.

That does not look good but it’s hard to discern the condition of the weight vs cracked paint. Does it appear to be structurally compromised in person?

[Guest]

38 minutes ago, 67 m20F chump said:

It hasn’t come apart in the last 55 years.  It’s not an AD so I think it’s good to go but I will replace it when they get weights.  I was waiting for my IA to sign off my new prop so I will get his thoughts Monday.

From the pictures you posted, Id be stripping the paint off the weight to determine if it’s cracked paint or a cracked weight. 

[67 m20F chump]

1 hour ago, M20Doc said:

From the pictures you posted, Id be stripping the paint off the weight to determine if it’s cracked paint or a cracked weight. 

It’s not the paint.

[Guest]

1 hour ago, 67 m20F chump said:

It’s not the paint.

Per the SB, cracked or not if you’ve got the referenced part number you’re supposed to be grounded.  Don’t become a test pilot or statistic.

[Igor_U]

On 10/6/2022 at 9:00 PM, Dmax said:

The bad weights were on the early 1967 F models. There were about 140 of these F models that used these weights. They mention the smooth skins elevators so as to eliminate all others. ...

Don,

Where is the above info coming from? My IPC shows all M20F to have affected Weight, P/N 430018-1. Visual inspection on RHS is not showing Hybrid balanced weight but how can we be sure it's not just the smooth pain?

However, RHS Elevator is having hybrid weight as it's clearly visible, albeit with no traces of corrosion. It seems few others have the same install. Is it possible that factory installed two different weights regardless of IPC? Oh, what a fun owning an 55y old plane! 

 

[Shadrach]

1 hour ago, Igor_U said:

Don,

Where is the above info coming from? My IPC shows all M20F to have affected Weight, P/N 430018-1. Visual inspection on RHS is not showing Hybrid balanced weight but how can we be sure it's not just the smooth pain?

However, RHS Elevator is having hybrid weight as it's clearly visible, albeit with no traces of corrosion. It seems few others have the same install. Is it possible that factory installed two different weights regardless of IPC? Oh, what a fun owning an 55y old plane! 

 

Two different weights with same P/N is the most plausible explanation. My F came off the line in July of 67 and does not have hybrid weights. I know they are original.

[Guest]

1 hour ago, Igor_U said:

Don,

Where is the above info coming from? My IPC shows all M20F to have affected Weight, P/N 430018-1. Visual inspection on RHS is not showing Hybrid balanced weight but how can we be sure it's not just the smooth pain?

However, RHS Elevator is having hybrid weight as it's clearly visible, albeit with no traces of corrosion. It seems few others have the same install. Is it possible that factory installed two different weights regardless of IPC? Oh, what a fun owning an 55y old plane! 

 

Back one page you’ll see excerpts from 1967 and 1968 IPC.  1968 shows a different part number.

[Shadrach]

16 minutes ago, M20Doc said:

Back one page you’ll see excerpts from 1967 and 1968 IPC.  1968 shows a different part number.

My 67 should have the part number mentioned in the SB but it is clearly not the hybrid weight.

[carusoam]

It would be near criminal to have different parts sharing the same part number…

GM proved this more recently with changing part designs and keeping the part numbers to hide a design flaw in there ignition switches…

This is more of a modern manufacturing piece of info…

As Computers have come into the manufacturing scene… complete traceability of parts is becoming more reliable… connecting the raw material that the parts were made from… all the way to the plane flying….

 

It appears the composite weights are getting a thin layer of corrosion going on at the interface…

Corrosion typically pulls oxygen into places it never fit before…. Thus expanding the gap at the interface…

As we have seen before… once corrosion begins…. It can spread quickly…

 

Some alloys are more malleable than others… this one seems to not be very malleable at all… as a small amount of stretching is turning into cracks…. (?)

We have a metallurgist around here somewhere….  

@Alan Fox @Jerry Pressley @SheryLoewen got any elevator counterweights for 67Fs?

Best regards,

-a-

[skykrawler]

Looking at the bulletin pictures, that condition is precisely the sort of thing that should be detected as un-airworthy during an annual inspection.

From the standpoint of replacement, as installed these weights seem to be installed with large rivets.  On other models bolts are used.  So is it 'acceptable' for the replacement to be retained with bolts?  This sort of thing often results in different opinions among A&P and IAs. 

 

[Pinecone]

Lead expands as it corrodes.  So it would expand, cracking the outer shell.

Hmmm, I would possibly consider flowing some low viscosity epoxy, like WEST System into the cracks if I were thinking of flying before having them replaced.

[Shadrach]

3 hours ago, Pinecone said:

Lead expands as it corrodes.  So it would expand, cracking the outer shell.

Hmmm, I would possibly consider flowing some low viscosity epoxy, like WEST System into the cracks if I were thinking of flying before having them replaced.

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.

[Alan Fox]

42 minutes ago, Pinecone said:

Lead expands as it corrodes.  So it would expand, cracking the outer shell.

Hmmm, I would possibly consider flowing some low viscosity epoxy, like WEST System into the cracks if I were thinking of flying before having them replaced.

Epoxy would not be a legal repair , If they are indeed lead , and not an alloy , ( pretty sure they are an alloy , as they are not soft like lead) , you could rebuild them and log it as a repair , Referencing part 43  , also , you could run thge part # , a NOS part IS legal , if you can find one..

[EricJ]

5 hours ago, skykrawler said:

Looking at the bulletin pictures, that condition is precisely the sort of thing that should be detected as un-airworthy during an annual inspection.

From the standpoint of replacement, as installed these weights seem to be installed with large rivets.  On other models bolts are used.  So is it 'acceptable' for the replacement to be retained with bolts?  This sort of thing often results in different opinions among A&P and IAs. 

The SB indicates that there'll be a revision or a new SB for installation of the replacement parts.   I suspect they'll specify the fasteners at that time.   The follow-on parts in the IPC and the "replacement" weights in the J model IPC use screws to fasten them.

[Igor_U]

16 hours ago, M20Doc said:

Back one page you’ll see excerpts from 1967 and 1968 IPC.  1968 shows a different part number.

Clarence,

I got that but my question was where the "early 1967 F models. There were about 140 of these F models that used these weights" is coming from?

The IPC is calling affected weigh p/n 430018-1 for all the 1966-67Fs and there were 539 built in as 67 model. I have hard time to believe they would not document the change in IPC as well as install two different weights on one plane. Since you have extensive experience with more then one Mooney, do you see such discrepancies often?

As mentioned, my plane has what it looks like a newer weight on RHS elevator but that might be simply become of smooth surfaces of the weight and paint job that held very good after all these years.

I guess, one way to check is to sand the pant off the part (INBD side as it's hidden) and have a look, then repaint again...

 

Thank you.

 

 

 

 

[EricJ]

9 minutes ago, Igor_U said:

I got that but my question was where the "early 1967 F models. There were about 140 of these F models that used these weights" is coming from?

That comment came from DMax (Maxwells) who I think work pretty closely with the factory on things like this.  They're a reliable source.

[Sheriff23]

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?!?  

 

 

[Shadrach]

18 hours ago, Igor_U said:

Clarence,

I got that but my question was where the "early 1967 F models. There were about 140 of these F models that used these weights" is coming from?

The IPC is calling affected weigh p/n 430018-1 for all the 1966-67Fs and there were 539 built in as 67 model. I have hard time to believe they would not document the change in IPC and install two different weight on one plane. Since you have extensive experience with more then one Mooney (like myself), do you see such discrepancies often?

As mentioned, my plane has what it looks like a newer weight on RHS elevator but that might be simply become of smooth surfaces of the weight and paint job that held very good after all these years.

I guess, one way to check is to sand the pant off the part (INBD side as it's hidden) and have a look, then repaint again...

 

Thank you.

From all of the pics that I have seen, paint is not going to prevent identification of hybrid vs solid counterweights unless someone went to the trouble of filling and sanding the counter weight prior to prep which seems to fly oppose the very nature of the counterweight.  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?

I have a 67F with a July airworthiness date.  I do not have hybrid counter weights. Presumably the weights I do have are also p/n 430018-1 given no other p/n existed at the time the aircraft was manufactured.  I know that the weights are original to my aircraft.

I think focusing on the p/n is a red herring. Either you have a hybrid weight or you don't. If you do, you are not required to ground (regardless of the wording in the SB), but it would obviously be a bad idea to fly if corrosion is detectable. 

I'm sure it's quite a challenge to word an SB given the multifaceted nature of the document (historical, technical, legal, statutory, etc)... However, when you separate the wheat form the chaff, the flow chart of this SB looks like this:

1) Does my aircraft have smooth control surface? 

A.   Yes - Go to step 2

B.   No (no further action required

2) Does my aircraft have hybrid  counterweights?

A.    Yes - Go to step 3

B.    No (No further action required)

3) Is my aircraft airworthy?

A.    If counterweights are intact and show no signs of corrosion then the aircraft is legally airworthy but will be operating outside the recommendations of the newly issued SB.

B.  If counterweights are corroded, cracked or showing signs of deterioration, the aircraft is not airworthy per 14 CFR 3.5(a).