Mooney Elevator AD

[BobbyH]

On 2/5/2023 at 6:51 PM, EricJ said:

The service bulletin says it has to come off just for the inspection, and also if the weights are replaced.

I would like to disagree with your conclusion.  SBM20-345A Step 1 - 1.2 clearly identifies that if inspected using method in 1.1 of same Step, "the aircraft may be flown and no further inspections are required for Service Bulletin M20-345A.  Record this inspection in Aircraft Log Book." 

One only needs to remove and re-balance the elevator if weights are replaced.  We need to be careful not to read into the SB what it isn't specifically requiring. 

 

[EricJ]

2 minutes ago, BobbyH said:

I would like to disagree with your conclusion.  SBM20-345A Step 1 - 1.2 clearly identifies that if inspected using method in 1.1 of same Step, "the aircraft may be flown and no further inspections are required for Service Bulletin M20-345A.  Record this inspection in Aircraft Log Book." 

One only needs to remove and re-balance the elevator if weights are replaced.  We need to be careful not to read into the SB what it isn't specifically requiring. 

 

There are two stages to the inspection.   The first stage determines whether the hybrid weight is present.   If it is not, you are correct that the elevator does not need to be removed.

If there is a hybrid weight, the inspection continues in Step 2 to further inspect the hybrid weight for condition.   According to the SB this requires removal and re-weighing of the elevator, even if the weights are not replaced if condition is satisfactory.

If the inspection of Step 2 indicates the weights need to be replaced, this is done while the elevator is off in Step 3.

[BobbyH]

Yes EricJ you are correct.  I misunderstood your intent was for an elevator with the Hybrid 430018-1 counter balance.  The SB is high overkill to ensure these eventually are totally removed from service.  Thanks for the clarification.

Hate it when that happens. 

[Kelpro999]

Let’s assume for a moment that someone goes through removing, inspecting and or replacing balance weights then checks balance only to find unbalance force is an ounce or two over limit. What now? With what method will corrections be made?

[Gary0747]

16 minutes ago, Kelpro999 said:

Let’s assume for a moment that someone goes through removing, inspecting and or replacing balance weights then checks balance only to find unbalance force is an ounce or two over limit. What now? With what method will corrections be made?

I have been communicating via PM with some who have already replaced their hybrid weight with a used -7 weight and one said they came up short of weight like you suggest.  I think he said his mechanic had to mount the weights outward from being fully inserted and had to use some kind of curable putty to get in balance.   Mounting outward in this case was also driven by having to drill new holes since the holes in the old weight did not line up with his elevator holes.     I wonder if the -7 weights actually weigh less than the -1 hybrid weights?  The SB says they are a different weight but it does not say which is heavier.  

[Kelpro999]

1 hour ago, Gary0747 said:

I have been communicating via PM with some who have already replaced their hybrid weight with a used -7 weight and one said they came up short of weight like you suggest.  I think he said his mechanic had to mount the weights outward from being fully inserted and had to use some kind of curable putty to get in balance.   Mounting outward in this case was also driven by having to drill new holes since the holes in the old weight did not line up with his elevator holes.     I wonder if the -7 weights actually weigh less than the -1 hybrid weights?  The SB says they are a different weight but it does not say which is heavier.  

   Haven’t tried that for a few reasons. 
Seems drilling holes in lead at that area is counterproductive and a forward position may look like it’s “moving” forward to an experienced inspector. Also decreases pass through gap. 
 I’m not sure how the F is but my C has no room for paint.   Strange how the SM specification says “applies only to painted surfaces “ or something like that as if unpainted surfaces are immune but all are are painted from the factory. There’s a bulletin out there that explains removing the weight and attaching lead to the trailing end …but the balance ratio makes this impractical. 
  

 

[carusoam]

There are a few side issues growing…

1) Mooney has traditionally been really good with serialization of part numbers…

2) Every part, when it’s design changes, ever so slightly… gets a new part number… no matter what the logic is for conserving part numbers… usually a dashed number on the end…

3) Recent History…. GM took it to a criminal level… with their ignition switches.  Intentionally not changing the part number when they updated the design of a safety related part…

4) not updating the part number allowed GM to not record who had the safe version and who had the not safe version… and how many unsafe versions there were in the field…

 

Newer Mooneys…

5) The lead weight is captured between the elevator and the horizontal stabilizer… limiting the distance that a new weight design can fit…

6) The design change of the lead weight...  has to fit in the allotted space.

7) This looks funny 100% of the time…

• on the ground… the elevator is hanging down, lead weight up in the air… no visual cue if it is in the right place… without holding the elevator up.
• when you hold the elevator up… the lead blob may appear to be oversized compared to the sheet metal around it…
• In the air… when you look back, the elevator is working with the trim… the lead blob is out in the airstream…

 

8) Be sure to use caution when changing anything related weights and balance of flight control surfaces…

Even the weight of painted surfaces has been known to make balance a challenge…

9) Flutter is real… and part destruction occurs rapidly… often, the  hinges are the first to go…

10) if unsure… continue to seek guidance… it is that important…

PP observations are from fuzzy memories… not sharp as if I looked at it today…

Best regards,

-a-

 

Edited February 8, 2023 by carusoam

[Gary0747]

9 hours ago, Kelpro999 said:

There’s a bulletin out there that explains removing the weight and attaching lead to the trailing end …but the balance ratio makes this impractical. 

Sounds like a good idea if there was a good way to attach it?  Do you know which SB that was?  Not sure what adding weight to the end of the weight inside the elevator would do that would hurt?  Changing the CG of the weight should not hurt anything as long as the correct specified moment was maintained?

[Gary0747]

6 hours ago, carusoam said:

9) Flutter is real… and part destruction occurs rapidly… often, the  hinges are the first to go…

I know this is true for high speed aircraft but Is this true for GA aircraft flying at normal speeds?    I can’t recall reading an accident report on any GA aircraft where flutter was mentioned as the cause?  Yes GA aircraft have lost tails when accidentally penetrating thunderstorms or conducting abrupt control movements but the cause there has been exceeding the g force limits of the aircraft design.  

[EricJ]

47 minutes ago, Gary0747 said:

I know this is true for high speed aircraft but Is this true for GA aircraft flying at normal speeds?    I can’t recall reading an accident report on any GA aircraft where flutter was mentioned as the cause?  Yes GA aircraft have lost tails when accidentally penetrating thunderstorms or conducting abrupt control movements but the cause there has been exceeding the g force limits of the aircraft design.  

Generally not at normal speeds, but sometimes the redline on the ASI is a flutter limitation. 

Flutter definitely happens on GA airplanes, though!  Even the model RC airplane guys worry about it.
 

 

[Kelpro999]

1 hour ago, Gary0747 said:

Sounds like a good idea if there was a good way to attach it?  Do you know which SB that was?  Not sure what adding weight to the end of the weight inside the elevator would do that would hurt?  Changing the CG of the weight should not hurt anything as long as the correct specified moment was maintained?

I could be mistaken and referencing rudder balancing, I’ve lost it in my messages but I’ll keep looking. It had more drilling and threading for attachment. The location of added weight was 3” closer to fulcrum , same with elevator and would exceed total mass limits in order to achieve under balance specifications. 

[Gary0747]

Here is another good video on flutter and things to look for and do to correct while flying.  Good learning for me since I was never taught all of this.

[Gary0747]

On 1/27/2023 at 7:17 PM, kortopates said:

Corrosion isn't always visible till the weight has been removed and the paint removed to look it over. We have one client whose weight had enough paint on it that it didn't look problematic. But when it was removed it too disintegrated where the solid bolt like material went through it - like the picture Don showed above. That was very surprising to the owner. So I get why Mooney requires removal and paint stripping to give it a detailed visual inspection. 

So If this is the reason for elevator removal, stripping paint for inspection, repainting and rebalancing, every 100hours, do you think it would be acceptable to either leave the weight bare or paint it with clear coat?  The 100 hour elevator removal will force replacement of good weights since nobody will want to be removing and balancing elevators every 100 hours.  

[carusoam]

Keep in mind…

Red line / Vne protection of the airframe is pretty much a guarantee… When everything on the plane is in accordance with the maintenance manual…

Goof up the balance on a control surface… the plane is no longer in AW status…

The forces on control surfaces are pretty strong…

If they start to flutter… they won’t stay around for very long….

 

Similar to having the baggage door pop open in flight… the airspeed you are flying at really counts…

We have one example of the baggage door coming open in cruise, torn off at the same time… bending itself around the horizontal stabilizer in parts of a second…  (video is around here somewhere…)

 

Its kinda a laws of physics thing…

The Maintenance Manual supplies the procedure to maintain the AW we expect to rely on…

If there are any questions… like “mine is different, what do I do now?” find the experts with the answers… MSC, factory, mechanic…

PP thoughts only, not a mechanic…

Best regards,

-a-

 

[kortopates]

1 hour ago, Gary0747 said:

The 100 hour elevator removal will force replacement of good weights since nobody will want to be removing and balancing elevators every 100 hours.

Personally, I think that is the smart answer - the 10 hr job one time, versus the 6 hr job every year till someday cracks are present and there is no choice. Then in retrospect, all those annual 6 hr jobs was a waste unless you don't have a long term ownership view.

[cliffy]

Flutter even in GA can be a BIG deal (Killer item). Its nothing to screw around with.

The faster you fly the bigger the issue. 

The "old" -7 weights are solid lead  The "newer" weights use steel as part of the weight

OK here's a question- Which weighs more- steel or lead? 

Second question- Which balance weight is heavier -7 solid lead  or the hybrid steel one in question?  

Come on this is not rocket science. 

Therefore if the elevator was in balance with the lighter hybrid weight and the -7 HEAVIER weight was used as 

a replacement there is no way that it would need to be moved fwd or added to for more weight to bring the surface into balance. 

Next is the fact that there is no provision in the AD  or SB to allow moving the weight fwd and drilling new holes in the tip structure.  The SB specifically says to match drill the weight to the existing tip holes. There is no allowance to "add" weight to the -7 weight itself.  It only allows the "REMOVAL" of lead to bring it in balance. 

Be sure to check that any replacement is done with new IRON rivets and new steel washers as per the SB. No other fastenings are allowed at this time (bolts, screws, etc) 

I postulate that if more weight is required to bring it into correct "under" balance condition then the elevator itself was not in correct "balance" before removal of the hybrid weight either due to unapproved repairs or too much paint and filler. 

With the hybrid weights YES every annual requires removal, inspection and rebalance of elevators with the hybrid weights. 

BTW, per Mooney, NO repairs (patches) to flight controls are allowed. Completer reskin can be done but no partial repairs or patches so if you have blanket patches to repair hangar rash it might be a good time to review that issue also. I got this straight from Mooney Engineering years ago. 

If problems are encountered one should always contact the factory for guidance. 

Shields up Mr. Sulu.

 

[cferr59]

Given that this issue is caused by dissimilar metal corrosion between the insert and the lead weight, is there any thought about corrosion between weight and the steel rivets used to hold the weight in place?

[takair]

10 minutes ago, cferr59 said:

Given that this issue is caused by dissimilar metal corrosion between the insert and the lead weight, is there any thought about corrosion between weight and the steel rivets used to hold the weight in place?

I was thinking the same thing.  My guess is that there is a lot more edge distance around the rivets and makes it flaw tolerant.  There just isn’t much lead holding the slug in place, so once it starts to crack it progresses.  

 

[hammdo]

Mine is done - no hybrid weights so no re-occurring AD…

-Don

[Jim Peace]

Just now, hammdo said:

Mine is done - no hybrid weights so no re-occurring AD…

-Don

Mine should be done this week at a MSC...I know I do not have the weights in question....How much do you think a sign off should be?  

Did they remove the paint from your weights or use the magnet method?

[hammdo]

Magnet, and it’s real obvious if you have the hybrids. We tested the magnets on led and we damn near could not get the magnet off. When we tried on my elevator’s weights, she did not stick at all - just slid off - oh, and we did use the exact magnet called for in the AD/SB.

My IA signed the log entry and sent me on my way, no charge (I was just there for annual and this came out a couple of days after so…). He reviewed the AD and the service bulletin, did the steps, said it’s pretty obvious I didn’t have them…

-Don

[Alan Fox]

If anyone in the northeast needs this AD signed off , I will be available by appointment only you fly it in , I inspect , I create log entry , and I sign it off ... 200.00  You will need to bring the logbook...   I am at KVAY  856 419 5209....

 

[MBDiagMan]

DMax Rocks!

I am SO fortunate to be 45nM from East Texas Regional, the home of Maxwell Aviation.

A few weeks ago, I discovered a leaking fuel tank.  I contacted Paul and asked when I could get it in.  A week later I left it with them and a week or so later both tanks were leak free and once I picked it up, saw how great it looked.  The plane was freshly painted only four years ago and you can hardly tell that it was touched in the tank patch process.

A friend of mine flew me over there yesterday in the back of his Citabria that had no ADS-B and no way to change the transponder code to something besides 1200.  We went over there low and slow and it was really fun sight seeing a route that I take frequently flying instead of enjoying the scenery.

Once there I had a short visit with Don while they were retrieving my plane.  Had a good flight home and got her tucked away in the hangar before noon with the comforting thought that she’s all up to date with no sqwauks, ready to enjoy.  In the afternoon, I was checking email and saw a marketing email from LASAR saying they had the AD covered.  AD?  What AD?  I came straight to Mooneyspace and the top thread (this one) told all about it and the planes mostly effected were ‘67 F’s.  Of course, I have a ‘67 F!

At that point I’m thinking, that’s not like Maxwell to have a plane in the shop, especially a ‘67 F model, with the AD being a hot topic, and they didn’t check it, point it out or something.  I knew there had to be an explanation.  First thing this morning I went to the hangar and my parts pickup magnet didn’t stick.  Went to Home Depot and got the Neo magnet and it didn’t stick.

I called for Don about 8:30 and he was out.  I left a message and he called back an hour or two later with the explanation.  My plane was probably the first one with the weights replaced some years ago.  If I go dig through the logs I’m quite sure I will find it logged, but Don will log the compliance, so I’m all good.  Thank you Maxwell Aviation!  I wouldn’t be surprised if Don or one of the other MSC’s are the ones that discovered all this and did it before anyone had a serious occurrence.

I told Don that I was not surprised that they were way ahead on this issue.

The Mooney community is so fortunate to have Don’s encyclopedic knowledge, and I’m fortunate to have he, Paul and their team only 45nM away.

[Jim Peace]

Just had mine done today at C&W at Caldwell NJ. Sean is one of the best. Highly recommend!!

 

[carusoam]

Nice pireps for C&W Caldwell NJ and DMax!

Thanks for sharing them, Gents!

Best regards,

-a-