Anyone have a used out of spec no back spring I can buy?

[A64Pilot]

40 minutes ago, M20Doc said:

Wouldn’t the manufacturer of the gear actuator have designed the actuator to handle the loads that Mooney provided them and then either manufactured or sourced the manufacturer of the spring.

In the case of the Plessey parts no longer exist.  In the case of the Eaton, has anyone tried to source them directly from Eaton if Mooney is unable to secure a steady supply?

Clarence

Most probably it’s a COTS part, Commercial Off The Shelf. It’s very rare for something as complex as an actuator to be specifically designed just for one application, way more likely for a COTS part to be sourced but it maybe modified in some manner or another IAW a Mooney drawing. 

But here is the thing, suppose you find out for instance Maule used an OMC solenoid for their starter, you buying the identical part from a boat dealer doesn’t make it a legal part, see it’s not a legal part until Maule inducts it into their Quality control system, so technically even if we sourced the springs from Eaton, technically they aren’t legal.

‘In searching for parts, smart manufacturers assign their own part number and remove the original, making it tough to find the original part. Wasn’t always done back in the day though as it was the internet that made parts searching by part number possible for Joe average. Maule for instance left the original OMC part number on the solenoid, so it wasn’t too tough to find.

If you look at the electrical draw and weight lifting performance on the data plate, both are way in excess of the loads the aircraft needs.

Edited February 21, 2022 by A64Pilot

[A64Pilot]

20 hours ago, milotron said:

Hi, I have this coming up soon. Is there really none available?

I am not familiar with this SB. Is it mandatory replacement or on condition?

I sounds like my annual next week is about to get a whole lot more expensive.

I think your in the majority of Mooney pilots, I had never heard of the thing either, and I’ve asked a few when I’ve run into them, never met one who had heard of this spring, I knew the IA well who had maintained my aircraft before I bought it, he had never heard of this spring.

So I think there are a whole lot of Mooney’s flying around with original springs.

I’ll still replace mine when I can though

[carusoam]

2 minutes ago, A64Pilot said:

Most probably it’s a COTS part, Commercial Off The Shelf. It’s very rare for something as complex as an actuator to be specifically designed just for one application, way more likely for a COTS part to be sourced but it maybe modified in some manner or another IAW a Mooney drawing. 

But here is the thing, suppose you find out for instance Maule used an OMC solenoid for their starter, you buying the identical part from a boat dealer doesn’t make it a legal part, see it’s not a legal part until Maule inducts it into their Quality control system, so technically even if we sourced the springs from Eaton, technically they aren’t legal.

‘In searching for parts, smart manufacturers assign their own part number and remove the original, making it tough to find the original part. Wasn’t always done back in the day though as it was the internet that made parts searching by part number possible for Joe average. Maule for instance left the original OMC part number on the solenoid, so it wasn’t too tough to find.

another side to this argument…

Mooney buys a COT part, and modifies it for final use…

the person getting the original part number may be unaware of what else needs to be done…

 

A similar example… Mooney used an ordinary plumbing elbow and modified it to be a check valve with a ball and a pin, and possibly modified a seat for the ball to sit in…

This assembly from the outside looks like an elbow…

Technically, it is the sniffle valve used on some IO360s….  

Using an elbow in place of a check valve, would lead to a whole bunch of lean challenges for an expensive motor…

Fram air filters, with a new part number placed right on top of the Fram part number are kind of funny….  

 

PP thoughts only, not a mechanic…

-a-

[A64Pilot]

Understood, at Thrush we took a 1/8 NPT elbow, filled it with silver solder and drilled a small hole in the solder, it’s purpose was to be a restrictor for the old type of oil pressure gauges, without the tiny hole a ruptured tube in the gauge or busted hose would be a major engine oil leak.

But as aircraft become orphaned, we the aircraft maintainers are going to have to become more involved to keep them flying, it can’t be just order x part from the manufacturer that’s no longer is in business.

The FAA has recognized this long ago and OPP is one example of them assisting, here is another example. BTW the below AC is applicable to ALL M20 Mooney’s 

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_23-27.pdf

Edited February 21, 2022 by A64Pilot

[carusoam]

7 minutes ago, A64Pilot said:

I think your in the majority of Mooney pilots, I had never heard of the thing either, and I’ve asked a few when I’ve run into them, never met one who had heard of this spring, I knew the IA well who had maintained my aircraft before I bought it, he had never heard of this spring.

So I think there are a whole lot of Mooney’s flying around with original springs.

I’ll still replace mine when I can though

The spring introduced itself to the Mooney world in a big fashion…

It single-handedly introduced a failure to the landing gear system that made operating the gear impossible by both the usual method, AND the back-up method… at the same time…

 

Then the spring manufacturing method and quality control procedures also wanted everyone to know how important they were…

 

So….

Under ordinary conditions… the Spring is a boring 5 cent part… with a documented replacement frequency… that is easy to ignore…

Similar to brake fluid, and Jack screw and gearbox grease….

 

Every now and then… a failure makes the news…. Amongst the Mooney owner crowd…

how well that info gets disseminated to the outside world… or how well it gets remembered anywhere… is hard to tell…

PP thoughts only…

-a-

[A64Pilot]

I still wonder if we are reacting to a batch of bad parts? Has the 1000 replacement interval always been there?

Very often replacement intervals are established after failure establishes first the fact that it fails and the interval, with of course additional safety or “scatter” factor.

On edit, you know I’m hoping it’s a bad batch, that’s how I can fly on a 2,000 spring

Edited February 21, 2022 by A64Pilot

[toto]

19 minutes ago, A64Pilot said:

I still wonder if we are reacting to a batch of bad parts? Has the 1000 replacement interval always been there?

Very often replacement intervals are established after failure establishes first the fact that it fails and the interval, with of course additional safety or “scatter” factor.

On edit, you know I’m hoping it’s a bad batch, that’s how I can fly on a 2,000 spring

Yep, it was one bad batch. The 1000-hour replacement interval has not always been there. 

SBM20-282A.pdf

[dylanac]

18 minutes ago, bluehighwayflyer said:

That is exactly my belief, @A64Pilot.   A single bad batch of springs, probably in the mid 1990s and probably all out of service by now.  Here is the history on the subject, as provided by Mooney.  Disassembling and lubricating the actuator every decade or so is in all likelihood more than sufficient to insure a very long service life.

https://www.mooney.com/wp-content/uploads/2020/12/SBM20-266A.pdf

https://www.mooney.com/wp-content/uploads/2020/12/SBM20-279C.pdf

https://www.mooney.com/wp-content/uploads/2020/12/SIM20-52C.pdf

https://mooneyspace.com/applications/core/interface/file/attachment.php?id=91538 230.61 kB · 94 downloads

Jim

Reading this thread worries me, as the original actuator on my E model has never been apart. Am I correct in assuming that mine does not have the same actuator as these because it was a retrofitted early E model (serial 1014)? none of the ACs you linked call out my serial number in range.

[dylanac]

4 minutes ago, bluehighwayflyer said:

Yes, you probably have a Dukes actuator which is a different thing entirely.  It, too, requires periodic re-greasing, though.  If so, check to see if yours has been modified with the 40.1 gears, which will make it actuate more slowly, reduce wear, and extend it’s service life.  They came with a 20.1 gear ratio.  

Yep, that's the one! I've got a 100hr lube and check AD but I'll take that over the elusive NBS spring. It has not been modified to 40:1 gears yet, that's on the (growing) short list.

[cliffy]

2 hours ago, M20Doc said:

Wouldn’t the manufacturer of the gear actuator have designed the actuator to handle the loads that Mooney provided them and then either manufactured or sourced the manufacturer of the spring.

Yes they probably did to Mooney's request (it may have been an off the shelf item) They would have made the spring to their initial design which Mooney adopted into their "approved" package -the TYPE CERTIFICATE

In the Type Certificate every part is called out and substantiating data is kept on the exact make up of each part by TC holder and parts are inspected incoming to the airframe manufacturer to verify that they conform to the type design. 

This then becomes the "traceability" factor to the part being an approved part that can be installed on a certified airplane. The part has to be :traceable" in design and manufacture back to its birth - the data package in the drawer. Does the part CONFORM (note not just look like) to how it was originally approved in all aspects?

Now let's go back to how a part can be approved to install on an airframe-

First they part itself has to be designed and made and approved for installation on an airplane THEN

In order to make the part and sell it the manufacturer has to hold a PMA for the part (Parts Manufacturing Approval) signifying that they have a process or system in place to prove that how they function internally to make the part conforms to the approved design. Traceability then goes back to the original design paperwork where every aspect of that part is specified. 

SO not only does the part have to have its own approval to go on an airplane but the manufacturer has to have a separate approval just to make the part to be sold to the general public (PMA)

This is where the installing A&P has to determine if the part can be installed on a certified airframe (the best way is an 8130 certificate)

Another way to have a certified part is the OPP (Owner Produced Part) route but that still has to have a reference to the original part and how it was made. Catch 22!

Another way is to hire a DER (Designated Engineering Representative) to design a part conforming to all the regulations and physics of the part and then get the FAA approval for the DESIGN of the part. 

 

[Marauder]

This spring discussion hits home. My FAVORITE recliner experienced an in flight failure. Fortunately, my landing gear was down and locked.

What I found interesting was that the replacement spring was available for $35 EACH!!!! There was no way I was going to pay that much. But when I searched for cheaper Chinese knock offs, I couldn’t find the exact spring.

So, being the Cheap Bast$&d I am, I decided that I could heat up the spring and uncoil it one loop to replace the broken loop. That was an utter failure. It broke again. So I tried again after watching some YouTube videos on the proper way to heat treat metals. Good news! It lasted a day longer than my first attempt.

After the failed attempts I was forced to buy a set of the knockoffs and made sure that I reclined responsibly.

On a more serious note, I think the suggestion to consolidate requests and approach the vendor may get the traction you need. Often when a product is no longer manufactured, the manufacturer will do a production run to support their OOPs (Out Of Production) obligations (i.e. warranty or extended support life). There is a good chance the original design requirements and testing protocols are available. It may not be a cheap path to go, but at least it is a path.

And if anyone knows how I could do an owner produced spring set for my recliner, I’d be indebted to you.



Sent from my iPhone using Tapatalk Pro

[PT20J]

Mooney and Eaton in SBM20-282 mention a single failure with no time in service noted. Mooney and Plessey in SIM20-92 mention two failures at 1200 and 1500 hours, which is evidently the basis for the 1000 replacement interval. I've seen nothing official that indicates that the failures were related to a bad batch of springs. On the contrary, if there were a bad batch of springs there should be traceability by serial number and I would expect only certain actuators to be affected, or at most a one-time replacement. So, the implication is that Mooney was concerned that the spring might have some life limitation.

I looked into the Eaton unit once and it appeared to be a standard part except for the emergency gear extension system which is probably what makes it special for Mooney.

I have never had one of these apart, and just looking at the pictures it is hard to understand exactly how it works. It is clearly a wrap spring. Wrap springs are generally used as a one-way clutch or a one-way brake. Clearly from the description in Eaton documents (and the name no-back) it performs a braking function to keep the gear retracted in the absence of up locks. However, it is difficult to visualize the mechanics that allow the driving mechanism (motor or manual) to drive the clutch input and output shafts in both directions and the spring to prevent rotation of the output shaft in only direction. Perhaps Clarence @M20Doc or someone that has examined one can explain how it works.

Skip

 

[PT20J]

4 hours ago, A64Pilot said:

Most probably it’s a COTS part, Commercial Off The Shelf. It’s very rare for something as complex as an actuator to be specifically designed just for one application, way more likely for a COTS part to be sourced but it maybe modified in some manner or another IAW a Mooney drawing. 

But here is the thing, suppose you find out for instance Maule used an OMC solenoid for their starter, you buying the identical part from a boat dealer doesn’t make it a legal part, see it’s not a legal part until Maule inducts it into their Quality control system, so technically even if we sourced the springs from Eaton, technically they aren’t legal.

‘In searching for parts, smart manufacturers assign their own part number and remove the original, making it tough to find the original part. Wasn’t always done back in the day though as it was the internet that made parts searching by part number possible for Joe average. Maule for instance left the original OMC part number on the solenoid, so it wasn’t too tough to find.

If you look at the electrical draw and weight lifting performance on the data plate, both are way in excess of the loads the aircraft needs.

For a lot of COTS parts, Mooney actually specifies the manufacturer's part numbers in the IPC or SMM (electrical parts). This provides the documentation you need to purchase the part from the manufacturer rather than Mooney. That doesn't help with a part internal to a higher assembly like a no-back spring, but it makes a lot of common parts legal to source from OEMs.

[A64Pilot]

knowing the source of manufacture in and of itself doesn’t make a part legal. The Ag plane I built used a Studerbaker truck master cylinder, we modified it by changing the seals to ones compatible to aircraft hydraulic fluid, you can’t legally go to NAPA and buy that master cylinder like we did, because it’s not been through the manufacturers QC system, that makes it an aircraft part.

However this AC can get you there if the parts are no longer available, difficult to obtain or unnecessarily expensive, exact verbiage is in the AC.

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_23-27.pdf

So were I to use an off the shelf part, I’d use this AC as a reference in the logbook entry, an AC  itself doesn’t give you the authority, but I bet it would go a long way towards not being dinged by an inspector.

For instance if we could get the springs from Eaton it’s my opinion that this AC helps in giving us the authority in using them. Ultimately it’s the installers responsibility of course.

Edited February 21, 2022 by A64Pilot

[A64Pilot]

1 minute ago, bluehighwayflyer said:

But these actuators have been in service in Mooney’s since 1978. Why no hint of a problem until 1998, after the majority of the fleet had undoubtedly greatly surpassed 1000 hours without issues?  It is all speculation, of course. We will never know for sure.

I’m leaning towards what your saying. My guess is that 1,000 replacement interval is Mooney’s most conservative response, replace everything out there with known good springs is the safest response, or it’s my opinion that the 1000 hour replacement would have been made mandatory as a safety issue if in fact every spring would fail upon accumulating x number of hours, assuming x is a realistic number. Given enough time (cycles) even the jack screw will eventually fail.

[toto]

1 hour ago, PT20J said:

On the contrary, if there were a bad batch of springs there should be traceability by serial number and I would expect only certain actuators to be affected, or at most a one-time replacement.

(Asking because I don’t know)

Does the date limitation in the SB lend any credence to the bad batch theory, or is this unrelated?

6. These new springs from MAC will have a discrete “Date Stamp” located on the identification tag attached to the clutch spring, and identified by a MAC QA stamp to signify that it has been approved from current stock inventory. These “Date Stamped” replacement clutch springs will be dated August 20, 2003 or later.

I’ve seen the “bad batch” description many times in many different publications, but I have no idea about the original source. 

Since it’s now almost 20 years past August 2003, and there’s been no update to that date, it suggests (maybe?) that something before August 2003 was suspect.

[toto]

54 minutes ago, A64Pilot said:

I’m leaning towards what your saying. My guess is that 1,000 replacement interval is Mooney’s most conservative response, replace everything out there with known good springs is the safest response, or it’s my opinion that the 1000 hour replacement would have been made mandatory as a safety issue if in fact every spring would fail upon accumulating x number of hours, assuming x is a realistic number. Given enough time (cycles) even the jack screw will eventually fail.

The SB also suggests an inspection every 100 hours, so I assume that an inspector could identify the fatigue before it became critical? I wonder how many electric Mooneys have their gear actuator removed at every annual for a NBS inspection. 

[PT20J]

4 hours ago, toto said:

The SB also suggests an inspection every 100 hours, so I assume that an inspector could identify the fatigue before it became critical? I wonder how many electric Mooneys have their gear actuator removed at every annual for a NBS inspection. 

SBM20-282 isn't clear about the item 3) 100 hour inspection. It says "100 hr operational inspection and inspection for visual damage." But it does not say that the inspection is specifically of the spring, so it is not clear what is to be inspected. This could be read to mean an normal gear check potentially performed more often than annually. Also, in Part II there were certain units that were to be removed and sent to Eaton, but the reason is not given and it may or may not have anything to do with the spring.

Skip

[A64Pilot]

4 hours ago, Marauder said:

This spring discussion hits home. My FAVORITE recliner experienced an in flight failure. Fortunately, my landing gear was down and locked.

What I found interesting was that the replacement spring was available for $35 EACH!!!! There was no way I was going to pay that much. But when I searched for cheaper Chinese knock offs, I couldn’t find the exact spring.

So, being the Cheap Bast$&d I am, I decided that I could heat up the spring and uncoil it one loop to replace the broken loop. That was an utter failure. It broke again. So I tried again after watching some YouTube videos on the proper way to heat treat metals. Good news! It lasted a day longer than my first attempt.

After the failed attempts I was forced to buy a set of the knockoffs and made sure that I reclined responsibly.

On a more serious note, I think the suggestion to consolidate requests and approach the vendor may get the traction you need. Often when a product is no longer manufactured, the manufacturer will do a production run to support their OOPs (Out Of Production) obligations (i.e. warranty or extended support life). There is a good chance the original design requirements and testing protocols are available. It may not be a cheap path to go, but at least it is a path.

And if anyone knows how I could do an owner produced spring set for my recliner, I’d be indebted to you.



Sent from my iPhone using Tapatalk Pro

Sure looks a lot like a military bed spring to me.

https://www.serviceofsupply.com/product/army-bed-springs-miscellaneous-lot/

[Guest]

8 hours ago, dylanac said:

Yep, that's the one! I've got a 100hr lube and check AD but I'll take that over the elusive NBS spring. It has not been modified to 40:1 gears yet, that's on the (growing) short list.

The AD on your Dukes actuator has a 100 hour lubrication requirement as well as a 200 remove and inspect requirement.

Failure of the gears teeth in your Dukes actuators renders both the main and back systems dead, resulting in a gear up landing.

Clarence

[PT20J]

The Dukes actuators don't need the no-back spring since they have a different drive mechanism using a worm and wheel gear combination which inherently prevents back driving. But as noted, they have other issues.

[Peter Rejto]

I was asked earlier if there was something I could share here of interest from the AMPA discussion.  With permission a statement from one of our most respected members:

"Folks who are planning to branch out into aircraft design and manufacturing should bear in mind that this item under discussion (despite its name) is NOT a spring. Its function has nothing to do with its "springiness". It is a uni-directional torque translator. It allows torque to pass in one direction from the motor and manual actuator to the extension mechanism but just free-wheels in the other direction. Its function depends on the slight reduction in diameter when it is "tightening" and expansion when it is turning in the other direction. The key is the phrase "no back" in the name."

Peter

[LANCECASPER]

This is for sale on EBay in Florida:

 

https://www.ebay.com/itm/165343150067?hash=item267f383ff3:g:TNsAAOSweHRf9x6W

[cliffy]

On 2/21/2022 at 5:38 AM, A64Pilot said:

But here is the thing, suppose you find out for instance Maule used an OMC solenoid for their starter, you buying the identical part from a boat dealer doesn’t make it a legal part, see it’s not a legal part until Maule inducts it into their Quality control system, so technically even if we sourced the springs from Eaton, technically they aren’t legal.

Again here is the crux of the matter  - It has to be an "approved part" to install it on a certified airframe.

Approved only gets approved in a couple of ways FOR SALE TO THE PUBLIC -

    The "part" itself has an approval to be installed and

   The company making the part IS APPROVED to make it (PMA approval)

   Certain parts are acceptable to be installed, AN, Space Qualified, etc  as they are for sale to the general public

Just because some company overseas can make something that LOOKS like the part won't make it available to be sold over the counter to the general public. The part has to be made to the exact specs that the original one was and traceable back to the original design. It needs some sort of design paperwork to verify its design. and the overseas company has to hold a PMA to sell the part over the counter. 

Another way to get approval is again Owner Produced Part but you still need some kind of reference back to the original part on how to make it- material, sizes. heat treat, etc. You as the owner can approve the part but you can't just make it up out of thin air AND your installing A&P still has to be convinced that the part is OK to be installed. He's the final authority AND the one on the hook if it isn't legal 9to be determined later by your wonderful FAA)

Another way is to hire a DER and have a new part professionally engineered and approved by him for installation. 

One might go the route of taking the DERs design and having it made as an OPP, That might be a way forward. I need to look into that some more. 

[thinwing]

when i look at this spring..I am reminded that it looks alot like a continental starter adaptor spring....when force is applied it either expands and grips a turning shaft or contracts and grips internally (inner radius dimension)regardless..somebody is making very similar springs for continental starter adaptors....