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

[toto]

1 minute ago, Aerodon said:

There are some parts that are reasonable for OPP.  An owner can give enough information to 'participate' in the process for things like electrical cables, control cables, baffles, pedal extensions, certain airframe parts etc.  Something like this NBS?  It is going to be questioned.  And this is a huge liability issue for the person that either provides enough information for it to be made, or the person who makes it. The FAA and Mooney are watching.  Once the word is out there that there is a batch of homemade springs, the next thing is there will be an AD to have them removed, grounding all the planes and no alternate in sight.   Who wants to be on the receiving end of the phone call from the FAA or insurance company for the first plane that does a wheels up because it failed sometime in the next 18 years?

I have no solution, but I am on the same page as @Cliffy, and the others waiting for a proper solution.

 

Aerodon

 

The NBS is one of the items that @Jonny said was being prioritized by the factory. Anyone know whether there is a new batch coming any time soon?

[A64Pilot]

On 1/16/2024 at 8:01 PM, toto said:

The NBS is one of the items that @Jonny said was being prioritized by the factory. Anyone know whether there is a new batch coming any time soon?

I had one on order that I had paid for at Top Gun, I finally just got my money back as it had been over a year, she was polite and it wasn’t a problem, she may in fact have contacted me about it I don’t remember.

However she said that they believe that the factory was working out the QC issues with the vendor and that we would be seeing a batch in the future, when that happens she said she would contact me.

[PT20J]

Frank Crawford would know the current status.

[MikeOH]

Ok, I'm lucky my F doesn't have this dreaded component.

But is the general consensus that the spring is really good for a lifetime but there was a period when a bad batch got into the field? (Bent tang after heat treat, or some such screwup??).

If so, based on date, could owners establish their spring was installed BEFORE the bad batch was made?  That would help at least some owners.

Any data on how many times a failed no-back spring has actually been the cause of a gear up?

[toto]

6 hours ago, MikeOH said:

Ok, I'm lucky my F doesn't have this dreaded component.

But is the general consensus that the spring is really good for a lifetime but there was a period when a bad batch got into the field? (Bent tang after heat treat, or some such screwup??).

If so, based on date, could owners establish their spring was installed BEFORE the bad batch was made?  That would help at least some owners.

Any data on how many times a failed no-back spring has actually been the cause of a gear up?

Iirc there has been at least one documented failure of a Plessy actuator and at least one documented failure of an Eaton actuator due to the NBS. I think @Pinecone mentioned that the faulty springs were not installed at the factory - the bad batch was all for replacements. 

[A64Pilot]

7 hours ago, MikeOH said:

Ok, I'm lucky my F doesn't have this dreaded component.

But is the general consensus that the spring is really good for a lifetime but there was a period when a bad batch got into the field? (Bent tang after heat treat, or some such screwup??).

If so, based on date, could owners establish their spring was installed BEFORE the bad batch was made?  That would help at least some owners.

Any data on how many times a failed no-back spring has actually been the cause of a gear up?

I really in my opinion don’t think there is enough real data to support any real statement. I think the suspect springs date range is known, just I don’t know what it is.

However nothing lasts forever and there is apparently some wear on this spring evidenced by apparently every now and again someone’s gear chatters on retract and it’s due to a worn spring.

However my assumption is that failures are more likely due to fatigue than wear, which if true lends credence to improper heat treat etc. Although you could argue fatigue is wear. By wear I mean physical removal of material on use, like brake or tire wear.

Then there is the issue that the actuator is grease lubricated, and grease over time breaks down meaning at some interval it’s probably a good idea that a knowledgeable individual disassembles, inspects, replaces worn parts etc and puts it back into service, why not replace the spring while your there, assuming of course they are available, it is a wear item it seems.

All of this is not from personal observation, I’ve never disassembled an actuator, rather it’s from what I have read and heard second hand, so take it for what it’s worth.

I think that gear ups from a failed spring in an Eaton actuator is rare, a problem is there may be more than we know, gear ups often aren’t really investigated, just repaired and if the actuator failed it’s usually replaced without any real investigation on what failed.

Example crankshafts still break even after the AD’s but it’s rare.