Plessey gear actuator- torsion spring- owner produced part?

[bmcconnaha]

Looking to comply with the service information letter for plessey gear actuators, that calls for replacing the torsion spring at 1000 hours.  After some research, it appears there is no supply of these springs anywhere.  Seems a few people have recommended trying to source an Eaton actuator, but I feel that is a little extreme.  My question is this, has anyone produced an owner produced part for this application?  If not, I was going to see if there was a spring at a wrecking yard I could have the metallurgy tested, and a few new ones machined.  Would anyone be willing to share their findings if they went this route, or willing to participate if I go this route?

 

[FLYFST]

I replaced my Plessey actuator and spring with Eaton actuator and new spring, apparently just in time. During Annual gear check my A&P could hear a “ratcheting sound” which appears to be an indicator of a spring or actuator getting ready to fail. Good luck.


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[Davidv]

11 minutes ago, bmcconnaha said:

Looking to comply with the service information letter for plessey gear actuators, that calls for replacing the torsion spring at 1000 hours.  After some research, it appears there is no supply of these springs anywhere.  Seems a few people have recommended trying to source an Eaton actuator, but I feel that is a little extreme.  My question is this, has anyone produced an owner produced part for this application?  If not, I was going to see if there was a spring at a wrecking yard I could have the metallurgy tested, and a few new ones machined.  Would anyone be willing to share their findings if they went this route, or willing to participate if I go this route?

 

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There have been lots of discussions on this over the years (search "plessy").  I'm in the same boat as are many other owners.  It would seem that if one person were able to remove their spring while their plane was down for a long period of time in overhaul or annual, some fabrication shop should be able manufacture.  I'm not a metals expert but there has to be a way to determine the specific material needed...maybe just very wishful thinking?

[bmcconnaha]

2 minutes ago, FLYFST said:

I replaced my Plessey actuator and spring with Eaton actuator and new spring, apparently just in time. During Annual gear check my A&P could hear a “ratcheting sound” which appears to be an indicator of a spring or actuator getting ready to fail. Good luck.


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Do I dare ask what the cost was to replace it with the Eaton? I’ll be swinging the gear with my A&P probably every 100 hours to be on the lookout for anything odd.  Strangely enough, I read an article that stated the plessey actuator was actually more robust than the Eatons internally, but obviously no support is an issue.  

[bmcconnaha]

2 minutes ago, Davidv said:

There have been lots of discussions on this over the years (search "plessy").  I'm in the same boat as are many other owners.  It would seem that if one person were able to remove their spring while their plane was down for a long period of time in overhaul or annual, some fabrication shop should be able manufacture.  I'm not a metals expert but there has to be a way to determine the specific material needed...maybe just very wishful thinking?

I have read everything so far, and I’m not seeing any real viable options other than an owner produced part.  If I can get my hands on the spring, I’d get working on getting it figured out.  There seem to be a few outfits that can tell me what exactly it’s composed of, and I found a spring maker that specializes in aerospace.  I’ll reach out to them once I know what it is exactly that I need.  My plane could be down for  extended period with an engine overhaul and avionics upgrade soon.  That might be the right time to pull it out and have a look anyways.  

[FLYFST]

5 hours ago, bmcconnaha said:

Do I dare ask what the cost was to replace it with the Eaton? I’ll be swinging the gear with my A&P probably every 100 hours to be on the lookout for anything odd.  Strangely enough, I read an article that stated the plessey actuator was actually more robust than the Eatons internally, but obviously no support is an issue.  

The price i was quoted by two different MSCs was $9,500 plus installation to replace the Plessey with an overhauled Eaton actuator and new spring, and that was based on first finding an Eaton actuator to overhaul.  I got away with a lot less than that by installing a new spring on an used Eaton actuator with low hours and not overhauling it.  My research also indicated that the Plessey is a more robust actuator.  But, the spring the Plessey uses is just not available, and neither are parts to overhaul that actuator.  That left the Eaton actuator with a new spring as the only option for me, consistent with the continued airworthiness certification of the aircraft.

[ArtVandelay]

Can’t we just disassemble and inspect it, if it’s good just lube and reassemble it. In Another words just IRAN it.

[Davidv]

Just now, ArtVandelay said:

Can’t we just disassemble and inspect it, if it’s good just lube and reassemble it. In Another words just IRAN it.

That’s what I believe most good mechanics do these days...

[bmcconnaha]

2 hours ago, ArtVandelay said:

Can’t we just disassemble and inspect it, if it’s good just lube and reassemble it. In Another words just IRAN it.

The problem is the R part of the IRAN.  Unless you mean the whole actuator.  Which isn’t cheap.  Sure would be good to have a spring ready to go, instead of replacing the actuator.  I plan to pull mine apart and lube it soon.  I’m doubtful it was ever done.  The logbook never references it, and the data plate appears undisturbed.  

[FLYFST]

Can’t we just disassemble and inspect it, if it’s good just lube and reassemble it. In Another words just IRAN it.

Take a look at MSB 20-282A. It details a very specific inspection process but for the Eaton springs only.


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[Hank]

On 8/23/2020 at 6:55 AM, bmcconnaha said:

I have read everything so far, and I’m not seeing any real viable options other than an owner produced part.  If I can get my hands on the spring, I’d get working on getting it figured out.  There seem to be a few outfits that can tell me what exactly it’s composed of, and I found a spring maker that specializes in aerospace.  I’ll reach out to them once I know what it is exactly that I need.  My plane could be down for  extended period with an engine overhaul and avionics upgrade soon.  That might be the right time to pull it out and have a look anyways.  

Give Lee Springs a call [www.leesprings.com]. Been using them for years at several jobs, they make about every spring possible out of most materials. They will need to know the material of the spring as best as you can tell, the wire thickness, OD and torsional force range. Should be fairly inexpensive [for the aviation world] to make a handful of them, but too pricey for most applications [a few hundred per spring?].

[ArtVandelay]

Give Lee Springs a call [www.leesprings.com]. Been using them for years at several jobs, they make about every spring possible out of most materials. They will need to know the material of the spring as best as you can tell, the wire thickness, OD and torsional force range. Should be fairly inexpensive [for the aviation world] to make a handful of them, but too pricey for most applications [a few hundred per spring?].

Somehow you’ll need to get one so they can make measurements. I wonder how many of these in circulation?

[Hank]

Just now, ArtVandelay said:

Somehow you’ll need to get one so they can make measurements. I wonder how many of these in circulation?

Call you local MSC, they may have an old one. Or find someone inspecting theirs, and spend 5 minutes with a set of calipers. But talk to Lee first and make sure you get everything they need!

[carusoam]

There are pics of the spring around here... I think Andrew had documented the issue...

 

The springs that were affected were showing surface cracks, lots of them...

It appeared as though it were a material/process challenge...

 

It shouldn’t be that hard to make a spring that works over a long period of time...

But, apparently it was for somebody... 

 

Best regards,

-a-

[bmcconnaha]

1 hour ago, Hank said:

Call you local MSC, they may have an old one. Or find someone inspecting theirs, and spend 5 minutes with a set of calipers. But talk to Lee first and make sure you get everything they need!

I’ll do that.  Thank you.