Another pilot bails

Half Fast said:
Remember that it's possible to reverse-engineer the parts if you can't obtain the OEM data. You can scan a piece of interior trim, for example, and manufacture it using a 3D printer, without having to obtain a 60-year-old drawing from Textron.
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Except all owner parts must be produced per approved data. And that can be data previous approved or new data you generate via one of two methods. You can reverse-engineer all you want to develop the production data but someone has to approve that data to be used. Most times we would use a 337 or DER to approve that data. Short of that the owner and installing mechanic will get owned when it is found. And to note, the best article on the subject is by the great Bill Obrien which the MB article above was taken from.

Kiddo's Driver said:
There is a certain part for a certain French plane that is $450. A comparable part for CPB American planes is $25-$50. The French one has metric threads. I found a company that makes the same part in metric, for $23 each, but does not have PMA approval. If I ask them to substitute a Viton o-ring instead of a Buna o-ring, and manufacture a half dozen of them for me, does that make it an owner-produced part?
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No. Now develop drawings and a process down to the oring and get that approved, then yes. But you cannot sell them if that was your intent. To sell them would require a PMA or similar.
 
While doing some reading on this, I stumbled across an FAA info paper on a related topic: standard parts. See attached.

Trivia question: who knew there was a TSO for fasteners?
 

Attachments

Cost are increasing to maintain an aircraft. Need to budget for the pesky $75 "shop supplies" charge. :rolleyes:
 
....and for that reason, I'm out. E-AB only for me. I'm here to smash bugs, not to keep A&P mechanics afloat or pay extra for FAA-PMA stickers on auto parts. I'll decide what is and isn't airworthy. I think experimentals will gain popularity largely because of this, at least until the FAA clamps down on them. Somebody will ruin it in some high profile incident and suddenly there'll be public outrage at the unregulated liberty.
 
Bell206 said:
Except all owner parts must be produced per approved data. And that can be data previous approved or new data you generate via one of two methods. You can reverse-engineer all you want to develop the production data but someone has to approve that data to be used. Most times we would use a 337 or DER to approve that data. Short of that the owner and installing mechanic will get owned when it is found. And to note, the best article on the subject is by the great Bill Obrien which the MB article above was taken from.


No. Now develop drawings and a process down to the oring and get that approved, then yes. But you cannot sell them if that was your intent. To sell them would require a PMA or similar.
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Not concerned about selling.
Just don’t want to pay $450 each for them.

Get them approved by whom?
 
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moparrob66 said:
....and for that reason, I'm out. E-AB only for me. I'm here to smash bugs, not to keep A&P mechanics afloat or pay extra for FAA-PMA stickers on auto parts. I'll decide what is and isn't airworthy. I think experimentals will gain popularity largely because of this, at least until the FAA clamps down on them. Somebody will ruin it in some high profile incident and suddenly there'll be public outrage at the unregulated liberty.
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I’m with you. Plus my LSRM-A just made E-AB that much easier.
 
moparrob66 said:
....and for that reason, I'm out. E-AB only for me. I'm here to smash bugs, not to keep A&P mechanics afloat or pay extra for FAA-PMA stickers on auto parts. I'll decide what is and isn't airworthy. I think experimentals will gain popularity largely because of this, at least until the FAA clamps down on them. Somebody will ruin it in some high profile incident and suddenly there'll be public outrage at the unregulated liberty.
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I'm also making said pivot. I will say, I'm grateful for having had the opportunity to have flown my family when the kiddo was young and lock in those memories. Something which I could only do in the "good old days" of the 2010s, with a fac-built. Experimental space was and still is very DINKish/empty nester centering. So credit where credit is due. I do lament not having had the confidence and information to have made the RV purchase back in 2012 when they could be had for a bag of peanuts. username checks, water under the bridge.

Also in fairness, I don't regret the embittering education a decade and a half of fac-built ownership "afforded" me. It's not the only conduit to that education to be clear, but in my life situation the experience just wasn't available to me tangentially. I was not born into an aviation legacy family, social media wasn't a thing, and people glaze the reality of this hobby anyways, so information is still not frank and transparent as it could be in 2025.

At any rate, it was an expensive education for sure, but it has made me very comfortable with EAB ownership going forward. That's my rationalization for my decisional mistakes, and I'm sticking to 'em :biggrin:
 
side question - why would alkaline energizers be preferred over non-rechargable lithium energizers
Lithiums have longer shelf life and are less prone to leak, right?
 
Brad W said:
side question - why would alkaline energizers be preferred over non-rechargable lithium energizers
Lithiums have longer shelf life and are less prone to leak, right?
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Alkalines are cheaper to use when manufacturing the packs, and you can require replacement at more frequent intervals. Follow the money.
 
DaleB said:
Alkalines are cheaper to use when manufacturing the packs, and you can require replacement at more frequent intervals. Follow the money.
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All true, but: The manufacturer would have to run the entire test/certification test over for batteries with a different chemistry. Likely the lithium cells would be more expensive, and there may be additional safety issues with them. I can really see the manufacturers deciding to skip the risk...oh, and it saves money as well....

Ron Wanttaja
 
Half Fast said:
Was the PIND test your own company's test, or part of the industry standard?
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Heard back from my battery guy, and the story was more interesting that I first knew.

The Aerospace Corporation is a non-profit that keeps a group of highly-qualified individuals for technical expertise. Normally, military officers are on a 3-4 year assignment cycle, so they don't necessarily gain that much experience. The Government thus subcontracts with Aerospace to monitor the work performed by its contractors.

That much, of course, I DID know. What I didn't know is when we decided to use COTS NiCd batteries on our spacecraft, the concept was passed to Aerospace for evaluation. Aerospace determined the type of testing that would be required for that, and, in fact, performed the testing itself...Including the PIND test, matching characteristics of individual cells, etc.

So the short answer is that it was not a company test, but one of several imposed by the Government watchdogs on our program. My battery guy still speaks fondly of the Aerospace lead that handled this testing; the guy had brains out the wazoo *and* understood the practical aspects of space operations.

As it turns out, I found a NASA paper on PIND. I find I had the acronym wrong, it's PARTICLE Impact Noise Detection, not Part Impact....

Ron Wanttaja
 
wanttaja said:
Heard back from my battery guy, and the story was more interesting that I first knew.

The Aerospace Corporation is a non-profit that keeps a group of highly-qualified individuals for technical expertise. Normally, military officers are on a 3-4 year assignment cycle, so they don't necessarily gain that much experience. The Government thus subcontracts with Aerospace to monitor the work performed by its contractors.

That much, of course, I DID know. What I didn't know is when we decided to use COTS NiCd batteries on our spacecraft, the concept was passed to Aerospace for evaluation. Aerospace determined the type of testing that would be required for that, and, in fact, performed the testing itself...Including the PIND test, matching characteristics of individual cells, etc.

So the short answer is that it was not a company test, but one of several imposed by the Government watchdogs on our program. My battery guy still speaks fondly of the Aerospace lead that handled this testing; the guy had brains out the wazoo *and* understood the practical aspects of space operations.

As it turns out, I found a NASA paper on PIND. I find I had the acronym wrong, it's PARTICLE Impact Noise Detection, not Part Impact....

Ron Wanttaja
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Bottom line, it seems the batteries were being tested and screened to a higher standard than the basic industry spec.
 
Half Fast said:
Bottom line, it seems the batteries were being tested and screened to a higher standard than the basic industry spec.
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We tested them higher than the basic industry spec for commercial terrestrial use, yes.

That's what bit us the second time around. We ordered the same part number from Sanyo, and when they got in we noticed they were a bit crude looking. Flunked the additional testing for use in our spacecraft. They were probably fine in RC cars (their intended use) and probably met the basic industry spec for that. Contacted Sanyo, and found that this batch was made by a subcontractor in another country. We ordered more batteries, specifying that they had to be manufactured by Sanyo in Japan. These met our elevated criteria and have been working on orbit for quite a while.

Ron Wanttaja
 
Brad W said:
side question - why would alkaline energizers be preferred over non-rechargable lithium energizers
Lithiums have longer shelf life and are less prone to leak, right?
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For aircraft applications, anytime there is a change in battery chemistry to lithium larger than 2 Wh require ACO level approval or an STC. Not worth the cost for older ELT battery pack and similar battery packs.
 
wanttaja said:
We tested them higher than the basic industry spec for commercial terrestrial use, yes.

That's what bit us the second time around. We ordered the same part number from Sanyo, and when they got in we noticed they were a bit crude looking. Flunked the additional testing for use in our spacecraft. They were probably fine in RC cars (their intended use) and probably met the basic industry spec for that. Contacted Sanyo, and found that this batch was made by a subcontractor in another country. We ordered more batteries, specifying that they had to be manufactured by Sanyo in Japan. These met our elevated criteria and have been working on orbit for quite a while.

Ron Wanttaja
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Yep. Went through something similar with power op amps. See https://www.pilotsofamerica.com/com...chnics-components-lately.144315/#post-3436350 Post #8.
 
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