You’d have to do an STC
So not under PMA.
Of course, with an STC almost anything is possible.
Avidyne did it to replace the S-Tec 55/55X computer
That is with an STC, no? It isn’t an identical product to the STEC.
Peter wrote:
You’d have to do an STCSo not under PMA.
The STC is the process by which the design of the PMA’d part is approved. PMA is Parts Manufacturing Approval, but the manufacture has to be against approved data.
In the case of the Avidyne DFC90, it’s meant to be a plug/play replacement for the STec 55/55X,
So, no PMA avionics 
STC doesn’t count because if you do an STC you have done, ahem, an STC.
wigglyamp wrote:
The STC is the process by which the design of the PMA’d part is approved. PMA is Parts Manufacturing Approval, but the manufacture has to be against approved data.
So how do the kind of PMA holders that Peter is referring to actually get the approved data? I wouldn’t think the design organisation hands them out for free.
Airborne_Again wrote:
So how do the kind of PMA holders that Peter is referring to actually get the approved data? I wouldn’t think the design organisation hands them out for free.
From the FAA guidance material referenced earlier. Edited to show just the headings
3. Basis for Design Approval. These methods are:
a. Identicality by Showing Evidence of a Licensing Agreement.
b. Identicality without a Licensing Agreement. The applicant also provides the data supporting the
identicality claim for review and approval.
c. Test and Computation. The applicant sends the ACO a data package for review and
approval.
d. Supplemental Type Certificate (STC). The applicant stipulates use of the approved
data from the STC and refers to the STC number.
wigglyamp wrote:
From the FAA guidance material referenced earlier. Edited to show just the headings
Can b and c really be used in practice?
Airborne_Again wrote:
Can b and c really be used in practice?
I guess ECI tried option b or c with their engine cylinders but it all went wrong.
This is how Superior describe the process:
As one of the largest PMA producers in the industry, one question we get asked a lot is: how we go about creating our FAA-Parts Manufacturer Approval (PMA) parts? Well, it’s a long process. The first step is determing why our customers need these parts in the first place?
The two biggest reasons are price and availability. OEM parts are becoming hard to get or they are becoming much too expensive.
Once the part is identified, we do a thorough design and metallurgical analysis. We also gather information from engine shops to find out if there are any opportunities to improve on the performance.
Of course the part’s form and function must match or exceed the original’s standards in order to receive our PMA from the FAA. With that as a foundation, our engineering team creates a new design for the part that takes advantage of any new advancements in materials or manufacturing.
Once the design is finalized, we then work with the best manufacturing facilities around the world to craft each part using the most advanced materials and production techniques available. The result is that our FAA-PMA parts often set new standards for the aviation industry
Can b and c really be used in practice?
That’s exactly what I was talking about originally.
It obviously has successfully been applied in mechanical items (the licensed option is likely very rare) but apparently never to electronic items.
Why not? That is the very question I was asking. Maybe the burden of proof of identicality is too high.
