All of the paper work and liability reduces competition and results in much higher prices for literally the same exact part.
What do you think “fake” means in this context? That the part is really a Loony Toons sketch of the real thing, stickytaped to the surrounding engine? No, it means it’s essentially an outwardly identical part without the appropriate QA/QC processes undertaken to certify it as genuine and to spec.
This may for example include destructive and nondestructive testing of parts, or it might include tracking the manufacturing process parameters to ensure correct outputs. For example, a cast component has sufficiently low levels of porosity, inclusions, etc. that might in time lead to premature failure. Or it might mean that there wasn’t sufficient record of the brew of the metal going into the casting or the casting process itself to confirm the part has the requisite material properties. In all but the most dire circumstances, it’s nearly impossible to verify whether any of that was done correctly just by looking at the part; for all intents and purposes, it’ll look identical to a real part.
In the case that the OP references regarding Virgin Australia [1], the parts were a low-presssure turbine blade and a high-pressure turbine nozzle seal. Both of them would fall into situations similar to the above. If cast, the turbine blade would need to prove what I outlined, amongst much more. If machined from billet, it’ll still need proof the ingot itself was manufactured correctly which mirrors a lot of the above. In the case of the seal, there’s similar processes to prove that the non-metallic material is to spec so that a Challenger-style failure doesn’t occur, except within expected operating parameters.
The link I provided regarding Virgin Australia gives much more detail about the core issue at play. This isn’t a situation where manufacturer B is stamping its parts as made by manufacturer A. It’s where manufacturer B says it can make a part compliant with the specifications, same as manufacturer A, but then does not have the required documentary evidence that it meets those specifications.
1: https://www.smh.com.au/business/companies/two-virgin-aircraf...
In the 60s and 70s, there was a lot of crossover between automotive and piston aircraft parts. In particular, Cessna used the same voltage regulator as Ford. Ford used millions of these and Cessna tens of thousands. They were all made on the exact same production line and all got a Ford part number.
Relying on statistical process control, Ford demanded a certain percentage of their parts get extra, manual QC inspection. Cessna demanded 100% inspection of their parts.
Solution: make all the parts on the same line, divert enough for the greater of (Cessna production plus spares) or (Ford’s SPC needs), QC that amount and stamp those inspected parts with a Cessna number (in addition to the Ford part number).
Ford and Cessna can each get parts cheaper than if they were handled separately.
Now, the question comes up: if there are no QC failures detected, are the Ford-only parts as safe as the Ford-or-Cessna parts coming off the line?
They absolutely fly entirely successfully (and legally) on E-AB aircraft (experimental-amateur built) using the same engine/alternator that Cessna uses.
Anyone who has spent time in less developed countries knows what a difference strong government regulations on the market make. People in Western Europe, the US and other developed areas tend to take for granted that the food they buy in the grocery store is what it says on the package. That doesn't just happen by itself, and it's not a safe assumption everywhere.
Why would they be the same parts? Why would their manufacturer go through extensive testing if they have no incentives in doing so?
Somehow people here seem to believe that “documentation” is expensive, but most of the expense doesn't come from the paperwork itself but from the things that you are required to do by these pieces of paper. And if you want to save costs, you're gonna save costs on the manufacturing process, not just on the paperwork.
That’s paperwork and an ink stamp as the only difference.
There are other cases now where NDT is used on high-grade bolts and Heim joints. Parts coming off the same line are sold with a -M suffix (“this bolt was individually magnaflux tested and can go on an aircraft”) or not (“this part can go on a tractor”).
Where no failures are ever found in NDT, I think most practical engineers would agree that the parts are physically identical.
Wait, of course they are identical… unless there is a defect!
But that's the point of testing: when you can tolerate 1% defect then you can just sample your production line, but if your “safety demonstration”[1] relies on the fact that no screw is going to fail catastrophically under load because there's a defect, then you have to check them all. It's not “That’s paperwork and an ink stamp as the only difference”, exhaustive testing vs statistical testing. The work needed for the testing process is actual work, it's not about filling the paperwork.
[1]: not sure this terminology exists in English, I'm just doing a literal translation of a nuclear Engineering concept I know in French only.
If you are buying a replacement part you would want to buy one with the same specs as the part you are replacing.
>Why would their manufacturer go through extensive testing if they have no incentives in doing so?
Manufacturers will test their parts so that buyers can see if the part is usable for their needs.
But without the paper, you cannot know for sure if the spec is the same (you can't see the difference between aviation grade screws and regular screws with naked eyes for instance).
> Manufacturers will test their parts so that buyers can see if the part is usable for their needs.
Manufacturers want to sell their parts, they don't want buyers to “see if the part is usable for their needs” (if the buyer doesn't buy, that's a missed sale).
I mean have you never buy anything? Sellers want you to believe their product is good so you buy it and they make money, that's how it works. And customers being disappointed by false marketing promises is routine stuff, including in the B2B sector.
Yeah, true.
Stops people from dying though, so who’s to say if it’s good or not.
No.