The manufacturer had to produce the material in a certain way, right? Mix specific amounts of other things into the titanium, use specific heat, specific cooling. (I don't know anything about metal, really, just assuming that these things are like how high-performance concrete is made.) Now, the choice of additives, amounts, temperatures, pressure etc. is based on testing, right? Someone chose a particular pressure after doing many tests using a range of pressures. The manufacturer isn't allowed to just set up a production process that matches that spec and just assume that the result will match the results elsewhere. But the manufacturer can't take decades to check the product at the normal passage of time either. So the manufacturer has to do some sort of accelerated test to check that the production process works as intended.
That testing is naturally not perfect. I understand that. And whatever testing Airbus/Boeing can do after taking delivery is also not perfect.
My question was rather: Why can't Airbus/Boeing reach the same standard of testing as the manufacturer? If the manufacturer can do some tests and document them (or just fake the documentation) and assert that its production process matches the spec, then I don't see why Airbus/Boeing can't. I do realise that it isn't sure to match reality, the thing I don't see is why Airbus/Boeing can't get as close to testing the spec as a (proper) manufacturer can. I'd like to understand that.
If the answer is that some significant aspect is unobservable afterwards, then my next question is how that was chosen to begin with.
Does this make more sense?
