True, Va is a wing calculation, it may not be the only critical structure, however it didn't break because of turbulence, it broke because the pilot didn't understand the control system limitations and the different modes the computer processes commands. The pilot waggled the tail harder than it could take thinking the FBW box would limit the command, but he was in an operating regime where it didn't.
Have you ever seen a cockpit video of someone doing high performance flying in a FBW Airbus? They just slam the controls to the limit and the FBW does the best job of it, it's really impressive because they have some serious performance capabilities, the pilot just hit it a bit too hard, and the tail is attached by a Carbon Fiber section... well, you know the failure mode for CF, it doesn't bend, it doesn't crack, it explodes. I think FBW limiters should always be used in airliners with structural components of straight CF. I'm wondering why the aviation sector has not adopted mixed material weaves.
I have done a couple small projects with a 25%CF, 25% Kevlar, and 50% polypropylene. Really good properties nice stiffness, nice toughness, light weight, broader range of failur with non total options, and much more reasonably priced. The weaves even look cool if you want to leave a brightwork finish.
One of the little sail boats is 3 years old now and I hear is doing fine and racing well for the gal. I did use a titanium white linear poly on it though, the UV factor was more than I wanted to risk, but it would have looked hot as hell if I hadn't painted it. There are UV filters in a clear form, but they do not work near as well, and polypro and UV don't get along well.
