As I have briefly mentioned elsewhere on this forum before, I learned not terribly long ago from one of my insurance agents that one repository of quite a bit of information about super bad/catastrophic crashes related to mechanical issues of various sorts is the big life insurers, at least here in the US. Before they cut a big check after one of these disasters, there is a thoroughgoing investigation. Because this info is collected to manage corporate insurer liability rather than for pure scientific reasons, nobody outside these companies usually sees it.