Your comment about the handwritten note made me think of Feymann's story of being tasked with find some note that had been scribbled before the Challenger launc

Your comment about the handwritten note made me think of Feymann's story of being tasked with find some note that had been scribbled before the Challenger launch with something akin to "go for it!" or the like. Presumably whatever was in the note was evidence of some sort of cavalier attitude towards safety. His conclusion, though, was that this was an extreme distraction and likely intentional misdirection to prevent them from spending time focusing on the real questions and systemic causes of the accident. Part of me does wonder how much of that is happening here. It would do Boeing wonders to be able to pinpoint as a "root cause" of these failures some sort of cavalier attitude by a few engineers rather than a very large systemic failure on the part of the company itself, which includes but is not limited to cost-cutting, regulatory capture, and abuse of their oversight authority.