there's a theme running through a lot of the posts and media postings that I'd like to counteract. The theme is this was an unforseen situation or a unique failure point or something never seen before or a multitude of little issues adding up or a complex engineering/HF scenario etc.
IT'S NOT. It's a basic basic basic engineering flaw to build a system that controls a flight surface based on a single input. Boeing is proud to have years and years of engineering heritage so it knows full well the design was flawed and cheap even as soon as the first person said "we could get away with just 1 input". 100 other engineers would have immediately said no way not ever. But obviously somewhere a commercial person stepped hard enough on the Engineers to get the single input design commissioned. Everything else is just collateral damage. I can even understand though not like the decision to have a primary control surface move just to send feedback back to the stick, rather than add a servo to do the job. All the bits were there so it was too tempting to add some lines of code and voila!
G