AFAIK the bugs were caught, known about, and deliberately ignored. In fact even when the bug caused a fatal error that brought an instance crashing (to the ground, literally!), it was ignored both by Boeing and the US government.
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“No, again, we provide all the information that’s needed to safely fly our airplanes,” he answered.
Bartiromo pressed: But was that information available to the pilots? “Yeah, that’s part of the training manual, it’s an existing procedure,” Muilenburg said.
“Oh, I see,” she said. But in fact, MCAS wasn’t in the manual, unless you counted the glossary, which defined the term but didn’t explain what the software did.
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A safety critical feature that can down a plane if not disabled in time... tucked away in a glossary.
The documentary 'Downfall: The Case Against Boeing' goes into great detail about the whole ordeal.
to make matters worse, as far as I understand, the bug was declared "out of scope" by Boeing claiming that dealing with a runaway stabilizer is part of standard 737 training/certification, so even if the MCAS goes bleh, it should be no problem.
which sounds reckless, after all if you make a system more complicated by introducing a "feature" at least try to make it fail gracefully, etc, etc.
then you learn that this glorious safety critical software thing thing was fed by one single angle-of-attack measurement device (oh and to make the system even more mystical the planes had two of these digitalized wind detector flappy flaps, but only one was active, and it switched on reboots, so if one pilot noticed that the system was behaving badly, and then the second one noticed that it was great after all ... the third one had no clue what to expect!)
