Originally Posted by
DaveReidUK
Yes, that the same defect apparently persisted through four consecutive sectors, and successive crews were in effect testing the outcome of failed rectification attempts, is inexcusable.
That said, an "inherent and unknown programming defect" (in any software environment, not just aerospace) by definition requires a specific, unforeseen combination of factors (possibly including other defects) in order to trigger it. It's entirely possible that the required combination of factors never emerged during the certification process.
If there had been precursors to this issue, while we might not have heard about them prior to the crash, they would undoubtedly have emerged in the last 10 days.
AFAIK, none have.
Thank you for some sanity! Late 70's our organization reviewed Airbus testing procedures for FBW SW under development. I'm going purely on dated memory here, but as I recall AB contracted out 3 separate test beds in three countries, none of whom knew of the other's existence, to independenly test FBW software. Each were expected to develop their own test procedures. We reviewed the test results and the rationale for their strategy (not for AB but for an independent program). AB expected that each location would find different 'bugs'. It didn't turn out that way. Well over 90% were identical findings with very little if any (I don't remember any at least) unique critical FBW bugs discovered. That is not the result that they expected.
There were also early and persistent concerns of deep stall potential with the F-16 at high AoA (unrelated to FBW). So I'll ask this question. Did Boeing put in some additional 'safeguards' to prevent a potential reoccurence of AF 447?