Originally Posted by
ecto1
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Those are the official excuses. I don't buy them. It was honestly a very reasonable system when safety was important but not as important as today, data buses did not exist and pilots came from the military.
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They're not "official excuses". The dual redundant system has been thoroughly analysed and its consequences known and calculated to a nicety.
What you're proposing is a hybrid system (disabling an input to a good system in case of a single failure on the other system) which will have its own consequences.
There is a solution, as has been implemented in FBW aircraft - if you are going to patch FBW onto a dinosaur, then its sensor suite must also be upgraded to meet those requirements and not rely on more patching to a grandfathered certification.