There's already two AoA vanes mandatory on every plane (even non-MAX planes). There is a warning if they disagree in the optional package that the North America

There's already two AoA vanes mandatory on every plane (even non-MAX planes). There is a warning if they disagree in the optional package that the North American airlines bought, but not any other airlines. The warning is not much of a warning, just a disagree light. It would have been impossible for the Lion Air pilots to benefit from this disagree light, because they didn't know that it was hooked up to a control surface and neither did any other pilots, it seems. > The planes seem eminently airworthy An uncontrolled nosedive caused by a single sensor failure is not in anyone's definition of airworthy. It must be fixed. This lack of airworthiness was not the pilots' fault.