Originally Posted by
GordonR_Cape
airman1900
I'm not sure if the article is poorly written, but that sentence sounds exactly like the bad old MCAS to me (a computer programmer). If a faulty AOA sensor keeps returning +20 degrees, what stops MCAS from repeatedly triggering? What if two stalls follow in close sequence, is each a separate event? More questions than answers about those specific details, including the AOA sensor validation algorithm.
Hopefully Boeing will make the details of the MCAS modification clearer soon. MCAS in its original implementation would run again in the presence of AOA failed high following any amount of pilot pitch trim command. One can envision a modification to require that the pilot have run the trim back nose up at least a certain amount before allowing MCAS to go again. Or how about requiring that AOA drop low after having been high before allowing MCAS to go again. There are lots of things that could be done to provide additional interlocks. I am certain that we will learn that simply blipping trim with the revised logic will not trigger MCAS to reset to the point of running in another full increment of airplane nose down stabilizer motion.