The automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models—intended to help cockpit crews avoid mistakenly raising a plane’s nose dangerously high—under unusual conditions can push it down unexpectedly and so strongly that flight crews can’t pull it back up. Such a scenario, Boeing told airlines in a world-wide safety bulletin roughly a week after the accident, can result in a steep dive or crash—even if pilots are manually flying the jetliner and don’t expect flight-control computers to kick in.
Boeing doesnt design its FCCs with a psycho mode.Qantas 72 isnt possible in a Boeing.The poor travelling public probably think the FCC forced the Lionair into a dive.It didnt.It trimmed the aircraft nose down in response to faulty AoA....the report from the previous commander clearly says "STS trimming the wrong way".The pilots just have to recognize that they are facing unreliable data,disengage the automation,disengage the AP stab trim motor and fly the plane using basic attitude/thrust combinations.
Unfortunately,it appears that the accident crew became a bit saturated and just played tug of war with the opposing trim until time ran out.Startle factor/panic reduces cognitive faculties.The continuous stick shaker activation will contribute greatly to that startle factor.
The A320 has three AoA sensors.
That just meant, in the Perpignan crash, that the two frozen ones outvoted the working one ...
See how difficult it is to design perfection?