The Lion Air incident, and possibly the Ethiopian Airlines incident, is looking like the primary cause might be linked to a single point of failure (an AOA vane) causing the activation of the previously undisclosed MCAS system while at the same time presenting the pilots with a host of distracting and confusing indications.

-The stick shakers would be activated without the ability to silence them for the duration of the flight (unless the CB’s were pulled).

-Possible invalid airspeed indications (not sure how a bad AOA vane is processed and then displayed to the pilot’s by the air data computer).

-Probably the red and yellow stall bars are biased up, contributing to the pilots (along with the stick shaker) thinking they’re in a stall.

-Nose down trim is being applied by MCAS while all of this is going on. Imo, there’s a good chance this wouldn’t even be recognized at first since the pilot’s brains are probably on fire trying to figure out wtf is going on with stick shakers and airspeed indications. They might think the increasing nose-down weight of the yoke has something to do with being in an actual stall.

-It would be a lot to process. We also don’t know for sure right now that there might not be some other indications or failure modes that contributed to one or both accidents. Lion Air has not issued a final report and Ethiopian Is only at the very initial stages of determining what happened. To me, it makes sense to ground right now. Two brand new airplanes crashing within less than five months of each other is likely not a coincidence (especially when there are only approx 300 MAX’s currently delivered).