Originally Posted by
phil gollin
[...] a single (?) AOA sensor failure [...] SEEMS to have activated the stick shaker
[...] there were two AOA sensors on the plane, so how did the FCS decide which one was at fault ?
[...] a failed AOA sensor causing one-sided stick-shaker operation seems optimistic.
This misconception has been floating around for long. The stick shaker is not an annunciation of a sensor failure.
It is the normal approach-to-stall warning triggered by a high AoA value. It does not know that that high AoA value is wrong, but for stall warning it is better to be safe than sorry, so the two stick shakers apparently are independent, and each each rely on the AoA probe on their respective side of the aircraft. Which makes perfect sense from a redundancy and failsale-design standpoint. If two AoA sensors disagree, don't try to be smart and figure out which might be wrong. Just activate a stick shaker on a high value. In most cases it is preferable to have a spurious stall warning when there is no stall, than not to have a stall warning on a real approach to stall.
TL;DR: A "failed sensor" did not activate the stick shaker. A high AoA value did.
Bernd