Alchad,
Ethiopian airliner down in Africa
No ‘wow’ response because an AOA Disagree alert has little value for pilots. There is no third system to resolve the ambiguity - which AoA is correct - not known; what can I do about it - nothing, info only (or distraction). Furthermore an alert could contribute to misdiagnosis in the UAS drill; stick shake + EFIS low speed awareness on the ‘left side’, this might incorrectly bias thoughts to the left, - speed correct - aircraft is slow.
Whereas the Air Data Disagree alerts for Speed / ALT each have a third, standby instrument which the crew can use to arbitrate and choose the most valid pairing; standby + right side = right Speed is best.
So without means of arbitration the AoA alert has little value.
From an engineering view, particularly with hindsight, AoA Disagree could have been used in the original MCAS design. It wasn’t because that design assumed that the effects in the accident would not occur - all of which were incorrect.
Limiting these problems using AoA Disagree provides an engineering solution. However for the crew, retaining the AoA alert would not clarify the accuracy of AoA - so don’t display the alert nor the optional gauge when there is disagreement.
The most important absence is the annunciation that MCAS is inoperative, which with a caution that flight in some (few) areas of the fight envelope requiring careful handing.