[Animats]

Using only one sensor at a time, there's no "sensors disagree" fault to tell the pilot there's a problem. Or to tell the flight control system it shouldn't be taking drastic action based on that sensor.

Airbus uses three angle of attack sensors and compares them. They've had at least one crash when two sensors failed in a consistent way.[1] The vulnerability of aircraft flight control systems to bad AOA data is well known.

[1] https://news.aviation-safety.net/2010/09/17/report-blocked-a...

[kirykl]

There wasn't a "sensors disagree" alert in the Lion Air plane because they didn't have installed the optional AOA Disagree indicator.

As comparison, Southwest had the indicator but has now also installed an enhanced AOA Disagree indicator as a result of the Lion incident

https://theaircurrent.com/aviation-safety/southwest-airlines...

[Animats]

That's not a feature which should be a extra cost option.