Yep. At this point in time they should have plenty of test cases and regression tests which should catch such situations. While Boeing may feel they are doing a

Yep. At this point in time they should have plenty of test cases and regression tests which should catch such situations. While Boeing may feel they are doing a lot of testing in the simulator - there are way fewer simulators staffed with test pilots than there are 737 MAX out there. When such errors surface at this time in manual testing it calls into question the development process. And a lot of the trust - aka. certification - is based on that process. As I have mentioned here before: The angle of attack sensor was never intended for the purpose it is now used for - military aircraft may do such things but not as an afterthought and not connected with a control surface which has a lot of delay (trim wheel winding. Delay is a major factor in destabilizing control loops). Equivalent sensors are the airspeed pitot tubes but they are a much more robust concept. Even they have brought down airplanes. We lack sufficient real world (heat, humidity, snow) information about the quality of the sensor data even before it may get distorted by transmission and processing on its way to the control law. Cleaning and validating sensor data is tricky under the best of circumstances. It does not sound like they have a handle on it. Hi Boeing, what real world data from mounted angle of attack sensors have you analyzed? Why do you believe this data sufficiently represents climate zones and flight conditions (take-off, landing, turbulence, malfunction modes)? How do you clean and validate the sensor data? Please explain, because otherwise I won't step into one of these machines.