Smythe, # 234
MCAS in normal operation worked exactly as designed; the system and design description appeared to meet the certification requirements. The AoA ‘failure’ was either not considered in the design, or judged insignificant in the failure effects analysis, thus it might never have been tested, ground or air. Theory and practice may have disagreed, but how can we tell.
0.6 to 2.5 appears to be a simple error; this might have been one of the self certification items without specific ground rig measurements, only software validation.
You appear to overlook that flight tests are not ‘stick free’, so the aircraft will not pitch unless the pilot fails to resist the change of stick force - change in force was the primary objective in the particular conditions. So during flight testing the difference in trim rate over time, opposed to absolute tail angle, would be perceived as a difference in stick force, except there was no lower value for comparison. The pilot would feel a change in force, and that the change (larger than necessary), meet the certification stability requirements which was the objective of MCAS.
MCAS involves stability (stick force); whereas approach to the stall 1.1 Vs is alerted with stick shake - not to be confused with the AoA failure in the accidents which generated a false stick-shake, and the stability certification requirements above 1.1 Vs, similarly comments re stalling Vs; (aircraft don’t think).
EASA generally validates FAA certifications - bilateral agreement, but can intervene at any level including flight tests; e.g NG question about trim.
Re AoA Disagree; see Boeing statement
https://boeing.mediaroom.com/news-re...ts?item=130431.
The alert alone is meaningless, has no value in determining failure or action, and even without any drill would only be relevant to the optional installation of the AoA indicators (not fitted).