Originally Posted by
MechEngr
This is nearly identical to the solution that the Speed Trim System (STS) provides with no notable problems. The first crew to encounter the adverse behavior commented that they thought STS was running backwards. Notable is that MCAS operated exactly as it was specified to operate - the ADIRU did not. To my way of thinking MCAS exposed a number of really bad decisions that should have been corrected decades earlier, including suppliers who were able to supply mis-calibrated AoA sensors due to a single switch on a multifunction test box (crash 1.)
Yup, the operation was a success, but the patient died. There was little in the whole sorry mess that didn't result in rolling of the eyes in shock. It waas not pretty, yet it was was result of the system that the industry has developed into. Placing band-aids on band-aids gets untidy. Being dismissive of QA systems reviews has consequences that can bite.