Originally Posted by
JohnBurke
Nothing "pushed the planes noses' downward" and we know that MCAS moved the stab trim at the rate of only 1/3 unit per second, max 2.4 units, and could be stopped at any time with standard procedures, and that keeping speed in check eliminated controllability issues. What happened in each case was the crews failure to fly the airplane.
As the Boeing representative noted, the procedure didn't differ with or without MCAS, and the standard procedure for runaway or unwanted pitch trim should have been applied (and was applied in the case of Ethiopian). Again, the procedure worked, or would have, if only the crew had flown the aircraft instead of allowing it to accelerate to destruction.
The repeated erroneous application of nose down trim by the automated system - with automation disconnected - that is the problem.
Several have now flown the profile and have only successfully recovered by using the porpoise technique. This technique has been in the manual but has not been taught for decades. Training. Training. Training. MCAS implications with AOA failure were never considered properly. It didn’t auto trim once. In fact the first application was imperceptible. Humans were distracted be erroneous airspeed indications and alarms. MCAS snuck up on them and killed them. I’m sure had they turned the cut off switches back on - retrimmed then turned them off they would have been fine. There wasn’t time by the time they gave up on an impossible to move stab. Yes reducing power could have helped but speed at their attitude would have taken a long time to reduce to a level where the stab could be moved manually. A crew, expecting this exact failure and focusing only on it, expecting it, could only recover using the porpoise technique unloading the stab. If the airplane was an NG with the same AOA failure this would not have happened. MCAS killed them. Not inexperience.