That may not be the whole story. MCAS -engages- when the autopilot is disengaged. That is one of the parameters when it automatically kicks in. So a pilot with an issue switches off autopilot, and MCAS kicks in and wants to start dropping the nose. The pilot is then fighting MCAS...which Boeing never revealed the existence of to operators. So insanely, the pilot can be fighting a system he did not even know was there.
Boeing screwed the pooch on this fiasco.
Thanks.
My understanding is that a bad sensor will affect the autopilot the same as MCAS.
http://www.b737.org.uk/mcas.htm
In the case of the Lion Air crash, the government agency investigating said the aircraft was not fixed after previous problems and shouldn’t have been put into service. On a previous flight of the same aircraft, the crew had the same problems as the accident flight, but responded correctly and disabled the automatic trim.
Here was Boeing’s response after the Lion Air crash:
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“As our customers and their passengers continue to fly the 737 Max to hundreds of destinations around the world every day, they have our assurance that the 737 Max is as safe as any airplane that has ever flown in the skies.”
Boeing said that “the appropriate procedure to address unintended horizontal stabiliser movement” was contained in the relevant flight manuals.
It said that the preliminary report showed that the correct procedures to counter the plane’s nose being pushed down were carried out during the Denpasar flight the day before the crash.
However, it was not clear if they procedures were followed during the 29 October flight that crashed, Boeing added.
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I think when all is said and done, Boeing’s liability is going to be minimal. They could make the system more fault tolerant, and my understanding is that those are the changes being made now. But any competent pilot should have known how to handle any runaway stabilizer problems caused by a bad sensor. No pilot has an excuse for not knowing about MCAS and or how to recover from the same conditions that caused the Lion Air crash. There was an airworthiness directive. The major portion of the blame is going to be on the airlines and their incompetent pilots.