The article doesn't seem to know what it's talking about. MCAS is (temporarily) disabled by pilot use of the electric trim. There's no two steps down, one step up scenario at play here, where MCAS has greater authority over the stabiliser than the pilot. The only way MCAS puts the aircraft in an unrecoverable dive is if the pilot fails to trim out MCAS nose down inputs and then activates the stab trim cutout switches, leaving the pilot with manual trim only.
I agree the article is badly worded. The point is, do you believe anything that Boeing and the FAA tell you at this stage? More proof is needed to regain trust, rather than assertions and paper circuit diagrams. Since MCAS cannot be independently turned on or off, there is no way for a maintenance technician to test any of this, nor a pre-flight check on a specific aircraft.
Originally Posted by
Water pilot
So that is a selonoid on the column cutout override switch, right? What happens if it sticks ON, perhaps because someone installed the wrong one? (I have seen this.). Since MCAS is never engaged normally such a fault could lie in wait a long time. What woukd be the consequence, there is not much detail in that schematic.
More questions for each answer in this thread! Having a non-redundant column cutout switch solenoid would be another single point of failure. Presumably the fact that there are two control columns has something to do with it. Since MCAS is wired into both columns, then either one can be used to control the stabiliser trim in the event that the other fails.