I thought that the flight immediately before this one had MCAS trouble too. Were both sensors busted, or was that actually an even number of cycles previous to the crash, and only the previous day?
The plane went through a maintenance cycle in-between the flights; it was suggested that the maintenance caused the chosen AoA sensor to flip twice.
I'm not sure of the exact mechanics of this, but it's conceivable the maintenance crew performed a full engine or board computer boot cycle. Therefore, when the pilots started on their flight, it was the second warm-up since the previous flight, hence the same sensor was selected.
There was an extra pilot in the cockpit uninvolved with flying the plane.
His participation in Crew Resource Management allowed the previous flight to correctly identify and remediate the issue before things became unrecoverable.
