Did the problem the previous day occur at the same stage of flight?
If I remember correctly maintenance took place and some changes were made between the flights?
moderating:
If you think another poster is making racist comments, take it to the pit, and substantiate it. This sort of drive-by post is completely inappropriate in this forum.
(bumping up to the mod loop for further discussion.)
Sorry, that was probably a bit over the top.
There are 3 possibilities. the mechanics made it better, no change, or worse.
Assuming you’re not a pilot you can still visualize what is happening without knowing a lot of technical information. When the plane takes off the pilots will set the auto pilot for a specific climb out. it would probably be something like a climb of 1800 feet per minute. They sit back and watch the gauges to see that the plane is doing what it’s programmed to do.
During this time the computer is operating the trim wheel back and forth to keep the climb within parameters. Enter MCAS. the pilots see and hear the trim wheel spinning like a circular saw and the nose starts dropping. It’s not a subtle event. there’s no question the trim system is the cause. It’s something that would have scared the pilots.
If it’s intermittent and they can keep the nose up then they go through diagnostic procedures. If the nose drops below the horizon then the clock is ticking. The closer they are to the ground the sooner they need to stop the decent. Diagnosing the problem is no long relevant because there is already a solution. Turn the system off before it trims the plane beyond the ability to manually recover.
Had Boeing properly included MCAS in their training manual the pilots would have known that the trim switch on the yoke interrupts it for short periods of time. It would have allowed them to recover from a trim setting that could not be controlled manually.
Without this information the intermittent issue is confusing. The result is a diagnostic process that obfuscates the need to stop the trim system before it gets out of hand.