Originally Posted by
Takwis
Well, they both "blipped" it, and we still don't know why...was it functional? Was it jammed? Or had they forgotten how to trim, as so many have opined?
If you are referring to the Ethiopian flight, there are plenty of examples from the FDR output that shows a pilot trim input followed by stab movement - there just weren’t enough pilot inputs to counter the MCAS inputs. There are too interesting “blips” at the end. However, by this time the aircraft had exceeded Vmo and there is no guarantee that anything is going to work as it is supposed to once outside the certified envelope.
I think it is much more informative to look at both Lion Air flights. On the first flight, both pilots (there was a transfer of aircraft control) successfully countered the MCAS input with the yoke trim switch until they turned off the stab cutout switches. On the second Lion Air flight (the accident aircraft), the Captain flew for something like 7-8 minutes and maintained aircraft control. At some point he transferred control to the First Officer, and I would suggest that this is the “inflection point” we see in the FDR output where the pilot inputs no longer keep up with the MCAS input. The Captain was likely heads down in the QRH at this point and didn’t realize his First Officer was losing the battle with MCAS.
As I pointed out previously, the evidence strongly indicates that 3 of the 5 aviators who acted as the flying pilot with a malfunctioning MCAS were actually able to keep the plane flying. Unfortunately, two of them were not. Given more time to work the problem, I think it is reasonable to ask whether either of the accident crews would have eventually gotten to the same solution as the first Lion Air crew.