So if it is stable. Then it crashed because of pilot error?
(No retraining required. These pilots never crashed a non MCAS plane, and MCAS was actively moving the plane towards the ground). <--- How do you conclude this plane is stable?
That malfunction manifested as the plane pitching down consistently. No matter what the input of the stick, it'd point to the floor.
Now, if a big flashy light+warning buzzer had been sounding (like with a stall warning) then this would have never happened. But it didn't, and because the pilots were not trained for this specific feature (cause it had the same rating) They didn't know what to do.
Its nothing to do with stable. the MCAS silently pointed the plane at the floor regardless of user input.
“There’s a simple explanation. MCAS is not meant to control an unstable aircraft. It is meant to restrain the aircraft from entering the regime where it becomes unstable. This is the same strategy used by other mechanisms of stall prevention—intervening before the angle of attack reaches the critical point. However, if Brady is correct about the instability of the 737 MAX, the task is more urgent for MCAS. Instability implies a steep and slippery slope. MCAS is a guard rail that bounces you back onto the road when you’re about to drive over the cliff.”
Boeing’s argument (and I’m inclined to agree on this specific point) is that the existing stab trim runaway checklist was an appropriate and sufficient pilot response here.
Lion Air crew did it the day before to save the aircraft. The Ethiopian Air crew almost saved their aircraft by executing that checklist. They then turned the trim back on and for whatever reason only initially commanded nose up electric trim and then stopped, leaving the system powered.
Boeing has significant fault here, but I don’t agree that pilots were not trained to deal with a stab trim runaway (obviously). The crux is whether existing stab trim runaway training was sufficient for the MCAS equipped Max. Evidence suggests it was not.
I think the pilots were trained in what to do. Runaway stabilizer trim? Cutoff the stabilizer trim power, as you've been trained to do as one of the only 14 memory items on a 737.
They weren't trained specifically in what to do in the event of an MCAS failure, because the thinking at Boeing was that the presentation was one of stab trim runaway, something that is already trained for. I have a lot of sympathy for this point of view when looking forward from several years' ago. It turns out to have been proven wrong in the field.
(No retraining required. These pilots never crashed a non MCAS plane, and MCAS was actively moving the plane towards the ground). <--- How do you conclude this plane is stable?