Originally Posted by
Machinbird
Sir. Thinking like that is cruising for a bruising.
With flight control problems, you should typically go for the center of the envelope and avoid the corners of the envelope, then explore cautiously.
Besides that, if they had managed to keep control much longer, their continued acceleration would likely have caused a structural failure! The aircraft has a Vmo limit for a reason.
What killed them was the loss of control authority that occurs in the 737 control system due to control surface forces exceeding the elevator actuator capability and loss of control movement due to cable stretch at very high control forces.
When you go really fast, that big HS can make bad stuff happen really fast before you have time to counteract with your dinky little elevator.
I agree they shouldn't have done that. I didn't say it wasn't a mistake. I was just saying it wasn't a mistake that is hard to explain. There are maneuvers that force you to get to the edge of the envelope to save the aircraft, like the terrain escape maneuver. So, out of everything they did, this is probably part that is the easiest to explain and excuse.
However I disagree with the statement that they kept accelerating. They accelerated for the first 2 minutes but, after getting close to VMO, their speed remained almost constant for about 3 minutes. The airspeed traces on the FDR chart were almost flat. They were not accelerating until MCAS activated again and brought the nose down.