Originally Posted by
gums
Salute!
Before back to the seafood gumbo on the stove......
My examination of the FAR requirements do not reference stall prevention, just a requirement to have increased back stick force or actual elevator force as AoA increases. They could have done the trim kludge at a much lower AoA.
Somehow, I cannot find "intent" on the applicable requirement sections. But on a personal level, I would always like for the plane to be harder to increase AoA the closer I got to the stall AoA. Maybe it's just me.
If you want to "prevent" a stall it is not easy for the engineers working with a 60 year old plane that has many changes in aerodynamic configuration and avionics. A FBW inmplementation that had AoA as a prime input might have made it thru the FAR process, but I doubt it. Even the 'bus had good longitudinal stability and such that the FBW laws could use. That was not the case with the Max. The thing did not meet the requirements and Boeing had to use the stab trim in a way most of us would not have anticipated.
Gums...
What is also puzzling is why, having used something as powerful as stab trim to increase the stick force, they had to go from an initial expectation of a much smaller 0.6 degrees max movement to a significanlty larger 2.5 degrees.