Originally Posted by
lomapaseo
these are called lessons learned and belong to all the aircraft manufacturers.
I'm quite sure that if they were obvious, that the likes of Airbus etal. would have pointed them out to the regulators
This is the stuff that calls for "Special Condition" in the certification basis and unfortunately like all other parts of our risks in life is sometimes learned the hard way
Interesting read from The Seattle Times article.
Quote
The original Boeing document provided to the FAA included a description specifying a limit to how much the system could move the horizontal tail — a limit of 0.6 degrees, out of a physical maximum of just less than 5 degrees of nose-down movement. That limit was later increased after flight tests showed that a more powerful movement of the tail was required to avert a high-speed stall, when the plane is in danger of losing lift and spiraling down.The behavior of a plane in a high angle-of-attack stall is difficult to model in advance purely by analysis and so, as test pilots work through stall-recovery routines during flight tests on a new airplane, it’s not uncommon to tweak the control software to refine the jet’s performance.