Originally Posted by
mattler
And just because you want to believe otherwise, doesn't make it so. That line goes both ways....
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The thing is, the word "stability" has a very particular meaning when it comes to aviation. It is a definition that anyone can look up and see if the data supports one's position. Part of the problem is that some posters like to use the word "unstable." That in itself is not correct usage. There are two types of stability - static and dynamic. Within these category, there are further qualifications of positive, neutral, and negative. When someone says the 737 is "unstable," then that implies that it demonstrates negative static or dynamic stability. There is no evidence in the record that supports this position.
That being said, "positive" stability is not a fixed value. An aircraft can demonstrate more or less positive stability according to how quickly it returns to its initial state after a perturbation. The Part 25 of the FAR's specify the minimum required stability performance for transport aircraft. The lightening of the control forces in the pitch axis at high AOA is an indication that the
degree of positive static stability decreases, but that doesn't mean it goes negative. MCAS does increase the positive stability characteristics of the 737, but that is a very different thing from saying that the aircraft is "unstable" without it.