[SystemSafety] [External] Re: "FAA chief '100% confident' of 737 MAX safety as flights to resume"
Peter Bernard Ladkin
ladkin at rvs.uni-bielefeld.de
Wed Nov 25 14:10:42 CET 2020
On 2020-11-25 00:22 , Tom Ferrell wrote:
> Glad you are amused, Peter.
Did you maybe misunderstand? I meant what I wrote.
> The safest thing to do with the max is to permanently ground this variant and not attempt to
> overcome the inherent aerodynamic instability in a certain flight regime.
I distinguished between aerodynamic instability, which is a tendency to diverge from a trimmed
unaccelerated flight attitude, and the particular kind of stability involved here, which is that in
a particular flight regime the stick forces stop rising (and maybe become lighter) as AoA becomes
higher. That is what "aerodynamic stability" means in Europe.
The FAA calls it "longitudinal stability", I believe.
Your views on how the engineering-safety culture at Boeing eroded seem to be held by many. I was
reading them ten years ago on PPRuNe, and I believe they also come out of the U. Puget Sound
studies, Greenberg, Grunberg, Moore, Sikora and then Grunberg, Moore, but I haven't read those.
> I was involved in looking for the byzantine type faults he mentions in the AIMS system.
I thought it was the control system, not AIMS, which exhibited Byzantine-type failures.
PBL
Prof. Peter Bernard Ladkin, Bielefeld, Germany
ClaireTheWhiteRabbit RIP
Tel+msg +49 (0)521 880 7319 www.rvs-bi.de
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