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Old 10th Apr 2019, 01:04
  #3787 (permalink)  
Join Date: Dec 2014
Location: Schiphol
Posts: 332
9th Apr 2019, 23:38 #3831 (permalink) Loose rivets

airman1900 #3824 Taken from Mike Sinnett's publication:

Underscoring the difference between the speed-trim system on the 737 Next Generation (NG) and the MAX, Sinnett says: “Mechanically, on the NG there is a column cutoff switch that stops any automatic trim when the column is back to a certain spot. On the MAX, we still needed automatic trim when you got to that spot."
@LooseRivets - The bee in my bonnet about that rear column cut-off switch having been removed on the MAX, is it seems, still open to interpretation. The inference is there, but not the statement.
The article also states:

On the MAX, we still needed automatic trim when you got to that spot. MCAS differs from speed trim at elevated alpha because it bypasses that switch by design.
Bypassing could also mean the switch is still there for use by other systems. So no removal?

Next to that you would like to know things like if we are talking column or columns. How many switches are there. Are they NG or MAX only. Etcetera, etc… Is there an official Boeing press release with this information? … stilll many questions…

So, Mr Sinnett’s statements add something but are not clear enough and not deep enough. Many would welcome more.

I posted earlier in the thread that my impression was that only a detailed public presentation and publication by the ‘chief engineer (with FAA delegated certification signature authority)’ of the MAX would do. I wonder if Mr Sinnett fits that bill? The text has a ‘nice and sunny taste’, rather more commercial than tech savvy …
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