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Old 1st May 2019, 20:04
  #4699 (permalink)  
WillFlyForCheese
 
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Originally Posted by Lost in Saigon
I think your interpretation is wrong.

My understanding is that MCAS was implemented ONLY to satisfy FAA Section 25.173

* * *

"MCAS is a longitudinal stability enhancement. It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and give a steady increase in stick force as the stall is approached as required by regulation."
I've been thinking about this - and don't believe it can be an accurate statement of the purposeful design of the system. Here's why . . .

MCAS will, when data input dictates, trim AND. It will do so for 9 seconds or so - and then take a 5 second break. When it's taking its break - it's not fulfilling the purpose of 25.173 - right?

If the purpose of the system is to compensate for stick feel - it wouldn't take a break - because the lift generated by the cowlings doesn't take a break.

If tdracer is still around on this topic - I'd like to know how the designed 5-second stand down plays into the purposeful design of the system. It just doesn't make sense to me.

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