[SystemSafety] "FAA chief '100% confident' of 737 MAX safety as flights to resume"

Peter Bernard Ladkin ladkin at causalis.com
Tue Dec 1 14:17:23 CET 2020

On 2020-12-01 13:54 , Olwen Morgan wrote:
> Question: If a 737 MAX is on climb-out and is at a speed and AoA at which the pitch-up tendency 
> starts to lift the aircraft's nose, what would happen, in the absence of any automatic controls 
> (including MCAS), if the pilot took his hands off the controls?
Oh, for goodness sake!

As far as I am aware, there is no "pitch-up tendency [which] starts to lift the aircraft's nose". 
(There could be one late in the manoeuvre; it has not been ruled out AFAIK. But nobody knowledgeable 
has been talking of one.)

I will substitute the phrase "raise the AoA" for "lift the aircraft's nose". One should please not 
confuse AoA and pitch angle. Travis did so in his IEEE Spectrum article, which is rather telling for 
someone who claims to be a private pilot, but there is no need to persist with it.

The phenomenon which MCAS is said to relieve is:
* in a particular flight regime (actually, in two, I think)
* if the pilot is putting in back stick to raise the AoA, heshe requires a certain stick force to do so
* as the AoA rises, that stick force remains the same or lessens. Regs say that is a no-no.

During this manoeuvre/these manoeuvres, if the pilot releases the stick, the aircraft will return 
towards its trimmed attitude (which means inter alia that AoA will decrease, since back stick was 
required to have/keep it high).


Prof. Peter Bernard Ladkin, Bielefeld, Germany
ClaireTheWhiteRabbit RIP
Tel+msg +49 (0)521 880 7319  www.rvs-bi.de

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