Daryo Mar 23, 2021:

Yes, that kind of "feathering" does have s.t. to do with aviation, although it would be relevant ONLY for airplanes propulsed by "variable pitch propellers" (more likely to be big heavy airplanes, BTW), but it's still NOT what "feathering off everything" would be about in this text.

airmailrpl Mar 22, 2021:

from the asker's context "talking to a pilot of small charter flight"

Daryo Mar 22, 2021:

This text is not about that kind of "feathering".
Makes no sense for several reasons, one being that not all airplanes have propellers, and not all propellers have a system of variable angle of attack for propeller blades.
And even when there is such system of varibale blade angle, that's far from being the one and only parameter to keep an eye on.
Or simple text analysis: the term is "feathering OFF"

airmailrpl Mar 22, 2021:

Feather b(1) : to change the angle of (airplane propeller blades) so that the chords become approximately parallel to the line of flight also : to change the angle of airplane propeller blades of (an engine) in such a manner. (2) : to change the angle of (a rotor blade of a rotorcraft) periodically in forward flight.

Feather | Definition of Feather by Merriam-Webster


Feathering Propellers in Airline Transport Operation - JSTOR
www.jstor.org › stable
by MG Beard · 1939 · Cited by 1 — explain. First, by 'stopping the rotation of an engine and propeller in flight, it protects the air- ... the blade to "feather" or, in other words, rotate to an angle of.