When I did my quick translation, I had quite frankly no idea what "gauchissement" meant; I don't recall having ever in my life heard this term.
Having now checked a
dictionary, I see that one of the definitions given is "Manœuvre des ailerons placés au bord de fuite d'une aile d'avion"; that is "maneuvering the ailerons". Which does not make things much clearer.