souffle descendant engendré par les rotors

OBS: «la rotation de la voilure sustentatrice engendre en effet un puissant souffle d'air dirigé de haut en bas...» (Le Siècle de l'avion, p. 355)

CONT: Helicopter Blow Off Method - One municipality hired a helicopter to blow the snow off their roof. This might work well with the light, powdery type of snow that would blow off easily. What happens though if the roof is loaded to its limit with snow and then a helicopter hovers overhead. Could the down blast cause a collapse? It's possible.