【单选题】The primary flight control system uses conventional control wheel, column and pedals to _____ the primary flight control surfaces, ailerons, elevators and rudder.
【单选题】The primary flight control system uses conventional control wheel, column and pedals to command the primary flight control surfaces, ailerons, _______ and rudder.
【单选题】The primary flight control system uses __________ control wheel, column and pedals linked mechanically to hydraulic power control units which command the primary flight control surfaces.