Abstract: The apparatus operates to prevent the rolling of an aircraft having an even number of propulsion units when one of the propulsion units stops operating due to a breakdown. Spoilers are mounted on the outboard wings. Each spoiler has an individual drive connected to a power circuit via a control valve which, in turn, is functionally associated with a failure detector of the propulsion unit disposed on the outboard wing opposite to that on which the respective spoiler is mounted. The apparatus is provided with an apparatus that is brought into action automatically, so as to counteract the rolling tendency of an aircraft when one of its propulsion units fails, or with a manual control for correcting the glidepath during landing, dissipating the lift and applying the aerodynamic braking during the landing roll.