Control system for controlling a shut-off valve of an aircraft, said shut-off valve being configured to open an initially closed bypass circuit, said bypass circuit being intended for supplying air to at least one engine of said aircraft without passing through at least one air filter provided on an air inlet, said control system comprising: • a manual control means for controlling said shut-off valve, it being possible for a pilot of said aircraft to manually actuate said manual control means in order to control opening of said bypass circuit, • a first measuring means performing a differential pressure measurement Δpt between a reference pressure and a pressure measured downstream of said at least one air filter in said air inlet, • a second measuring means for determining a value of the utilisation power P of said at least one engine, and • at least one computer configured to calculate a current value of a clogging level TC of said at least one air filter, said clogging level TC being a function of said differential pressure measurement Δpt, of a first predetermined limit Δpc and a second predetermined limit Δpd at said value of the utilisation power P of said at least one engine, said first limit Δpc being a predetermined lower limit equal to a differential pressure value for a clean air filter at said value of the utilisation power P of said at least one engine, said second limit Δpd being a predetermined upper limit equal to a differential pressure value for a dirty air filter at said value of the utilisation power P of said at least one engine, said first measuring means and said second measuring means each being connected to said at least one computer, • at least one comparator for comparing said current value of said clogging level TC with a first threshold value TC 1 and with a second threshold value TC 2, said second threshold value TC 2 being greater than said first threshold value TC 1, and • at least one alerter (12, 22) for generating a first sensory signal which is generated when said current value of said clogging level TC reaches said first threshold value TC 1 and a second sensory signal which is generated when said current value of said clogging level TC reaches said second threshold value TC 2, said first sensory signal being different from said second sensory signal. • a manual control means for controlling said shut-off valve, it being possible for a pilot of said aircraft to manually actuate said manual control means in order to control opening of said bypass circuit, • a first measuring means performing a differential pressure measurement Δpt between a reference pressure and a pressure measured downstream of said at least one air filter in said air inlet, • a second measuring means for determining a value of the utilisation power P of said at least one engine, and • at least one computer configured to calculate a current value of a clogging level TC of said at least one air filter, said clogging level TC being a function of said differential pressure measurement Δpt, of a first predetermined limit Δpc and a second predetermined limit Δpd at said value of the utilisation power P of said at least one engine, said first limit Δpc being a predetermined lower limit equal to a differential pressure value for a clean air filter at said value of the utilisation power P of said at least one engine, said second limit Δpd being a predetermined upper limit equal to a differential pressure value for a dirty air filter at said value of the utilisation power P of said at least one engine, said first measuring means and said second measuring means each being connected to said at least one computer, • at least one comparator for comparing said current value of said clogging level TC with a first threshold value TC 1 and with a second threshold value TC 2, said second threshold value TC 2 being greater than said first threshold value TC 1, and • at least one alerter (12, 22) for generating a first sensory signal which is generated when said current value of said clogging level TC reaches said first threshold value TC 1 and a second sensory signal which is generated when said current value of said clogging level TC reaches said second threshold value TC 2, said first sensory signal being different from said second sensory signal.