A system and method for controlling an aircraft turbine engine. The control system includes: a nominal-mode processing chain including a global corrector designed to control a speed of rotation of the turbine engine by delivering a position setpoint for a fuel metering device, and a local corrector designed to control a position of the fuel metering device by delivering a nominal-mode control current, a degraded-mode processing chain including a direct corrector designed to control the speed of rotation of the turbine engine by delivering a degraded-mode control current, and a mode management module designed to deliver, to the fuel metering device, the nominal-mode control current in the absence of failure of a position sensor measuring a position of the fuel metering device, and the degraded-mode control current in the case of failure of the position sensor.