The present invention concerns a method for switching, by a local processing unit (1,2) of a flight control system of an aircraft, configured to control at least one local actuator, connected to at least one local sensor and connected via at least one link (3,4) to an opposite processing unit (2,1) configured to control at least one opposite actuator and be connected to at least one opposite sensor, said local processing unit (1,2) being further configured to be connected to backup communication means (13,14) enabling data exchanges between the local processing unit (1,2) and the opposite processing unit (2,1) in the case of failures of the links connecting same (3,4), said backup communication means comprising an array of sensors or actuators (13) and/or a secure onboard network for the avionics (14), comprising steps of: •—sending, to the opposite processing unit (2,1), acquisition data relative to the at least one local sensor and actuator data relative to the at least one local actuator, •—receiving, from the opposite processing unit (2,1), acquisition data relative to the at least one opposite sensor and actuator data relative to the at least one opposite actuator, •—receiving an item of opposite health data and determining an item of local health data, •—switching said local processing unit (1,2) from a first state to a second state chosen from an active state (15), a passive state (16) and a slave state (18), depending on the opposite health data received and the local health data determined.