Two-way architecture

A switching method applied by a first processing unit, called local processing unit, of a flight control system of an aircraft comprising at least one engine,

• said local processing unit being configured for controlling at least one actuator, called local actuator, so as to control the engine of the aircraft, and being able to be connected to at least one local sensor and to be connected via at least one link to a second processing unit, called opposite processing unit, configured for controlling at least one opposite actuator and being connected to at least one opposite sensor, said local processing unit being further configured so as to be connected to emergency communication means giving the possibility of ensuring exchanges of data between the local processing unit and the opposite processing unit in the case of failures of said at least one link connecting them, said emergency communication means comprising at least one of a network of sensors, a network of actuators and an onboard secure network for avionics,
• said method comprising steps of:
• sending to the opposite processing unit 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 acquisition data relative to the at least one opposite sensor and actuator data relative to the at least one opposite actuator,
• receiving a health datum relative to the health condition of the opposite processing unit, called opposite health datum,
• determining a health datum relative to the health of said local processing unit, called local health datum,
• switching of said local processing unit from a first state to a second state, depending on said received opposite health datum and on said determined local health datum,
• said steps of sending, receiving acquisition data and of receiving a health datum being applied via said at least one link or said emergency communication means, and said states being from among an active state in which the local processing unit ensures control of the engine of the aircraft, a passive state in which the local processing unit does not ensure the control of the engine of the aircraft and a slave state in which the local processing unit gives over to the opposite processing unit the control of said local actuators for controlling the engine of the aircraft,
• wherein the switching step comprises:
• determining, from the local health datum, a state datum relative to the state of said local processing unit and from a health status datum of the local processing unit relative to the capability of the local processing unit of ensuring control of the engine, and
• switching said local processing unit into the slave state:
• when the state datum indicates that the local processing unit is in a passive state and,
• when the health status datum indicates a status in which:
• the local processing unit is capable of communicating with the opposite processing unit,
• the local processing unit is incapable of ensuring the control of the engine,
• and the local processing unit is capable of controlling the local actuators.