A method for synchronising there between engines of an airplane, using at least one activation logic per engine, the activation being intended to check the safety and/or activation conditions in order to apply the synchronisation, with each activation logic (10, 10') defining and switching between at least a deactivated state, an armed state, and an activated state, with the method comprising, per engine: - the switching of the activation logic from the deactivated state to the armed state when an activation order is given by the pilot of the airplane; - the periodical checking of the safety and/or activation conditions relative to said states, in order to define whether said conditions are met or not met, - the switching (40, 41, 42) of the activation logic from the armed state to the activated state when some of the safety and/or activation conditions are met; and - the switching (24, 34) of the activation logic from the activated state or the armed state to the deactivated state when a deactivation order is given by the pilot or when some of said safety conditions are not met, characterized in that: - the switching (40, 41, 42) of the activation logic from the armed state to the activated state is carried out via a first and then a second successive intermediate state (38, 39) of the activation logic, - for every switching of the activation logic from the second intermediate state to the activated state, an exchange of said data between the engines is carried out by an exchange digital link, so that: -- the switching of the activation logic of one of the engines to the activated state requires that the safety and activation conditions applied to the other engine(s) are all met, -- and, if the activation logic of one of the engines switches to the deactivated state, the activation logic of the other engine(s) does so as well, automatically, and - for each engine, the switching (41, 42) of the activation logic from the armed state to the first and then to the second intermediate state takes place automatically when a first part and then a second part, different from the first one, of the safety and/or activation conditions are met. - the switching of the activation logic from the deactivated state to the armed state when an activation order is given by the pilot of the airplane; - the periodical checking of the safety and/or activation conditions relative to said states, in order to define whether said conditions are met or not met, - the switching (40, 41, 42) of the activation logic from the armed state to the activated state when some of the safety and/or activation conditions are met; and - the switching (24, 34) of the activation logic from the activated state or the armed state to the deactivated state when a deactivation order is given by the pilot or when some of said safety conditions are not met, - the switching (40, 41, 42) of the activation logic from the armed state to the activated state is carried out via a first and then a second successive intermediate state (38, 39) of the activation logic, - for every switching of the activation logic from the second intermediate state to the activated state, an exchange of said data between the engines is carried out by an exchange digital link, so that: -- the switching of the activation logic of one of the engines to the activated state requires that the safety and activation conditions applied to the other engine(s) are all met, -- and, if the activation logic of one of the engines switches to the deactivated state, the activation logic of the other engine(s) does so as well, automatically, and -- the switching of the activation logic of one of the engines to the activated state requires that the safety and activation conditions applied to the other engine(s) are all met, -- and, if the activation logic of one of the engines switches to the deactivated state, the activation logic of the other engine(s) does so as well, automatically, and - for each engine, the switching (41, 42) of the activation logic from the armed state to the first and then to the second intermediate state takes place automatically when a first part and then a second part, different from the first one, of the safety and/or activation conditions are met.