A method and system of detection of rotor damage to an aircraft engine

The invention relates to detecting damage to the rotor of an aircraft engine including means for measuring vibration and rotor speed for a determined flight and comprising the following steps: - acquisition (10) of data relative to the rotor speed as well as the amplitude and the phase of rotor vibrations from said measurement means, - calculation (20, 30, 40) of a mean vibration vector over a rotor speed range determined from said acquired data, - calculating (61) a vector difference between the mean vibration vector of said determined flight and the mean vibration vector of a reference flight for a given rotor speed range, - comparing (90) modulus of said vector difference with a predetermined threshold value, and- emitting a warning signal when the modulus of said vector difference exceeds a predetermined threshold value.