Method and system for monitoring a turbojet

The invention relates to a method and a turbojet engine monitoring system. The method includes acquiring (E10) a signal representative of a level of vibration of a rotor during operation of the turbojet, acquiring (E20) a rotational speed of the rotor in operation, comparing (E40) the amplitude of the signal to at least a predetermined vibration threshold as a function of the rotor rotation speed, and if the threshold is exceeded by a peak amplitude, analyzing (E50) the signal over a time window defined around the amplitude peak to determine (E60 ) if the phenomenon giving rise to the amplitude peak is a mechanical shock to the rotor of the turbojet engine or electronic disturbance signal.