Method for monitoring a starting sequence of a turbomachine and monitoring system implementing said method

A method for monitoring a starting sequence of a turbomachine comprising a compressor provided with a rotor, a starter capable of rotating the rotor and a combustion chamber wherein a mixture of air and fuel is ignited by an ignition device, the method comprising:

• acquiring a measurement signal of an engine speed of the rotor during the starting sequence:
• determining a bracketing of a time zone during which an ignition instant takes place, the bracketing being defined by a lower limit corresponding to an event necessarily taking place before the ignition instant and an upper limit corresponding to an event necessarily taking place after the ignition instant;
• and
• determining between the lower limit and the upper limit, a break point in a variation with time of the measurement signal, said break point corresponding to an ignition instant of the air-fuel mixture in the combustion chamber.