Abstract: A method for monitoring a degradation in an on-board device of an aircraft, comprising a step of comparing an abnormality score obtained for a given flight of said aircraft with a decision threshold (S) and a step of transmitting an alert in the event of said decision threshold (S) being exceeded, said decision threshold (S) being automatically determined for a given probability of alert Pa, corresponding to the probability of an alert being transmitted during the monitoring method when said on-board device is healthy, by means of a plurality of steps, including a step of reading the antecedent of the continuous adjusted division function for the value 1?Peac, said antecedent corresponding to said decision threshold (S), with Peac being the elementary probability of exceeding the threshold for confirmation per k exceedances of threshold during n consecutive flights and being a function of the probability of alert Pa.

Abstract: A method for monitoring a degradation in an on-board device of an aircraft, comprising a step of comparing an abnormality score obtained for a given flight of said aircraft with a decision threshold (S) and a step of transmitting an alert in the event of said decision threshold (S) being exceeded, said decision threshold (S) being automatically determined for a given probability of alert Pa, corresponding to the probability of an alert being transmitted during the monitoring method when said on-board device is healthy, by means of a plurality of steps, including a step of reading the antecedent of the continuous adjusted division function for the value 1?Peac, said antecedent corresponding to said decision threshold (S), with Peac being the elementary probability of exceeding the threshold for confirmation per k exceedances of threshold during n consecutive flights and being a function of the probability of alert Pa.