Method for monitoring a degradation of an on-board device of an aircraft with automatic determination of a decision threshold

• Main Authors: BOULET XAVIER, HMAD OUADIE, MASSE JEAN-REMI ANDRE, BEAUSEROY PIERRE JEAN EMILE, GRALL-MAES EDITH
• Format: Patent
• Language: English
• Published: 24.05.2016
• Subjects: AIRCRAFT; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSIONTRANSMISSIONS IN AIRCRAFT; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDEDFOR ELSEWHERE; AVIATION; CALCULATING; CHECKING-DEVICES; COMPUTING; CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; COSMONAUTICS; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; GENERATING RANDOM NUMBERS; MEASURING; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PARACHUTES; PERFORMING OPERATIONS; PHYSICS; REGISTERING OR INDICATING THE WORKING OF MACHINES; REGULATING; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR; TIME OR ATTENDANCE REGISTERS; TRANSPORTING; VOTING OR LOTTERY APPARATUS

A method for monitoring degradation of an on-board device of an aircraft includes comparing an abnormality score obtained for a given aircraft flight to a decision threshold and emitting an alarm when the decision threshold is exceeded. The decision threshold is determined automatically for a given alarm probability Pa, corresponding to probability of an alarm being emitted during the monitoring when the on-board device is undamaged, by: calculating plural abnormality scores for plural flights of the aircraft without degradation to obtain a probability density distribution of the abnormality score, the distribution being specific to a physical nature of the on-board device; adjusting the distribution using a non-parametric estimator of the probability density to obtain a continuous adjusted distribution function; calculating a continuous adjusted allocation function from the continuous adjusted distribution function; and reading precedent of the continuous adjusted allocation function for value 1-Pa, the precedent corresponding to the decision threshold.