Patent ID: 6845468

Claim:
An aircraft fault monitoring system comprising: a fault detection mechanism for providing a fault status indication of a monitored discrete aircraft operating parameter; an integrator for incrementing a count in one direction by a predetermined fault increment when the fault detection mechanism provides a fault indication in relation to said parameter, and for incrementing said integrator count in an opposite direction by a predetermined no-fault increment in the absence of fault detection; a threshold detector for generating a hard fault indication when the integrator count reaches a threshold value in relation to said parameter; a sub-threshold detector for generating a further fault indication in relation to said parameter when the integrator count lies between the threshold value and a sub-threshold value set below the threshold value; an integrator count monitor for generating information indicative of the state of the integrator count when between the threshold value and the sub-threshold value, thereby to provide an indication of a non-hard fault condition in relation to said parameter; and a correlator for correlating said information generated by the integrator count monitor with system operating parameters so as to provide a fault status or a diagnostic in response to the correlation.