SYSTEM COMPRISING A HELICOPTER ROTOR AND BEARINGS WITH SENSORS AND METHOD OF MONITORING THE SYSTEM

A system comprises a plurality of identical helicopter pitch control bearings (22a - 22d) operating under identical conditions, wherein each of the bearings (22a - 22d) is equipped with at least one sensor (30a - 30d) for measuring the same operating parameter for each of the bearings (22a - 22d) at a given time, and a monitoring unit (32) configured to receive and process the signals of the sensors (30a - 30d) and to generate maintenance data based on the sensor signals, whereby the sensors are configured to obtain, at the same given time, measurement values of the same operating parameter for each of the bearings (22a-22d); the monitoring unit (32) is configured to calculate at least a standard deviation or variance at the given time from the sensor signals by comparing the measurement values obtained at the same time, the standard deviation or variance quantifying a width of a distribution of the measurement values; and in that the monitoring unit is further configured to compare the standard deviation or variance with a threshold value and to generate a signal indicating that one of the bearings (22a - 22d) requires replacement if the calculated standard deviation or variance exceeds the threshold value.