A method of determining the axial load on load-sharing thrust bearings including: providing first and second thrust bearings, each including an inner race and an outer race supported by at least one resilient element; applying a test axial load to each of the first and second thrust bearings to elastically deform the at least one resilient element so as to axially displace the outer race; determining the test axial displacement of each outer race to obtain calibration data comprising values of axial load versus axial displacement; applying an in-service axial load to the first and second thrust bearings to elastically deform the resilient elements so as to axially displace the respective outer races; measuring the in-service axial displacement of each outer race; and based on the measured in-service axial displacements, inferring from the calibration data the values of the in-service axial loads on the first and second thrust bearings.