Estimating residual useful life of a rolling element bearing in an operating gas turbine engine is provided. A processor receives a vibration signal from a vibration sensor. The vibration signal includes a vibratory response of the rolling element bearing. Processor detects a vibratory pattern of the rolling element bearing from the vibration signal and compares the vibratory pattern to a reference vibratory pattern. Processor identifies a failure propagation stage in which the vibratory pattern matches the reference vibratory pattern. Processor correlates the failure propagation stage to the residual useful life remaining in the rolling element bearing and generates an output signal representing the residual useful life remaining in the rolling element bearing.