An apparatus comprising: an input interface configured to receive an input signal associated with at least one stage of an impeller (100a-100h) and with multiple frequencies associated with operation of the impeller; a processor configured to identify a specific failure mode in the impeller using the input signal; and an output interface configured to provide an indicator identifying a health of the impeller; wherein the processor is configured to identify the specific failure mode by: determining a family of frequencies related to at least one of the multiple frequencies associated with operation of the impeller, the family of frequencies including a vane pass frequency and its harmonics; decomposing the input signal by performing a transform of the input signal and isolating components of the transformed input signal into selected frequency bands; reconstructing an impeller signal using portions of the decomposed input signal within the selected frequency bands associated with the family of frequencies; comparing the reconstructed impeller signal to a baseline signal; and identifying the specific failure mode based on failure mode rules that identify effects that the specific failure mode has on the multiple frequencies associated with operation of the impeller. an input interface configured to receive an input signal associated with at least one stage of an impeller (100a-100h) and with multiple frequencies associated with operation of the impeller; a processor configured to identify a specific failure mode in the impeller using the input signal; and an output interface configured to provide an indicator identifying a health of the impeller; wherein the processor is configured to identify the specific failure mode by: determining a family of frequencies related to at least one of the multiple frequencies associated with operation of the impeller, the family of frequencies including a vane pass frequency and its harmonics; decomposing the input signal by performing a transform of the input signal and isolating components of the transformed input signal into selected frequency bands; reconstructing an impeller signal using portions of the decomposed input signal within the selected frequency bands associated with the family of frequencies; comparing the reconstructed impeller signal to a baseline signal; and identifying the specific failure mode based on failure mode rules that identify effects that the specific failure mode has on the multiple frequencies associated with operation of the impeller. determining a family of frequencies related to at least one of the multiple frequencies associated with operation of the impeller, the family of frequencies including a vane pass frequency and its harmonics; decomposing the input signal by performing a transform of the input signal and isolating components of the transformed input signal into selected frequency bands; reconstructing an impeller signal using portions of the decomposed input signal within the selected frequency bands associated with the family of frequencies; comparing the reconstructed impeller signal to a baseline signal; and identifying the specific failure mode based on failure mode rules that identify effects that the specific failure mode has on the multiple frequencies associated with operation of the impeller.