A power management system includes a data fusion unit configured to receive first health indicators from an engine diagnostics module and second health indicators from a power assurance module. The data fusion unit is configured to data fuse the first and second health indicators. A power assessment and decision support unit is coupled to the data fusion unit and configured to generate power available based on the fused first and second health indicators. A system diagnostic reasoner unit is coupled to the data fusion unit, and configured to provide a system level fault diagnosis based on the fused first and second health indicators. A graphical user interface is coupled to the power assessment and decision support unit and the system diagnostic reasoned unit. The graphical user interface is configured to display the system level fault diagnosis and the power available.