Propulsion prognostics apparatus and systems for an unmanned aerial vehicle (UAV) are provided. One propulsion prognostics apparatus comprises a prognostics module configured to generate prognostics data and a power output sensor configured to be coupled to the engine system and configured to generate power output data representing an actual power output of the engine system. The propulsion prognostics apparatus further comprises a processor coupled to the prognostics module and the power output sensor. The processor is configured to receive the prognostics data and the power output data, compare the prognostics data and the power output data, and determine the airworthiness of the UAV based on the comparison. A propulsion prognostics system includes a UAV having an engine system and the above propulsion prognostics apparatus coupled to the UAV.