A system is provided. The system includes a combustor assembly that receives a fuel flow. The system includes a pressure sensor disposed within the combustor assembly that measures a pressure of the fuel flow from a fuel supply to a fuel nozzle of the combustor assembly. The system includes a controller communicatively coupled to the pressure sensor. The controller is configured to receive a pressure measurement from the pressure sensor. The pressure measurement is a current operating parameter of the combustor assembly. The controller is configured to determine a predicted fuel flow based at least in part on the pressure measurement, determine a fuel composition factor based on a comparison of the predicted fuel flow with a commanded fuel flow, and adjust control of the combustor assembly based on the fuel composition factor. The fuel composition factor is indicative of a change in a fuel composition of the fuel flow.