In one exemplary embodiment of the present disclosure, a method of operating a fuel system for an aeronautical gas turbine engine is provided. The method includes: providing a flow of fuel to a fuel nozzle of the aeronautical gas turbine engine during a wind down condition; operating a fuel oxygen reduction unit to reduce an oxygen content of the flow of fuel provided to the fuel nozzle of the aeronautical gas turbine engine during the wind down condition; and ceasing providing the flow of fuel to the fuel nozzle of the aeronautical gas turbine engine, the fuel nozzle comprising a volume of fuel after ceasing providing the flow of fuel to the fuel nozzle; wherein operating the fuel oxygen reduction unit comprises operating the fuel oxygen reduction unit to reduce an oxygen content of the volume of fuel in the fuel nozzle to less than 20 parts per million.