A method for operating a hybrid electric propulsion system of an aircraft, the hybrid electric propulsion system comprising a turbomachine, an electric machine coupled to the turbomachine, and a propulsor coupled to the turbomachine, the method comprising: operating the turbomachine to drive the propulsor; receiving data indicative of a failure condition of the hybrid electric propulsion system; and extracting power from the turbomachine using the electric machine to slow down one or more rotating components of the turbomachine in response to receiving the data indicative of the failure condition.