A method of operating a hybrid propulsion engine including: operating a hybrid propulsion engine during a first segment of flight of an aircraft in a first mode of operation, the hybrid propulsion engine including a propulsor , a gas turbine engine , and an electric motor , wherein in the first mode of operation the gas turbine engine is driving the propulsor ; operating the hybrid propulsion engine during a second segment of flight of an aircraft in a second mode of operation wherein the electric motor is driving the propulsor ; and prior to operating the hybrid propulsion engine in the second mode of operation: receiving, at a controller , an input signal requesting to switch modes from the first mode of operation to the second mode of operation; determining, via the controller , whether one or more mode-change parameters are satisfied; based on a determination that the one or more mode-change parameters are satisfied, sending a first command signal , via the controller , to start the electric motor ; sending a second command signal , via the controller , to shut down the gas turbine engine ; and prior to sending the second command signal to shut down the gas turbine engine , verifying, via the controller , that the electric motor has started and is driving the propulsor . operating a hybrid propulsion engine during a first segment of flight of an aircraft in a first mode of operation, the hybrid propulsion engine including a propulsor , a gas turbine engine , and an electric motor , wherein in the first mode of operation the gas turbine engine is driving the propulsor ; operating the hybrid propulsion engine during a second segment of flight of an aircraft in a second mode of operation wherein the electric motor is driving the propulsor ; and prior to operating the hybrid propulsion engine in the second mode of operation: receiving, at a controller , an input signal requesting to switch modes from the first mode of operation to the second mode of operation; determining, via the controller , whether one or more mode-change parameters are satisfied; based on a determination that the one or more mode-change parameters are satisfied, sending a first command signal , via the controller , to start the electric motor ; sending a second command signal , via the controller , to shut down the gas turbine engine ; and prior to sending the second command signal to shut down the gas turbine engine , verifying, via the controller , that the electric motor has started and is driving the propulsor . receiving, at a controller , an input signal requesting to switch modes from the first mode of operation to the second mode of operation; determining, via the controller , whether one or more mode-change parameters are satisfied; based on a determination that the one or more mode-change parameters are satisfied, sending a first command signal , via the controller , to start the electric motor ; sending a second command signal , via the controller , to shut down the gas turbine engine ; and prior to sending the second command signal to shut down the gas turbine engine , verifying, via the controller , that the electric motor has started and is driving the propulsor . <EOS>