A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.