Abstract: The present disclosure is directed to a method of operating an active clearance control system for an interdigitated turbine engine. The method includes flowing air from a compressor section to a rotatable outer shroud of an interdigitated turbine section; and adjusting the flow of air to the outer shroud based at least on an engine condition of the turbine engine. The present disclosure is further directed to a gas turbine engine including a low speed turbine rotor comprising an inner shroud, an outer shroud, and at least one connecting airfoil coupling the inner shroud and the outer shroud. The outer shroud includes a plurality of outer shroud airfoils extended inward along a radial direction. The engine further includes a turbine frame at least partially surrounding the low speed turbine rotor; a seal assembly disposed between the outer shroud of the low speed turbine rotor and the turbine frame; and a fifth manifold coupled to the turbine frame.