Aircraft engine having a scroll case and a turbine support case secured together

An aircraft engine, comprising:

• a turbine including a turbine rotor rotatable about a central axis;
• a scroll case having an inlet fluidly connected to a source of combustion gases and an outlet fluidly connected to the turbine, and a conduit extending around the central axis from the inlet to the outlet;
• a bearing housing extending around the central axis, the bearing housing including a support flange;
• and
• a turbine support case secured to the bearing housing, the turbine support case having spokes distributed around the central axis and extending along a direction having an axial component relative to the central axis, each of the spokes extending through the scroll case and radially supported by the bearing housing,
• one of the turbine support case and the scroll case defining lugs circumferentially distributed around the central axis, the other of the turbine support case and the scroll case defining slots, the turbine support case and the scroll case circumferentially locked to one another via the lugs engaging the slots.