A turbine exhaust case mixer assembly for an aircraft engine, comprising: a center body extending along a central axis of the TEC mixer assembly, the center body including a hub, the hub at least partially enclosing a center body cavity and having a first wall portion and a second wall portion axially spaced apart from the first wall portion, the first wall portion and the second wall portion together defining an outer periphery of the center body, the first wall portion and the second wall portion each having a respective axial end segment, the axial end segment of the first wall portion and the axial end segment of the second wall portion removably coupled to each other radially inwardly from the outer periphery of the center body via a fixing arrangement including at least one fastener, the at least one fastener enclosed within the center body cavity; an axial spring including a gap axially defined between portions of the respective axial end segments of the first wall portion and the second wall portion, the gap defined at the outer periphery of the center body; and a mixer extending peripherally about the center body and spaced radially outward from the hub by a plurality of struts extending between the hub and the mixer, the plurality of struts axially offset from the gap at a strut-hub interface, characterised in that the fixing arrangement includes a plurality of fasteners including the at least one fastener, the plurality of fasteners being circumferentially spaced about the outer periphery of the center body, the plurality of fasteners extending through the axial end segment of the first wall portion and the axial end segment of the second wall portion. a center body extending along a central axis of the TEC mixer assembly, the center body including a hub, the hub at least partially enclosing a center body cavity and having a first wall portion and a second wall portion axially spaced apart from the first wall portion, the first wall portion and the second wall portion together defining an outer periphery of the center body, the first wall portion and the second wall portion each having a respective axial end segment, the axial end segment of the first wall portion and the axial end segment of the second wall portion removably coupled to each other radially inwardly from the outer periphery of the center body via a fixing arrangement including at least one fastener, the at least one fastener enclosed within the center body cavity; an axial spring including a gap axially defined between portions of the respective axial end segments of the first wall portion and the second wall portion, the gap defined at the outer periphery of the center body; and a mixer extending peripherally about the center body and spaced radially outward from the hub by a plurality of struts extending between the hub and the mixer, the plurality of struts axially offset from the gap at a strut-hub interface, characterised in that the fixing arrangement includes a plurality of fasteners including the at least one fastener, the plurality of fasteners being circumferentially spaced about the outer periphery of the center body, the plurality of fasteners extending through the axial end segment of the first wall portion and the axial end segment of the second wall portion.