A case (60; 160; 260) for a gas turbine engine (20; 58) having a central longitudinal axis, the case comprising: a radially outer ring and a radially inner ring; a plurality of circumferentially spaced apart struts, the radially inner ring being supported relative to the radially outer ring by said plurality of circumferentially spaced apart struts; and a bearing compartment being disposed radially inward of the radially inner ring, the radially outer ring and the radially inner ring defining an annular flow path therebetween, the radially inner ring comprising a first flange that extends radially outward from the bearing compartment, the first flange comprising an undulation (86; 186; 286) that extends axially away from the plurality of struts and a radial portion, wherein the undulation (86; 186; 286) comprises an apex, a first undulation portion (90A; 190A; 290A) and a second undulation portion (90B; 190B; 290B), the first and second undulation portions (90A, 90B; 190A, 190B; 290A, 290B) meeting at said apex, wherein the first flange defines a load path between the bearing compartment and the radially outer ring, wherein the radially inner ring comprises a second flange that extends radially inward towards the bearing compartment, the plurality of struts are at least partially disposed between the first and second flanges (82, 94), and the second flange moves freely relative to the bearing compartment (72; 472), wherein the first flange is at least partially axially forward of the plurality of struts, and the second flange is at least partially axially aft of the plurality of struts, wherein the radial portion is disposed between the undulation (86; 186; 286) and the bearing compartment, and the apex of the undulation (86; 186; 286) is axially forward of the radial portion, the first undulation portion (90A; 190A; 290A) meets the radial portion at a first bend having a first radius of curvature (R 1), and extends with at least a component in an axial direction from the first bend to the apex, and the second undulation portion (90B; 190B; 290B) extends with at least a component in an axial direction from the second bend towards to the radial portion wherein the first and second undulation portions (90A...290B) meet at the apex at a second bend having a second radius of curvature (R 2) that is less than the first radius of curvature (R 1); the case being characterised in that the radial portion is perpendicular to the central longitudinal axis. a radially outer ring and a radially inner ring; a plurality of circumferentially spaced apart struts, the radially inner ring being supported relative to the radially outer ring by said plurality of circumferentially spaced apart struts; and a bearing compartment being disposed radially inward of the radially inner ring, the radially outer ring and the radially inner ring defining an annular flow path therebetween, the radially inner ring comprising a first flange that extends radially outward from the bearing compartment, the first flange comprising an undulation (86; 186; 286) that extends axially away from the plurality of struts and a radial portion, wherein the undulation (86; 186; 286) comprises an apex, a first undulation portion (90A; 190A; 290A) and a second undulation portion (90B; 190B; 290B), the first and second undulation portions (90A, 90B; 190A, 190B; 290A, 290B) meeting at said apex, wherein the first flange defines a load path between the bearing compartment and the radially outer ring, wherein the radially inner ring comprises a second flange that extends radially inward towards the bearing compartment, the plurality of struts are at least partially disposed between the first and second flanges (82, 94), and the second flange moves freely relative to the bearing compartment (72; 472), wherein the first flange is at least partially axially forward of the plurality of struts, and the second flange is at least partially axially aft of the plurality of struts, wherein the radial portion is disposed between the undulation (86; 186; 286) and the bearing compartment, and the apex of the undulation (86; 186; 286) is axially forward of the radial portion, the first undulation portion (90A; 190A; 290A) meets the radial portion at a first bend having a first radius of curvature (R 1), and extends with at least a component in an axial direction from the first bend to the apex, and the second undulation portion (90B; 190B; 290B) extends with at least a component in an axial direction from the second bend towards to the radial portion wherein the first and second undulation portions (90A...290B) meet at the apex at a second bend having a second radius of curvature (R 2) that is less than the first radius of curvature (R 1); the case being characterised in that the radial portion is perpendicular to the central longitudinal axis.