An assembly for a gas turbine engine (20, 120) comprising: a first annular case including a first body extending from a first end portion; and a second annular case including a second body extending along a longitudinal axis of the assembly from a second end portion, wherein: the first end portion includes a first flange, the first flange including at least one mounting assembly, the at least one mounting assembly including a first aperture dimensioned to receive a fastener and a first ramped surface that extends axially relative to the longitudinal axis from the first aperture; the second end portion includes at least one flange defining a receptacle dimensioned to receive the first end portion, a second aperture dimensioned to receive the fastener, and a second ramped surface; and the first annular case is moveable in an axial direction (D1, D2) relative to the longitudinal axis through an axial opening of the receptacle such that the first end portion is received in the receptacle, and is rotatable about the longitudinal axis to define an interface between the first and second ramped surfaces (184, 190) to interlock the first end portion in the receptacle and limit movement of the first annular case relative to the longitudinal axis. a first annular case including a first body extending from a first end portion; and a second annular case including a second body extending along a longitudinal axis of the assembly from a second end portion, wherein: the first end portion includes a first flange, the first flange including at least one mounting assembly, the at least one mounting assembly including a first aperture dimensioned to receive a fastener and a first ramped surface that extends axially relative to the longitudinal axis from the first aperture; the second end portion includes at least one flange defining a receptacle dimensioned to receive the first end portion, a second aperture dimensioned to receive the fastener, and a second ramped surface; and the first annular case is moveable in an axial direction (D1, D2) relative to the longitudinal axis through an axial opening of the receptacle such that the first end portion is received in the receptacle, and is rotatable about the longitudinal axis to define an interface between the first and second ramped surfaces (184, 190) to interlock the first end portion in the receptacle and limit movement of the first annular case relative to the longitudinal axis. the first end portion includes a first flange, the first flange including at least one mounting assembly, the at least one mounting assembly including a first aperture dimensioned to receive a fastener and a first ramped surface that extends axially relative to the longitudinal axis from the first aperture; the second end portion includes at least one flange defining a receptacle dimensioned to receive the first end portion, a second aperture dimensioned to receive the fastener, and a second ramped surface; and the first annular case is moveable in an axial direction (D1, D2) relative to the longitudinal axis through an axial opening of the receptacle such that the first end portion is received in the receptacle, and is rotatable about the longitudinal axis to define an interface between the first and second ramped surfaces (184, 190) to interlock the first end portion in the receptacle and limit movement of the first annular case relative to the longitudinal axis.