A gas turbine engine includes a fan case assembly adapted to extend around blades of a fan rotor included in the gas turbine engine. The fan case assembly includes an annular case that extends around an axis, an acoustic panel coupled to the annular case and configured to dampen vibrations and a bolting arrangement that couples the acoustic panel to the annular case.

Aspects of the disclosure are directed to a bolt comprising: a body having a head, a circumferential sidewall, a central bore extending at least a portion of a length of the bolt, and a plurality of slots extending through the sidewall from the bore, a plurality of positioning arms at least partially located within an interior of the bolt, and a screw seated within the head, where a position of the screw within the head controls an extent to which the plurality of the positioning arms are extended through the sidewall.

Aspects of the disclosure are directed to a tube assembly comprising: a first tube having a radial exterior surface, a second tube composed of a plurality of segments, the first tube co-axially nested within the second tube, at least a first spacer coupled to the first tube, and a second spacer coupled to the at least a first spacer, where a first segment of the plurality of segments is coupled to a first axial end of the second spacer, and a second segment of the plurality of segments is coupled to a second axial end of the second spacer.

A vane arc segment includes an airfoil fairing that has a platform and an airfoil section that extends therefrom. The platform defines periphery edge faces, a gaspath face, and a non-gaspath face. The platform has a flange that projects radially from the non-gaspath face. The flange defines a forward flange face, an aft flange face, and a radial flange face. The flange has an end portion adjacent one of the periphery edges. The end portion includes a step that defines a radial step face that is radially intermediate the radial flange face and the non-gaspath face.

A vane arc segment includes an airfoil fairing that has a platform and an airfoil section that extends therefrom. The platform defines periphery edge faces, a gaspath face, and a non-gaspath face. The platform has a flange that projects radially from the non-gaspath face. The flange defines a forward flange face, an aft flange face, and a radial flange face. The flange has an end portion adjacent one of the periphery edges. The end portion includes a step that defines a radial step face that is radially intermediate the radial flange face and the non-gaspath face.

An airfoil incudes an airfoil section that defines an internal cavity. The airfoil section is formed of a fiber-reinforced composite that is comprised of fiber plies. The fiber plies include core fiber plies and an overwrap fiber ply that wraps around the core fiber plies. The core fiber plies are arranged as first and second tubes. each of the first and second tubes defines a plurality of windows therein. The windows of the first tube align with the windows of the second tube so as to form radially-spaced ribs that extend across the internal cavity. At least one of the first or second tubes has at least one tab that is radially between the radially-spaced ribs. The at least one tab interlocks the first and second tubes.

An airfoil incudes an airfoil section that defines an internal cavity. The airfoil section is formed of a fiber-reinforced composite that is comprised of fiber plies. The fiber plies include core fiber plies and an overwrap fiber ply that wraps around the core fiber plies. The core fiber plies are arranged as first and second tubes. each of the first and second tubes defines a plurality of windows therein. The windows of the first tube align with the windows of the second tube so as to form radially-spaced ribs that extend across the internal cavity. At least one of the first or second tubes has at least one tab that is radially between the radially-spaced ribs. The at least one tab interlocks the first and second tubes.

An attachment system intended to equip a wall (17), the system including a nut intended to receive a screw (31) of which the orientation is normal to the wall (17), the screw (31) passing through an element such as an outer panel (32) in order to attach the element to the wall (17). The attachment system comprises a socket (26) having a threaded cylindrical outer face (34) intended to be screwed into a hole (29) passing through the wall (17) and having dimensions greater than the dimensions of the fastener that the repair socket (26) replaces, the socket (26) carrying, in the central region of same, a nut (28) receiving the attachment screw (32).

A state observation device (30) uses an ADC (37) to digitize a detection signal from a gap sensor (21) at a low-speed sampling period and uses a separation unit (38) to separate the digitized detection signal into vane detection signals considered to be for the detection of a vane of a compressor impeller and non-vane detection signals considered not to be for the detection of a vane. Further, the determination unit (39) extracts a vane peak detection signal considered to be for a vane peak by comparing a vane detection signal with vane detection signals corresponding to other vanes and non-vane detection signals, and a shaft vibration and tip clearance are determined as states of the compressor impeller on the basis of the extracted vane peak detection signal. Thus, the state observation device (30) is capable of observing the state of a rotary machine without carrying out high-speed sampling.

It is aimed to improve circularity. In a casing, in which a cylindrical shape thereof is divided into two parts in a radial direction thereof and the casing is connected in the cylindrical shape via flanges thereof protruding outward in the radial direction at both divided ends thereof; increased thickness portions that increase radial direction thickness thereof are formed in a portion excluding the divided ends and circular arc center portions farthest from the divided ends, the portion being between the divided ends and the circular arc center portions.