Abstract: A fan blade containment assembly (38) for a turbofan gas turbine engine (10) comprises a cylindrical, or frustoconical, casing (40) arranged to surround an arrangement of fan blades (26). At least one hollow tubular member (66) is arranged radially within and secured to the casing (40) and the at least one hollow tubular member (66) contains a filler material (68). The at least one hollow tubular member (66) extends circumferentially. The hollow tubular member (66) is helical and the axial spacing between the adjacent turns of the tubular member (66) varies and the density of the filler material (68) varies in order to match the severity of the impact expected at each axial location along the casing 40 of the fan blade containment assembly (38).

Abstract: A stage of fan aerofoils (10) lies within a fan cowl (12). The fan duct (16) is defined in part by a hard casing (14) that in turn surrounds aerofoils (10). Hard casing (14) includes wedge members (26) that fill the annular gap between ring (14) and an outer ring (20). In the event of an aerofoil (10) breaking off, the hard ring (14) and wedges (26) absorb sufficient of the kinetic energy expended by the broken aerofoil (10), as to prevent it passing through outer ring (20) on to the fan cowl (12).

Abstract: Two metal blocks (50, 52) are welded to respective metal sheets (30, 32) to form sealed assemblies. The sealed assemblies are then diffusion bonded together to form two metal preforms (54, 56). The thick ends (36) and (40) of the metal sheets (30, 32) and the metal blocks (50, 52) are hot formed so that a continuation of the plane X of the first surfaces (42, 46) of the metal sheets (30, 32) extends through and across the metal blocks (50, 52). The metal preforms (54, 56) are machined to remove the portion of the metal blocks (50, 52) extending above the first surfaces (42, 46) of the metal sheets (30, 32) respectively. The metal preforms (54, 56) and a metal sheet (58) are assembled into a stack (64). The metal preforms (54, 56) and the metal sheet (58) are diffusion bonded together and then superplastically formed to produce a hollow fan blade (10). The method enables thinner metal workpieces with better microstructure to be used and increases the yield of metal workpieces.