Abstract: A pneumatic tire has a radially outer tread. The tread has a plurality of circumferential grooves, a plurality of lateral grooves, and a plurality of shoulder grooves. The tread includes bottoms and sides of each circumferential groove being textured for improving snow traction, each circumferential groove being textured with flat-topped pyramids, bottoms and sides of each lateral groove being textured for improving snow traction; and bottoms and sides of each shoulder groove being textured for improving snow traction.

Abstract: A fan track liner assembly for ducted fan engine which provides for reduced strain and deformation of front of fan case in the event of a fan blade off event. Various assemblies are proposed. In one aspect, assembly includes fan track liner panel and plurality of fasteners which are arranged to secure panel to fan case of engine, wherein: a forward portion of panel includes hinged portion which operates as trapdoor to permit blade or blade fragment to pass through, and fasteners are arranged to fail in the event of blade or blade fragment passing through trapdoor causing panel to be displaced rearwards in fan case. Other aspects provide for reduced height of support on fan case for attaching fan track liner and for collapsible comb box.

Abstract: A pneumatic tire has a radially outer tread. The tread has a plurality of circumferential grooves, a plurality of lateral grooves, and a plurality of shoulder grooves. The tread includes bottoms and sides of each circumferential groove being textured for improving snow traction, each circumferential groove being textured with flat-topped pyramids, bottoms and sides of each lateral groove being textured for improving snow traction; and bottoms and sides of each shoulder groove being textured for improving snow traction.

Abstract: A fan track liner assembly for a ducted fan engine which provides for ease of installation and replacement. The assembly includes a plurality of panels; and a plurality of fastening members which are arranged to secure the panels to the fan case of the engine, wherein: each fastening member has a base portion and an elongate arm member, and further wherein: the base portion has an attachment portion which is used to secure the fastening member to the fan case; and the arm member extends from the base portion, and each panel has slotted edge portions on opposing edges at one end of the panel which are each arranged to engage with respective arm members of fastening members on either side of the panel when the panel is assembled with the fastening members by sliding the panel onto the fastening members or vice-versa.

Abstract: A fan containment system for fitment around an array of radially extending fan blades mounted on a hub in an axial gas turbine engine. The fan containment system comprises an annular casing element for encircling an array of fan blades. An annular fan track liner is positioned substantially coaxial to the annular casing element. A hook projects in a generally radially inward direction from the annular casing element and is positioned axially forward of an array of fan blades when the fan containment system is fitted around said fan blades. Tabs protrude from the hook in a generally rearward direction and are spaced circumferentially along the hook. Fasteners connect the fan track liner to the tabs. The fasteners are configured so as to permit movement of the fan track liner towards the annular casing element when the fan track liner is impacted by a released fan blade.