Abstract: A method of repairing a composite beam having a longitudinal direction including: removing material from a damaged area of the composite beam to form a cut out region; machining a plurality of elongate slots into the composite beam, the elongate slots each having a length in the longitudinal direction of the composite beam and spanning across the damaged area, the elongate slots extending into the composite beam to a depth greater than a depth of the cut out region; introducing a plurality of reinforcing inserts into the respective elongate slots and fixing the reinforcing inserts into the slots with adhesive.

Abstract: A fuel tank is disclosed including a lower cover and an upper cover. The lower cover or the upper cover includes a panel assembly. The panel assembly includes a panel and a stringer attached to the panel. The stringer includes a pair of portions which are spaced apart in a lengthwise direction of the stringer and connected to each other by a bridge. Each portion is connected to a respective end of the bridge, and each end of the bridge deviates away from the panel. The stringer includes reinforcement fibres which extend between the portions via the bridge. Each reinforcement fibre deviates away from the panel at each end of the bridge. The stringer includes a stringer recess between the bridge and the panel, and a flow passage in the stringer recess through which fluid can flow across the stringer.

Abstract: A panel assembly is disclosed having a panel, a beam attached to the panel, and a plurality of stiffeners attached to the panel. Each stiffener includes a respective bridge which crosses over the beam at an intersection from a first side of the beam to a second side of the beam. Each bridge has an outer surface facing away from the panel and an inner surface facing towards the panel. The inner surface of each bridge deviates away from the panel to form a recess at the intersection, and the outer surface of each bridge deviates away from the panel to form a protrusion at the intersection.

Abstract: A stiffener is disclosed including a core and a shell which surrounds the core. The shell is formed from a fibre material, and the core includes first and second battens arranged side by side, and a foam spacer between the battens. The stiffener extends in a lengthwise direction, and the battens and the foam spacer have respective lengths which extend in the lengthwise direction of the stiffener. The core is assembled with the spacer between the battens, then surrounded with the shell. The stiffener may be a stringer for an aircraft wing.

Abstract: An aircraft panel assembly with a panel and a plurality of stiffeners on the panel is disclosed. Each stiffener has an attachment part attached to the panel and a structural part spaced apart from the panel. A rib foot beam crosses the stiffeners at a series of intersections. At each intersection the rib foot beam is located between the panel and the structural part of a respective one of the stiffeners.