A method of designing and manufacturing apparatus. The method comprises: creating a design space; analysing expected loads acting on the design space to calculate a first load path within the design space; analysing expected loads acting on the design space when the apparatus is in a damaged state to calculate a second load path within the design space; selecting a region of the second load path which falls outside the first load path; and creating a final design which includes: a primary structure falling within the first load path; and a damage indication feature falling within the selected region. The damage indication feature is designed to provide a visual indication when the load transmitted by the damage indication feature exceeds a threshold.The load generates a stress in the primary structure which exceeds the stress in the damage indication feature until the primary structure becomes damaged, at which point the load generates a stress in the damage indication feature which exceeds the stress in the primary structure.