Patent ID: 7647809

Claim:
A method of identifying subsurface damage to a composite material aircraft caused by a mechanical impact, comprising the steps of: providing a plurality of panels made from a low ductility composite material, with each panel having a surface wherein the low ductility of the material is characterized by a tensile elongation to failure of less than about 2 percent; preparing an indicator paint having an impact-sensitive component that produces a visible change when subjected to a mechanical impact, wherein the indicator paint comprises a mixture of a first reactant and a second reactant separated by a barrier that is rupturable so that the first reactant and the second reactant mix and produce the visible change when the indicator paint is subjected to the impact; covering the surface of each panel with the indicator paint wherein each panel is mounted on a support structure to substantially maintain a form for the panel; visually inspecting each supported panel periodically to locate the visible change indicative of a panel deformation caused by the mechanical impact; and in response to locating the visible change on a respective panel, evaluating the respective panel to identify any subsurface damage.