A component for use in a gas turbine engine comprises an indicator operable to provide a visual indication when strain over a threshold value has been experienced by the component by transitioning from a rest state to an indication state on occurrence of strain above the threshold value. Also disclosed is a method of detecting foreign object damage in a component of a gas turbine engine, comprising: identifying at least one of a component or a region of a component that is subject to increased strain during a foreign object impact; and mounting an indicator on the identified component or region of a component, the indicator providing a visual indication when increased strain has been experienced.