A method of inspecting a component in an assembled gas turbine engine includes inserting a boroscope and a conduit through an aperture in a casing of the engine. The conduit has an applicator tip. The boroscope and conduit are directed to the component to be inspected. A dye penetrant is supplied through the conduit to the applicator tip. The applicator tip is arranged to contact the surface of the component and dye penetrant is supplied onto the surface of the component from the applicator tip such that the dye penetrant enters any defects in the surface of the component. The applicator tip includes a porous and malleable member. Light is directed onto the component and the surface of the component is viewed through the boroscope to determine if any defects are present in the surface of the component.