Exterior aircraft light, aircraft comprising an exterior aircraft light, and method for providing an extent of erosion of an exterior surface of a light transmissive cover of an exterior aircraft light

An exterior aircraft light includes a support and a light transmissive cover having a light transmissive body with an interior surface and an exterior surface. The light includes at least one light source arranged between the support and the light transmissive cover; and a first light detector. The light transmissive cover has a first light guide path within the light transmissive body from a first light entry region to a first light exit region, wherein the first light detector is arranged to receive light that travels along the first light guide path and that exits the light transmissive cover at the first light exit region. The first light detector is configured to provide sensor measurements corresponding to the amount of light incident on the first light detector.