An exterior aircraft light unit includes a power input coupleable to an aircraft on-board power supply; at least one LED coupled to the power input for receiving power from the aircraft on-board power supply and configured to emit a light output; an optical sensor arranged for sensing an intensity detection portion of the light output and configured to output a detection signal indicative of an intensity level of the light output; an end of life detector, coupled to the optical sensor for receiving the detection signal and configured to determine an end of life condition; and a fuse circuit coupled to the end of life detector; wherein the fuse circuit is configured to irreversibly disable an LED circuit board upon the end of life detector communicating the end of life condition to the fuse circuit.