Aerial lighthouse

An aerial lighthouse is a lighthouse used to guide aircraft with lighted beacons at night. A network of aerial lighthouses was established in the United Kingdom and Europe during the 1920s and 1930s. Use of the lighthouses has declined with the advent of radio navigation aids such as NDB (non-directional beacon), VOR (VHF omnidirectional ranging) and DME (distance measuring equipment). The last operational aerial lighthouse in the United Kingdom is on top of the cupola over the RAF College main hall at RAF Cranwell.