Before the formation of BLEU, an automatic landing was made at the Telecommunications Flying Unit (TFU) of the TRE at RAF Defford in a Boeing 247D aircraft, DZ203, early in 1945, using the American SCS 51 radio guidance system. Landings were made in complete darkness, with no landing lights and all other lights obscured by the wartime blackout. There was no flare-out; the low approach speed and shallow glide angle meant that the aircraft could be allowed to fly straight onto the ground.[8][9] SCS 51 was the basis for the Instrument Landing System (ILS), adopted by ICAO in 1948.[10]