When the fifth runway at Schiphol Airport came into operation, it was decided to enlarge the existing control tower into a combined radar and air traffic control tower. To achieve this dual purpose, the radar antenna and the protecting radome were removed from the existing tower and replaced by a prefabricated steel air traffic control centre. This octagon atop a concrete shaft is supported by a steel structure that goes on to guarantee the stability of the tower as a whole. The supporting structure is entirely in silver-coloured steel, as is the structure guiding the external panorama lift looking out to the southwest. The original radar equipment and radome have been reinstalled on the roof of the new glass dome up on the sixteenth floor where the air traffic controllers work.