 For low-speed flight and landing, the rotor drive system was restarted to provide hovering capability.Tethered flights at White Waltham were followed by the first free flight in January 1954, but a full transition from helicopter to autogyro flight was not achieved until March 1955, piloted by John N. Dennis.System proving continued and by September 1956, 190 transitions and 140 autorotative landings had been completed.