The Heron prototype registered to the de Havilland Aircraft Company, Hatfield, UK as "G-ALZL" undertook its first flight with Geoffrey Pike at the controls on 10 May 1950. The aircraft was unpainted at the time, and after 100 hours of testing was introduced to the public on 8 September 1950 at the Farnborough Airshow, still glistening in its polished metal state. By November, the prototype had received its formal British Certificate of Airworthiness and had flown to Khartoum and Nairobi for tropical trials.