18 September 1913

The Avro 504 was first flown on 18 September 1913. It was powered by an 80 hp Gnome Lambda rotary engine. Production during World War I totalled 8,970 and continued for almost 20 years, making it the most-produced aircraft of any kind that served in that conflict. Over 10,000 were built by the time production ended in 1932.