A 'Special Duty Flight' was formed here in about 1926 to work with the Experimental Gas School at Porton Down, not far away. This used a handful of aircraft including a Bristol Fighter, a Dart and a Horsley, and was transferred to Netheravon in 1928. In April 1924, 16 Squadron was re-formed at Old Sarum for cooperation with Army units in Southern Command. Initially equipped with Bristol Fighters, it subsequently received the Armstrong Whitworth Atlas, in January 1931, and Audaxes in December 1933. With these types it took part in exercises all over southern England. In June 1938 it became the first unit to equip with the Westland Lysander.