The Air Ministry ordered two CA.15C from Blackburn. One was a monoplane and the other a biplane (G-ABKW). Other than the wings, the aircraft were identical with the objective of assessing the advantages of one configuration over the other. The monoplane was shown to be superior and the biplane was scrapped. G-ABKV was taken on charge by the RAF as K4241 and joined the Royal Aircraft Establishment fleet at Farnborough. It was used in the development of autopilots and fir radio experiments. Withdrawn in 1936. Photo from: Imperial War Museums