In 1932 the old Avro 504K trainers were replaced by the more modern Hispano Aviación E-30. Between 1934 and 1935 the Republican Navy tried to modernize its ageing seaplane fleet and contemplated replacing the Dornier Do J Wal seaplanes with Breguet 521 Bizerte and the Macchi M.18 with Potez 452.
