 Four Avro 636s were ordered by the Irish Air Corps in December 1934.These aircraft were powered by old Armstrong Siddeley Jaguar IVC engines, which had originally been purchased by the Irish in 1930 for use in Vickers Vespa army co-operation aircraft.Although the Jaguar IVC powered aircraft was planned to be designated as the Avro 667, they were always referred to as Avro 636s.