The production Mirage1110 aircraft delivery commenced from the major contractor, the GAF, to the RAAF in March 1964. The secondary contractor to the Mirage project, the CAC, realising the need for a fast jet "lead in" training aircraft, and the only such type in the 1960s, being the supersonic T-38 that was originated for the USAF's F-5 aircraft in service, presented their proposed design for a locally designed and manufactured low cost supersonic training aircraft that would meet the flying and weapons training requirements of the RAAF to the powers that be in 1967. The rationale behind the proposal was the technological advances of aircraft such as the Mirage creating a less than satisfactory learning curve for student pilots advancing from piston engined CAC Winjeel basic trainers through to first generation sub-sonic deHavilland jet trainers into the world of high technology "fast jet" fighter aircraft operation. The original design featured a tail plane less fuselage and a double delta wing to be powered by a General Electric – J85 turbojet engine that was later seen to have a fuel consumption that would unduly impinge on the range and endurance of the aircraft and the design, that had advanced to the stage of constructing a full size mockup, was revised to incorporate the Rolls Royce RB172-T-260 turbojet engine. The aircraft would feature two zero zero Martin Baker ejection seats and be capable of carrying a load of 1815 kg on four wing and two fuselage hardpoints, and be capable of a maximum speed of Mach1.5 at altitude and very high subsonic speeds at low level. In the event, the design was not proceeded with and work ceased at the end of 1970 as the RAAF were going to receive the dual seat trainer version of the Mirage, the 111D, from 1973, and the RAAF initial jet trainer requirement advanced from the deHavilland Vampire to the Aermacchi MB326H aircraft built by the CAC under license in 1967. ​The CA-31 mock up survived and was donated to the Museum in mid 1974CAC designed supersonic trainer