With the Mirage IVB considered to be too expensive, the medium-sized Mirage IVA, slightly larger than the first prototype, was chosen for three more prototypes to be produced. This aircraft had a wing area of and weighed about On 4 April 1960, a formal order for 50 production Mirage IVA aircraft was issued. The three prototype aircraft were built between 1961 and 1963, with first flights on 12 October 1961, 1 June 1962, and 23 January 1963. By 1962, the second prototype had conducted simulated nuclear bombing runs in the trials range at Colomb-Bechar in southern Algeria. The third prototype was equipped with the navigation/bombing systems and flight refuelling probe. The fourth prototype Mirage IVA-04 was essentially representative of the production aircraft that would follow.