engine. The first 48 aircraft to be produced were equipped with Hispano-Suiza 14AB02/03 engines, these were succeeded on later models by the improved Hispano-Suiza 14AB10/11. In December 1937, regular contracts took the place of the provisional letters; a further order for 50 Potez 633 light bombers was also received, bringing the total orders for the type to 180, including the ten prototypes that had been ordered. During the late 1930s, the Potez 630 received considerable foreign interest; in addition to France, many countries were in the process of re-equipping their air forces. One such foreign venture was the acquisition of a licence to manufacture by the Czechoslovakian aircraft firm Avia to produce a variant of the aircraft, designated as the Potez 636; none were completed prior to Czechoslovakia's annexation by Nazi Germany in 1938. In 1938, a further 50 additional Potez 631s were ordered, of which 20 were to be diverted to Finland, although they never reached that country. A number of firm foreign orders was placed with SNCAN for the type; the Republic of China ordered four Potez 631 and five Potez 633, the Kingdom of Yugoslavia ordered two Potez 630 and one Potez 631, the Kingdom of Romania ordered 20 Potez 633, the Kingdom of Greece ordered 24 Potez 633, and Switzerland ordered one Potez 630 and one Potez 633. In May 1937, series production of the Potez 630 commenced. Manufacturing work on the aircraft's various sections and components was shared out across various SNCAN facilities; the fuselage and tailplanes were produced in Caudebec-en-Caux, Normandy, the wings were made at Le Havre, Normandy, and final assembly was initially performed at Méaulte; the assembly work was later transferred to Les Mureaux. In February 1938, the first production Potez 630 conducted its maiden flight; on 23 February, the French Air Force accepted their first production 630 aircraft. Early on, production of the Potez 630 was hit by considerable delays, caused by a shortage of engines, propellers, and cannons; the first batch of Potez 630s were armed with four machine guns instead of the two 20 mm Hispano-Suiza cannons. On 2 August 1938, the first Potez 631 was officially accepted. On 15 March 1938, a major re-equipment and expansion program of the French Air Force, known as Plan V, was approved. While there had been intentions to order a more capable twin-engine aircraft, these were not ready for production, thus the