The Potez 633 B2 was a light bomber version of the Potez 63 twin engined design. Although it was initially ordered in large numbers for the Armée de l'Air, these orders were soon cancelled and only those aircraft ordered for export were built.
After the initial trials with the prototypes of the Potez 630 and Potez 631 an order was placed for ten evaluation aircraft. At first this was to include two Potez 633 B2 light bombers, but when the order was confirmed this was changed to one Potez 633 B2 and one Potez 639 AB2 low-level attack bomber.
The Potez 633 was structurally similar to the standard fighter versions, but with the middle crew position replaced with a vertical bomb bay, with the two remaining crew members separated by the top of the bomb bay. The aircraft could carry eight 110lb bombs, all in the internal bomb bay. The 20mm cannon were removed from the nose and the Potez 633 only carried three defensive machine guns - one fixed forward firing, one fixed rear firing and one flexibly mounted rear-firing gun.
In December 1937 the first production order for Potez 630s and 631s was confirmed and an order for fifty Potez 633 B2s was placed. The plans for French rearmament began to accelerate during 1937, and Armament Plan V of 15 March 1938 called for 449 two-seat light day bombers. Most of these were to be newer designs, but an extra 75 Potez 633s were ordered on 25 March, bringing the total on order up to 125. This order would be short-lived. In May 1938 the French Air Force decided that all light bombers should be three-seaters. The Potez 633 couldn't be modified to carry a third crew-member, and so the order was modified to one for 125 Potez 631s.
The Potez 633 BW was the most popular member of the Potez 63 family in the export market. China ordered five, Greece twenty-four, Romanian forty in two orders and Switzerland one. Production of these aircraft continued after the French order was cancelled, and as war became increasingly likely most were taken over by the Armée de l'Air (thirteen were delivered to Greece and twenty to Romania. The Greek aircraft were scrapped after the German invasion). By August 1939 nineteen aircraft from the Romanian order and three from the Chinese order had been accepted by the air force. On 1 September the first three entered service, forming an experimental flight within G.B. I/54.
During the Phoney War period the Potez 633 was used to equip a number of Groupes de Bombardement d'Assaut to give their crews experience of using a more modern aircraft than the Potez 540 while they awaited delivery of the Breguet 691 and Breguet 693. At some point G.B.A. I/54, II/54, I/51, II/51 and II/35 used the aircraft, but as the Breguets entered service these units began to convert to the newer aircraft, and by 10 May 1940 only I/51, II/51 and II/35 were still operating the type, in each case alongside the Breguet 691. GBA II/51 was the only one to use the type in combat. On 19 May it moved to Etampes to support Groupement 18, taking with it eight Potez 633s and five Breguet 693s. Six of the eight Potez bombers were lost in operations between 20-30 May.
Engine: Two Gnome-et-Rhone 14 M4/M5 or M6/M7 engines
Power: 570hp at sea level, 660hp at 16,400ft, 700hp at take-off
Wing span: 52ft 6in
Length: 36ft 4in
Height: 11ft 10.5in
Empty Weight: 5,401lb
Normal loaded weight: 9,921lb
Armament: Three 7.5mm machine guns, one forward firing and two rear firing
Bomb-load: Eight 110lb bombs, total of 880lb