The Blériot-SPAD S.56 was a family of prototype Frenchairliners developed in the 1920s as various refinements of the S.33 design. All S.56 versions shared two new features: the first was a newly designed, all-metal wing, replacing the wooden wing of earlier related designs and the second was a redesigned passenger cabin, replacing the S.33's four single seats in a row with two rows of double seats. A second access door was also added.
similar to S.56/2 with improved landing gear and 280 kW (380 hp) Gnome & Rhône 9Aa engine. (8 built)
major fuselage revision; cockpit relocated between engine and passenger cabin (in all previous S.33 derivatives, it had been aft of the cabin) and an extra double seat added to the cabin, increasing internal passenger capacity to six. 8 built, plus 2 modified from S.56/3s, powered by 310 kW (420 hp) Gnome & Rhône 9Ady engines.
revised passenger cabin with four seats located in one compartment, and two in a second compartment that could be quickly converted to a freight hold (3 modified from S.56/3s)