SPAD S.A-4 – an improved A.2 with a less powerful 80-hp Le Rhône 9C engine. – 59 built.
The SPAD S.A (also called S.A.L.) was a French two-seat tractor biplane first flown in 1915. It was used by France and Russia in the early stages of the First World War in the fighter and reconnaissance roles. It was a unique aircraft that carried its observer in a nacelle ahead of wing, engine and propeller.