Arado Ar 66 was a two-seat training biplane, developed in 1933 and had an Argus As 10 air-cooled engine(240 hp), which drove a 2.5 m two-blade propeller. It was also used for night ground-attack missions on the Eastern Front. The crew consisted of two: instructor pilot and trainee, seated in open tandem cockpits equipped with dual controls and aircraft was equipped with instrument flight systems with photographic cameras were mounted as optional equipment.