3 decal variants:
1. Arado Ar 66C, Nationalist Spanish A.F., 1937
2. Arado Ar 66C, Czechslovakia, airfield Přelouč, 1946
3. Arado Ar 66C, Romania, was captured from the Luftwaffe, 1945
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.