and served with 1. Staffel of Kampfgeschwader 253 from 1 March to 30 April 1938. He was then posted to the Jagdfliegerschule (Fighter Pilot School) at Werneuchen, under the command of Oberst (Colonel) Theodor Osterkamp. Since July 1938, he served as a Staffeloffizier (squadron officer) with the Stab of I. Gruppe (1st group) of Jagdgeschwader 77 (JG 77—77th Fighter Wing), which later became IV./Jagdgeschwader 51 (JG 51—51st Fighter Wing). This unit underwent a series of redesignations which started with VI./Jagdgeschwader 132 (JG 132—132nd Fighter Wing), was renamed on 2 November 1938 to I./Jagdgeschwader 331 (JG 331—331st Fighter Wing). While based at Breslau-Schöngarten (currently called Copernicus Airport Wrocław), it was redesignated again, this time to I./JG 77 on 1 May 1939, which was redesignated to IV./JG 51 on 21 November 1940. World War II World War II in Europe began on Friday 1 September 1939 when German forces invaded Poland. Nordmann claimed his first aerial victory when he shot down a Polish PZL.43 on 3 September 1939. Nordmann achieved his next victory during the Battle of France and seven more in the Battle of Britain. He was appointed Staffelkapitän (squadron leader) of the 12. Staffel (12th squadron) of Jagdgeschwader 51 (JG 51—51st Fighter Wing) on 1 March 1940, replacing Oberleutnant (First Lieutenant) Erwin Neuerburg who became Staffelkapitän of 7. Staffel of Jagdgeschwader 3 (JG 3—3rd Fighter Wing). In this function, he was promoted to Oberleutnant on 1 April 1940. Nordmann was victorious over two Royal Air Force (RAF) Supermarine Spitfires on 17 October 1940 and achieved his ninth aerial victory on 6 May 1941. In June 1941, JG 51 and the majority of the Luftwaffe were transferred to the Eastern Front in preparation for Operation Barbarossa, the invasion of the Soviet Union. On 20 July 1941 Nordmann was appointed to command IV./JG 51, succeeding Major Friedrich Beckh who was selected to command JG 51 as Geschwaderkommodore (Wing Commander). Command of the 12. Staffel was passed on to Oberleutnant Heinrich Bär. Less than two weeks later, on 1 August 1941 Nordmann was awarded the Knight's Cross of the Iron Cross () after a total of 31 victories which was presented to him by General der Flieger Bruno Loerzer. Unteroffizier (Sergeant) Franz-Josef Beerenbrock flew as Nordmann's Rottenflieger (wing man) around this time. Nordmann achieved his 40th victory in total on 16 August and his 50th on 28 August. Only three weeks later he