members swore an oath of loyalty to Adolf Hitler, were subject to German disciplinary regulations, and wore Luftwaffe uniforms. After attending Luftwaffe training schools, the fighter group was sent to the Eastern Front and designated as 15. (Kroatische) Staffel (squadron) of III. Gruppe (Group) of Jagdgeschwader 52 (52nd Fighter Wing, or JG 52). Meanwhile, Dukovac was transferred to the Luftwaffe Flugzeugführerschule A/B 120 (pilot school 120) in Prenzlau, Germany in September or October. In April 1942 he underwent advanced training, and in June he was transferred to Jagdfliegerschule 4 (fighter pilot school 4) at Fürth. In October 1942, Leutnant Dukovac and seven other pilots joined 15./JG 52, which was operating in the Caucasus flying Messerschmitt Bf 109G-2 fighters. On 29 October, Dukovac had his first 15-minute familiarisation flight, and by the afternoon of that day the new members of the unit were flying as wingmen to the veteran pilots of the Staffel. First victory On 11 November 1942, Dukovac was flying his 12th mission, escorting Junkers Ju 87 Stuka dive bombers to Lazarevskoye. During the mission, he and his companion were intercepted by Polikarpov I-16 Rata fighters, and Dubovac downed one of the attackers over the city of Tuapse to register his first confirmed aerial victory. Dukovac was unable to build upon his success at this time, as four days later the whole Staffel rotated back to the NDH because most of the personnel had endured a year of constant combat. The men of 15./JG 52 had a break of three months, commencing their return journey on 12 February 1943, collecting their aircraft at Kraków in German-occupied Poland on 18 February then flying to Lvov. They flew on to Nikolayev on 21 February. The Eastern Front had changed significantly during their absence, with the strategic initiative passing to the Soviets. Second tour On 30 March 1943, 15./JG 52 transferred from Nikolayev to Kerch, and it flew the first missions of its second tour the following day. On 15 April, Dukovac and Feldwebel Viktor Mihelčić took off on a patrol of the Krymskaja–Abinskaja area, and Dukovac shot down a US-made Bell P-39 Airacobra. Five days later, Dukovac was late taking off and was catching up to his Schwarm when he downed a LaGG-3 fighter during an engagement with four of the Soviet aircraft, but there were no witnesses to confirm his claim. Later that day, he and three other pilots were