Complex sentence: Following his 83rd aerial victory, Müncheberg was summoned to his commanding officer, "Geschwaderkommodore" Schöpfel, who informed him of his transfer to Jagdgeschwader 51 (JG 51--51st Fighter Wing) on the Eastern Front.
Split into simpler sentences: Following his 83rd aerial victory, Müncheberg was summoned to his commanding officer, "Geschwaderkommodore" Schöpfel. Schöpfel had to informed him of his transfer to Jagdgeschwader 51 (JG 51--51st Fighter Wing) on the Eastern Front.