During the early days of the Belkan War, Rainer and Orbert flew interception tasks in Belka's southern defense line, the "Hydrian Line". In these days, the Gelb Squadron effectively served as "errand boys" for the Belkan military, flying as much as five sorties in a single day's span without even basic maintenance. As time passed and the southern battlefield expanded, logistics took a major blow, becoming increasingly infrequent or even paralyzed in wide areas. Despite these unfavorable circumstances, Rainer and his flight lead managed to rack up considerable kill scores.