In May 1942 was rushed northward to combat a Soviet offensive at Kharkov under the command of "Fliegerkorps" IV. I. "Gruppe" experienced Soviet air resistance almost immediately. "Kapitan" Ivan Pilipenko led six Polikarpov I-16s from 40 IAP and shot down three He 111s. The KG 55 war diary noted "Russian fighters had rarely appeared in such force as they had over this sector of the front." III "Gruppe" flew an average of 49 sorties per day, dropping 7.75 tons of bombs between 13 and 17 May. Days after the conclusion of Kharkov, KG 55 were involved in Operation "Wilhelm" against Volchansk, supporting the German 6. Armee's advance to capture the city and secure a staging area for Case Blue, the German summer offensive aimed and capturing the Caucasus oilfields. Kurt Pflugbeil, commanding IV "Fliegerkorps", ordered KG 55 and his bomber groups to support Army Group A's advance to the Don river. The capture of Rostov allowed the German army group to advance into the northern Caucasus. Bridges, rail and road transport—operational level interdiction—targets were KG 55's quarry. At this early stage in Case Blue, the "Luftfwaffe" had air superiority. III./LG 1, KG 51, and I./KG 100 supported KG 55. ZG 1 offered close air support and JG 52 and JG 53 provided fighter escort and air cover.