The increasing numbers of Soviet armour led to a rethink in how to combat the threat. In the summer, 1943, Ju 87 crews had suffered heavy losses. The Henschel Hs 129 had suffered 495 losses from a total production of 664. It was decided to replace them with the Fw 190. On 18 October, "Sturzkampfgeschwader 1", "Sturzkampfgeschwader 3" and "Sturzkampfgeschwader 5" were renamed "Schlachtgeschwader" 1, 3 and 5. "Sturzkampfgeschwader 2" and "Sturzkampfgeschwader 77" were reformed as mixed fighter and dive bomber units. Two "Geschwader", "Schlachtgeschwader 9" and "Schlachtgeschwader 10" were formed to deal with the threat. It was not until March 1944 that the "Geschwaders" were able to exchange their Ju 87s for the Fw 190. Some units, such as the one commanded by Hans-Ulrich Rudel, continued to fly the Ju 87 (and Fw 190) until the end of the war. In the meantime, the Fw 190 units fought an increasing number of defensive battles. The Lower Dnieper Offensive and Second Battle of Kiev witnessed large scale air battles. During these actions, Walter Nowotny claimed his 256th and final victory on the front, and was nearly shot down himself on 11 November 1943. JG 54, operating the Focke-Wulf, claimed 71 victories in December 1943, for the loss of 14 Fw 190s. This represented a decreasing victory-to-loss ratio. However, the Soviets were gaining in number and quality. The Red Army was pushing back both Army Group South, and soon Army Group North. Only Army Group Centre remained in strong defensive positions. By the spring, 1944, the German fighter units victory to loss ratio had shrunk from 4:1 at the Battle of Kursk to 1.5:1. Soviet fighter aircraft were now equal to the "Luftwaffe's" best. "Schlachtgeschwader" losses amounted to 175, which included a number of Fw 190s.