The Schweinfurt-Regensburg missions are a famous example of the failure of the self-defence concept. On August 17, 1943, 230 USAAF bombers launched a mission against the ball bearing factories in Schweinfurt and another 146 against the aircraft factories in Regensburg. Of this force, 60 aircraft were lost before returning to base and another 87 had to be scrapped due to irreparable damage. The Germans claimed 27 fighters lost, serious enough, but small in comparison to the losses on the part of the US forces. The Second Raid on Schweinfurt on October 14, 1943, remembered as "Black Thursday", proved even more bloody; of the 291 aircraft on the mission, 60 were lost outright, with a further 17 damaged beyond repair. Daylight missions into Germany were cancelled in order to rebuild the forces.