This day Lt. Boos shot down his 8-10 VVS aircraft in two seperate missions during the late afternoon. Both times he was covering the back of his commander Oblt. Karl-Gottfried Nordmann. The aircraft claimed this day by him was all Soviet recognaissance airceaft, One R-5 shot down at 17:15. the next one a R-10 who was downed at 19:33 and the final abscüsse for the day, a R-3 downed five minutes later. The commander of IV./JG 51 and his wingman was a deadly combinations this day, with Nordmann claming another three recognaissance aircraft during the same two missions.

This machine was lost five days later, on 7 August, when Boos experiance engine problems and have to belly land his machine, resulted in 100% damage. Althoug nothing is mention about he beeing wounded, he was not able to score before 12 November 1941. perhaps he was just shaken up by the ordeal?

Oblt. Karl Boos would score his two last kills on 20 April 1943, flying as the commander of 1./JG 51 he downed two La-5s. However the next day he was was forced to bail out after an air combat, unfortunatly his chute failed to open and he fell to his death. In total Karl Boos was by the time of his death credited with a total of 41 victories.