There is an award list of a Il-2 rear gunner from the 448th ShAP which probably describes (or presents a version) Frädrich being shot down 26 July 1944.

The award list claims that while on a combat mission in Narva area mladshiy leitenant Bakharev's Il-2 was shot down by a Fw 190. Bakharev parachuted first. Right after that the rear gunner starshina Litvinov managed to shot down a Fw 190 which appeared 30 meters away from the falling Il-2. Then also Litvinov parachuted and landed on Soviet territory. The German pilot from the Fw 190 parachuted and was captured by Soviet ground troops.

The award list can be read here:
http://podvignaroda.mil.ru/?#id=3063...DetailDocument