I happened to have the Chinese Air Carriers timetable next to me when I saw this query.

The list of aircraft types at the front of the book includes the Tupolev TU-154, the Ilyushin IL-86, and the Antonov AN-24.

I started opening the book at random and after scrutinizing about 30 spreads had failed to find a single flight by any of these. Then I started picking Former Soviet Union destinations and found Tupolev flights between Irkutsk and Shenyang and Samara, as well as Yak-42 flights (I'm vaguely under the impression that's a Chinese-built plane, and I flew on one in Yunnan, but that's nearly 20 years ago). But these were with Siberian and Samara Airlines--not Chinese.

I also found Tupolev and Ilyushin flights between Novosibirsk and Beijing, but again with Siberian and Fulkovo--again not Chinese.

This isn't a comprehensive survey, but it seems unlikely that you'll find a domestic flight on Russian/Soviet aircraft now. Out of Beijing the only destinations are Novosibirsk, Pyongyang, and Saint Petersburg, all with non-Chinese airlines. Even MIAT flies a 737 (although I flew on a Russian machine domestically in Mongolia about five years ago).

Peter N-H