Any proofs? Everywhere articles says that accident was during joint exercise.
You can read the details here using google translate if you like: https://ru.wikipedia.org/wiki/Катастрофа_Ту-154_над_Чёрным_м...
No, I mentioned it because a joint Russian-Ukrainian exercise is unthinkable now.
And yet you wrote it was not a joint exercise. Russia Today can be proud of you, comrade!
[0] https://en.wikipedia.org/wiki/Ukrainian_involvement_in_the_I...