Smolensk forum just explained (to each other), that the previous, also Russian made, airplane, that brought in journalists, that very morning - HAD something Russian electronic for? can't explain. something for plane navigation a system allowing to go in fog. Will give a link.
And Kachinsky's TU - HASN'T. All TU-154 have, and TU-154M - and it was "M" - doesn't have it. According to Tupolev site, "when up-grading a TU154 into TU154M - that system is de?-molished? extracted out.
Likewise - when a TU154M, a new one is made to order - that navigation system is not included."
Strange "upgrade" to me
, taking something nice that allows to navigate blind is extracted, but may be in the new ones - now that foreign system is put instead, and the Russian old one is not incorporated any more into the new planes or the old planes when up-grading them.
So Kachinsky plane was in disadvantage by make-up, compared to ordinary Yak. I mean, he wasn't, since he had something that foreign good instead. But may be something that foreign was not appliccable at a Russian straightforward old aerodrome ?
So the previous plane could navigate in fog