Still more speculation about radio systems
Sukhoi.ru etc can tell: "According to the bulletin of the Tupolev Design Bureau, during the modernization of the Polish Tu-154 to version Tu-154M, the RSBN system was dismantled...
...but the Yak-40 has RSBN-7C". Therefore 36SPLT Yak-40 pilot, Lt. Arthur Wosztyl probably could tell whether he had an opportunity to try to use RSBN or not during the approach (ref: sukhoi.ru).
According to several sources the airport radio navigation systems were not in official use - although allegedly tested after the accident.