Well, an ex military pilot at smolensk blog has suggested that in his view Capt. Protasiuk planned "to do a rat" (don't know if it's the same), because he thinks him quite able to follow the recommended glidepath if he intended to. He thinks the Capt. recognised his resource deficiencies, of un-trained manual approach, that he knew it will be very exhausting enterprise to enter on the runway without deviation in fog when guided by just 2 beacons, instead of ILS, that he didn't trust the dilapidated aerodrome and its ATC entirely, that he knew he will get limited support from hs crew, also untrained to get oriented in fog by two beakons plus what the controller says, add to this the Capt. had no time even for go-around, no time for second attempts, as they were awfully late for the ceremony beg.
He thinks the Capt., given these limitations, would try "to do a rat". Namely (as I understood it), to lower to 40 metres height before the runway, and possibly even down to 20, given the time the plane would take to assume parallel to the ground flight sorry for my un-avionic English, then go parallel along hoping to see the runway right below in front, and, should he see it being too leftwards or too rightwards - to go away what to do, but should the runway appear suddenly more or less straight ahead - to turn down to it.
With chances 50/50 provided the ground below has no those hills and holes. (of which the Captain didn't think)
It was pointed out by several folks in the smolensk place that what the Yak said to TU was not passed over to Capt. Protasiuk in full beauty.
Namely, to Capt Protasiuk was re-told that the Yak saw the ground at 50 metres, that the Yak thinks the border of the cloud is there.
But then Yak added, re visibility, "its total xxxxx here now" - which the second pilot did not copy-say to Protasiuk, telling him only ab 50 metres. According to the transcripts. In effect, Capt. Protasiuk could have formed an idea that lower than 50 metres it is more or less alright with visibility. And got interested in crossing those 50 metres "level".
It's not that that Russian pilot thinks it's alright to do those "rats" but his idea explains, at least, why the crew kept cool, Captain was following his plan, was not lost and dis-oriented, not perfect as it were - there was still a plan behind what he was doing. There were simply a bit of holes in that imperfect planning - the actual landscape, for one thing.
Just an idea.