This article
quotes an employee of the Smolensk airport, Mr. Alexiey Korochnin,a jet fighter pilot and chief electric engineer of the Seviernyi airport.
This is an interesting part of the above article:
Despite the fog everything proceeded ok until ca. 1.5 km before the airstrip. At that point the plane lost too much altitude and clipped the radiolocator tower and hit first trees. Pilots tired to save the aircraft but they failed and the aircraft already started falling apart. It hit trees again several meters above the ground and then crashed down. 'Pilots must had been top professionals' says Mr. Korochnin. They were reducing altitude very smoothly, almost with horological precision. They were only a few meters too low. Had they been flying some 10-15 m higher, they would manage to land safely. Their skills are also confirmed by the fact that the plane did not fall down all at once and it didn't fall apart immediately and didn't explode, but it was kind of falling apart piece by piece.
According to Mr. Korochnin, the plane did not deviate from the glidepath by as much as 150 m to the left, as it was reported by the Russian Minister Mr. Siergiey Shoygu. 'That was the result of the plane collision with trees' explains Mr. Korochnin. Pilot apparently tried to pull up the aircraft, lifting its right wing and this is why it deviated to the left but it all happened while the plane was already falling down, not during its flight. 'The plane was on the correct course. Pilots were very skillful. The problem was they should not attempt to land in that fog anyway' suggests Mr. Korochnin.