re "why they don't give us the exact time of the crash"; Smolensk site believes that 16 min later is when it was officially, like, verified, may be ? written in some procedural ? books. Registered. May be the time when the aerodrome staff and the meeting, Polish group staff - made it onto the scene.
First were definitely fire brigades, they drove the run-way and turned right into the? field - but stuck there - the first truck turned around spoke it's no go from this side, drove the run-way back, so that others don't follow them here, and they drove to the crash side from the outer, other side.
But they find important to pin-point it as several media wrote "at 8:50 the plane ...." "flying over... and "at 9 o'clock the aircraft" noting that at "8:50" the aircraft and at "9 o'clock" "the aircraft" - did nothing of the kind. As has crashed already.
There was even a joke there, on the site, that the investigation committees - Polish and Russian - wait for what this on-line Smolesnk investigation blog has to say on the matter - afraid to publish something - and get wrong - against Smolesnk forum facts!