This looks like a deliberate provocation by Turkey. They shoot down the plane and take credit within half an hour, the pilots are killed by bullets while decending midair, the helicopter looking for the pilots is hit by an American TOW missle, and everything is nicely recorded and video clips posted online.
There seemed to be a lot of goodwill between Russia and France after the tragedies and there were hopes for a united fight against ISIS and a political solution in Syria. Turkey just killed any chance of that.
It has been a loooong time coming, the turks have told Russia not to intrude turkish airspace and told them, they would shoot them down, if it happen again, which it did.