Perhaps a combination of the plane tumbling a bit while (quite literally) falling out of the air, and the pilot overcorrecting then freezing, as the pane gets just enough air speed (from gravity) to "amplify" the tumble. -Stoic Joker
There is a point where air-speed is totally unuseable for the flaps/ailerons. Turning the controls left or right will have NO EFFECT. The only useable control surface at this point will be the Horiontal Stabilizers, in which the pilot would push down the controls forcing the nose down, therefore gaining enough airspeed for the other control surfaces to be useable. Of course, when your that close to the ground you don't have enough time to gain airspeed before the aircraft impacts the ground.
IF he had of been flying lite (empty cargo) then he would have had enough thrust from the engines to power out of the stall condition with little loss of altitude. This is why most aircraft incidents happen during landing and takeoff (mostly landing), it's when your flying at minimum airspeeds where the loss of forward flight can happen with just a few knots too little.
There's an old pilot saying: "Flying is the second most exciting thing you can do. The first most exciting is landing", which, by the way, was always the funnest thing about flying to me. There were many of my flights where I never left the traffic pattern just doing "touch and go's" for hours at a time. It really sharpens your flying skills since it's the most difficult to do, but I just think it's fun.
