Its actually not that old of a plane, its a Caribou on its final certification flight with a couple of new turbo prop Pratt and Whitneys. What happened was the pilot left the gust lock controls on. From what I understand the gust control locks lock only if there has been a movement of one of the control surfaces ( not the standard 172 yolk locks) so when the pilot began his acent the elevator and rudder locked into position causing the plane to stall, roll and crash into the ground.