the overload failure of the horizontal stabilizers and elevators due to a pilot induced oscillation at a speed at or above Vne, which exceeded the design stress limits of the structure. Also causal was the intentional alteration by an unknown person or persons of the elevator down spring assembly, which likely reduced the stick force per G from a nominal 10 pounds to less than 1, and led to the pilot induced oscillation. An additional cause was the pilot's decision to operate the aircraft at, above, or near never exceed speed.