THE RIGHT FLAP PUSH ROD EXPERIENCED A PROGRESSIVE TYPE FAILURE FROM REPEATED EXCESSIVE FORCE BEING APPLIED BY THE FLAP DRIVE MOTOR. THE EXCESSIVE FORCE WAS CAUSED BY THE FLAP ROLLERS BEING NEGLECTED DURING MAINTENANCE TO THE EXTENT THAT THEY BECAME DRY AND SLID ON THE FLAP TRACK INSTEAD OF ROTATING. THE FLAP TRACK ALSO CONTAINED NOTICABLE WEAR ALTHOUGH THE LAST ANNUAL INSPECTION WAS COMPLETED ONLY THREE MONTHS PRIOR TO THE ACCIDENT. THE AIRCRAFT BECAME UNCONTROLLABLE DUE TO SPLIT FLAPS DURING THE FINAL PORTION OF ITS FINAL APPROACH FOR LANDING. THE AIRCRAFT TOUCHED DOWN BUT WAS VEERING LEFT. IN ORDER TO PREVENT A COLLISION WITH PARKED AIRCRAFT THE PILOT ADVANCED THE THROTTLE AND BECAME AIRBORNE. AFTER CLEARING THE PARKED AIRCRAFT THE PILOT ATTEMPTED A FORCED LANDING WHICH TERMINATED IN A GROUP OF TREES ON THE EDGE OF THE AIRPORT.