Abstract: A TRACTOR OVERTURNED WHEN THE OPERATOR ATTEMPED TO MAKE A SHARP U-TURN. THE VEHICLE WAS CONFIGURED WITH A SINGLE WHEEL IN FRONT AND TWO DRIVE WHEELS IN THE REAR. THIS CONFIGURATION IS UNSTABLE WHEN SHARP TURNS OR U-TURNS ARE ATTEMPTED. A SECOND TRACTOR WAS BEING DRIVEN BY A CO-WORKER. HE STATED TO THE POLICE THAT BOTH TRACTORS WERE TRAVELLING SOUTH ON ARIZONA AVENUE (CHANDLER, ARIZONA) AT 20 MILES PER HOUR. THE OPERATOR OF THE OVERTURNED TRACTOR WAS DRIVING WITH HIS RIGHT HAND ON THE WHEEL AND A SOFT DRINK CAN IN HIS LEFT HAND. THE BRAKE PEDALS (LEFT AND RIGHT) WERE NOT LOCKED TOGETHER. THE DRIVER WAS ATTEMPTING TO MAKE A U-TURN WHEN THE UNIT OVERTURNED, PINNING THE OPERATOR UNDER THE SEAT AND AXLE.