SMA WITH LOW TIME PLT VEERS OFF RWY ON LNDG.

Narrative

DID A VERY COMPLETE PREFLT BECAUSE OF ONCOMING DARKNESS. PLAN WAS TO FLY IN PATTERN OF AMG AND PRACTICE TOUCH-AND- GO LNDGS. ON THE SECOND LNDG; AFTER FLARE; AND ON TOUCHDOWN; A SLIGHT VEER TO THE R WAS NOTICED BUT CORRECTED WITH L RUDDER. THE VEER TO THE R WAS NOT SIGNIFICANT ENOUGH TO ABORT PRACTICE. ON THE THIRD LNDG; MY PLAN WAS TO MAKE A SLOW APCH TO ELIMINATE ANY EXCESS SPD AT TOUCHDOWN. THE APCH WAS PERFECT. IMMEDIATELY AT TOUCHDOWN; THE AIRPLANE VEERED TO THE R. I GAVE HARD L RUDDER WITH NO EFFECT. AT THAT POINT I PUT SLIGHT L BRAKE INTO ACTION; AGAIN NO CORRECTIVE EFFECT. AT THIS POINT; I AM OFF THE RWY IN THE GRASS; STILL TRYING TO COME L. THERE IS A DITCH AT AMG APPROX 50 YARDS W OF RWY 15. THE AIRPLANE NOSED OVER INTO THE DITCH. BECAUSE OF THE SLOW APCH AND SLOW SPD THERE WERE NO INJURIES AND MINIMAL DAMAGE. I HIT MASTER SWITCH OFF AND GOT OUT BECAUSE I WAS CARRYING MAX FUEL. THERE ARE NO CONTRIBUTING FACTORS TO MY KNOWLEDGE; NO WIND; GOOD VISIBILITY; TEMP MID 50'S; NO MOISTURE. THERE ARE NO NEGATIVE FACTORS AFFECTING MY JUDGEMENT OR PERFORMANCE. I DO NOT KNOW THE CAUSE YET. I HAVE REFLOWN EVERY ITEM IN MY MIND MANY TIMES AND I CAN THINK OF NO MISTAKES OR ANYTHING THAT I COULD OR WOULD DO DIFFERENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES HE AND INSTRUCTOR HAVE GONE OVER THE EVENTS AND FEEL THERE WAS NOT MUCH ELSE HE COULD HAVE DONE. INSTRUCTOR SAYS THERE IS A TRENCH ON THE R SIDE OF RWY AND WHEN FIRST ENCOUNTERING THAT AREA SOMETHING MUST HAVE LOCKED UP. FBO OPERATOR ALSO CAME TO THE SCENE AND ACCEPTED THE INCIDENT AS 'JUST ONE OF THOSE THINGS.' ENCOURAGED RPTR TO FLY AGAIN AS SOON AS POSSIBLE. WHICH HE HAS DONE. FAA HAS DONE NO FOLLOW UP SINCE VIEWING THE SCENE.