SMA TAXI IS TOO FAST; RUNS OFF END OF RWY.

Narrative

I WAS TAXIING AT MEM AT XA30 PM SBOUND ON TXWY BB IN A TWIN SMA. I FELT THAT I WAS FAMILIAR WITH THE ARPT DUE TO MY FREQ OF USE OF THE TXWYS AT MEM. UNFORTUNATELY; I WAS NOT FAMILIAR WITH THE S END OF TXWY BB. I DECIDED TO TAXI AT A FASTER PACE THAN NORMAL TAXI SPD TO REDUCE THE OPERATING COST OF THE AIRPLANE. TO SAVE THE WEAR ON THE WING LIGHTS I DECIDED TO LEAVE THEM OFF. THE COMBINED CONFIGN OF A HIGH SPD TAXI; A REDUCTION IN FORWARD ILLUMINATION; AND UNFAMILIARITY OF THE TXWY IN USE; SET THE STAGE FOR A DANGEROUS SIT. SEVERAL FT BEYOND THE END OF TXWY BB; THE GRASS SURFACE DECLINES AT ABOUT A 15 PERCENT GRADE APPROX 20 FT VERTICALLY. BY THE TIME I SAW THE END OF TXWY BB; I WAS UNABLE TO CEASE FORWARD MOTION OF THE AIRPLANE BEFORE LEAVING THE END OF THE TXWY ONTO THE GRASS SURFACE. UNFORTUNATELY; I DIDN'T STOP FULLY UNTIL I WAS ON THE UPPER PART OF THE DECLINING SURFACE. FORTUNATELY; NO ONE WAS HURT AND THE AIRPLANE DID NOT RECEIVE ANY DAMAGES; BUT EMBARRASSINGLY THE ACFT HAD TO BE TOWED FROM THE DECLINING SURFACE. I LEARNED THAT THE RISK OF LIVES; POTENTIAL DAMAGE TO THE AIRPLANE; POTENTIAL SUSPENSION OF MY AIRMAN CERTIFICATE; AND A $200.00 TOWING FEE; COSTS A LOT MORE THAN A FEW TENTHS OF THE HOBBS METER.