RWY EXCURSION BY LTT DURING LNDG PROC ROLLOUT.

Narrative

UPON LNDG ON RWY 10 AT IYK; THE CAPT PULLED THE RPM LEVERS TO LOW AND THE ACFT STARTED TO DRIFT R. I MADE SURE THE R RPM LEVER WAS LOW TO ENGAGE THE NOSE WHEEL STEERING (NWS). THE CAPT PUSHED THE STEERING BUTTON ON THE L PWR LEVER TO OVERRIDE ANY STEERING MALFUNCTION. HE ALSO PUSHED THE PARK BUTTON TO GAIN MORE STEERING AUTHORITY. STILL; WITH FULL L RUDDER; L BRAKE; FULL L REVERSE; AND POSITIVE R THRUST; THE ACFT CONTINUED TO DRIFT R. WE LEFT THE RWY ABOUT 7 KTS; 1700 FT FROM THE ROLLOUT END. THE ACFT CAME TO A STOP ABOUT 30 FT OFF THE PAVEMENT. THE NWS THEN RESPONDED NORMALLY TO INPUTS SO WE TAXIED BACK ONTO THE PAVEMENT AND TO THE GATE. NONE OF THE 8 PAX WERE INJURED. THE ACFT SUSTAINED 1 BENT PROP TIP FROM A LARGE BUSH. THIS WAS THE SECOND LEG AFTER A 13 HR OVERNIGHT SO BOTH CREW WERE VERY FRESH AND ALERT. THE ACFT HAD BEEN WRITTEN UP 2 DAYS PREVIOUS FOR A SIMILAR PROBLEM BY ANOTHER CREW. ACCORDING TO THE MAINT LOG THE PROBLEM HAD BEEN CORRECTED. I FEEL THAT EVERYTHING THAT COULD BE DONE WAS DONE. I DO NOT KNOW IF THE ACTIONS TAKEN WERE CORRECT BUT I FEEL THAT THEY WERE.