NOSEWHEEL STEERING PROB CAUSES LTT TO VEER OFF RWY DURING LNDG ROLL.

Narrative

UPON LNDG ROLLOUT ON RWY 29R THE FO WAS FLYING AND AS THE ACFT SLOWED DOWN; THE CAPT AT 60 KTS TOOK CTL OF THE ACFT AND CALLED FOR SPD LEVERS LOW. I PROCEEDED TO BRING THE SPD LEVERS BACK AND IN A MATTER OF SECONDS THE ACFT ABRUPTLY TURNED TO THE R. THE CAPT USED RUDDER AND BRAKES TO TRY TO STRAIGHTEN THE ACFT OUT. THIS WASN'T WORKING AND WERE STILL IN A SHARP R TURN. THE CAPT SWITCHED THE NOSEWHEEL STEERING OFF BUT IT ALL HAPPENED TOO FAST AND WE CAME TO REST ABOUT 50-100 FT OFF THE R SIDE OF RWY 29R. NOBODY WAS INJURED AND IT APPEARS THAT NO DAMAGE TO THE ACFT OCCURRED. I BELIEVE THE CAPT DID THE BEST JOB HE COULD UNDER THESE CIRCUMSTANCES. THE ACFT WAS OUT OF CTL WITH NO WARNING ON THE ANNUNCIATOR PANEL AND MANUFACTURER HAS TO DO SOMETHING ABOUT THE NOSEWHEEL STEERING ON THE LTT. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR SAID THE NOSEWHEEL STEERING IS NOT ENGAGED DURING THE EARLY STAGES OF THE LNDG BUT IS ENGAGED WHEN THE SPD LEVERS ARE BROUGHT TO THE LOW POS. HE SAID IT WAS STRANGE; THERE WAS A 4-5 SECOND DELAY AFTER THIS ACTION BEFORE THE NOSEWHEEL GAVE A HARD-OVER R TURN AND THE ACFT LEFT THE RWY. HE SAID 2 WIRES WERE FOUND DISLODGED AND WERE THE APPARENT CAUSE OF THE PROB. THE CAPT HAD TO TAKE HIS L HAND OFF THE YOKE AND GET TO A TOGGLE SWITCH ON HIS CONSOLE TO TURN OFF THE NOSEWHEEL STEERING. THIS IS WHY HE COULDN'T TURN IT OFF IMMEDIATELY. THE NOSEWHEEL WAS FOUND IN THE FULL R POS.