ACR FLYING AN SA227 LEAVES RWY AT LYNCHBURG; VA; WITH NOSEWHEEL STEERING PROBS.

Narrative

AFTER MAKING A NORMAL VISUAL APCH AND LNDG TO RWY 21 AT LYH (WHILE TRANSITIONING TO TAXI); IE; AERODYNAMIC FLT CTL HAD DECAYED. I ARMED THE NOSEWHEEL STEERING SYS WITH THE ARMING SWITCH AND ATTEMPTED TO ENGAGE THE NOSEWHEEL STEERING ENGAGE BUTTON ON THE PWR LEVER. THE NOSEWHEEL STEERING AT FIRST SEEMED TO ENGAGE FOR ABOUT A HALF SECOND; THEN I REALIZED I HAD LOST OR NEVER HAD NOSEWHEEL STEERING. THE ACFT WAS BY THIS TIME VEERING TO THE R TOWARDS A SNOW BERM AT THE RWY EDGE. I USED ALL THE OPPOSITE REVERSE AVAILABLE AND MAX BRAKING; BUT IT LOOKED LIKE AT LEAST THE R MAIN WOULD EXIT THE RWY. AT THIS TIME I STOPPED AND FEATHERED BOTH ENGS TO PREVENT DAMAGE TO PROPS AND ENGS WHILE STILL UTILIZING MAX BRAKING. THE ACFT CAME TO A STOP WITH THE NOSEWHEEL APPROX 15 FT OFF THE RWY AND THE R MAINS 12 INCHES OFF WITH NO DAMAGE TO OCCUPANTS OR ACFT. UPON INSPECTION THE NOSEWHEEL STEERING ENGAGE BUTTON ASSEMBLY WAS FOUND TO BE LOOSE. THE ACFT HAD BEEN SITTING FOR A WK ALTERNATELY FREEZING AND THAWING WHICH COULD HAVE CAUSED CONDENSATION TO FORM IN AND AROUND THE MICROSWITCH (NOSEWHEEL STEERING). ADDITIONALLY; BY THE WAY THE ACFT PULLED TO THE R IT COULD HAVE POSSIBLY HAD A FROZEN BRAKE.