COMMUTER LTT HAS NOSEWHEEL PROB ON LNDG ROLL; RWY EXCURSION.

Narrative

AIRLINES FLT FROM DTW TO LEX. WX WAS 25000 FT THIN SCATTERED; WINDS WERE 190 DEGS AT 4 KTS AND RWY CONDITIONS WERE CLEAN AND GOOD BRAKING ACTION. ON LNDG TO RWY 22 (CAPT WAS PF); WITH A NORMAL APCH AND CHKLISTS ALL COMPLETE; A TOUCHDOWN WAS MADE IN THE TOUCHDOWN ZONE AT VREF. AFTER NOSEWHEEL CONTACTED DRY PAVEMENT; CAPT (PF) SELECTED REVERSE THRUST. 2 BETA LIGHTS WERE OBSERVED AND CALLED OUT BY ME (FO; PNF). AT 90 KTS; I CALLED OUT JUST THAT '90 KTS' AND CAPT THEN SELECTED FULL REVERSE; OBSERVING NO ADVERSE YAWING. ACFT WAS MAINTAINING CTRLINE AT THIS POINT. AT APPROX 70 KTS; ACFT BEGAN TO VEER TO R SLOWLY AT FIRST; THEN MORE QUICKLY AS TIME PROGRESSED. CAPT (PF) BEGAN APPLYING L BRAKE BUT IT DIDN'T CORRECT SIT. THEN CAPT (PF) APPLIED FULL L BRAKE AND L RUDDER. ACFT CONTINUED TO R. I (FO; PNF) PULLED L PWR LEVER AFT TO TRY AND CORRECT; BUT IT WAS ALREADY FULL AFT SO THERE WAS NO CHANGE IN DIRECTION. PLT (CAPT) ENGAGED NOSEWHEEL STEERING BUTTON BUT NOW ACFT VEERED FURTHER R WITH L BRAKE AND RUDDER FULLY APPLIED. CAPT (PF) DISENGAGED STEERING BUTTON PRIOR TO LEAVING RWY. WE OBSERVED NO NOSE STEERING BUTTON FAIL LIGHT. ACFT MAINTAINED R TRACK; LEAVING PAVEMENT AT APPROX 60-70 DEG ANGLE FROM CTRLINE. ACFT STOPPED 35 FT OFF RWY. NO FIRES OCCURRED; AFTER LNDG AND SHUTDOWN CHKS WERE COMPLETED; I (FO) ASSISTED PAX OFF ACFT INTO FBO VAN. CAPT NOTIFIED AUTHS. NO INJURIES OCCURRED. NO RWY LIGHTS WERE DESTROYED. ACFT WAS NOT DAMAGED AND TOWED TO MAINT. AFTER TALKING WITH MAINT; THE SAID PROB WAS CAUSED BY A FRAYED AND DISCONNECTED GND WIRE THAT CAUSED NOSEWHEEL STEERING TO COCK TO 1 SIDE AND FAIL IN THAT POS. ACFT IS A FAIRCHILD METRO 3 WHICH IS NOTORIOUS FOR NOSE STEERING PROBS. SYS HAS BAD DESIGN FEATURES AND SHOULD BE CORRECTED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT HIS COMPANY HAS THE BIGGEST METRO FLEET OF ANY ACR AND THEY EXPERIENCE SUCH PROBS FREQUENTLY. HE FEELS IT IS A BASIC DESIGN PROB. THE CHIEF PLT WHEN CHKING OUT THE PLTS ALWAYS ASKS IF THE PLT HAS GONE INTO THE WEEDS YET. CHIEF PLT THEN ADDS; IF YOU HAVEN'T; YOU WILL. APPARENTLY THE SYS FAILS AND COCKS THE NOSEWHEEL TO ONE SIDE AND THERE IS NO CTL. SOMETIMES THE TURN IS 90 DEGS AND THERE IS NO WAY TO REMAIN ON THE RWY. RPTR SAYS THIS IS TRUE IN THE EARLIER MODELS OF THE METRO AS WELL; NOT JUST THE 3.