SA226 MADE UNCOMMANDED ROLL WHEN AUTOPILOT WAS DISENGAGED. CONTROL WAS REGAINED; AND FLT PROCEEDED TO THE ALT.

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I WAS BEING VECTORED FOR AN ILS RWY 17L AT AUS. THE AUTOPLT WAS USED DURING THE CRUISE AND DSCNT PORTION OF THE FLT. I DISCONNECTED THE AUTOPLT JUST PRIOR TO LOC INTERCEPT. AT THAT TIME THE AIRPLANE MADE AN UNCTLED TURN TO THE R. I NOW FOUND MYSELF USING ALMOST 45 DEGS OF YOKE TRAVEL TO THE L TO HOLD THE WINGS LEVEL. I SHOULD HAVE GONE MISSED APCH AT THIS TIME; BUT I DID TRY TO SALVAGE THE APCH WHICH WAS A MISTAKE ON MY PART. AFTER FINALLY MAKING THE DECISION TO GO MISSED; I BELIEVE THERE WERE SEVERAL HDG DEVS AND ALTDEVS BEFORE I HAD THE AIRPLANE COMPLETELY UNDER CTL. I THEN XFERRED FUEL FROM THE R WING TO THE L WING. THIS SEEMED TO CORRECT THE PROB. I THEN WENT TO MY ALTERNATE. AS PART OF THE DSCNT AND LNDG CHKLIST IS AN ITEM TO CHK FUEL QUANTITY AND BAL. ACCORDING TO THE GAUGES THERE WAS LESS THAN A 300 LB IMBAL (WELL WITHIN THE 500 LB LIMIT). WE ARE NOW WAITING FOR THE MAINT SHOP TO CHK THE ACCURACY OF THE FUEL GAUGES. ALTHOUGH I HAVE SEVERAL HUNDRED HRS IN THIS MAKE AND MODEL AIRPLANE; I ONLY HAVE APPROX 6 HRS IN THIS AIRPLANE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THE ACFT IS UNDERGOING AN AVIONICS UPGRADE; AND WILL ALSO UNDERGO A THOROUGH WT AND BAL ASSESSMENT. FUEL GAUGES WILL ALSO BE CALIBRATED AT THAT TIME. AT THIS STAGE; INACCURATE FUEL GAUGES ARE SUSPECTED.