A CANADAIR CL65 ON TKOF ROLL. AT 20 KTS THE ACFT MOVED HARD R FROM THE RWY CTRLINE. TKOF ABORTED. SECOND ATTEMPT AFTER CHKLISTS COMPLETED RESULTED IN HARD R TRACKING. TKOF ABORTED.

Narrative

AS INITIAL TKOF ROLL COMMENCED (FO'S TKOF) ALL ENG INSTS APPEARED NORMAL. AT APPROX 20 KTS; ACFT STARTED TO MOVE HARD R FROM RWY CTRLINE. FO MADE COMMENT AS TO ACFT TRACKING. ABORT WAS CALLED. I TOOK OVER ACFT AND NOTED IT TOOK HARD FULL L RUDDER TO KEEP ACFT ON RWY. XWIND WAS 7 KTS. EXITED RWY. AFTER LNDG CHKS COMPLETED; NO UNUSUAL SETTINGS NOTED. CTL CHK REDONE. IT WAS EVERYTHING NORMAL. SECOND TKOF ATTEMPT STARTED. AT SAME POINT ACFT BEGAN HARD R TRACKING TAKING FULL L RUDDER AND MY BRAKE TO CTL HDG. TKOF ABORTED. RETURNED TO GATE. ACFT TURNED OVER TO MAINT. ON TAXI BACK TO GATE; PAX TOLD OF ACFT TRACKING PROB AND WOULD BE RETURNING TO GATE FOR MAINT. REBOARDED ALL PAX LATER ON ANOTHER ACFT AND THEY SEEMED HAPPY TO BE GOING TO ZZZ1. ADDITIONAL: AFTER FIRST TKOF ATTEMPT; I OBSERVED NO MECHANICAL DISCREPANCIES; MALFUNCTIONS OR ABNORMALITIES REGARDING THE ACFT CTLS; INCLUDING STEERING. THEREFORE; I CONCLUDED MAYBE THE FO MISAPPLIED THE CTLS/BRAKES DURING THE FIRST TKOF ATTEMPT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CAUSE OF THE ACFT TRACKING PROB IS UNKNOWN; AS MAINT DID NOT ADVISE THE CREW OF THE CORRECTIVE ACTION.