What was found
(CAN) CREW REPORTED THAT THE FLAPS OPERATED NORMALLY ON APPROACH, WHEN SELECTED TO FLAPS 45. AFTER LANDING AND DURING TAXI, WHEN THE CREW SELECTED FLAPS 0, THEY RECEIVED A FLAP FAIL AND THE FLAPS REMAINED AT 45. CONTRACT MAINTENANCE RETRIEVED THE CODES FROM THE FECU AND THE IDENTIFIED A POSSIBLE MISRIG OF THE BPSU. THE FLAPS WERE THEN CYCLED THREE TIMES WITH NO FAULTS FOUND, A/C WAS RETURNED TO SERVICE. BPSU RIGGING WAS CHECKED SERVICEABLE. THE A/C WAS FLOWN FOR A BEAM REPAIR AND IT WAS DECIDED THAT TASK RJ2-275002 (FLAP LUBE AND INSPECTION WOULD BE COMPLETED.) IT WAS DISCOVERED THAT LT AND RT NR 2 FLAP FLEX DRIVES WERE UNSERVICEABLE, ONE WAS WORN, THE OTHER HAD A SLIGHT KINK AND REQUIRED REPLACEMENT. BOTH WERE REPLACED AND THE FLAP SYSTEM WAS CHECKED SERVICEABLE. (TC NR 20070917007)