What was found
(CAN) IN DESCENT AFTER GLIDER RELEASE AND AFTER EXTENDING FLAPS TO 27 DEGREES, PILOT NOTICED UNCOMMANDED ROLL TO THE RIGHT. VISUAL INSPECTION INDICATED THAT THE LEFT FLAP APPEARED TO BE IN APPROPRIATE POSITION, WHILE RIGHT FLAP WAS AT APPROXIMATELY 7-12 DEGREES. CONSTANT STICK LEFT WAS REQUIRED TO MAINTAIN LEVEL ATTITUDE. ON GROUND, BOTH FLAPS APPEARED TO BE OF SIMILAR DEFLECTION AT ALL SETTINGS. UNCOMMANDED ROLL ONLY OCCURRED AT FULL FLAP GREATER THAN 21 DEGREE SETTINGS.