What was found
(CAN) ON PRE-FLIGHT INSPECTION, THE FLIGHT CREW NOTICED A LARGE TEAR ON THE OTBD SECTION OF THE RT AILERON. THE TEAR STEMMED FROM THE OVERLAP BETWEEN THE L/E AND T/E SKINS. MM 27-10-00, PG 202 HAS A SPECIAL NOTE TO INSPECT THIS AREA OF THE RT AILERON. UNFORTUNATLY, DESPITE REGULAR INSPECTIONS OF THIS AREA, A VISUAL INSPECTION OF THE OVERLAP WAS NOT ADEQUATE TO DETECT A PENDING PROBLEM. THE AILERON IS A MAGNESIUM SKIN. THE ACFT IS CURRENTLY GROUNDED, PENDING THE ARRIVAL OF A NEW AILERON.