What was found
WHILE PERFORMING 36 MONTH FUEL COLLECTOR TANK INSP, INSPECTOR WAS UNABLE TO LOCATE THE COLLECTOR TANK AFT DRAIN OPENING IN LT COLLECTOR TANK. REMOVED DRAIL LINES FROM LOWER NACELLE AREA TO INSERT PIN UP THROUGH DRAIN FITTING TO TANK AREA TO LOCATE HOLES BUT FOUND DRAIN HOLE PLUGGED. INSERTED DRILL BIT UP THROUGH DRAIN FITTING TO OPEN DRAIN HOLE COVERED OVER IN SEALANT. FOUND FWD HOLE CLEAR. WHILE INSPECTING RT SIDE, FOUND SAME CONDITION EXISTED. WITH THE FWD DRAIN HOLE OPEN, THERE WOULD BE NO WAY TO TELL IF A DRAIN WAS PLUGGED SINCE BOTH DRAINS ARE CONNECTED TO A SINGLE DRAIN FITTING ON THE LOWER OTBD NACELLE.