What was found
ON A MAINTENANCE SERVICE CHECK, MECHANIC NOTED POPPED RIVET HEAD ON EXTERNAL SKIN, FRAME 21, LOWER LEFT SIDE, AND SEVERAL BULGES IN SKIN. UPON FURTHER INSPECTION, FOUND CORROSION BETWEEN SKIN AND TITANIUM STRAP. CUT OUT CORRODED AREA, FABRICATED AND INSTALLED DOUBLER AND FILLER AT FRAME 21 ON LOWER LEFT HAND SIDE SKIN IAW EMB 120 SRM 53-00-01 PG 208 AND 213.