What was found
DURING ANNUAL INSPECTION, FOUND LT AND RT ELEVATOR TRIM TAB TO HORN FAYING SURFACE/CORRODED. HORN PN 44337-3 FAYING SURFACES EXHIBIT LEVEL 1 CORROSION (RUST). DUE TO SURFACE CONDITION, UNABLE TO ESTABLISH IF FAYING SURFACES TREATED/PRIMED/COATED PRIOR TO INSTALLATION. TRIM TAB PN 44020-9 AND DASH 10 FAYING SURFACES EXHIBIT LEVEL 2 CORROSION. ESTABLISHED FROM SMALL UNCORRODED AREA, NO SURFACE PREPARATION WAS CARRIED OUT PRIOR TO ASSY. UNCOATED DISSIMILAR METALS AND MODULE INGRESS IS FACTOR. CONSIDERING FLEET AGE (20 PLUS YEARS), SUBMITTER SUGGESTED ONE-TIME INSPECTION FOR PROPER SURFACE PREPARATION AND POTENTIAL CORROSION CLEAN-UP.