What was found
DURING HEAVY CHECK MAINTENANCE FOUND CORROSION - LH SILL AT FRAMES 13, 14, 15 AND 16. REMOVED DAMAGED LH SILL AT FRAMES 13-16. LOCATED, DRILLED, AND INSTALLED NEW LH SILL, AT FRAMES 13-16. SURFACE PROTECTION APPLIED. REF. SRM 51-40-08, 51-23-00. A/C REMAINS IN CHECK.