What was found
DURING ROUTINE C-CHECK INSPECTION, INSTL; FWD LAV DRAIN MAST PLUG AT LOWER CENTER LINE. PERFORMED MAJOR REPAIR IAW FAA FORM 8110-3 DATED 01-19-06, ATI DWG H74-102 REV B DATED 01-19-06, EO SEMAN 2006114 DATED 01-19-06. REMOVED EXISTING DRAIN MAST IAW DC8 SRM 51-3-0. FABRICATED REPAIR DOUBLER (AL7075T6 0.125) IAW ATI DWG H74-102. CLEANED, TREATED AND PRIMED AREA + REPAIR DOUBLER IAW DC8 SRM 51-1-8B. APPLIED SEALANT TO FAYING SURFACES IAW DC8 SRM 51-1-11. INSTALLED REPAIR DOUBLER IAW ATI DWG H74-102, DC8 SRM 51-3-0, DC8 SRM 51-3-1 (TORQUE).