What was found
FORWARD LOWER CARGO FUSELAGE STATION 412 LBL 46 LOWER SIDE OF UPPER CHORD, BELOW CARGO FLOOR, IS SPLIT WITH INTERNAL CORROSION AT NUTPLATE LOCATION. REMOVED PDU L1 & L2, REMOVED ROLLER TRAYS. R & R DRILLED & INSTALLED CORD PT STATION 412, REINSTALLED ROLLER TRAYS, & PDUS IAW B767-200 SRM 51-40-02, AMM 25-53-52 & DRAWING 141T1224. LEVEL 2 CORRODED, LOC STATION 412 LBL46 PN 141R1224Y6, PN 141R1224Y6, SN NA. AIRCRAFT WAS GROUNDED.