What was found
AFT RT SILL (FLOOR) FR 17-21 RBL 41"- RBL 49" HAS CORROSION AT FR 17. REMOVED AND REPLACED SILL REF. SRM 51-40-08. RESTORED SURFACE PROTECTION REF. SRM 51-23-04, 51-23-05, AND 51-23-06. SEE W/O H6609 SN 414 FOR WORK DETAILS. AIRCRAFT REMAINS IN HEAVY CHECK BNA.