What was found
PAE - FLT NR 3791 - DURING ROUTINE SCHEDULED C-4/S-1 MAINTENANCE CHECK, FOUND CORROSION AT AFT SERVICE DOOR THRESHOLD SUPPORT STRUCTURE X3254, 3 CM FORWARD OF FR 68, Y-1250, Z-540. REMOVED CORROSION AND CUT OUT UPPER FLANGE. FABRICATED PART AND INSTALLED AT 3254, Y1250, Z-540 PER SRM 53-00-14.