What was found
DURING ROUTINE C CHECK INSPECTION, NOSE SECTION. RT PRIMARY HEAT EXCHANGER AFT LWR CORNER HAS STRUCTURAL MODIFICATION CRACKED .7500 ON DOUBLER STA 12.000 L-27R. PERFORMED MAJOR REPAIR IAW MM 53-30-09, EO SEMAN NR 20051205 DATED 09-21-05. REMOVED FASTENERS IAW SRM 51-1-21. REMOVED DAMAGED SECTION IAW SRM 53-30-09 PG 207. PERFORMED NDT INSP OF REWORKED AREA IAW NDT SPM PART 06-10-01-001. NEITHER CRACK NOR CORROSION FOUND. FABRICATED REPAIR DOUBLER (AL7075T6 0.100) + FILLER (AL7075T6 0.100) IAW MM. CLEANED, TREATED, PRIMED AREA + REPAIR PARTS IAW SRM. APPLIED SEALANT TO FAYING SURFACES IAW SRM 51-1-11 PG 9. INSTALLED REPAIR PARTS IAW MM 53-30-09 PG 201-202, 208-209, SRM 51-1-20D, SRM 51-3-1 (TORQUE).