As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SJO - DURING C-CHECK, THE FUSELAGE BETWEEN BS 947 AND BS 967, BETWEEN STRINGERS 24L AND 27L, DOUBLER WAS FOUND WITH CORROSION. REPLACED FUSELAGE SKIN INTERNAL DOUBLER BETWEEN BS 947 AND BS 967 FROM STRINGER 24 TO 27 LEFT SIDE DUE TO CORROSION PER SRM 51-10-1 PAGE 5 AND SRM 51-30-2. (M)