As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY CHECK MAINTENANCE FOUND CRACK ON RIB 12A INTERNALLY ON LH HORIZONTAL BETWEEN MID SPAR AND FRONT SPAR JUST AFT OF 4TH RIVET FROM FRONT SPAR UPPER RIVET ROW. REMOVED AND REPLACED RIB 12A ON LH HORIZONTAL REF SRM 51-40-08. A/C REMAINS IN CHECK.