As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE AIRCRAFT WAS IN HEAVY CHECK MAINTENANCE FOUND THE LEFT HORIZONTAL STABILIZER LEADING EDGE NUMBER 4 RIB CRACKED. MAINTENANCE REPAIRED THE LEFT HORIZONTAL LEADING EDGE NUMBER 4 RIB IAW EMB ETD 2013-170-003578. THE AIRCRAFT IS OUT OF SERVICE IN HEAVY CHECK.