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 REPORTED LEVEL 2 CORROSION ON CENTER FUSELAGE III UNDER FLOOR AT STR 21L BETWEEN FR 88-89. MAINTENANCE (REPAIRED) REMOVED AND REPLACED STR 21L BETWEEN FR 88-89 IAW ETD2019-170-032802 AND SRM 53-23-03. AIRCRAFT IS CURRENTLY STILL OUT OF SERVICE FOR HEAVY CHECK COMPLETION.