What was found
DURING HEAVY CHECK MAINTENANCE FOUND STGR 21L AND ATTACHED BONDING BRACKET CORRODED AT ATTACHMENT BETWEEN FR 89-FR90. REMOVED DAMAGED PORTION OF STGR 21L, FROM FR 88 - 90.5. LOCATED, DRILLED AND INSTALLED REPAIR FILLER AND REPAIR SPLICE, ON STGR 21L, AT FR 88 - 90.5. SURFACE PROTECTION APPLIED. REF EMB ETD2020-170-007474. A/C REMAINS IN CHECK.