As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE A/C WAS IN FOR HEAVY CHECK FOUND LT ENGINE FIRE EXT DISCHARGER TUBE HAS LIGHT SURFACE CORROSION IN INBOARD FLAP WELL ABOVE AFT PYLON AND INSIDE PNL 522CB. MX REMOVED AND REPLACED LT ENGINE FIRE EXT DISCHARGER TUBE INSIDE PNL 522CB IAW EMB 175 AMM 20-10-03. P/N 170-08084-403. A/C REMAINS IN CMH FOR HEAVY CHECK COMPLETION.