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 PACK EMERGENCY VALVE PROFILE CRACKED. MAINTENANCE REMOVED AND REPLACED THE LEFT PACK EMERGENCY VALVE PROFILE IAW EMB 170 SRM 51-40-02, AND 51-41-01. THE AIRCRAFT IS OUT OF SERVICE IN HEAVY CHECK.