What was found
YYZ - DURING C-CHECK INSPECTION, THE LEFT HAND UPPER COWLING (425AT) WAS FOUND TO BE CRACKED AT THE LEFT HAND CHANNEL. MAINTENANCE REMOVED AND REPLACED THE AFFECTED CHANNEL IN ACCORDANCE WITH ATR42-320 SRM 54-12-61, AND 51-25-01, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.