What was found
ER/A 634152-14; A220-300 / REAR BARREL FUSELAGE WASTE BOX INTERNAL DOUBLER & SERVICE DOOR CORROSION. SUBJECT REPAIR REQUIRES FOLLOW-ON ACTION. ACCOMPLISH 634152-14, SECTION II REPETITIVE INSPECTION WITHIN EVERY 1,000 FLIGHT HOURS FROM 13,074 TOTAL AIRCRAFT FLIGHT HOURS AS OF 27APR26 UNTIL SECTION III IS ACCOMPLISHED. ACCOMPLISH SECTION III PERMANENT REPAIR WITHIN 10,000 FLIGHT HOURS FROM 15,032 TOTAL AIRCRAFT FLIGHT HOURS AS OF 27APR26. ADDITIONAL ENGINEERING AUTHORIZATION (ER/A REVISION) IS REQUIRED FOR FLIGHT BEYOND THIS LIMIT. ASSOCIATED ER/A 14-634152 ADDED FOR AC 8304. (LP# 1580561; AIRCRAFT WAS GROUNDED)