As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON ETOPS WALKAROUND MAINTENANCE FOUND LOOSE PIECES OF HEAT PROOFING STICKING OUT OF THE #1 ENGINE THRUST REVERSER COWLING. UPON FURTHER INSPECTION FOUND THAT THE PNEUMATIC Y DUCT GOING TO THE HIGH PRESSURE TURBINE ACTIVE CLEARANCE CONTROL AND THE LOW PRESSURE TURBINE ACTIVE CLEARANCE CONTROL HAD RUPTURED. MAINTENANCE REPLACED THE Y DUCT PER AMM 75-21-10.