As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON NOV 7TH, AE 857 FLIGHT EXPERIENCED THAT TWO FAN BLADE PLATFORMS FAILED CAUSING THE LT ENGINE TO HAVE HIGH VIBRATION. CREW FOUND LT ENGINE VIBRATION INDICATION POINTED TO 5 AFTER TAKEOFF. CREW FOLLOWED QRH, CONFIRMED ENGINE VIBRATION TRUE. A/C AIR TURNED BACK, AND LANDED SAFELY. GROUND INSPECTION FOUND THAT THE NR 19 AND NR 20 FAN BLADE PLATFORMS WERE RUPTURED. AND THE DEBRIS CAUSED TO SOME OUTLET GUIDE VANES DENT OR CRACK.