As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - NR 1 ENGINE FAILED SCHEDULED BORESCOPE INSPECTION. FOUND ONE HPT 1 BLADE 2/3 MISSING AND TWO BLADES CRACKED. REPLACED ENGINE. OPERATIONAL CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE. ENGINE UNDER INVESTIGATION AT GE. INVESTIGATION BY THE ENGINE MANUFACTURER (GE) HAS BEEN COMPLETED. IT HAS BEEN CONCLUDED THAT MODIFICATION OF THE HPT1 DAMPNER (ALONG WITH RE-WORK OF THE ACCLERATOR) IS THE CORRECTIVE ACTION FOR THE REMOVED ENGINE. A PLAN HAS BEE DEVISED TO INCORPORATE THIS MOD IN THE NEXT FEW QUARTERS.