As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) NR 1 ENGINE MAKING (POPPING) SOUNDS. SOUNDS INCREASED WHEN THRUST LEVER INCREASED AND DECREASED WHEN THRUST LEVER RETARDED. BORESCOPE INSPECTION FOUND HPC BLADES DAMAGED BEYOND LIMITS. INVESTIGATION CONTINUING. (CASA NR 510001772)