What was found
FLT 270 ON CLIMBOUT, LEVEL 8000FT, FLT CREW HEARD 4-5 BANGS, WITH VIBRATION. CREW REVIEWED ENG & SYS PAGES OF ECAM, ALL NORM. NO ECAM MESSAGES OR WARNINGS. SUSPECT COMPRESSOR STALL, RETURNED TO EWR. LANDING UNEVENTFUL. BORESCOPED ENGINES NO DEFECTS NOTED. POWER ASSURANCE RUN PER AMM 71-00-00-710-008 UNSAT, DUE TO NR 2 ENG COMPRESSOR STALL ON GROUND RUN. ENG REPLACED. REMOVAL REASON CONFIRMED. CHORD WIDTH EROSION & DETERIORATION FOUND IN HPC. REMOVED/REPLACED HARDWARE, INCLUDING HPC BLADES & VANES IAW SBS & ENG MANUAL, TESTED PER THE 56-5B/P MANUAL. COMPLIED WITH AD 2002-13-03, AS APPLICABLE. RETURNED TO SERVICE.