What was found
PIT - FLT 111 - AT 30,500 FEET, THE NR 1 ENGINE EXPERIENCED A FIRST AND SECOND COMPRESSOR STALL. CREW STARTED DESCENT AND GOT A THIRD STALL. CREW PULLED THROTTLE BACK AND COMPRESSOR STALLS CEASED. CREW CONTINUED DESCENT AND DIVERTED TO PIT WHERE THE FLIGHT LANDED SAFELY WITH NO FURTHER INCIDENT. MAINTENANCE REPLACED THE NR 1 ENGINE ASSEMBLY PER JOB CARD. OPERATIONAL CHECK AND LEAK CHECK NORMAL. (M)