What was found
DURING CLIMB, FLIGHT CREW REPORTED HOT PLASTIC, VARNISH ODOR & SMOKE IN COCKPIT. TURNED OFF RECIRCULATION FAN & SMOKE DISSIPATED. ATTEMPTED PACK BURNOUT PROCEDURE IAW AMM 21-20-02-201 DURING WHICH BLACK SMOKE & SPARKS WERE OBSERVED EXITING NR 1 ENGINE TAIL CONE. AIR INTERRUPT, EMERGENCY DECLARED, AND LANDING UNEVENTFUL. R & R NR 1 ENG IAW MCCS 71-91-99 & 7948. LEAK & PERFORMANCE RUN ACCOMPLISHED IAW MCC 71-91-03. SYS CHECKED NORMAL. DAMAGE FOUND TO LPC STAGE 6 & ALL HPC STAGE BLADES & STATORS, ATTRIBUTED TO FOD OF UNKNOWN ORIGIN.