What was found
VISIBLE SMOKE IN CABIN DURING CRUISE. EMERGENCY LANDING/ NORMAL LANDING. NO ALARMS OR CAUTION LIGHTS ON CAUTION PANEL. BLEED NR 1 AND NR 2 ON. PACKS NR 1 AND NR 2 IN AUTO. DID NOT NOTICE ANY ENGINE FLUX. C/W FIM TASK 71-00-00-810-817, PAR 1-5 F. COULD NOT DUPLICATE SMOKE IN CABIN. C/W FIM TASK 71-00-00-810-817 STEP 5.G BORESCOPE OF THE NR 1 ENGINE. FOUND OIL IN HP TURBINE, GAS GENERATORE CASE AREA, ALSO BORESCOPED NR 2 ENGINE IAW ABOVE REF WITH NO DEFECTS. REPLACED NR 1 ENGINE IAW MTC:6710003 AND 6710004. ALL CHECKS GOOD, NO ODORS IN CABIN OR COCKPIT. RETURNED TO SERVICE.