What was found
IN CRUSE AT 34,000 FEET A CHANGE IN ENG TONE WAS NOTED. WITHIN 20 SECONDS THICK SMOKE ENTERED THE CABIN. PILOT DECLARED EMERGENCY AND DESCENDED. LT ENG 'OIL PRESSURE LOW' LIGHT CAME ON AROUND 20,000 FEET AND ENG WAS SHUTDOWN. AFTER SHUTDOWN THE SMOKE IN THE CABIN CLEARED UP. LANDING WAS MADE. THERE WAS NO DAMAGE TO THE ACFT AND NO ONE WAS HURT. SUSPECTED FAILURE IS THE NR 2 BEARING AIR/CARBON SEAL IN THE LT ENG WHICH CAUSE ENG OIL TO ENTER INTO COMPRESSOR SECTION OF ENG AND THEN INTO THE CABIN THROUGH THE BLEED PORTS. ENG IS BEING REMOVED FROM ACFT AND SENT TO REPAIR CENTER.