What was found
(CAN) WHEN THE CREW INITIATED DESCENT TO APPROACH, FUME/MIST IN THE CABIN WAS REPORTED. THE CREW SHUTOFF THE NR 1 BLEED SYSTEM AND UNEVENTFULLY LANDED AT THE DESTINATION. THE CREW REPORTED THAT THEY HEARD A KNOCKING SOUND FROM LT SIDE OF THE COCKPIT/ENTRY DOOR DURING T/O. POSSIBLY SURGE/STALL ON NR 1 ENGINE, MAINTENANCE REPORTED EVIDENCE OF WET OIL AROUND THE 2.7 BLEED VALVE. OPERATOR DECIDED TO REPLACE THE NR 1 ENGINE. THE NR 1 ENGINE, SN PCE FA0224 WAS INSTALLED TO THE ACFT ON 8TH NOV 2011. TSCO/CSCO IS 1011FH/1194FC. REASON FOR THE LAST SHOP VISIT WAS HOT SECTION REFURBISHMENT. THE ENGINE WAS SENT BACK TO ANA POWER PLANT SHOP FOR BORE SCOPE. REFER TO THE ATTACHED FINDINGS, THE LEAK IS LIKELY FROM NR 3 BEARING CARBON SEAL. THE ENGINE IS IN TRANSIT FOR TEAR DOWN INVESTIGATION.