What was found
THE ACFT WAS ON APPROACH, TOWER REPORTED SMOKE COMING FROM THE LT ENGINE. THE ACFT LANDED WITHOUT INCIDENT. UPON INSP OF LT ENGINE, FOUND OIL LEAKING FROM REAR TURBINE BEARING HOUSING. SUSPECT REAR TURBINE BEARING SCAVENGE PUMP FAILURE AND SUBSEQUENT SEAL FAILURE CAUSING LOSS OF OIL INTO EXHAUST STREAM. THERE WAS NO EVIDENCE OF OIL LOSS FORWARD OF THE REAR TURBINE BRG. TEARDOWN REPORT CONFIRMED THAT THE REAR TURBINE BRG FAILED. SCHEDULED ENGINE CHANGE. RETURNING UNSERVICEABLE ENGINE TO O/H FACILITY FOR TEARDOWN AND EVALUATION. TEARDOWN REPORT RECEIVED 2/28/07. PN BEARING HAS A LIFE OF 3500 HRS. DUE REPLACEMENT IAW SB TPE331-72--180R31. BRG DUE REPLACEMENT WITH BRG PN 3108098-1, SB TPE331-72-0189R31.