What was found
A 1 INCH CRACK WAS FOUND IN THE WELD AREA OF THE TURBINE EXHAUST DUCT DRAIN LOCATED AT THE 6 O'CLOCK POSITION. OIL HAD PUDDLED INSIDE THE EXHAUST DUCT DUE TO A FAILURE OF THE POWER TURBINE SHAFT NR 3 BEARING SEAL. DUE TO THE HIGH TEMPERATURE, THE OIL COKED AND RETAINED THE LATENT HEAT LONGER THAN THE SURROUNDING AREA. THIS CONCENTRATED HEAT IS SUSPECTED TO HAVE CAUSED A THERMAL STRESS THAT INDUCED THE CRACK. THE AFFECTED ASSEMBLY WAS SENT TO P & WC FOR REPAIR.