What was found
AIRCRAFT DEPARTED AS FLIGHT 81391 REPOSITIONING EMPTY UNDER FAR 91. 15 MINUTES INTO FLIGHT THE PIC NOTED OIL PRESSURE FLUCTUATIONS FOLLOWED BY DECREASING OIL PRESSURE. THE PIC DIVERTED AND ENROUTE NOTED TORQUE FLUCTUATIONS OF APPROXIMATELY 500 FT/LBS. THE PIC LANDED AND OTED OIL INSIDE EXHAUST PIPE AND ON RT SIDE OF AIRCRAFT. PRELIMINARY MAINTENANCE INSPECTION REVEALED THAT DAMAGE OR DETERIORATION TO THE CARBON SEAL IS LIKELY THE CAUSE OF THE OIL LEAK AND SUBSEQUENT OIL PRESSURE FLUCTUATIONS. (K)