What was found
RIGHT ENGINE LOW OIL PRESSURE ANNUNCIATOR ILLUMINATED WITH THE MASTER WARNING LIGHT CLIMBING THROUGH ABOUT 3000 FT. THE OIL PRESSURE GAUGE INDICATED BELOW 20 PSI & WAS RED. FELT A SUDDEN CHANGE IN THRUST ON THE RT ENGINE. POWER WAS REDUCED ON BOTH ENGINES TO LEVEL THE ACFT AT 5000 & IMMEDIATELY RETURNED TO DEPARTURE. SMOKE WAS NOTICED IN THE CABIN & COCKPIT. ONCE THE POWER WAS REDUCED THE SMOKE SEEMED TO DISSIPATE. ON THE TAXIWAY & WHILE BEING INSPECTED THE OIL PRESSURE GAUGE WAS READING IN THE NORMAL RANGE. AFTER SHUTDOWN, THE RT ENGINE STARTED SMOKING FROM THE FRONT OF THE NACELLE. R & R THE RT ENGINE DUE TO INTERNAL FAILURE CAUSING OIL PRESSURE LOSS. HEAVY OIL IN & AROUND FAN NOSE CONE, EXHAUST & BYPASS AREA. ACCOMPLISHED LAW EMM 71-00-00 & 72-00-00.