Golden Eagle 421
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 50; Flight Crew Total 4600; Flight Crew Type 80
Workload; Distraction
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Inflight Shutdown; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
Maintenance work had been performed on the right engine (E2); cylinders #2; 4; 6 pushrod seals. Valve covers were removed and reinstalled on each.Departed; and after being handed off to TRACON (ATC); pilot observed white smoke exiting right (E2) nacelle top louvers and oil streaming out of the inboard (left) side of the nacelle. ATC informed the pilot that someone in a truck at the end of the departing runway had noticed smoke coming from the right engine and asked if we were okay. Pilot informed ATC that (paraphrase) 'We're okay for now; probably residual oil left over from the maintenance work and washing.'After leveling at 11;000 MSL; pilot monitored E2 oil psi and oil temperature. No abnormal indications were noted for the first few minutes after leveling. Oil pressure began to decrease slowly and oil temperature remained unchanged. The pilot informed ATC that a return was needed. ATC issued a right or left turn at the pilot's discretion. The pilot turned left 180 degrees. During the turn ATC asked if fire equipment/trucks were requested.' Okay. Yes; that's probably a good idea just in case.' Upon wings level direct to [departure airport]; the pilot observed oil pressure further decreasing and a slight increase in oil temperature (oil PSI/temperature needles indicated in the gauges green arc).Before shutting down the abnormal engine; the pilot 'tested' the single engine flying capability by reducing the power to idle on the abnormal engine. Once the pilot confirmed that the normal working engine (E1) could maintain altitude; the pilot informed passengers (3) that the right engine would be shut down as a precautionary measure to avoid an unscheduled shutdown during approach/landing (critical phase of flight); to eliminate the distraction of monitoring the E2 gauges so as to focus attention on landing safely; and to preclude a possible vibration and/or fire from the affected engine. At this point the oil pressure and oil temperature were still operating in the normal ranges.The pilot completed the memory items for an inflight engine shutdown and then completed the appropriate emergency checklist. Once the E2 engine was shut down; secured; and appropriate checklists completed; the pilot informed ATC (now Tower as the hand off was given prior) that the engine had been shut down just to keep everyone in the loop who was helping during the situation. Tower requested the pilot enter left downwind to land. The pilot agreed and replied (winds were gusting up to 20 knots from the southwest). Tower cleared [us] to land. Pilot replied to clearance. A safe and successful landing was made and the aircraft was taxied to the ramp under its own power (E1).The same maintenance staff that had completed the work mentioned above immediately removed the E2 cowlings and inspected the engine. The problem was identified; corrected; and a maintenance log entry was made.
C421 pilot reported returning to departure airport after noticing smoke and decreasing oil pressure associated with the right engine.