Merlin III
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 97; Flight Crew Total 16500; Flight Crew Type 1150
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport
Aircraft
After level off at 8000 feet MSL the left engine oil pressure started to fluctuate. The lower part of the fluctuation arc was going into the yellow section of the oil pressure gauge. We decided to return to ZZZ and advised Departure Control of our decision. The controller approved a descent to 4000 feet and a turn toward a 10 to 12 mile final for at ZZZ. After arriving on final the fluctuations became more pronounced and we elected to shut the engine down. A safe landing was made.
SW3 Merlin Captain reported loss of oil pressure on left engine so the engine was shut down; and a return to departure airport executed.