Tecnam P2012 pilot reported loss of engine oil pressure in flight. Flight crew continued to destination; landed; and turned the aircraft over to maintenance.

Narrative

During cruise; approximately 20-25 mins from ZZZ the engine instruments were checked and the Captain; pilot monitoring; identified a fluctuation in oil pressure from the left engine. At that time; oil pressure was fluctuating within the green arc. We continued to monitor the fluctuation. Approximately 10 minutes later the fluctuation in oil pressure reduced and continued to fluctuate between normal operation and yellow caution range. Once the oil pressure fell into the yellow caution range; the Captain pointed out black smoke coming from the exhaust of the left engine. At that time; we began planning for possibly securing the engine and [requested priority handling]; if the oil pressure dropped any further. The QRH was pulled and we began reviewing procedures. I continued flying and monitoring flight controls while the Captain continued to monitor the engine instruments. Approximately 10 minutes from ZZZ; the oil pressure began fluctuating steadily in the yellow caution range and then progressively became worse between Yellow caution and Red warning. At that time; we decided to [request priority handling] with ATC with the possibility of securing the critical engine. We began to review engine securing procedures and confirmed them with the QRH. We reviewed what to expect if the engine was to be secured and what to expect upon landing with the potential of emergency landing areas. We worked with ATC to become a priority aircraft. We also decided to stay up higher and make a steeper approach as we would benefit from the altitude; should an engine be secured or seized on our approach. On approach; upon power reduction; the oil pressure fell steady into the Red Warning range. The approach and landing were safely completed without further incident. The airplane was met and followed into the gate by Airport Crash Rescue trucks. The airplane engine remained in operation and provided power for taxi until shut down at the gate area. Maintenance was contacted and [aircraft] towed back to the hangar. This is not the first time this has occurred. This particular airplane was written up just 3 days ago with the same issue; where the pilot also [requested priority handling]. Other airplanes are down for similar incidents; including Aircraft Y flown by Person A; which is grounded in ZZZ2. This seems to be a reoccurring issue in the Tecnam itself and not just isolated to a specific tail. The company needs to be made aware of the issue before it becomes catastrophic. Just today a few of the pilots stated they were beginning to feel unsafe operating the Tecnam airplane. Possible cylinder or engine issue.Replacement cylinders or replacement engines