As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - AFTER DEPARTING, PILOT EXPERIENCED OIL PRESSURE FLUCTUATIONS ON LEFT ENGINE. AIRCRAFT RETURNED TO BOS WIHOUT INCIDENT. MAINTENANCE REPLACED LEFT ENGINE OIL PRESSURE TRANSMITTER AND CANNON PLUG. ALL CHECKS WERE GOOD PER BEECH MM, CHAPTER 79. AIRCRAFT RETURNED TO SERVICE. (X)