As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT THE MAIN GEARBOX LOW OIL PRESSURE WARNING LIGHT ILLUMINATED INTERMITTENTLY AT IDLE. A NEW OIL PRESSURE TRANSMITTER WAS INSTALLED AND NO FURTHER FALSE INDICATIONS NOTED. THIS SWITCH HAS A MODERATE FAILURE RATE USUALLY BY LOSING ITS LOW END CALIBRATION AND ILLUMINATING WHEN AC IS IDLING. SUGGEST A DESIGN UPDATE IS REQUIRED TO IMPROVE THIS TRANSMITTERS RELIABILITY. (K)