As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) LOSS OF RGB OIL PRESSURE DURING TRAINING FLIGHT, AIRCRAFT EXPERIENCED LOSS OF RGB OIL. PILOT WAS FORCED TO MAKE AN UNSCHEDULED LANDING. INVESTIGATION REVEALED LOSS OF OIL PRESSURE WAS CAUSED BY A LOOSE TEE FITTING ON THE OIL PRESSURE SWITCH DUE TO THE HELICOIL COMING OUT OF THE RGB BOSS. GEARBOX IS BEING REMOVED FOR REPAIR.