As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE DOING PILOT TRAINING, THE LT OIL PRESSURE WARNING LIGHT CAME ON. PILOTS LOOKED DOWN AT OIL PRESSURE GAUGE, THE PRESSURE WAS DROPPING SO THEY SHUTDOWN THE ENGINE AND FEATHERED THE PROP. THEY RETURN TO BASE. ENGINE REMOVED FOR FURTHER INSPECTION. (TC NR 20080117007)