What was found
(CAN) PROP GOVERNING MALFUNCTION #1 ENGINE, DURING TRAINING AT XXX AIRPORT. ACTIONED THE FAILURE WITH EMERGENCY CHECKLIST. SECURED ENGINE, LANDED MAINTENANCE TROUBLESHOOTING AIRCRAFT AND IN THE PROCESS OF REPLACING THE PROP CONTROLLER. PROP CONTROLLER WAS REPLACED AND DID NOT RECTIFY THE SNAG. PROP DOME WAS DISASSEMBLED TO CHECK SEALS AND PROP SEALS WERE FOUND TO BE TWISTED AND FLUID WAS BYPASSING IN PROP DOME. PROP SEALS WERE REPLACED. (TC# 20190422018)