PA-44 Seminole/Turbo Seminole
Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Commercial
Flight Crew Last 90 Days 142; Flight Crew Total 1547; Flight Crew Type 60
Aircraft Equipment Problem Critical
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; Flight Crew Inflight Shutdown
Aircraft
After introducing an engine failure in flight to a student; after doing a full shutdown and restart; as I went to cruise the rpm out with the prop lever; the RPM's had no decrease and were above red line. I then used the 'Prop Overspeed Checklist' and completed it and there was little/no change. The left engine was producing strong vibrations and rattling so I made the decision to shut down the engine and secure it. I believe the propeller governor failed which caused the red line RPM which I was unable to reduce properly. To further prevent another occurrence of this situation; it is best for maintenance to check the governor more often to verify its usability.
PA44 instructor pilot reported a safe landing following the shutdown of an engine.