Flight Crew Commercial
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Inflight Shutdown; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
After departing we noticed unusual sounds coming from the engine.   After examining the engine gauges we noticed the torque on the number 1 engine was over 125% and the RPM was approximately 400.  After we concluded that the aircraft had a number 1 engine unscheduled feather we preformed the appropriate checklist and shut down the number engine.  After handling the checklist I talked to the Flight Attendant and ATC.  The Captain continued to fly the plane while I ran the remainder of the Single Engine checklist.  After landing we had the fire department inspect the number one engine before taxing back to the gate.  After deplaning the passenger the Captain then called Dispatch.
After takeoff a DHC-8-100 number one engine autofeathered so with the appropriate checklist the crew shut the engine down and returned to the departure airport.