Narrative:

After a normal takeoff; I called for the after takeoff checklist. When the captain was done with his radio calls; he started to perform the checklist. Suddenly; there was a loud noise and then a repetitive smacking noise similar to that of a seatbelt hanging outside of a fabric aircraft. I immediately felt the need to add right rudder and noticed the left wing drooping. I added all the right rudder I could and lifted the left wing. I then applied right rudder trim to help; but it still was not enough to compensate. We continued to climb. I kept our speed at 148 KTS while the captain identified the problem as a left engine failure; with the inputs I was giving on the controls and a quick look at the gauges; I agreed. The captain performed the memory items and engine failure checklist as I continued flying and handled talking to center. We decided to declare an emergency; get vectors; and return to ZZZ for a landing since it was the nearest suitable airport. I was asked to maintain 3;800 ft by center. I reset the altitude selector to 3;800 ft from 5;000 ft; but then did not attain the altitude because we were already above 3;800 ft. I received a higher clearance. I noticed the right engine torque gauge indicating 112%. I mentioned the torque setting to be high. Once we did level off; we maintained 5;000 ft; which we did receive clearance for. As the captain was performing his checklists; I pointed to the high torque indication on the right side; which was now 118%; and then proceeded to start to ease back the right power lever. The captain stopped me; informing me the constant torque on takeoff was not yet off (for fear of bringing the power lever below the 64 pla and disengaging the constant torque on takeoff automatically). I released my hand from the power lever and waited until the constant torque on takeoff had been turned off in the checklist before making any more power lever adjustments. We continued to receive headings from ATC while the captain finished the checklist and tried multiple times to contact dispatch. I operated the right engine at 80% torque and 1230 propeller RPM to maintain 5;000 and a speed near 200 KTS. We continued to set up the aircraft for a landing on runway 31; verifying with the use of the ILS runway 31. I landed the aircraft without issue; informing the captain of the awkward rudder input needed. As he took over the controls on the ground; I adjusted the rudder trim for him; notifying him of the change. We taxied off of the runway with ease and proceeded to the ramp. The fire truck was waiting for us and followed us to the gate. A normal after landing and shut down checklist were completed. The passengers deplaned in our normal fashion without issue.

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Original NASA ASRS Text

Title: SF340 flight crew details their response to a failure of the left engine.

Narrative: After a normal takeoff; I called for the After Takeoff checklist. When the Captain was done with his radio calls; he started to perform the checklist. Suddenly; there was a loud noise and then a repetitive smacking noise similar to that of a seatbelt hanging outside of a fabric aircraft. I immediately felt the need to add right rudder and noticed the left wing drooping. I added all the right rudder I could and lifted the left wing. I then applied right rudder trim to help; but it still was not enough to compensate. We continued to climb. I kept our speed at 148 KTS while the Captain identified the problem as a left engine failure; with the inputs I was giving on the controls and a quick look at the gauges; I agreed. The Captain performed the memory items and Engine Failure checklist as I continued flying and handled talking to Center. We decided to declare an emergency; get vectors; and return to ZZZ for a landing since it was the nearest suitable airport. I was asked to maintain 3;800 FT by Center. I reset the altitude selector to 3;800 FT from 5;000 FT; but then did not attain the altitude because we were already above 3;800 FT. I received a higher clearance. I noticed the right engine torque gauge indicating 112%. I mentioned the torque setting to be high. Once we did level off; we maintained 5;000 FT; which we did receive clearance for. As the Captain was performing his checklists; I pointed to the high torque indication on the right side; which was now 118%; and then proceeded to start to ease back the right power lever. The Captain stopped me; informing me the Constant Torque on Takeoff was not yet off (for fear of bringing the power lever below the 64 PLA and disengaging the Constant Torque on Takeoff automatically). I released my hand from the power lever and waited until the Constant Torque on Takeoff had been turned off in the checklist before making any more power lever adjustments. We continued to receive headings from ATC while the Captain finished the checklist and tried multiple times to contact Dispatch. I operated the right engine at 80% torque and 1230 propeller RPM to maintain 5;000 and a speed near 200 KTS. We continued to set up the aircraft for a landing on Runway 31; verifying with the use of the ILS Runway 31. I landed the aircraft without issue; informing the Captain of the awkward rudder input needed. As he took over the controls on the ground; I adjusted the rudder trim for him; notifying him of the change. We taxied off of the runway with ease and proceeded to the ramp. The fire truck was waiting for us and followed us to the gate. A normal after landing and shut down checklist were completed. The passengers deplaned in our normal fashion without issue.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.