Dash 8-300
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft; Procedure
The First Officer was the pilot flying on this leg. On the takeoff roll the First Officer called 'set power' at the appropriate time; and I verified that he had correctly set the power (no adjustment was necessary). I called '70 KTS;' 'V1;' 'Rotate' and the First Officer began rotating to the command bars. As the nose wheel lifted off the ground; we both noticed a slight hesitation in the #1 engine as the torque initially dropped 5-10%. We continued through lift-off; adjusting the torque to takeoff power. We put the gear up and coming through 400-500 feet; the torque dropped to appox 75%.  The torque then shot back up 100%. At this point I advised Tower we were having engine issues and would need to return. The surges continued to become increasingly sporadic and as we approached acceleration height the surge dropped the torque so far that it triggered the autofeather system. Our plan just prior to this was to do a precautionary shutdown above acceleration height; but the plane took care of that for us. I declared an emergency for the engine failure while we ran the EAP for an engine failure below acceleration height. We completed the engine fire/failure checklist and engine clean-up items checklist. At this point I briefed the cabin on the situation and called the Flight Attendant; advising her of the situation; to prepare for an emergency landing with the anticipation of a completely normal landing in 5-10min. She indicated that the cabin was prepared and the passengers were all calm and cooperative. Being so close to the airport (at this point on a downwind vector from ATC) I elected not to call dispatch but rather to prepare for landing. We ran the single-engine landing checklist as we turned base. At this point all checklists were completed and we were cleared for the ILS. The approach and landing were normal in every way aside from the engine situation. ARFF was awaiting us but we advised we would not need their assistance after we exited the runway. We taxied back to the gate and parked without further incident.Since this is apparently the third time this plane has had a torque surge induced #1 engine shutdown; I suggest we either send the engine to Pratt & Whitney for complete overhaul or else scrap that engine before it gets someone killed. I'm trying pretty hard to be level headed here but; what are we doing? Whatever is being replaced each time this happens IS NOT WORKING. Stop putting band aids on this and fix it or get rid of it.
[Narrative provided no additional information].
DHC-300 flight crew experiences fluctuating torque on the number one engine at rotation that quickly increases in amplitude until auto feather is triggered. An emergency is declared and flight returns to the departure airport. This engine had a history of similar incidents.