Date: 201708
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Dash 8-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
ATC / advisory: TRACON ZZZ
Aircraft component: Turbine Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Executed Go Around / Missed Approach; Flight Crew Landed in Emergency Condition
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Flight had been conducted normally during the beginning phases of flight (engine start; taxi; pre-takeoff; takeoff). Upon completion of our 'after takeoff' checklist we noticed a significant torque discrepancy with our number 2 engine. The power levers were set even; but the #2 engine was not producing the requested power. In order to compensate for this problem; we advanced the respective (#2) power lever further up from the initial setting and this action gave us a power lever split/gap of approximately 1.5 to 2 inches. However; we decided to continue; and as we climbed our power demand was increasing as well; which ultimately aggravated the split/gap between our power levers. We noticed that the #1 engine was responding normally; but not our #2.We decided to stop the climb at 6;000 feet and better investigate the abnormality. First; we did 'the cruise checklist' and after that slowly increased the power on both engines up to 99.5% plus torque; we did have an even power indication; but the #2 power lever had a split/gap of 2.5 plus inches; and couple seconds later the #2 torque started to develop an un-commanded increase. We fixed this situation by moving the # 2 power lever to normal power settings. We performed this test to verify our malfunctioning engine behavior at high power settings in case of a 'go-around'. Then; we decided to test our engines at low power settings (landing behavior); #1 engine responded normally; but #2 started to reduce its power very slowly. We did have an even torque of 50%; 40%; 30%; and 10%; but with a significant and constant power levers split. At the end of this test; we decided to return to [our departure airport] and notified ATC as well as to our flight attendants.While moving the power levers only the number #1 engine responded properly; the other engine stayed at 7% torque and did not respond to any power lever commands or setting. I would like to mention that all other engine indications such as Interstage Turbine Temperature (ITT); fuel flow; Hn; Hl were normal; additionally; weather conditions were VFR with light winds. At this point; we decided to fully shut down #2 engine; [request priority handling]; conducted our E/A checklists (engine failure checklist; engine clean up) and continued back to the airport.During the landing configuration as we were working with the single engine landing checklist; we were unsuccessful trying to extend the landing gear and decided to go missed and try a second attempt. The aircraft was stabilized on final approach just above 1;000 feet AGL; but not fully configured; and the landing checklist was stopped at 'configuration to go' 'final checks-memory response'. After the go around; we worked with the respective checklist (single engine missed approach) and followed with the 'alternate gear extension' check list; which performed successfully and allowed us to land safely.Upon landing on the runway we were able to take 'X' intersection and the aircraft couldn't taxi because the nose gear steering system was disabled (probably related to the loss of #2 main hydraulic pump). Emergency crews inspected the aircraft and found no significant damage or safety concerns; and finally; ramp personnel towed us back to gate where we deplaned. I would like to mention that this was an overweight landing; and the 'brace' signal was not used.


Second narrative: [Report narrative contained no additional information.]


Synopsis: DHC8-200 crew reported an unresponsive #2 engine on climb out that was shut down. On return to the airport; the landing gear did not extend which necessitated a single engine go around; an alternate gear extension and eventual successful landing.