Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
After takeoff from ZZZ; I went to pull the power back into climb power. Upon doing so I noticed severe engine roughness with the left engine; and the throttles were split several inches. I applied full power as I thought the left engine was going to quit. When I contacted departure; they advised that an Airport Operations vehicle witnessed billowing black smoke from the left engine as I entered the clouds. I left the power full as any time I brought the power back it felt like the left engine was going to quit. I notified ATC. They vectored me for the ILS XX; when i did bring the power back to fly the approach and land; the engine was smooth and did not quit. As a precaution I had the airport fire trucks come over and make sure there was no sign of fire or further smoke upon landing. They advised they didnt see anything unusual. I then taxied to the gate and wrote the airplane up.
Light Twin Cessna Captain reported an uneventful air return due to left engine severe engine roughness during initial climb.