Cessna Twin Piston Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport
Aircraft; Weather
On climb out through 4;500 feet right engine began running rough with black smoke. Returned to ZZZ and landed after notifying ATC. Black smoke indicated a mixture issue.
During climb out; aircraft performance began to deteriorate. Full power was set and the aircraft struggled to maintain greater than 110 KIAS and climb beyond 200-300 FPM. Shortly after initiating full power an unusual vibration was noticed by Captain; and I noticed an unusual amount of black smoke trailing from the engine. Given the icing weather conditions and potential engine issue the Captain made the decision to return to ZZZ as we had only gotten to VOR 1 at time of incident. With the amount of ice accumulating on the aircraft; full power was necessary to maintain a safe airspeed. Conferred with Maintenance post-flight and they believe smoke was due to a mixture-rich situation. Icing + over rich engine mixture.
Air carrier flight crew reported icing and engine vibration after takeoff.