SR20
Workload; Time Pressure; Troubleshooting
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification
Aircraft
The aircraft was operating normal during initial climbout; at around 1;200 ft; 105 kt cruise climb; full power; and pilot under instruction under the hood. As soon as we switched over to Departure Control the engine suddenly began to shake violently. The Instructor took over controls; leveled off at 1;600 ft and reduced the power. At 50% power; the engine roughness ceased. The instructor informed Departure Control requesting turnback to the airport. As the aircraft was being vectored back; the instructor began to slowly increase the power lever. Power was restored and the roughness was gone. Continued with a non-emergency visual short approach. During short final the engine roughness came back at idle; and once more during taxiback to ramp.
Flight Instructor reported engine vibrations on climb out resulted in a return to the departure airport.