Narrative:

Experienced unusual and significant vibration in the yoke; rudder pedals; flight crew seats and power levers after takeoff. The vibration was significant enough to be noticed by flight attendants in the cabin. I asked the #1 flight attendant to investigate the problem and he informed us that it seemed more noticeable in the aft cabin and his opinion was that this condition was unusual in his experience. First officer was flying pilot. We transferred controls twice during the flight trying to assess the problem and I was unable to determine a specific input that made the condition change. Autopilot was never engaged. I contacted maintenance to acquire more information about the history of the aircraft. The first officer and I decided the best course of action was to return to the departure airport. We noticed the vibration during all phases of flight; both high and low airspeed. A jump seating pilot from another airline later told me he felt the vibration lessen when the power settings were low during descent and approach. He was sitting in the first row. First officer noticed an unusual feel on the rudder pedals after selecting yaw damp off early during the approach. He also mentioned the aircraft rolled significantly left when flaps 15 were selected. I briefed the flight attendants; made a PA to the passengers and followed the normal checklists and returned for a normal landing.

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Original NASA ASRS Text

Title: ATR72 Captain reports strange vibration felt in the flight controls and throughout the aircraft shortly after takeoff. After some discussion and trouble shooting flight returned to departure airport.

Narrative: Experienced unusual and significant vibration in the yoke; rudder pedals; flight crew seats and power levers after takeoff. The vibration was significant enough to be noticed by flight attendants in the cabin. I asked the #1 Flight Attendant to investigate the problem and he informed us that it seemed more noticeable in the aft cabin and his opinion was that this condition was unusual in his experience. First Officer was flying pilot. We transferred controls twice during the flight trying to assess the problem and I was unable to determine a specific input that made the condition change. Autopilot was never engaged. I contacted maintenance to acquire more information about the history of the aircraft. The First Officer and I decided the best course of action was to return to the departure airport. We noticed the vibration during all phases of flight; both high and low airspeed. A jump seating pilot from another airline later told me he felt the vibration lessen when the power settings were low during descent and approach. He was sitting in the first row. First Officer noticed an unusual feel on the rudder pedals after selecting yaw damp off early during the approach. He also mentioned the aircraft rolled significantly left when flaps 15 were selected. I briefed the flight attendants; made a PA to the passengers and followed the normal checklists and returned for a normal landing.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.