SR20
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 13; Flight Crew Total 2900; Flight Crew Type 189
Situational Awareness
Aircraft Equipment Problem Critical
Aircraft Aircraft Damaged; Flight Crew Landed As Precaution
Aircraft
35 - 40 minutes into the flight while on downwind we experienced a bouncing up and down of the aircraft - like a very fast light chop - a regular rhythmic motion at several times/ second. I saw that the right aileron was bouncing up and down at the trailing edge - oscillating. I then looked at the left aileron and saw that it was not bouncing up and down. Immediately; I told the pilot flying that we need to land the plane now. Intermittent; periodic oscillations continued to occur as we turned base; flaps 50% were deployed. Turn to final was completed and full flaps were deployed. Shortly after leveling from the turn to final the right aileron departed the aircraft.Control was maintained and the aircraft continued on final without incident. The NTSB was notified of the incident later that evening. Prior to the incident flight; a preflight walk around was completed with no damage; issues noted. I did a full deflection control check while taxiing out for takeoff. No issues in control feel or deflection were noted.
Flight Instructor flying SR20 reported aerodynamic flutter on aileron surface.