Incident Overview
During the approach, while the aircraft was on the downwind leg at an estimated airspeed of 155 miles per hour, a severe vibration developed. This vibration was caused by the separation of the outer portion of the right ruddervator and the counterweight for the left ruddervator from the airframe. Throughout the descent and approach, no turbulence was encountered.
Pilot Response
In response to the vibration, the pilot closed the throttle and extended the landing configuration in an attempt to slow the airplane. The pilot subsequently made an uneventful landing at the intended airport.
Examination Findings
A post-flight examination of the ruddervators revealed that both were out of balance. The imbalance resulted from a combination of unauthorized sheet metal repairs, improper paint application techniques, and the use of a locally manufactured counterweight. These factors collectively led to the imbalance that allowed the components to separate from the airframe during flight.