Event Description
During the descent for a landing approach, the pilot encountered an uncommanded roll divergence. The aircraft was at approximately 240 knots, in a clean configuration, and with power reduced at the time of the occurrence. The aircraft was following an MD-80 when the event occurred.
Pilot Actions
The first pilot was at the controls when the uncommanded rolls began. The captain assumed control early during the sequence. The initial divergence was a 20-degree right roll. As the right roll developed, the pilot applied a left correction, causing the aircraft to roll 30 degrees left. The pilot then applied right rudder, resulting in the wings returning to a level attitude. It was noted that the autopilot altitude hold was engaged.
Post-Event Examination
An examination of the flight control system failed to reveal any anomalies.