A Boeing 737-232 aircraft of Delta Express, a subsidiary of Delta Air Lines, Inc., experienced an uncommanded rudder movement event while cruising over north-central Florida on September 28, 1999, the N.T.S.B. says. The short to medium-range Boeing airliner, registration N310DA, was delivered to Delta Air Lines in February, 1984.
The aircraft involved was cruising at Flight Level 310 near the city of Ponte Vedra Beach, Florida (approximately 65 nautical miles north of Ormond Beach VOR) on a flight from Washinton, D.C. to Orlando when the flight-crew reported that the plane suddenly yawed and rolled violently to the left. They applied 40 to 50 degrees of control wheel movement to the right and disconnected the yaw damper. The aircraft returned to normal flight and continued onto its scheduled destination.
Delta Air Lines personnel in Orlando stated that after the aircraft landed, the yaw damper coupler and the rudder power control unit were replaced, the aircraft was tested, and placed back into service. The Digital Flight Data Recorder was removed from the aircraft for evaluation, and the replaced rudder components will be disassembled and tested.