History of Flight  On April 27, 1995, about 1735 eastern
daylight time, Northwest Airlines flight 352, an Airbus
A320-211, N331NW, while on visual approach to runway 18 at
Washington National Airport, experienced what the Captain
reported as several uncommanded roll oscillations up to 30
degrees of bank. The crew executed a go-around. On the second
approach another roll was experienced and the crew landed the
airplane. There was no damage to the aircraft. The flight crew,
cabin crew, and passengers did not report any injuries.  The
Captain's report of the incident stated, "Below 200 ft aircraft
started rolling left and right. Max stick couldn't control the
aircraft. Went around. On second approach at 50 ft aircraft
started to roll again. We landed. We were 7 miles behind a 757
and a 727 took off just before we landed. No mech faults found."
Diagnostics were conducted on the flight control systems and no
reason for the roll oscillations was found. The airplane was
placed back in service.  Meteorological Infor