On August 9, 2003, a Sabena Brussels Airlines Airbus Industrie A330, registered in Belgium as OO-SFO, had to return to Brussels, Belgium after the pilots felt a vibration in the left engine, a General Electric CF6-80E1turbofan. The airplane was enroute from Brussels at is cruising altitude of 35,000 feet when the pilots reported feeling a short duration, heavy vibration. The pilots reduced the power to idle and returned to Brussels for an uneventful landing. The investigation of this incident is under the jurisdiction of the Belgium Ministry of Communications and Infrastructure. This report is for information purposes only and contains information that was release by or obtained from the Government of Belgium. Further information pertaining to this incident may be obtained from: Ministry of Communications and Infrastructure Air Accidents and Investigations Center Communication North - 4th floor Rue du Progres, P.O. Box 5 B-1039 Brussels, Belgium Fax: (32) 2 277 4260