What was found
CREW REPORTED VIBRATION (AIRCRAFT LEFT) ON TAKEOFF ROLL. THE NR 1 ENGINE N1 VIBRATION INDICATION WAS 5.0 JUST AFTER LIFT OFF. VIBRATION INCREASED TO 7.5 N1 AMBIENT TEMP. TEMP AT TAKEOFF WAS +14 C. AN EMERGENCY WAS DECLARED AND AIRCRAFT RETURNED TO CLT. POST FLIGHT INSPECTION OF NR 1 ENGINE INDICATED A BIRD STRIKE. BLADES NR 35 AND NR 17 WERE REPLACED IAW AIRBUS MAINTENANCE MANUAL 72-21-00-300-020. TO BE SUBMITTED AFTER CONFIRMATION OF PART/SERIAL NUMBERS FOR SECOND FAN BLADE. PART/SERIAL NUMBER PROVIDED FOR SECOND FAN BLADE REPLACED.