What was found
AIRCRAFT STRUCK ONE, POSSIBLY TWO SEAGULLS ON TAKEOFF, IMMEDIATE VIBRATION FELT. TAKEOFF ABANDONED AND AIRCRAFT RETURNED TO GATE. MAINTENANCE CONDUCTED 'BIRD STRIKE INSPECTION' PER MM 05-51-18, DAMAGES FOUND AT NR 1 ENGINE FAN BLADES NR 11, 12, 13. FURTHER INSPECTION REVEALED BLADES 11 AND 12 DAMAGED BEYOND LIMITS, BLADES 11 AND 12 REPLACED IAW MM72-21-02, MATCHING BLADES ALSO REPLACED (23 AND 24). BLADES PLATFORMS BETWEEN FAN BLADE 11 AND 12, AND 12 AND 13 REPLACED IAW MM 72-21-02. BORESCOPE OF NR 1 ENGINE COMPLETED, NO FAULTS FOUND. ENGINE RUNS COMPLETED, SYSTEM CHECKS SERVICEABLE. AIRCRAFT RETURNED TO SERVICE WITH NO FURTHER INCIDENTS TO REPORT.