What was found
FLIGHT 6484 GPT ON TAKEOFF ROLL, APPROXIMATELY 50 KNOTS, CREW EXPERIENCED UNKNOWN AND CONSTANT HUMMING NOISE, NO SIGNIFICANT VIBRATION ASSOCIATED WITH IT. ACCOMPLISHED RTO. OCM DISCOVERED A BENT FAN BLADE IN THE NR 2 ENGINE. FURTHER INVESTIGATION REVEALED NR 2 ENGINE INGESTED A BIRD ON TAKEOFF. SHUTTLE AMERICA MAINTENANCE FROM CMH REPLACED BLADES NR 3, 4 & 17 AND BORESCOPED NR 2 ENGINE.