Flight Crew Air Transport Pilot (ATP)
Time Pressure; Situational Awareness
Aircraft Equipment Problem Less Severe
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action
Aircraft; Procedure; Company Policy
During initial takeoff roll; aircraft had a vibration that seemed to be associated with nose gear tires; but nothing extreme. Passing 90 KTS; when I expected the vibration to dissipate; the vibration slightly intensified; but still nothing extreme. At approximately 120 KTS; the vibration became extreme with tremendous effects in the cockpit. Executed the rejected takeoff (RTO) procedure as soon as I could when this vibration intensified; deeming the aircraft unsafe to fly. Exited runway; followed QRH procedure for RTO; determined brake demands; communicated with Tower; Ramp Tower; and Maintenance to return to gate. I was occupying the left seat in role of Check Airman for a First Officer student that had been off for over a week; thus I elected to operate the first leg in the role of pilot flying.Aircraft had been sitting over the weekend. Maintenance informed us that work had been performed on the fuel system; requiring the aircraft to be fueled to full capacity. Evidently the aircraft sat in this condition so long that the nose tires developed severe flat spots. This is what made the vibration intensify with increased airspeed. Maintenance changed both nose gear tires and informed us it was definitely the flat spots that caused the observed vibration.If we could limit the time the aircraft sits on the ramp in the full fuel condition that would certainly alleviate the ensuing flat spots. However; once we returned to the gate; entire team did a nice job working together to get us back out as soon as possible.
A B757-200 Captain rejected the takeoff at 120 KTS when the nose tire vibration became excessive due to flat spots developed because the aircraft sat fully loaded with fuel over a weekend.