摘要: |
Time-based flow metering (TBFM) of traffic to capacity-constrained areas such as airport runways and arrival fixes is considered a key element of the Next Generation Air Transportation System (NextGen) operational concept for managing high density air traffic. The principal operational TBFM system is the Traffic Management Advisory (TMA). TMA is used to optimize the flow of aircraft through various control points (e.g., arrival fixes, final approach fixes, and runway thresholds) so as to maximize airspace capacity without compromising safety.TMA makes continuous predictions of aircraft estimated time of arrivals (ETAs) at various metering points along the flight's trajectory. Scheduling algorthms use the ETAs to compute scheduled times of arrival (STAs) for each aircraft to specific scheduling point. The desired change in aircraft arrival time to the meter fix is provided to en route controllers who then accomplish speed and/or trajectory changes such that the plane passes over the arrival fix at the desired time. The required arrival fix time adjustment is continuity updated as the plane proceeds to the arrival fix to provide closed loop-control. During non-convective weather, TMA usage as resulted in increased capacity, reduced aircraft fuel burn, and decreased delay. |