Methodology for incorporating aircraft accident risk considerations in airport high speed exit taxiway design

Abstract

High speed exit taxiways are used as a method of increasing runway operational capacities by means of reducing runway occupancy times of aircraft. With the increased utilization of high speed exits, the number of accidents that could take place at these exits in the future could increase. Following the research gap on high speed exit taxiways-related risk analyses, the study developed methodologies to evaluate the associated risk at high speed exit taxiways. These methodologies are to evaluate exit overrun risk at a given exit location (R2), aircraft veer-off risk during the turning maneuver (R4) and incursion risk at the high speed exit and parallel taxiway intersection (R6). Due to a lack of data for developing statistical models, the R4, and R6 followed a novel approach. For the R2, the existing landing overrun model was modified for planning risk-based exit locations against the aircraft’s operational and metrological-related variables. A deterministic model was derived to evaluate aircraft veer-off risk at distinct operating conditions. The R4 was used to compare taxiway design characteristics such as acute angle, radius of curvature, etc. against veer-off risk. The analytical approach under R6 evaluated incursion risk due to violations of minimum separations between aircraft on the high speed exit taxiway and parallel taxiway. The methodology developed under this study could be used to evaluate aircraft risk at high speed taxiways and planning taxiway design elements. One of the key findings of this study was that every 250 m of displacement of high speed exit location towards the runway end reduces exit overrun risk by 30 percent with respect to the previous location. Further, a 30-percent increase in taxiway width and taxiway design radius result in 32-percent and 60-percent reductions in veer-off risk respectively. By incorporating risk, the methodology provides an approach for risk-based planning of high speed exit taxiways to improve runway capacity without compromising aircraft safety.