Risk and capacity impacts of ATC separation rules

Some of the most significant factors in determining runway capacity are air traffic control regulations. Interaircraft separation regulations have been established to provide maximum safety to the travelling public. Thus any modification of these regulations, in an attempt to increase capacity, must have sufficient benefits to outweigh any increase in risk. A simulation indicated that the required separation between two arriving aircraft of 5,490 m could be reduced to 4,570 m, with a modeled 15% increase in capacity and a 1.5% increase in risk. Further simulations indicated that parallel runways spaced as close as 914 m apart could be operated independently, with capacity increases of between 38% and 95% and no estimated increase in risk. Reducing the present requirement to separate arriving aircraft from departing aircraft by 3,560 m to 1,825 m was estimated to result in a 25% increase in capacity with only a 1.5% increase in risk.