Requirements for metrics of aircraft separation and sector capacity

We address issues in the design of metrics to be used to ensure the separation of aircraft. We expand our previous work on dynamic density to include sector capacity. Dynamic density is a measure of the complexity and severity of pairwise conflict from the viewpoint of the flightdeck. Sector capacity is a similar measure from the viewpoint of air traffic control. We examine four alternative metrics and find that no one metric can be expected to capture conflict severity while maintaining a low false alarm rate.