To solve traffic delay in peak hours and improve airspace capacity to accept increasing demand, reduction of lateral and longitudinal separation minima utilizing advanced navigation equipments and procedures are essential. For example, 3 parallel routes with 50NM Lateral Separation Minimum in 150NM wide airspace will be able to be restructured to have 5 parallel routes with 30NM Lateral Separation Minimum. An ATS route segment with 50 NM Longitudinal Separation Minimum between aircraft will be able to accept 66% more aircraft in the same segment, if 30NM Longitudinal Separation Minimum is applied.
However, the navigation, communication and surveillance performance of aircraft flying in the airspace where these types of reduced separation minina (performance-based horizontal separation minima: PBHSM) are applied must be approved by the State civil aviation authority. Additionally, assessment of airspace safety before implementation and on-going monitoring after implementation is required to apply PBHSM.