Mixed airspace?
Hi, I'm currently involved in a similar project. You should consider the fleet environment, in other words if you have simultaneously in the same airspace acft flying RNP AR procedures and conventional NAV procedures you MUST use the more restrictive criteria that it would be to consider all acft flying conventional NAV means. For me to give you a more detailed answer I should have more info about your project. Keywords: airspace concept, ICAO PBN Manual, Fleet capabilities, etc.
ICAO states (DOC4444)
5.4.1.2.1.4 Lateral separation of aircraft on published adjacent instrument flight procedures for arrivals and departures
5.4.1.2.1.4.1 Lateral separation of departing and/or arriving aircraft, using instrument flight procedures, will exist:
a) where the distance between RNAV 1, Basic RNP 1, RNP APCH and/or RNP AR APCH tracks is not less than 13 km (7 NM); or
b) where the protected areas of tracks designed using obstacle clearance criteria do not overlap and provided operational error is considered.
Note 1.— The 13 km (7 NM) value was determined by collision risk analysis using multiple navigation specifications.
Information on this analysis is contained in Circular 324, Guidelines for Lateral Separation of Arriving and Departing Aircraft on Published Adjacent Instrument Flight Procedures.
Note 2.— Circular 324 also contains information on separation of arrival and departure tracks using non-overlapping protected areas based on obstacle clearance criteria, as provided for in the Procedures for Air Navigation Services — Aircraft Operations, Volume II — Construction of Visual and Instrument Flight Procedures
(PANS-OPS, Doc 8168).
Note 3.— Provisions concerning reductions in separation minima are contained in Chapter 2, ATS Safety
Management, and Chapter 5, Separation Methods and Minima, Section 5.11.
Note 4.— Guidance concerning the navigation specifications is contained in the Performance-based Navigation
(PBN) Manual (Doc 9613).
5.4.1.2.1.5 RNAV operations where RNP is specified on parallel tracks or ATS routes. Within designated airspace or on designated routes, where RNP is specified, lateral separation between RNAV-equipped aircraft may be obtained by requiring aircraft to be established on the centre lines of parallel tracks or ATS routes spaced at a distance which ensures that the protected airspace of the tracks or ATS routes does not overlap.