ICAO CIRCULAR 341

Abstract

This circular is limited to the application of lateral separation of aircraft operating on intersecting or non-intersecting tracks in a procedural control environment applying area navigation. <br><strong>PURPOSE</strong> <br>This circular provides guidance for the implementation of lateral separation minima intended for the separation of aircraft approved for performance-based navigation (PBN) and/or global navigation satellite system (GNSS) operations. It applies to lateral separation of aircraft on intersecting and non-intersecting tracks. The material supports provisions included in Chapter 5 of the <em>Procedures ,for Air Navigation Services &#8212; Air Traffic Management</em> (PANS-ATM. Doc 4444). 5.4.1.2.1.6 and 5.4.1.2.1.7 &#8212; sec also Chapter 2 of this circular. <br>Implementation guidance is also provided in the <em>Performance-based Navigation (PBN) Manual</em> (Doc 9613). The manual identifies the relationship between arca navigation (RNAV) and required navigation performance (RNP) applications and the advantages and limitations of choosing one or the other as the navigation specification requirement for an airspace concept. The manual also aims at providing practical guidance to States. air navigation service providers and airspace users on how to implement RNAV and RNP applications, and how to ensure that the performance requirements arc appropriate for the planned application. <br><em>&#160;Note.&#8212; Guidance ihr the implementation of lateral separation minima in terminal airspace is provided in ICAO circular 324</em>&#8212; Guidelines for Lateral Separation of Arriving and Departing Aircraft on Published Adjaccnt Instrumcnt Flight Procedures. <br>The Separation and Airspace Safety Panel (SASP) developed the separation minima detailed in this circular in response to the ICAO policy on global implementation of PBN. the large number of aircraft equipped with instrument flight rules (IFR) GNSS systems and the potential for using such equipment for scparation of aircraft in a procedural environmcnt. <br>Two of the separation minima covered in this document under the PBN umbrella wcrc originally developed by the Review of the General Concept of Separation Panel (RGCSP) in the 1990s for use within the RNP concept. The first minimum developed was the 93 km (50 NM) lateral separation minimum for RNP followed by the 30 NM lateral separation minimum for RNP 4. Both minima were initially publishcd in <em>Annex 11&#8212; Air Tredic Services</em>, but were transferred from Annex 11 to the PANS-ATM at a later date. Improved modelling of RNP subsequently indicated that the 30 NM separation minimum could be reduced to 42.6 km (23 NM) if gross error rates could be sufficiently limited. The SASP found that achieving the prescribed limits was contingent on the application of Required communication performance 240 (RCP 240) and Requiral Surveillance Performance 180 (RSP 180). <br>During the transition to full implementation of PBN. there will be a nccd to provide separation minima based on IFR GNSS systems in aircraft that have yet to obtain appropriate PBN operational approvals. To accommodate the widespread availability of such systems. which provide highly accurate navigation capability. the SASP has developed separation minima that may be applied to aircraft indicating GNSS equipage in the filed flight plan (FPL).