ICAO Doc 4444 Air Traffic Management-75-131-P1 PDF

Chapter 5 SEPARATION METHODS AND MINIMA 5.1 INTRODUCTION Note 1.— With the exceptions stated below, Chapter 5 contains procedures and procedural separation mini...

Chapter 5 SEPARATION METHODS AND MINIMA 5.1 INTRODUCTION Note 1.— With the exceptions stated below, Chapter 5 contains procedures and procedural separation minima for use in the separation of aircraft in the en-route phase as well as aircraft in the arrival and departure phases of flight. Note 2.— Procedures and separation minima applicable to approaches to parallel runways are contained in Chapter 6. Procedures and separation minima applicable in the provision of aerodrome control service are contained in Chapter 7 and procedures and separation minima applicable to the use of ATS surveillance systems are contained in Chapter 8. Note 3.— Attention is drawn to the use of strategic lateral offset procedures (SLOP) described in Chapter 16, 16.5. Note 4.— Procedures applicable to data link initiation capability (DLIC) are contained in Chapter 4. Procedures applicable to automatic dependent surveillance — contract (ADS-C) are contained in Chapter 13. Procedures applicable to controller-pilot data link communications (CPDLC) are contained in Chapter 14. 5.2 PROVISIONS FOR THE SEPARATION OF CONTROLLED TRAFFIC 5.2.1 General 5.2.1.1 Vertical or horizontal separation shall be provided: a) between all flights in Class A and B airspaces; b) between IFR flights in Class C, D and E airspaces; c) between IFR flights and VFR flights in Class C airspace; d) between IFR flights and special VFR flights; and e) between special VFR flights, when so prescribed by the appropriate ATS authority; except, for the cases under b) above in airspace Classes D and E, during the hours of daylight when flights have been cleared to climb or descend subject to maintaining own separation and remaining in visual meteorological conditions. Conditions applicable to the use of this procedure are contained in Section 5.9. 5.2.1.2 No clearance shall be given to execute any manoeuvre that would reduce the spacing between two aircraft to less than the separation minimum applicable in the circumstances. 5.2.1.3 Larger separations than the specified minima should be applied whenever exceptional circumstances such as unlawful interference or navigational difficulties call for extra precautions. This should be done with due regard to all relevant factors so as to avoid impeding the flow of air traffic by the application of excessive separations. PANS-ATM 5-1 10/11/16 5-2 Air Traffic Management (PANS-ATM) Note.— Unlawful interference with an aircraft constitutes a case of exceptional circumstances which might require the application of separations larger than the specified minima, between the aircraft being subjected to unlawful interference and other aircraft. 5.2.1.4 Where the type of separation or minimum used to separate two aircraft cannot be maintained, another type of separation or another minimum shall be established prior to the time when the current separation minimum would be infringed. 5.2.2 Degraded aircraft performance Whenever, as a result of failure or degradation of navigation, communications, altimetry, flight control or other systems, aircraft performance is degraded below the level required for the airspace in which it is operating, the flight crew shall advise the ATC unit concerned without delay. Where the failure or degradation affects the separation minimum currently being employed, the controller shall take action to establish another appropriate type of separation or separation minimum. 5.3 VERTICAL SEPARATION 5.3.1 Vertical separation application Vertical separation is obtained by requiring aircraft using prescribed altimeter setting procedures to operate at different levels expressed in terms of flight levels or altitudes in accordance with the provisions in Chapter 4, Section 4.10. 5.3.2 Vertical separation minimum The vertical separation minimum (VSM) shall be: a) a nominal 300 m (1 000 ft) below FL 290 and a nominal 600 m (2 000 ft) at or above this level, except as provided for in b) below; and b) within designated airspace, subject to a regional air navigation agreement: a nominal 300 m (1 000 ft) below FL 410 or a higher level where so prescribed for use under specified conditions, and a nominal 600 m (2 000 ft) at or above this level. Note.— Guidance material relating to vertical separation is contained in the Manual on a 300 m (1 000 ft) Vertical Separation Minimum Between FL 290 and FL 410 Inclusive (Doc 9574). 5.3.3 Assignment of cruising levels for controlled flights 5.3.3.1 Except when traffic conditions and coordination procedures permit authorization of cruise climb, an ATC unit shall normally authorize only one level for an aircraft beyond its control area, i.e. that level at which the aircraft will enter the next control area whether contiguous or not. It is the responsibility of the accepting ATC unit to issue clearance for further climb as appropriate. When relevant, aircraft will be advised to request en route any cruising level changes desired. 5.3.3.2 Aircraft authorized to employ cruise climb techniques shall be cleared to operate between two levels or above a level. 10/11//16 Chapter 5. Separation Methods and Minima 5-3 5.3.3.3 If it is necessary to change the cruising level of an aircraft operating along an established ATS route extending partly within and partly outside controlled airspace and where the respective series of cruising levels are not identical, the change shall, whenever possible, be effected within controlled airspace. 5.3.3.4 When an aircraft has been cleared into a control area at a cruising level which is below the established minimum cruising level for a subsequent portion of the route, the ATC unit responsible for the area should issue a revised clearance to the aircraft even though the pilot has not requested the necessary cruising level change. 5.3.3.5 An aircraft may be cleared to change cruising level at a specified time, place or rate. Note.— See 5.3.4.1.1 concerning procedures for vertical speed control. 5.3.3.6 In so far as practicable, cruising levels of aircraft flying to the same destination shall be assigned in a manner that will be correct for an approach sequence at destination. 5.3.3.7 An aircraft at a cruising level shall normally have priority over other aircraft requesting that cruising level. When two or more aircraft are at the same cruising level, the preceding aircraft shall normally have priority. 5.3.3.8 The cruising levels, or, in the case of cruise climb, the range of levels, to be assigned to controlled flights shall be selected from those allocated to IFR flights in: a) the tables of cruising levels in Appendix 3 of Annex 2; or b) a modified table of cruising levels, when so prescribed in accordance with Appendix 3 of Annex 2 for flights above FL 410; except that the correlation of levels to track as prescribed therein shall not apply whenever otherwise indicated in air traffic control clearances or specified by the appropriate ATS authority in AIPs. 5.3.4 Vertical separation during climb or descent 5.3.4.1 An aircraft may be cleared to a level previously occupied by another aircraft after the latter has reported vacating it, except when: a) severe turbulence is known to exist; b) the higher aircraft is effecting a cruise climb; or c) the difference in aircraft performance is such that less than the applicable separation minimum may result; in which case such clearance shall be withheld until the aircraft vacating the level has reported at or passing another level separated by the required minimum. 5.3.4.1.1 When the aircraft concerned are entering or established in the same holding pattern, consideration shall be given to aircraft descending at markedly different rates and, if necessary, additional measures such as specifying a maximum descent rate for the higher aircraft and a minimum descent rate for the lower aircraft should be applied to ensure that the required separation is maintained. 5.3.4.2 Pilots in direct communication with each other may, with their concurrence, be cleared to maintain a specified vertical separation between their aircraft during ascent or descent. 10/11/16 5-4 Air Traffic Management (PANS-ATM) 5.4 HORIZONTAL SEPARATION Note 1.— Nothing in the provisions detailed in Sections 5.4.1 and 5.4.2 hereunder precludes a State from establishing: a) other minima for use in circumstances not prescribed; or b) additional conditions to those prescribed for the use of a given minimum; provided that the level of safety inherent in the provisions detailed in Sections 5.4.1 and 5.4.2 hereunder is at all times assured. Note 2.— Details on track spacing between parallel routes are provided in Annex 11, Attachments A and B. Note 3.— Attention is drawn to the following guidance material: a) Air Traffic Services Planning Manual (Doc 9426); b) Manual on Airspace Planning Methodology for the Determination of Separation Minima (Doc 9689); and c) Performance-based Navigation (PBN) Manual (Doc 9613). Note 4.— Provisions concerning reductions in separation minima are contained in Section 5.11 and in Chapter 2, ATS Safety Management. 5.4.1 Lateral separation 5.4.1.1 LATERAL SEPARATION APPLICATION 5.4.1.1.1 Lateral separation shall be applied so that the distance between those portions of the intended routes for which the aircraft are to be laterally separated is never less than an established distance to account for navigational inaccuracies plus a specified buffer. This buffer shall be determined by the appropriate authority and included in the lateral separation minima as an integral part thereof. Note.— In the minima specified in 5.4.1.2 an appropriate buffer has already been included. 5.4.1.1.2 Lateral separation of aircraft is obtained by requiring operation on different routes or in different geographical locations as determined by visual observation, by the use of navigation aids or by the use of area navigation (RNAV) equipment. 5.4.1.1.3 When information is received indicating navigation equipment failure or deterioration below the navigation performance requirements, ATC shall then, as required, apply alternative separation methods or minima. 5.4.1.1.4 Where a route flown by an aircraft involves a specified turn which will result in the minimum lateral separation being infringed, another type of separation or another minimum shall be established prior to the aircraft commencing the turn (see Figures 5-1 and 5-2). Note 1.— For flyover waypoints aircraft are required to first fly over the waypoint before executing the turn. After the turn the aircraft may either navigate to join the route immediately after the turn or navigate to the next defined waypoint before re-joining the route. This will require additional lateral separation on the overflown side of the turn (refer to Figure 5-1). Note 2.— An aircraft may commence a fly-by turn up to 37 km (20 NM) prior to the turn waypoint, and fly a path displaced from that waypoint by as much as 16.7 km (9.0 NM). The defined radius for the fixed radius transition (FRT) turn dictates how early the aircraft starts the turn and the displacement from the waypoint. Fly-by and FRT turns, therefore, have the possibility of affecting a restricted area or another route on the inside of the turn. For instrument flight procedures, the radius arc to a fix (RF) path terminator will provide consistent turn performance (refer to Figures 5-1 and 5-2). Further details on this issue can be found in the Manual on the Use of Performance-based Navigation (PBN) in Airspace Design (Doc 9992). Note 3.— An example of a prescribed lateral separation minima based on a specific navigation performance can be found in 5.4.1.2.1.6. 8/11/18 10/11//16 No. 8 Chapter 5. Separation Methods and Minima 5-5 Adjacent ATS route Minimum lateral separation not infringed Fly-by waypoint rn s t tu L ate Minimum lateral separation infringed n t t ur rl ies Ea Restricted, prohibited or danger area Route as depicted on chart Flight path flown by an aircraft Fly-by turns An aircraft will calculate a turn radius and angle of bank (AOB) subject to performance characteristics, airspeed, altitude, angle of turn and wind conditions. The aircraft determine to initiate the turn, prior to the waypoint, based on the calculated radius — this may be up to 20 NM before the waypoint. There will be a variation in the paths because each aircraft calculates its own turn radius (indicated by the grey area in the figure within which the flight path of the aircraft will be located). This variation becomes more apparent at higher altitudes and greater turn angles. The controller can expect the aircraft track to be on the inside of the waypoint. Figure 5-1. Turn over flyover waypoint and turn at fly-by waypoint (see 5.4.1.1.4) 8/11/18 10/11/16 No. 8 5-6 Air Traffic Management (PANS-ATM) Adjacent ATS route Minimum lateral separation infringed Flyover waypoint Minimum lateral separation not infringed Restricted, prohibited or danger area Route as depicted on chart Flight path flown by an aircraft Flyover turns An aircraft will come to the overhead of the waypoint before initiating the turn onto the next leg. Therefore, if the minimum prescribed lateral separation is applied, it will be infringed upon as the aircraft manoeuvres onto its next leg. The controller can expect the aircraft track to be on the outside of the waypoint. Figure 5-1 (cont.d). Turn over flyover waypoint and turn at fly-by waypoint (see 5.4.1.1.4) 8/11/18 10/11//16 No. 8 Chapter 5. Separation Methods and Minima 5-6A Adjacent ATS route Defined radius + D e fi ne d r ad i us + Route as may be depicted on chart Flight path flown by all aircraft Aircraft adjusts AOB to follow the defined path Fixed radius transition (FRT) An FRT for published en-route RNP ATS routes has a turn radius specified by the airspace planner. Approaching the waypoint, the FMC/FMS will calculate the arc centre and will initiate the turn at a point at which the flight path is perpendicular to the radius which links the point to the calculated centre. This turn type should provide highly consistent and repeatable turn performance. Figure 5-2. Fixed radius transition (FRT) and radius arc to a fix (RF) turn (see 5.4.1.1.4) 8/11/18 10/11/16 No. 8 5-6B Air Traffic Management (PANS-ATM) Doc 4444 — Chapter 5 Adjacent ATS route nt s e gm e ed rv cu RF Defined radius D e fi n ed r ad i us + Route as depicted on chart and Flight path flown by all aircraft Aircraft adjusts AOB to follow the desired path Radius arc to a fix (RF) An RF for instrument flight procedures (IFP) is a curved route segment that has been designed with a published radius and arc centre. Aircraft will initiate the turn at the waypoint defining the start of the curved segment and will follow the published route until the next waypoint. This turn type should provide highly consistent and repeatable turn performance. Figure 5-2 (cont.d). Fixed radius transition (FRT) and radius arc to a fix (RF) turn (see 5.4.1.1.4) 8/11/18 10/11//16 No. 8 Chapter 5. Separation Methods and Minima 5-7 5.4.1.2 LATERAL SEPARATION CRITERIA AND MINIMA 5.4.1.2.1 Means by which lateral separation may be applied include the following: 5.4.1.2.1.1 By reference to the same or different geographic locations. By position reports which positively indicate the aircraft are over different geographic locations as determined visually or by reference to a navigation aid (see Figure 5-3). 5.4.1.2.1.2 By use of NDB, VOR or GNSS on intersecting tracks or ATS routes. By requiring aircraft to fly on specified tracks which are separated by a minimum amount appropriate to the navigation aid employed. Lateral separation between two aircraft exists when: a) VOR: both aircraft are established on radials diverging by at least 15 degrees and at least one aircraft is at a distance of 28 km (15 NM) or more from the facility (see Figure 5-4); b) NDB: both aircraft are established on tracks to or from the NDB which are diverging by at least 30 degrees and at least one aircraft is at a distance of 28 km (15 NM) or more from the facility (see Figure 5-5); c) GNSS/GNSS: each aircraft is confirmed to be established on a track with zero offset between two waypoints and at least one aircraft is at a minimum distance from a common point as specified in Table 5-1; or d) VOR/GNSS: the aircraft using VOR is established on a radial to or from the VOR and the other aircraft using GNSS is confirmed to be established on a track with zero offset between two waypoints and at least one aircraft is at a minimum distance from a common point as specified in Table 5-1. Table 5-1. Lateral separation for aircraft flying VOR and GNSS Aircraft 1: VOR or GNSS Aircraft 2: GNSS Angular difference between tracks FL010 – FL190 FL200 – FL600 measured at the common point Distance from a common point Distance from a common point (degrees) 15 – 135 27.8 km (15 NM) 43 km (23 NM) The distances in the table are ground distances. States must take into account the distance (slant range) from the source of a DME signal to the receiving antenna when DME is being utilized to provide range information. Note 1.— The values in Table 5-1 are from a larger table of values derived by collision risk analysis. The source table for separation of aircraft navigating by means of GNSS and VOR is contained in Circular 322, Guidelines for the Implementation of GNSS Lateral Separation Minima based on VOR Separation Minima. States may refer to Circular 322 for greater detail and other angular differences and separation distances. Note 2.— The values in Table 5-1 have accounted for distances from the common point encompassed by the theoretical turn area for fly-by turns as specified in the Minimum Aviation System Performance Standard: Required Navigation Performance for Air Navigation (ED-75B/DO-236B), section 3.2.5.4, and fixed radius transition (FRT) turns as defined in the Performance-based Navigation (PBN) Manual (Doc 9613). Note 3.— Guidance material for the implementation of GNSS lateral separation is contained in Circular 322, Guidelines for the Implementation of GNSS Lateral Separation Minima Based on VOR Separation Minima. 8/11/18 10/11/16 No. 8 5-8 Air Traffic Management (PANS-ATM) Figure 5-3. Using same or different geographic locations (see 5.4.1.2.1.1) 28 km (15 NM) VOR 15° Figure 5-4. Separation using the same VOR (see 5.4.1.2.1.2 a)) 28 km (15 NM) NDB 30° Figure 5-5. Separation using the same NDB (see 5.4.1.2.1.2 b)) 5.4.1.2.1.2.1 When aircraft are operating on tracks which are separated by considerably more than the minimum in 5.4.1.2.1.2 a) and b), States may reduce the distance at which lateral separation is achieved. 5.4.1.2.1.2.2 Before applying GNSS-based track separation, the controller shall confirm the following: a) ensure that the aircraft is navigating using GNSS; and 10/11//16 Chapter 5. Separation Methods and Minima 5-9 b) in airspace where strategic lateral offsets are authorized, that a lateral offset is not being applied. 5.4.1.2.1.2.3 In order to minimize the possibility of operational errors, waypoints contained in the navigation database or uplinked to the aircraft flight management system should be used in lieu of manually entered waypoints, when applying GNSS-based track separation. In the event that it is operationally restrictive to use waypoints contained in the navigation database, the use of waypoints that require manual entry by pilots should be limited to a half or whole degree of latitude and longitude. 5.4.1.2.1.2.4 GNSS-based track separation shall not be applied in cases of pilot-reported receiver autonomous integrity monitoring (RAIM) outages. Note.— For the purpose of applying GNSS-based lateral separation minima, distance and track information derived from an integrated navigation system incorporating GNSS input is regarded as equivalent to GNSS distance and track. 5.4.1.2.1.2.5 GNSS receivers used for applying separation shall meet the requirements in Annex 10, Volume I, and be indicated in the flight plan. 5.4.1.2.1.3 By use of different navigation aids or methods. Lateral separation between aircraft using different navigation aids, or when one aircraft is using RNAV equipment, shall be established by ensuring that the derived protected airspaces for the navigation aid(s) or RNP do not overlap. 5.4.1.2.1.4 Lateral separation of aircraft on published 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 any combination of RNAV 1 with RNAV 1, or RNP 1, RNP APCH or RNP AR APCH tracks is not less than 13 km (7 NM); or b) where the distance between any combination of RNP 1, RNP APCH or RNP AR APCH tracks is not less than 9.3 km (5 NM); or c) where the protected areas of tracks designed using obstacle clearance criteria do not overlap and provided operational error is considered. Note 1.— Distance values contained in a) and b) above were 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. 10/11/16 5-10 Air Traffic Management (PANS-ATM) Note.— The spacing between parallel tracks or between parallel ATS route centre lines for which an RNP type is required will be dependent upon the relevant RNP type specified. Guidance material related to the spacing between tracks or ATS routes based on RNP type is contained in Annex 11, Attachment B. 5.4.1.2.1.6 Lateral separation of aircraft on parallel or non-intersecting tracks or ATS routes. Within designated airspace or on designated routes, lateral separation between aircraft operating on parallel or non-intersecting tracks or ATS routes shall be established in accordance with Table 5-2: Table 5-2. Lateral separation of aircraft on parallel or non-intersecting tracks or ATS routes Minimum Spacing Between Tracks Performance Requirements Additional Requirements Airspace where SLOP is not authorized, or is Airspace where only authorized up to SLOP up to 2 NM 0.5 NM is authorized Navigation Communication Surveillance 93 km (50 NM) 93 km (50 NM) RNAV 10 Types of (RNP 10) communication RNP 4 other than direct RNP 2 controller-pilot VHF voice 37 km (20 NM) 42.6 km (23 NM) RNP 4 RCP 240 RSP 180 Conformance monitoring shall be RNP 2 ensured by establishing an ADS-C event contract specifying a lateral deviation change event with a maximum of 5 NM threshold and a waypoint change event 37 km (20 NM) 42.6 km (23 NM) RNP 2 or Types of While one aircraft GNSS communication climbs/descends through the level equipage other than direct of another aircraft remaining in controller-pilot level flight VHF voice 27.8 km (15 NM) 33.4 km (18 NM) RNP 2 or Direct GNSS controller-pilot equipage VHF voice communications 16.7 km (9 NM) 22.3 km (12 NM) RNP 4 RCP 240 RSP 180 While one aircraft RNP 2 climbs/descends through the level of another aircraft remaining in level flight 13 km (7 NM) 19 km (10 NM) RNP 2 or Direct While one aircraft GNSS controller-pilot climbs/descends through the level equipage VHF voice of another aircraft remaining in communications level flight Note 1.— Guidance material for the implementation of the navigation capability supporting the lateral separation minima above is contained in the Performance-based Navigation (PBN) Manual (Doc 9613). Information regarding the implementation of the lateral separation minima above is contained in Circular 349, Guidelines for the Implementation of Lateral Separation Minima. Note 2.— Guidance material for the implementation of communication and surveillance capability supporting the lateral separation minima above is contained in the Performance-based Communication and Surveillance (PBCS) Manual (Doc 9869) and the Global Operational Data Link (GOLD) Manual (Doc 10037). Note 3.— See Appendix 2, ITEM 10: EQUIPMENT AND CAPABILITIES, in relation to the GNSS prescribed in Table 5-2 above. Note 4.— Refer to 16.5 for further details regarding application of strategic lateral offset procedures (SLOP). 5/11/20 10/11//16 No. 9 Chapter 5. Separation Methods and Minima 5-11 5.4.1.2.1.7 When the minima in 5.4.1.2.1.6 are applied by requiring one or both aircraft to establish a specified lateral offset, vertical separation shall be maintained by the controller until the manoeuvring aircraft is established on the applicable lateral offset. 5.4.1.2.1.8 Lateral separation of aircraft on intersecting tracks or ATS routes. Lateral separation between aircraft operating on intersecting tracks or ATS routes shall be established in accordance with the following. a) an aircraft converging with the track of another aircraft is laterally separated until it reaches a lateral separation point that is located a specified distance measured perpendicularly from the track of the other aircraft (see Figure 5-6); and b) an aircraft diverging from the track of another aircraft is laterally separated after passing a lateral separation point that is located a specified distance measured perpendicularly from the track of the other aircraft (see Figure 5-6). This type of separation may be used for tracks that intersect at any angles using the values for lateral separation points specified below: Navigation Separation RNAV 10 (RNP 10) 93 km (50 NM) RNP 4 42.6 km (23 NM) RNP 2 27.8 km (15 NM) 5.4.1.2.1.9 When applying the 27.8 km (15 NM) separation minima specified in the table above, a GNSS, as indicated in the flight plan by the letter G meets the specified navigation performance. Note.— Guidance material for the implementation of the navigation capability supporting 93 km (50 NM), 42.6 km (23 NM), and 27.8 km (15 NM) lateral separation minima is contained in the Performance-based Navigation (PBN) Manual (Doc 9613). Supporting information for the implementation of the 93 km (50 NM), 42.6 km (23 NM) and 27.8 km (15 NM) lateral separation minima is contained in Circular 349, Guidelines for the Implementation of Lateral Separation Minima. 5.4.1.2.1.10 Transitioning into airspace where a greater lateral separation minimum applies. Lateral separation will exist when aircraft are established on specified tracks which: a) are separated by an appropriate minimum; and b) diverge by at least 15 degrees until the applicable lateral separation minimum is established; providing that it is possible to ensure, by means approved by the appropriate ATS authority, that aircraft have the navigation capability necessary to ensure accurate track guidance. 5.4.2 Longitudinal separation 5.4.2.1 LONGITUDINAL SEPARATION APPLICATION 5.4.2.1.1 Longitudinal separation shall be applied so that the spacing between the estimated positions of the aircraft being separated is never less than a prescribed minimum. Longitudinal separation between aircraft following the same or diverging tracks may be maintained by application of speed control, including the Mach number technique. When applicable, use of the Mach number technique shall be prescribed on the basis of a regional air navigation agreement. Note 1.— Attention is drawn to the guidance material contained in the Air Traffic Services Planning Manual (Doc 9426) regarding the application of the Mach number technique to separation of subsonic aircraft. Note 2.— The Mach number technique is applied using true Mach number. 8/11/18 10/11/16 No. 8 5-12 Air Traffic Management (PANS-ATM) D L L D D L L D Legend: = Lateral separation points = Intersecting angle D = Distance to/from the intersection point D = Figure 5-6. Lateral separation points (see 5.4.1.2.1.7) 5.4.2.1.2 In applying a time- or distance-based longitudinal separation minimum between aircraft following the same track, care shall be exercised to ensure that the separation minimum will not be infringed whenever the following aircraft is maintaining a higher airspeed than the preceding aircraft. When aircraft are expected to reach minimum separation, speed control shall be applied to ensure that the required separation minimum is maintained. 5.4.2.1.3 Longitudinal separation may be established by requiring aircraft to depart at a specified time, to arrive over a geographical location at a specified time, or to hold over a geographical location until a specified time. 5.4.2.1.4 Longitudinal separation between supersonic aircraft during the transonic acceleration and supersonic phases of flight should normally be established by appropriate timing of the start of transonic acceleration rather than by the imposition of speed restrictions in supersonic flight. 8/11/18 10/11//16 No. 8 Chapter 5. Separation Methods and Minima 5-13 5.4.2.1.5 For the purpose of application of longitudinal separation, the terms same track, reciprocal tracks and crossing tracks shall have the following meanings: a) Same track (see Figure 5-7): same direction tracks and intersecting tracks or portions thereof, the angular difference of which is less than 45 degrees or more than 315 degrees, and whose protected airspaces overlap. b) Reciprocal tracks (see Figure 5-8): opposite tracks and intersecting tracks or portions thereof, the angular difference of which is more than 135 degrees but less than 225 degrees, and whose protected airspaces overlap. c) Crossing tracks (see Figure 5-9): intersecting tracks or portions thereof other than those specified in a) and b) above. 5.4.2.1.6 Time-based separation applied in accordance with 5.4.2.2 and 5.4.2.4 may be based on position information and estimates derived from voice reports, CPDLC or ADS-C. 5.4.2.2 LONGITUDINAL SEPARATION MINIMA BASED ON TIME 5.4.2.2.1 AIRCRAFT MAINTAINING THE SAME LEVEL 5.4.2.2.1.1 Aircraft flying on the same track: a) 15 minutes (see Figure 5-10); or b) 10 minutes, if navigation aids permit frequent determination of position and speed (see Figure 5-11); or c) 5 minutes in the following cases, provided that in each case the preceding aircraft is maintaining a true airspeed of 37 km/h (20 kt) or more faster than the succeeding aircraft (see Figure 5-12): 1) between aircraft that have departed from the same aerodrome; 2) between en-route aircraft that have reported over the same exact significant point; 3) between departing and en-route aircraft after the en-route aircraft has reported over a fix that is so located in relation to the departure point as to ensure that five-minute separation can be established at the point the departing aircraft will join the air route; or d) 3 minutes in the cases listed under c) provided that in each case the preceding aircraft is maintaining a true airspeed of 74 km/h (40 kt) or more faster than the succeeding aircraft (see Figure 5-13). 5.4.2.2.1.2 Aircraft flying on crossing tracks: a) 15 minutes at the point of intersection of the tracks (see Figure 5-14); or b) 10 minutes if navigation aids permit frequent determination of position and speed (see Figure 5-15). 10/11/16 5-14 Air Traffic Management (PANS-ATM) 45° Less than 45° or more than 315° 315° Figure 5-7. Aircraft on same track (see 5.4.2.1.5 a)) 135° More than 135° and less than 225° 225° Figure 5-8. Aircraft on reciprocal tracks (see 5.4.2.1.5 b)) 10/11//16 Chapter 5. Separation Methods and Minima 5-15 135° 45° 45° to 135° 225° to 315° 225° 315° Figure 5-9. Aircraft on crossing tracks (see 5.4.2.1.5 c)) Navigation Navigation aid aid 15 min 10 min Figure 5-10. Fifteen-minute separation between aircraft Figure 5-11. Ten-minute separation between aircraft on same track and same level (see 5.4.2.2.1.1 a)) on same track and same level (see 5.4.2.2.1.1 b)) 10/11/16 5-16 Air Traffic Management (PANS-ATM) Aerodrome or 37 km/h (20 kt) Aerodrome Reporting point or more faster or 74 km/h (40 kt) Reporting point or more faster 5 min 3 min Figure 5-12. Five-minute separation between aircraft Figure 5-13. Three-minute separation between aircraft on same track and same level (see 5.4.2.2.1.1 c)) on same track and same level (see 5.4.2.2.1.1 d)) Navigation aid Navigation aid 15 min 10 min Navigation aids Figure 5-14. Fifteen-minute separation between aircraft Figure 5-15. Ten-minute separation between aircraft on crossing tracks and same level (see 5.4.2.2.1.2 a)) on crossing tracks and same level (see 5.4.2.2.1.2 b)) 5.4.2.2.2 AIRCRAFT CLIMBING OR DESCENDING 5.4.2.2.2.1 Aircraft on the same track. When an aircraft will pass through the level of another aircraft on the same track, the following minimum longitudinal separation shall be provided: a) 15 minutes while vertical separation does not exist (see Figures 5-16A and 5-16B); or b) 10 minutes while vertical separation does not exist, provided that such separation is authorized only where ground-based navigation aids or GNSS permit frequent determination of position and speed (see Figures 5-17A and 5-17B); or c) 5 minutes while vertical separation does not exist, provided that: 1) the level change is commenced within 10 minutes of the time the second aircraft has reported over a common point which must be derived from ground-based navigation aids or by GNSS; and 10/11//16 Chapter 5. Separation Methods and Minima 5-17 2) when issuing the clearance through third party communication or CPDLC a restriction shall be added to the clearance to ensure that the 10-minute condition is satisfied (see Figures 5-18A and 5-18B). Note.— To facilitate application of the procedure where a considerable change of level is involved, a descending aircraft may be cleared to some convenient level above the lower aircraft, or a climbing aircraft to some convenient level below the higher aircraft, to permit a further check on the separation that will be obtained while vertical separation does not exist. 5.4.2.2.2.2 Aircraft on crossing tracks: a) 15 minutes while vertical separation does not exist (see Figures 5-19A and 5-19B); or b) 10 minutes while vertical separation does not exist if navigation aids permit frequent determination of position and speed (see Figures 5-20A and 5-20B). 5.4.2.2.3 Aircraft on reciprocal tracks. Where lateral separation is not provided, vertical separation shall be provided for at least ten minutes prior to and after the time the aircraft are estimated to pass, or are estimated to have passed (see Figure 5-21). Provided it has been determined that the aircraft have passed each other, this minimum need not apply. 15 min FL 260 (7 900 m) FL 250 15 min (7 600 m) FL 240 15 min (7 300 m) Figure 5-16A. Fifteen-minute separation between aircraft climbing and on same track (see 5.4.2.2.2.1 a)) 15 min FL 260 (7 900 m) FL 250 15 min (7 600 m) FL 240 15 min (7 300 m) Figure 5-16B. Fifteen-minute separation between aircraft descending and on same track (see 5.4.2.2.2.1 a)) 10/11/16 5-18 Air Traffic Management (PANS-ATM) 10 min FL 260 (7 900 m) FL 250 10 min (7 600 m) FL 240 10 min (7 300 m) Navigation aid/waypoint Figure 5-17A. Ten-minute separation between aircraft climbing and on same track (see 5.4.2.2.2.1 b)) 10 min FL 260 (7 900 m) FL 250 10 min (7 600 m) FL 240 10 min (7 300 m) Navigation aid/waypoint Figure 5-17B. Ten-minute separation between aircraft descending and on same track (see 5.4.2.2.2.1 b)) 10/11//16 Chapter 5. Separation Methods and Minima 5-19 5 min FL 260 (7 900 m) FL 250 5 min (7 600 m) 10 min FL 240 5 min (7 300 m) Navigation aid/common point Figure 5-18A. Five-minute separation between aircraft climbing and on same track (see 5.4.2.2.2.1 c) 2)) 5 min FL 260 (7 900 m) FL 250 5 min (7 600 m) 10 min FL 240 5 min (7 300 m) Navigation aid/common point Figure 5-18B. Five-minute separation between aircraft descending and on same track (see 5.4.2.2.2.1 c) 2)) 10/11/16 5-20 Air Traffic Management (PANS-ATM) 15 min FL 260 (7 900 m) FL 250 15 min (7 600 m) FL 240 15 min (7 300 m) Figure 5-19A. Fifteen-minute separation between aircraft climbing and on crossing tracks (see 5.4.2.2.2.2 a)) 15 min FL 260 (7 900 m) FL 250 (7 600 m) 15 min FL 240 15 min (7 300 m) Figure 5-19B. Fifteen-minute separation between aircraft descending and on crossing tracks (see 5.4.2.2.2.2 a)) 10/11//16 Chapter 5. Separation Methods and Minima 5-21 10 min FL 260 (7 900 m) FL 250 10 min (7 600 m) FL 240 10 min (7 300 m) Navigation aid Figure 5-20A. Ten-minute separation between aircraft climbing and on crossing tracks (see 5.4.2.2.2.2 b)) 10 min FL 260 (7 900 m) FL 250 10 min (7 600 m) FL 240 10 min (7 300 m) Navigation aid Figure 5-20B. Ten-minute separation between aircraft descending and on crossing tracks (see 5.4.2.2.2.2 b)) 10/11/16 5-22 Air Traffic Management (PANS-ATM) Estimated time of passing 10 min 10 min Figure 5-21. Ten-minute separation between aircraft on reciprocal tracks (see 5.4.2.2.3) 5.4.2.3 LONGITUDINAL SEPARATION MINIMA BASED ON DISTANCE USING DISTANCE MEASURING EQUIPMENT (DME) AND/OR GNSS Note.— Where the term “on track” is used in the provisions relating to the application of longitudinal separation minima using DME and/or GNSS, it means that the aircraft is flying either directly inbound to or directly outbound from the station/waypoint. 5.4.2.3.1 Separation shall be established by maintaining not less than specified distance(s) between aircraft positions as reported by reference to DME in conjunction with other appropriate navigation aids and/or GNSS. This type of separation shall be applied between two aircraft using DME, or two aircraft using GNSS, or one aircraft using DME and one aircraft using GNSS. Direct controller-pilot VHF voice communication shall be maintained while such separation is used. Note.— For the purpose of applying GNSS-based separation minimum, a distance derived from an integrated navigation system incorporating GNSS input is regarded as equivalent to GNSS distance. 5.4.2.3.2 When applying these separation minima between any aircraft with area navigation capability, controllers shall specifically request GNSS-derived distance. Note.— Reasons making a pilot unable to provide GNSS distance information may include inadequate on-board equipment, no GNSS input into an integrated navigation system, or a loss of GNSS integrity. 5.4.2.3.3 AIRCRAFT AT THE SAME CRUISING LEVEL 5.4.2.3.3.1 Aircraft on the same track: a) 37 km (20 NM), provided: 1) each aircraft utilizes: i) the same “on-track” DME station when both aircraft are utilizing DME; or ii) an “on-track” DME station and a collocated waypoint when one aircraft is utilizing DME and the other is utilizing GNSS; or 10/11//16 Chapter 5. Separation Methods and Minima 5-23 iii) the same waypoint when both aircraft are utilizing GNSS; and 2) separation is checked by obtaining simultaneous DME and/or GNSS readings from the aircraft at frequent intervals to ensure that the minimum will not be infringed (see Figure 5-22); DME 37 km (20 NM) and/or collocated waypoint or same waypoint Figure 5-22. 37 km (20 NM) DME and/or GNSS-based separation between aircraft on same track and same level (see 5.4.2.3.3.1 a)) b) 19 km (10 NM), provided: 1) the leading aircraft maintains a true airspeed of 37 km/h (20 kt) or more faster than the succeeding aircraft; 2) each aircraft utilizes: i) the same “on-track” DME station when both aircraft are utilizing DME; or ii) an “on-track” DME station and a collocated waypoint when one aircraft is utilizing DME and the other is utilizing GNSS; or iii) the same waypoint when both aircraft are utilizing GNSS; and 3) separation is checked by obtaining simultaneous DME and/or GNSS readings from the aircraft at such intervals as are necessary to ensure that the minimum is established and will not be infringed (see Figure 5-23). 5.4.2.3.3.2 Aircraft on crossing tracks. The longitudinal separation prescribed in 5.4.2.3.3.1 shall also apply provided each aircraft reports distance from the DME station and/or collocated waypoint or same waypoint located at the crossing point of the tracks and that the relative angle between the tracks is less than 90 degrees (see Figures 5-24A and 5-24B). 5.4.2.3.4 AIRCRAFT CLIMBING AND DESCENDING 5.4.2.3.4.1 Aircraft on the same track: 19 km (10 NM) while vertical separation does not exist, provided: a) each aircraft utilizes: 10/11/16 5-24 Air Traffic Management (PANS-ATM) 37 km/h (20 kt) or more faster DME 19 km (10 NM) and/or collocated waypoint or same waypoint Figure 5-23. 19 km (10 NM) DME and/or GNSS-based separation between aircraft on same track and same level (see 5.4.2.3.3.1 b)) i) the same “on-track” DME station when both aircraft are utilizing DME; or ii) an “on-track” DME station and a collocated waypoint when one aircraft is utilizing DME and the other is utilizing GNSS; or iii) the same waypoint when both aircraft are utilizing GNSS; and b) one aircraft maintains a level while vertical separation does not exist; and c) separation is established by obtaining simultaneous DME and/or GNSS readings from the aircraft (see Figures 5-25A and 5-25B). Note.— To facilitate application of the procedure where a considerable change of level is involved, a descending aircraft may be cleared to some convenient level above the lower aircraft, or a climbing aircraft to some convenient level below the higher aircraft, to permit a further check on the separation that will be obtained while vertical separation does not exist. 5.4.2.3.4.2 Aircraft on reciprocal tracks. Aircraft utilizing on-track DME and/or collocated waypoint or same waypoint may be cleared to climb or descend to or through the levels occupied by other aircraft utilizing on-track DME and/or collocated waypoint or same waypoint, provided that it has been positively established that the aircraft have passed each other and are at least 10 NM apart, or such other value as prescribed by the appropriate ATS authority. 5.4.2.4 LONGITUDINAL SEPARATION MINIMA WITH MACH NUMBER TECHNIQUE BASED ON TIME 5.4.2.4.1 Aircraft subject to Mach number technique shall adhere to the true Mach number approved by ATC and shall request ATC approval before making any changes thereto. If it is essential to make an immediate temporary change in the Mach number (e.g. due to turbulence), ATC shall be notified as soon as possible that such a change has been made. 5.4.2.4.2 If it is not feasible, due to aircraft performance, to maintain the last assigned Mach number during en-route climbs and descents, pilots of aircraft concerned shall advise ATC at the time of the climb/descent request. 5/11/20 10/11//16 No. 9 Chapter 5. Separation Methods and Minima 5-25 and/or collocated waypoint or same waypoint DME NM m ) (2 0 7 k 3 Second aircraft not to be inbound from the shaded area Figure 5-24A. 37 km (20 NM) DME and/or GNSS-based separation between aircraft on crossing tracks and same level (see 5.4.2.3.3.2) and/or collocated 37 km/h (20 kt) waypoint or same or more faster waypoint DME NM m ) (10 9 k 1 Second aircraft not to be inbound from the shaded area Figure 5-24B. 19 km (10 NM) DME and/or GNSS-based separation between aircraft on crossing tracks and same level (see 5.4.2.3.3.2) 10/11/16 5-26 Air Traffic Management (PANS-ATM) 19 km (10 NM) FL 260 (7 900 m) FL 250 19 km (7 600 m) (10 NM) FL 240 19 km (7 300 m) (10 NM) On-track DME and/or collocated waypoint or same waypoint Figure 5-25A. 19 km (10 NM) DME and/or GNSS-based separation between aircraft climbing and on same track (see 5.4.2.3.4.1 c)) 19 km (10 NM) FL 260 (7 900 m) 19 km 19 km (10 NM) (10 NM) FL 250 (7 600 m) FL 240 (7 300 m) On-track DME and/or collocated waypoint or same waypoint Figure 5-25B. 19 km (10 NM) DME and/or GNSS-based separation between aircraft descending and on same track (see 5.4.2.3.4.1 c)) 10/11//16 Chapter 5. Separation Methods and Minima 5-27 5.4.2.4.3 When the Mach number technique is applied and provided that: a) the aircraft concerned have reported over the same common point and follow the same track or continuously diverging tracks until some other form of separation is provided; or b) if the aircraft have not reported over the same common point and it is possible to ensure, by radar, ADS-B or other means, that the appropriate time interval will exist at the common point from which they either follow the same track or continuously diverging tracks; minimum longitudinal separation between aircraft on the same track, whether in level, climbing or descending flight shall be: 1) 10 minutes; or 2) between 9 and 5 minutes inclusive, provided that: the preceding aircraft is maintaining a true Mach number greater than the following aircraft in accordance with the following: — 9 minutes, if the preceding aircraft is Mach 0.02 faster than the following aircraft; — 8 minutes, if the preceding aircraft is Mach 0.03 faster than the following aircraft; — 7 minutes, if the preceding aircraft is Mach 0.04 faster than the following aircraft; — 6 minutes, if the preceding aircraft is Mach 0.05 faster than the following aircraft; — 5 minutes, if the preceding aircraft is Mach 0.06 faster than the following aircraft. 5.4.2.4.4 When the 10-minute longitudinal separation minimum with Mach number technique is applied, the preceding aircraft shall maintain a true Mach number equal to or greater than that maintained by the following aircraft. 5.4.2.5 LONGITUDINAL SEPARATION MINIMA WITH MACH NUMBER TECHNIQUE BASED ON DISTANCE USING RNAV Note.— Guidance material on RNAV operations is contained in the Performance-based Navigation (PBN) Manual (Doc 9613). 5.4.2.5.1 Aircraft subject to Mach number technique shall adhere to the true Mach number approved by ATC and shall request ATC approval before making any changes thereto. If it is essential to make an immediate temporary change in the Mach number (e.g. due to turbulence), ATC shall be notified as soon as possible that such a change has been made. 5.4.2.5.1.1 If it is not feasible, due to aircraft performance, to maintain the last assigned Mach number during en-route climbs and descents, pilots of aircraft concerned shall advise ATC at the time of the climb/descent request. 5.4.2.5.2 RNAV distance-based separation minima shall not be applied after ATC has received pilot advice indicating navigation equipment deterioration or failure. 5.4.2.5.3 Separation shall be established by maintaining not less than the specified distance between aircraft positions as reported by reference to RNAV equipment. Direct controller-pilot communications should be maintained, while such separation is used. Where high frequency or general purpose extended range very high frequency air-ground communication channels are used for area control service and are worked by air-ground communicators, suitable arrangements shall be made to permit direct controller-pilot communications, or monitoring by the controller of all air-ground communications. 10/11/16 5/11/20 No. 9 5-28 Air Traffic Management (PANS-ATM) 5.4.2.5.3.1 To assist pilots to readily provide the required RNAV distance information, such position reports should, wherever possible, be referenced to a common waypoint ahead of both aircraft. 5.4.2.5.4 RNAV distance-based separation may be applied between RNAV-equipped aircraft when operating on designated RNAV routes or on ATS routes defined by VOR. 5.4.2.5.5 A 150 km (80 NM) RNAV distance-based separation minimum with Mach number technique may be used on same-direction tracks in lieu of a 10-minute longitudinal separation minimum with Mach number technique, provided: a) each aircraft reports its distance to or from the same “on-track” common point; b) separation between aircraft at the same level is checked by obtaining simultaneous RNAV distance readings from the aircraft at frequent intervals to ensure that the minimum will not be infringed (see Figure 5-26); c) separation between aircraft climbing or descending is established by obtaining simultaneous RNAV distance readings from the aircraft (see Figures 5-27A and 5-27B); and d) in the case of aircraft climbing or descending, one aircraft maintains a level while vertical separation does not exist. 5.4.2.5.6 When the 150 km (80 NM) longitudinal separation minimum with Mach number technique is applied, the preceding aircraft shall maintain a true Mach number equal to or greater than that maintained by the following aircraft. Note.— To facilitate application of the procedure where a considerable change of level is involved, a descending aircraft may be cleared to some convenient level above the lower aircraft, or a climbing aircraft to some convenient level below the higher aircraft, to permit a further check on the separation that will be obtained while vertical separation does not exist. 5.4.2.5.7 Aircraft on reciprocal tracks. Aircraft utilizing RNAV may be cleared to climb or descend to or through the levels occupied by other aircraft utilizing RNAV provided it has been positively established by simultaneous RNAV distance readings to or from the same “on-track” common point that the aircraft have passed each other and are at least 150 km (80 NM) apart (see Figure 5-28). Common point 150 km (80 NM) Figure 5-26. 150 km (80 NM) RNAV-based separation between aircraft at the same level (see 5.4.2.5.5 b)) 10/11//16 Chapter 5. Separation Methods and Minima 5-29 150 km Common point (80 NM) FL 260 (7 900 m) FL 250 150 km (7 600 m) (80 NM) FL 240 150 km (7 300 m) (80 NM) Figure 5-27A. 150 km (80 NM) RNAV-based separation between aircraft climbing and on same track (see 5.4.2.5.5 c)) 150 km Common point (80 NM) FL 260 (7 900 m) FL 250 150 km (7 600 m) (80 NM) FL 240 150 km (7 300 m) (80 NM) Figure 5-27B. 150 km (80 NM) RNAV-based separation between aircraft descending and on same track (see 5.4.2.5.5 c)) 10/11/16 5-30 Air Traffic Management (PANS-ATM) Waypoint 150 km Common point (80 NM) Figure 5-28. 150 km (80 NM) RNAV-based separation between aircraft on reciprocal tracks (see 5.4.2.5.7) 5.4.2.6 LONGITUDINAL SEPARATION MINIMA BASED ON DISTANCE USING RNAV WHERE RNP IS SPECIFIED Note.— Guidance material is contained in Attachment B to Annex 11, the Performance-based Navigation (PBN) Manual (Doc 9613), the Air Traffic Services Planning Manual (Doc 9426) and the Manual on Airspace Planning Methodology for the Determination of Separation Minima (Doc 9689). 5.4.2.6.1 Within designated airspace, or on designated routes, separation minima in accordance with the provisions of this section (5.4.2.6) may be used, subject to regional air navigation agreements. 5.4.2.6.2 Separation shall be established by maintaining not less than the specified distance between aircraft positions as reported by reference to the same “on-track” common point, whenever possible ahead of both aircraft, or by means of an automated position reporting system. Note.— The term “on track” means that the aircraft is flying either directly inbound to or directly outbound from the station or waypoint. 5.4.2.6.2.1 When information is received indicating navigation equipment failure or deterioration below the navigation performance requirements, ATC shall then, as required, apply alternative separation minima. 5.4.2.6.2.2 Direct controller-pilot communications shall be maintained while applying a distance-based separation minima. Direct controller-pilot communications shall be voice or CPDLC. The communication criteria necessary for CPDLC to satisfy the requirement for direct controller-pilot communications shall be established by an appropriate safety risk assessment. Note.— The communication criteria which are used as a basis for the derivation of the separation minima in this section are set out in Appendix 5 of the Manual on Airspace Planning Methodology for the Determination of Separation Minima (Doc 9689). Guidance material for CPDLC is contained in the Manual of Air Traffic Services Data Link Applications (Doc 9694). 5/11/20 10/11//16 No. 9 Chapter 5. Separation Methods and Minima 5-31 5.4.2.6.2.2.1 Prior to and during the application of a distance-based separation minimum, the controller should determine the adequacy of the available communication link, considering the time element required to receive replies from two or more aircraft, and the overall workload/traffic volume associated with the application of such minima. 5.4.2.6.2.3 When aircraft are at, or are expected to reduce to, the minimum separation applicable, speed control techniques, including assigning Mach number, shall be applied to ensure that the minimum distance exists throughout the period of application of the minima. 5.4.2.6.3 LONGITUDINAL DISTANCE-BASED SEPARATION MINIMA 5.4.2.6.3 IN AN RNP RNAV ENVIRONMENT NOT USING ADS-C 5.4.2.6.3.1 For aircraft cruising, climbing or descending on the same track, the following separation minimum may be used: Separation RNP Communication Surveillance Distance verification minimum type requirement requirement requirements 93 km (50 NM) 10 Direct Procedural At least every controller-pilot position reports 24 minutes communications Note 1.— Where a considerable change of level is involved using distance-based separation, a descending aircraft may be cleared to some convenient level above the lower aircraft, or a climbing aircraft to some convenient level below the higher aircraft (e.g. 1 200 m (4 000 ft) or less) to permit a further check on the separation that will be maintained while vertical separation does not exist. Note 2.— It should be noted that the separation minimum depicted above is based on safety risk assessments performed specifically for a particular network of tracks or routes. As such, the assessments evaluated traffic characteristics which might be unique to the network being assessed. Note 3.— The separation minimum above was developed in accordance with a collision risk analysis which dictates conditions under which this separation can be applied. Note 4.— Detailed information on the analysis used to determine the separation minimum and on performing safety risk assessments is contained in the Manual on Airspace Planning Methodology for the Determination of Separation Minima (Doc 9689). 5.4.2.6.3.2 During the application of the 93 km (50 NM) separation, when an aircraft fails to report its position, the controller shall take action within 3 minutes to establish communication. If communication has not been established within 8 minutes of the time the report should have been received, the controller shall take action to apply an alternative form of separation. 5.4.2.6.3.3 Where automated position reporting applies, a common time reference shall be used. 5.4.2.6.3.4 Aircraft on reciprocal tracks. Aircraft may be cleared to climb or descend to or through the levels occupied by the other provided that it has been positively established that the aircraft have passed each other and the distance between them is equal to at least the applicable separation minimum. 10/11/16 5/11/20 No. 9 5-32 Air Traffic Management (PANS-ATM) 5.4.2.7 LONGITUDINAL SEPARATION MINIMA BASED ON DISTANCE USING ADS-B IN-TRAIL PROCEDURE (ITP) Note 1.— Attention is drawn to Circular 325, In-Trail Procedure (ITP) Using Automatic Dependent Surveillance — Broadcast (ADS-B). Note 2.— Guidance material on ITP equipment can be found in RTCA DO-312/EUROCAE ED-159 Safety Performance and Interoperability Requirements Document for the In-Trail Procedure in Oceanic Airspace (ATSA-ITP) Application and Supplement and RTCA DO-317A/EUROCAE ED-194, Minimum Operational Performance Standards (MOPS) for Aircraft Surveillance Application (ASA) System. 5.4.2.7.1 The routes or airspace where application of the in-trail procedure is authorized, and the procedures to be followed by pilots in accordance with the provisions of Section 5.4.2.7, shall be promulgated in aeronautical information publications (AIPs). 5.4.2.7.2 ITP requests and clearances shall be communicated via a CPDLC message exchange only and in accordance with the appropriate message elements in Appendix 5. 5.4.2.7.3 Longitudinal separation between a climbing or descending ITP aircraft and reference aircraft shall be applied in accordance with 5.4.2.7.3.1, 5.4.2.7.3.2 and 5.4.2.7.3.3. An ITP aircraft shall not be separated simultaneously from more than two reference aircraft using the ITP separation minimum (see Figure 5-29). ITP “BEHIND” CLIMB (1 or 2 reference aircraft) ITP “BEHIND” DESCENT (1 or 2 reference aircraft) ITP “AHEAD OF” CLIMB (1 or 2 reference aircraft) ITP “AHEAD OF” DESCENT (1 or 2 reference aircraft) ITP COMBINED “BEHIND AND AHEAD OF” ITP COMBINED “BEHIND AND AHEAD OF” CLIMB DESCENT Note.— In the diagrams above, the “ITP aircraft” is the aircraft to which the arrow indicating climb or descent is attached. Other aircraft in the diagrams are the “reference aircraft”. Figure 5-29. ITP flight level change scenarios (see 5.4.2.7.3) 10/11//16 Chapter 5. Separation Methods and Minima 5-33 5.4.2.7.3.1 An ITP climb or descent may be requested by the pilot provided the following ITP criteria are satisfied: a) the ITP distance between the ITP aircraft and the reference aircraft shall be: 1) not less than 28 km (15 NM) with a maximum closing ground speed of 37 km/h (20 kt); or 2) not less than 37 km (20 NM) with a maximum closing ground speed of 56 km/h (30 kt); b) the ITP on-board equipment shall indicate that the angle between the current tracks of the ITP aircraft and reference aircraft is less than 45 degrees; c) the altitude difference between the ITP aircraft and any reference aircraft shall be 600 m (2 000 ft) or less; d) the climb or descent shall be conducted at a rate of not less than 1.5 m/s (300 ft/min), or any higher rate when specified by the controller; and e) the climb or descent shall be performed at the assigned Mach number. If no Mach number has been assigned by ATC, the ITP aircraft shall maintain the current cruise Mach number throughout the ITP manoeuvre. Note.— These criteria are designed to ensure a minimum separation of 19 km (10 NM) between the ITP aircraft and the reference aircraft during the climb or descent. 5.4.2.7.3.2 A controller may clear an aircraft for an ITP climb or descent provided the following conditions are satisfied: a) the ITP climb or descent has been requested by the pilot; b) the aircraft identification of each reference aircraft in the ITP request exactly matches the Item 7 — aircraft identification of the corresponding aircraft’s filed flight plan; c) the reported ITP distance between the ITP aircraft and any reference aircraft is 28 km (15 NM) or more; d) both the ITP aircraft and reference aircraft are either on; 1) same identical tracks and any turn at a waypoint shall be limited to less than 45 degrees; or 2) parallel tracks or same tracks with no turns permitted during the manoeuvre. Note.— Same identical tracks are a special case of same track defined in 5.4.2.1.5 a) where the angular difference is zero degrees. e) no speed or route change clearance shall be issued to the ITP aircraft until the ITP climb or descent is completed; f) the altitude difference between the ITP aircraft and any reference aircraft shall be 600 m (2 000 ft) or less; g) no instruction to amend speed, altitude or route shall be issued to any reference aircraft until the ITP climb or descent is completed; h) the maximum closing speed between the ITP aircraft and each reference aircraft shall be Mach 0.06; and i) the ITP aircraft shall not be a reference aircraft in another ITP clearance. 10/11/16