Section (a) where a mix of GPS and DME distances - Manual of Standards Part 172—Air Traffic Services - (a) where a mix of GPS and DME distances is used, distance reports must not be used if one aircraft is within 20 NM of the reference point; | Zoe
(a) where a mix of GPS and DME distances(a) where a mix of GPS and DME distances is used, distance reports must not be used if one aircraft is within 20 NM of the reference point;
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10.6.7 Application of Longitudinal Distance Separation
10.6.7.1 Distance based longitudinal separation minima must only be applied when:
(a) Direct Controller Pilot Communications (DCPC) exist; or
(b) ATC monitors all distance reports made by the aircraft.
Note: The requirement for DCPC is met by the use of Controller Pilot Datalink Communications (CPDLC).
10.6.7.2 All distance reports must be made with reference to the same DME beacon or waypoint.
This diagram illustrates that longitudinal distance separation minima may be applied between two aircraft using distance information from a distance measuring equipment (DME) beacon or waypoint:
a. directly on the track being flown by both aircraft or
b. on one side of the track being flown by both aircraft.
This is conditional on both aircraft reporting distance from the same DME installation or waypoint.
10.6.7.3 When applying same direction distance separation, an off-track waypoint or beacon may be used provided the positions of the aircraft relative to the beacon/waypoint are such that the distance readings are together increasing or decreasing.
This diagram is a geometrical illustration of the requirements of paragraph 10.6.7.3 – that is when applying same direction distance separation, an off-track waypoint or DME beacon may be used provided the positions of the aircraft relative to the beacon/waypoint are such that the distance readings are together increasing or decreasing. The diagram includes an illustration showing that it is not acceptable to use the method after the preceding aircraft has passed abeam the off-track waypoint or DME beacon and its distance is now increasing, while the following aircraft distances to the off-track waypoint or DME beacon is still decreasing.
10.6.7.4 A DME beacon may be taken to be co-sited with a waypoint or the azimuth navigation aid providing tracking guidance only when the DME site is located within 600 m of the waypoint or azimuth aid.
10.6.7.5 Where aircraft have been issued with different route clearances, and the difference in routes would apply during the period when distance separation is required, the leading aircraft must be tracking directly to or from the beacon/waypoint or co-sited navaid.
This diagram is a geometrical illustration of the requirements of paragraph 10.6.7.5 – that is Where aircraft have been issued with different route clearances, and the difference in routes would apply during the period when distance separation is required, the leading aircraft must be tracking directly to the beacon/waypoint or co-sited navaid.
This diagram is a geometrical illustration of the requirements of paragraph 10.6.7.5 – that is Where aircraft have been issued with different route clearances, and the difference in routes would apply during the period when distance separation is required, the leading aircraft must be tracking directly from the beacon/waypoint or co-sited navaid.
10.6.7.6 If a mix of DME and LRNS distances is being used:
(a) LRNS distance information must be based on the coordinates of the en route tracking aid, and not on the location of the DME site; and
(b) LRNS derived distance may be used for longitudinal separation only when the en route tracking aid and DME are co-sited.
10.6.7.7 Where distance information is required from a specific navigation source, the source must be included in the request (e.g. “REPORT DISTANCE FROM NWN DME”, “REPORT GPS DISTANCE FROM BEZZA” or “REPORT RNAV DISTANCE FROM PONAN”).
10.6.7.8 During the application of same direction distance minima, the distance between aircraft must be checked at sufficient intervals to ensure that the required separation is maintained. The frequency of these regular distance checks will depend on the performance and disposition of the aircraft, but must be made at intervals not exceeding 30 MIN.
10.6.7.9 When the ATS surveillance system derived distance between the aircraft is less than the sum of the distance required by the procedural separation minimum and the applicable ATS surveillance system separation minimum, a distance check must be made before the first aircraft leaves ATS surveillance system coverage.
10.6.7.10 Separation minima D4, D7 and R3 (change of level) may also be applied between 2 aircraft if:
(a) the aircraft are confirmed to be on opposite sides of an en-route navigation aid, and 1 aircraft’s distance is established by RNAV/DME to be not closer to that aid than the distance required by the separation minimum; or
(b) the distance determined by an ATS surveillance system, or by the position of 1 identified aircraft and an RNAV/DME report from the other, establishes that the distance between the aircraft is at least the distance required by the procedural separation minimum plus the applicable ATS surveillance system separation minimum; or
(c) 1 aircraft’s distance is established by RNAV/DME and the second aircraft’s position is established, by day, with reference to a visual fix, if:
(i) the fix is a prominent topographical feature within 10 000 ft of the aircraft; and
(ii) the feature is displayed on maps available to ATC.
10.6.7.11 Except for standard R6, closing speed between aircraft may exist provided that:
(a) separation is in excess of the minimum distance required;
(b) distance checks are made at intervals not exceeding 15 MIN; and
(c) when aircraft are cruising at levels not vertically separated, the closing speed is not greater than 35 KT IAS or M 0.06.
10.6.8 Use of DME/GPS Separation
10.6.8.1 In the description and application of these separation minima, ‘DME’ includes TACAN for distance measurement. TACAN distances may be used for the same purpose as DME provided that all tolerances and conditions shown for DME are applied.
10.6.8.2 In CTA only, GPS distance information may be provided by GPSRNAV or GPSOCEANIC aircraft for the application of minima D1-4, subject to the following conditions:
(a) where a mix of GPS and DME distances is used, distance reports must not be used if one aircraft is within 20 NM of the reference point;
(b) when GPS is used by both aircraft, the standard may also be applied with reference to published waypoints.
10.6.9 RNAV Separation
10.6.9.1 RNAV distance minima may be applied between aircraft with approved LRNS, or between an aircraft with approved LRNS equipment and an aircraft with DME.
10.6.9.2 RNAV minima must not be applied after pilot advice of:
(a) operation of LRNS equipment outside prescribed criteria, including deterioration or failure; or
(b) operation of an INS/IRS outside the time limits mentioned in the operational approval:
(i) CTA — 5 hours multiple sensor or 3 hours single sensor; or
(ii) OCA — 12 hours multiple sensor, 5 hours single sensor or 4.5 hours MNPS; or
(c) RAIM loss or loss of integrity, for more than 5 minutes; or
(d) operation of the GPS receiver in dead reckoning mode, for more than 1 minute; or
(e) loss of the GPS receiver navigation function, for more than 1 minute.
10.6.9.3 If there is concern that the update criteria mentioned in paragraphs 10.6.9.2 (a) and (b) may not be met throughout the application of an RNAV standard, the time of the last update must be obtained from the pilot.
10.6.9.4 Separation based on RNP approval may only apply in RNP airspace.
10.6.10 Longitudinal Distance Separation Using ADS-C
10.6.10.1 When using ADS-C reports from FANS-1/A aircraft as the sole means of establishing and monitoring longitudinal distance separation standards, only those standards specifically identified as being approved for ADS-C may be used.
10.6.10.2 Longitudinal distance separation using ADS-C may be established by measuring the distance between:
(a) the displayed positions of 2 or more FANS-1/A aircraft reporting by ADS‑C; or
(b) an ADS-C report symbol of a FANS-1/A aircraft and the position of another aircraft determined by an alternative form of position fixing, such as radar, ADS-B, voice or CPDLC reports.
10.6.10.3 All system tool tolerances must be taken into account in any measurement.
10.6.10.4 When 2 FANS-1/A aircraft reporting by ADS-C are flying on the same identical tracks (same or opposite direction), the measurements may be taken directly between the 2 ADS-C symbols.
This diagram is a simple geometrical illustration of the requirements of paragraph 10.6.10.4 – that is when 2 FANS-1/A aircraft reporting by ADS-C are flying on the same identical tracks (same or opposite direction), the measurements may be taken directly between the 2 ADS-C position symbols.
10.6.10.5 For a bend in track, the measurements may only be taken between each symbol and the turning point, not between the 2 symbols:
This diagram is a simple geometrical illustration of the requirements of paragraph 10.6.10.5 – that is when 2 FANS-1/A aircraft reporting by ADS-C are flying on track where there is a bend in track between the positions of the two aircraft, the measurements may only be taken between each aircraft position symbol and the turning point, not between the 2 position symbols for the aircraft.
10.6.10.6 If 2 FANS-1/A aircraft are flying on diverging or converging route clearances, then measurements may be either to or from a common point on the route clearances:
This diagram is a simple geometrical illustration of the requirements of paragraph 10.6.10.6 – that is when 2 FANS-1/A aircraft reporting by ADS-C are flying on diverging or converging route clearances, then measurements may be either to or from a common point on the route clearances.
or taken from where the abeam position of 1 aircraft intersects the route of the other.
This diagram is a simple geometrical illustration of the requirements of paragraph 10.6.10.6 – that is when 2 FANS-1/A aircraft reporting by ADS-C are flying on diverging or converging route clearances, then measurements may be taken from where the abeam position of 1 aircraft intersects the route of the other.
10.6.10.7 When longitudinal distance separation is to be determined between FANS-1/A and non-FANS-1/A aircraft:
(a) the measurement may only be commenced after receiving an ADS-C report from the FANS-1/A aircraft; and
(b) the request for the voice report must be made as soon as possible after the ADS-C report symbol is displayed; and
(c) this procedure may only be used when a distance greater than the minimum of the applicable standard is available.
10.6.10.8 When comparing an ADS-C report symbol from a FANS-1/A aircraft with a voice report from another aircraft, the measurement from or to the ADS-C symbol must be taken with reference to the beacon or waypoint reported by the other aircraft.