8-9-3. LONGITUDINAL SEPARATION
In accordance with Chapter 8, Offshore/Oceanic Procedures, Section 3, Longitudinal Separation, apply the following:
- Minima based on time:
- 15 minutes between aircraft; or
- 10 minutes between turbojet aircraft whether in level, climbing or descending flight, provided that the aircraft concerned follow the same track or continuously diverging tracks until some other form of separation is provided; or
- The prescribed minima in accordance with para 8-3-3, Mach Number Technique.
- Reciprocal track aircraft - Where lateral separation is not provided, vertical separation must be provided at least 10 minutes before and after the time the aircraft are estimated to pass or are estimated to have passed.
- Clear an aircraft for an ADS-B In Trail Procedure (ITP) climb or descent provided the following conditions are satisfied:
- The ITP climb or descent has been requested by the pilot;
- 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;
- The reported ITP distance between the ITP aircraft and any reference aircraft is 15 NM or more;
- Both the ITP aircraft and reference aircraft are either on:
- (a) Same identical tracks and any turn at a waypoint shall be limited to less than 45 degrees; or
- (b) same tracks with no turns permitted that reduce required separation during the ITP.
NOTE: Same identical tracks are where the angular difference is zero degrees.
- No speed or route change clearance shall be issued to the ITP aircraft until the ITP climb or descent is completed;
- The altitude difference between the ITP aircraft and any reference aircraft shall be 2000 ft or less;
- No instruction to amend speed, altitude or route shall be issued to any reference aircraft until the ITP climb or descent is completed;
- The maximum closing speed between the ITP aircraft and each reference aircraft shall be Mach 0.06; and
- The ITP aircraft shall not be a reference aircraft in another ITP clearance.
NOTE: ATOP is designed to check for the above criteria prior to allowing the minima to be provided.
- Minima based on distance using Automatic Dependent Surveillance - Contract (ADS-C):
- Apply the minima as specified in TBL 8-9-1, ADS-C Criteria, between aircraft on the same track within airspace designated for Required Navigation Performance (RNP), provided:
- (a) Direct controller/pilot communication via voice or Controller Pilot Data Link Communications (CPDLC) is established, and
- (b) The required ADS-C periodic reports are maintained and monitored by an automated flight data processor (e.g., ATOP);
TBL 8-9-1 ADS-C Criteria
||Maximum ADS-C Periodic Reporting Interval
- Aircraft on reciprocal tracks may be cleared to climb or descend to or through the altitude(s) occupied by another aircraft provided that:
- (a) An ADS-C position report on at least one of the aircraft has been received beyond the passing point, and
- (b) The aircraft have passed each other by the applicable separation minimum.
NOTE: ATOP has been designed to check for the above criteria prior to allowing the minima to be provided.
- When an ADS-C periodic or waypoint change event report is overdue by 3 minutes, the controller must take action to obtain an ADS-C report.
- If no report is received within 6 minutes of the time the original report was due, the controller must take action to apply another form of separation.
- Aircraft on the same track may be cleared to climb or descend through the level of another aircraft provided:
- (a) The longitudinal distance between the aircraft is determined from near simultaneous ADS C demand reports and the ATOP software is used to ensure the following conditions are met;
- (b) The longitudinal distance between the aircraft, as determined in a) above, is not less than:
- (1) 15 NM when the preceding aircraft is at the same speed or faster than the following aircraft; or
- (2) 25 NM when the following aircraft is not more than Mach 0.02 faster than the preceding aircraft
- (c) The altitude difference between aircraft is not more than 2000 ft;
- (d) The clearance is for a climb or descent of 4000 ft or less;
- (e) Both aircraft are filed as single flights not flying in formation with other aircraft;
- (f) Both aircraft are in level flight at a single altitude;
- (g) Both aircraft are same direction;
- (h) Neither aircraft are on a weather deviation;
- (i) Neither aircraft have an open CPDLC request for a weather deviation;
- (j) Neither aircraft are on an offset with a rejoin clearance; and
- (k) The clearance is issued with a restriction that ensures vertical separation is re-established within 15 minutes from the first demand report request.
- Minima based on distance without ADS-C:
- Apply 50 NM between aircraft cruising, climbing or descending on the same track or reciprocal track that meet the requirements for and are operating within airspace designated for RNP-10 operations provided:
- (a) Direct controller/pilot communication via voice or CPDLC is maintained; and
- (b) Separation is established by ensuring that at least 50 NM longitudinal separation minima exists between aircraft positions as reported by reference to the same waypoint.
- (1) Same track aircraft - whenever possible ahead of both; or
- (2) Reciprocal track aircraft - provided that it has been positively established that the aircraft have passed each other.
- Distance verification must be obtained from each aircraft at least every 24 minutes to verify that separation is maintained.
- If an aircraft fails to report its position within 3 minutes after the expected time, the controller must take action to establish communication. If communication is not established within 8 minutes after the time the report should have been received, the controller must take action to apply another form of separation.
NOTE: When same track aircraft are at, or are expected to reduce to, the minima, speed control techniques should be applied in order to maintain the required separation.
- Minima based on DME/RNAV:
Apply the following DME/RNAV minima in Control 1234H, Control 1487H and the Norton Sound High Control areas to turbojet aircraft established on or transitioning to the North Pacific (NOPAC) Route System.
- 30 NM between aircraft when DME reports or radar observations are used to establish the distance, otherwise at least 40 NM based on RNAV must be applied; and
- Unless both aircraft are radar identified, both aircraft must provide DME/RNAV distance reports via direct voice that indicates the appropriate separation exists; and
- Application of DME/RNAV separation without direct voice communications may not continue for more than 90 minutes; and
- The preceding aircraft is assigned the same or greater Mach number than the following aircraft; and
- Both aircraft must be advised of the other aircraft involved, including the distance relative to the flights.
- “Maintain Mach point eight four, same direction traffic, twelve o’ clock, three five miles.”